ORCID Profile
0000-0003-2351-8489
Current Organisation
Monash University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) | Psychology | Cognitive neuroscience | Biological psychology | Motor control
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2006
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.NEUROIMAGE.2009.06.027
Abstract: Functional imaging studies have shown that elderly in iduals activate widespread additional brain networks, compared to young subjects, when performing motor tasks. However, the parameters that effect this unique neural activation, including the spatial distribution of this activation across hemispheres, are still largely unknown. Here, we examined the effect of task complexity and body side on activation differences between older and younger adults while performing cyclical flexion-extension movements of the ipsilateral hand and foot. In particular, easy (isodirectional) and more difficult (non-isodirectional) coordination patterns were performed with either the left or right body side at a self-selected, comfortable rate. Even in the absence of imposed pacing the older group activated a larger brain network, suggestive of increased attentional deployment for monitoring the spatial relationships between the simultaneously moving segments and enhanced sensory processing and integration. Evidence of age-dependent underactivation was also found in contralateral M1, SMA and bilateral putamen, possibly reflecting a functional decline of the basal ganglia-mesial cortex pathway in the older group. An ANOVA model revealed significant main effects of task complexity and body side. However the interaction of these factors with age did not reach significance. Consequently, we conclude that under self-paced conditions, task complexity and body side did not have a modulatory effect on age-related brain activation.
Publisher: Public Library of Science (PLoS)
Date: 17-08-2011
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.BRAINRES.2004.10.062
Abstract: Previous studies have shown that the excitability of corticomotor projections to forearm muscles exhibit phasic modulation during passive movement (flexion-extension) about the wrist joint. We examined the stimulus-response properties of flexor carpi radialis (FCR) and extensor carpi radialis (ECR) to transcranial magnetic stimulation (TMS) applied over the contralateral motor cortex while the wrist was moved passively at two different sinusoidal frequency- litude relationships. Movement velocity (and therefore, the rate of change in muscle length) at the time of stimulation was held constant. Motor evoked potential (MEP) litudes were facilitated during passive muscle shortening and suppressed during passive muscle lengthening with suppression being more evident at higher stimulation intensities. For both FCR and ECR, during the shortening phase, responses were facilitated during the large litude movement relative to the small litude movement. It is suggested that the altered gain may be related to the thixotropic properties of muscle.
Publisher: eLife Sciences Publications, Ltd
Date: 29-04-2019
DOI: 10.7554/ELIFE.46323
Abstract: Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide 12 easy-to-implement consensus recommendations and point out the problems that can arise when they are not followed. Furthermore, we provide user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis.
Publisher: American Physiological Society
Date: 07-2014
Abstract: Motor learning requires practice over a period of time and depends on brain plasticity, yet even for relatively simple movements, there are multiple practice strategies that can be used for skill acquisition. We investigated the role of intracortical inhibition in the primary motor cortex (M1) during motor skill learning. Event-related transcranial magnetic stimulation (TMS) was used to assess corticomotor excitability and inhibition thought to involve synaptic and extrasynaptic γ-aminobutyric acid (GABA). Short intracortical inhibition (SICI) was assessed using 1- and 2.5-ms interstimulus intervals (ISIs). Participants learned a novel, sequential pinch-grip task on a computer in either a repetitive or interleaved practice structure. Both practice structures showed equivalent levels of motor performance at the end of acquisition and at retention 1 wk later. There was a novel task-related modulation of 1-ms SICI. Repetitive practice elicited a greater reduction of 1- and 2.5-ms SICI, i.e., disinhibition, between rest and task acquisition, compared with interleaved practice. These novel findings support the use of a repetitive practice structure for motor learning because the associated effects within M1 have relevance for motor rehabilitation.
Publisher: Wiley
Date: 27-12-2017
DOI: 10.1113/JP274660
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.BRS.2009.01.001
Abstract: Repetitive transcranial magnetic stimulation can be used to explore functional connectivity between cortical areas. To determine the effects of two theta burst stimulation (TBS) patterns (intermittent, iTBS and continuous, cTBS) of left dorsal premotor cortex (PMd). Left PMd was identified in 11 participants using functional magnetic resonance imaging (fMRI), during performance of complex sequential finger movements. Each participant received iTBS, cTBS, or sham TBS of left PMd in three separate sessions within a randomized, single-blind design. The speed and accuracy of simple and complex sequential reaction time (RT) task performance was measured before and after TBS. The excitability of primary motor cortex (M1) bilaterally, and interhemispheric facilitation from left PMd to right M1, were also measured before and after TBS. iTBS sped up the preparation of complex sequences performed with the right hand, with no detectable changes in M1 excitability. RT performance was maintained after cTBS, in the presence of increased left M1 excitability and suppressed right M1 excitability. Facilitatory and inhibitory TBS protocols applied to left PMd differentially alter corticomotor excitability and behavior, which suggests that these protocols affect different neuronal populations.
Publisher: Informa UK Limited
Date: 11-2022
DOI: 10.2147/NSS.S368335
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.NEUROIMAGE.2009.10.052
Abstract: Functional magnetic resonance imaging was used to reveal the shared neural resources between movements performed with effectors of the left versus right body side. Prior to scanning, subjects extensively practiced a complex coordination pattern involving cyclical motions of the ipsilateral hand and foot according to a 90 degrees out-of-phase coordination mode. Brain activity associated with this (nonpreferred) coordination pattern was contrasted with pre-existing isodirectional (preferred) coordination to extract the learning-related brain networks. To identify the principal candidates for effector-independent movement encoding, the conjunction of training-related activity for left and right limb coordination was determined. A dominantly left-lateralized parietal-to-(pre)motor activation network was identified, with activation in inferior and superior parietal cortex extending into intraparietal sulcus and activation in the premotor areas, including inferior frontal gyrus (pars opercularis). Similar areas were previously identified during observation of complex coordination skills by expert performers. These parietal-premotor areas are principal candidates for abstract (effector-independent) movement encoding, promoting motor equivalence, and they form the highest level in the action representation hierarchy.
Publisher: American Physiological Society
Date: 06-2006
Abstract: Volitional inhibition is the voluntary prevention of a prepared movement. Here we ask whether primary motor cortex (M1) is a site of convergence of cortical activity associated with movement preparation and volitional inhibition. Volitional inhibition was studied by presenting a stop signal before execution of an anticipated response that requires a key lift to intercept a revolving dial. Motor evoked potentials (MEPs) were elicited in intrinsic hand muscles by transcranial magnetic stimulation (TMS) to assess corticomotor excitability and short interval intracortical inhibition (sICI) during task performance. The closer the stop cue was presented to the anticipated response, the harder it was for subjects to inhibit their response. Corticomotor pathway excitability was temporally modulated during volitional inhibition. Using subthreshold TMS, corticomotor excitability was reduced for Stop trials relative to Go trials from 140 ms after the cue. sICI was significantly greater for Stop trials compared with Go trials at a time that preceded the onset of muscle activity associated with the anticipated response. These results provide evidence that volitional inhibition is exerted at a cortical level and that inhibitory networks within M1 contribute to volitional inhibition of prepared action.
Publisher: Oxford University Press (OUP)
Date: 20-03-2008
DOI: 10.1093/BRAIN/AWN051
Abstract: After stroke, the function of primary motor cortex (M1) between the hemispheres may become unbalanced. Techniques that promote a re-balancing of M1 excitability may prime the brain to be more responsive to rehabilitation therapies and lead to improved functional outcomes. The present study examined the effects of Active-Passive Bilateral Therapy (APBT), a putative movement-based priming strategy designed to reduce intracortical inhibition and increase excitability within the ipsilesional M1. Thirty-two patients with upper limb weakness at least 6 months after stroke were randomized to a 1-month intervention of self-directed motor practice with their affected upper limb (control group) or to APBT for 10-15 min prior to the same motor practice (APBT group). A blinded clinical rater assessed upper limb function at baseline, and immediately and 1 month after the intervention. Transcranial magnetic stimulation was used to assess M1 excitability. Immediately after the intervention, motor function of the affected upper limb improved in both groups (P < 0.005). One month after the intervention, the APBT group had better upper limb motor function than control patients (P < 0.05). The APBT group had increased ipsilesional M1 excitability (P < 0.025), increased transcallosal inhibition from ipsilesional to contralesional M1 (P < 0.01) and increased intracortical inhibition within contralesional M1 (P < 0.005). None of these changes were found in the control group. APBT produced sustained improvements in upper limb motor function in chronic stroke patients and induced specific and sustained changes in motor cortex inhibitory function. We speculate that APBT may have facilitated plastic reorganization in the brain in response to motor therapy. The utility of APBT as an adjuvant to physical therapy warrants further consideration.
Publisher: SAGE Publications
Date: 28-10-2016
Abstract: Background. Traumatic brain injury (TBI) has been associated with impairments in inhibiting prepotent motor responses triggered by infrequent external signals (ie, reactive inhibition). It is unclear whether proactive preparation to inhibit upcoming responses is also affected (ie, proactive inhibition). Successful inhibition relies on frontosubcortical interactions therefore, impairments might be linked with gray matter atrophy in subcortical structures. Objective. We investigated reactive and proactive inhibition in TBI and control groups, and their relationship with subcortical gray matter. Methods. Participants performed a response inhibition task in which the probability of stopping was manipulated. Reactive inhibition was measured as the stop-signal reaction time (SSRT) when the probability of stopping was low. Proactive inhibition was measured as the change in SSRT and in go response time with increasing probability of stopping. Subcortical gray matter structures were automatically segmented with FSL-FIRST. Group differences in subregional volume and associations with reactive and proactive inhibition efficiency were investigated using shape analysis. Results. Reactive inhibition was impaired in TBI, as indicated by longer SSRTs. Moreover, the degree of atrophy in subregions of subcortical structures was predictive for SSRT in TBI. In contrast, proactive inhibition was not affected because both groups showed no response time slowing as a function of stopping probability. Proactive inhibition efficiency could be predicted by local volume in the anterior left putamen, bilateral pallidum, and right thalamus in controls but not in TBI. Conclusions. Our results reveal that proactive inhibition seems unaffected in TBI and that volume of subregions of subcortical nuclei is predictive for response inhibition proficiency and of clinical relevance in TBI.
Publisher: Society for Neuroscience
Date: 09-11-2011
DOI: 10.1523/JNEUROSCI.4159-11.2011
Abstract: Proprioceptive information from the foot/ankle provides important information regarding body sway for balance control, especially in situations where visual information is degraded or absent. Given known increases in catastrophic injury due to falls with older age, understanding the neural basis of proprioceptive processing for balance control is particularly important for older adults. In the present study, we linked neural activity in response to stimulation of key foot proprioceptors (i.e., muscle spindles) with balance ability across the lifespan. Twenty young and 20 older human adults underwent proprioceptive mapping foot tendon vibration was compared with vibration of a nearby bone in an fMRI environment to determine regions of the brain that were active in response to muscle spindle stimulation. Several body sway metrics were also calculated for the same participants on an eyes-closed balance task. Based on regression analyses, multiple clusters of voxels were identified showing a significant relationship between muscle spindle stimulation-induced neural activity and maximum center of pressure excursion in the anterior–posterior direction. In this case, increased activation was associated with greater balance performance in parietal, frontal, and insular cortical areas, as well as structures within the basal ganglia. These correlated regions were age- and foot-stimulation side-independent and largely localized to right-sided areas of the brain thought to be involved in monitoring stimulus-driven shifts of attention. These findings support the notion that, beyond fundamental peripheral reflex mechanisms, central processing of proprioceptive signals from the foot is critical for balance control.
Publisher: Cold Spring Harbor Laboratory
Date: 11-12-2020
DOI: 10.1101/2020.12.11.422006
Abstract: Voluntary movements are accompanied by an increase in gamma-band oscillatory activity (60-100Hz) and a strong desynchronization of beta-band activity (13-30Hz) in the motor system at both the cortical and subcortical level. Conversely, successful motor inhibition is associated with increased beta power in a fronto-basal-ganglia network. Intriguingly, gamma activity also increases in response to a stop-signal. In this study, we used transcranial alternating current stimulation to drive beta and gamma oscillations to investigate whether these frequencies are causally related to motor inhibition. We found that 20Hz stimulation targeted at the pre-supplementary motor area enhanced inhibition and increased beta oscillatory activity around the time of the stop-signal in trials directly following stimulation. In contrast, 70Hz stimulation seemed to slow down the braking process, and predominantly affected go task performance. These results demonstrate that the effects of tACS are state-dependent and that especially fronto-central beta activity is a functional marker for successful motor inhibition.
Publisher: Cold Spring Harbor Laboratory
Date: 09-09-2020
DOI: 10.1101/2020.09.09.288910
Abstract: Working memory (WM) refers to the capacity to temporarily retain and manipulate finite amounts of information a critical process in complex behaviours such as reasoning, comprehension, and learning. This cognitive function is supported by a parietal-prefrontal network and linked to the activity of key neurotransmitters, such as gamma-aminobutyric acid (GABA). Impairments in WM are seen in a range of psychiatric and neurological disorders, and there are currently no effective treatments. In this study, we analysed secondary outcome measures from a trial investigating the effects of multi-day rTMS on cognition. Participants received four days of 20 Hz rTMS to an in idualised region of left parietal cortex in one week, and an in idualised region of pre-supplementary motor area (pre-SMA) in a separate week. We assessed changes to WM function before and after each week of stimulation (N = 39), and changes to GABA concentration before and after stimulation in week one using MR spectroscopy (N = 18 per stimulation condition). We hypothesised that parietal rTMS would enhance WM and alter GABA concentration at the site of stimulation, but this was not observed. Instead, we report some evidence of improved WM function following the first week of pre-SMA rTMS stimulation, and a generalised increase in GABA concentration across both parietal and pre-SMA voxels following pre-SMA rTMS. Additionally, we found that higher cardiorespiratory fitness was associated with greater WM improvement following pre-SMA stimulation. This study does not support the use of parietal multi-day rTMS for the enhancement of working memory. In contrast, the results suggest that increasing cardiorespiratory fitness may provide a novel approach to enhance the effects of pre-SMA rTMS on cognition.
Publisher: MIT Press - Journals
Date: 06-2009
Abstract: Converging lines of evidence show that volitional movement prevention depends on the right prefrontal cortex (PFC), especially the right inferior frontal gyrus (IFG). Selective movement prevention refers to the rapid prevention of some, but not all, movement. It is unknown whether the IFG, or other prefrontal areas, are engaged when movement must be selectively prevented, and whether additional cortical areas are recruited. We used rapid event-related fMRI to investigate selective and nonselective movement prevention during performance of a temporally demanding anticipatory task. Most trials involved simultaneous index and middle finger extension. Randomly interspersed trials required the prevention of one, or both, finger movements. Regions of the right hemisphere, including the IFG, were active for selective and nonselective movement prevention, with an overlap in the inferior parietal cortex and the middle frontal gyrus. Selective movement prevention caused a significant delay in movement initiation of the other digit. These trials were associated with activation of the medial frontal cortex. The results provide support for a right-hemisphere network that temporarily “brakes” all movement preparation. When movement is selectively prevented, the supplementary motor cortex (SMA re-SMA) may participate in conflict resolution and subsequent reshaping of excitatory drive to the motor cortex.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.NEUROBIOLAGING.2011.06.013
Abstract: Aging is characterized by brain structural changes that may compromise motor functions. In the context of postural control, white matter integrity is crucial for the efficient transfer of visual, proprioceptive and vestibular feedback in the brain. To determine the role of age-related white matter decline as a function of the sensory feedback necessary to correct posture, we acquired diffusion weighted images in young and old subjects. A force platform was used to measure changes in body posture under conditions of compromised proprioceptive and/or visual feedback. In the young group, no significant brain structure-balance relations were found. In the elderly however, the integrity of a cluster in the frontal forceps explained 21% of the variance in postural control when proprioceptive information was compromised. Additionally, when only the vestibular system supplied reliable information, the occipital forceps was the best predictor of balance performance (42%). Age-related white matter decline may thus be predictive of balance performance in the elderly when sensory systems start to degrade.
Publisher: Springer Science and Business Media LLC
Date: 17-08-2019
DOI: 10.1007/S00221-019-05622-Y
Abstract: Studies in which single- and paired-pulse TMS was applied during motor task performance have shed considerable light on the functional relevance of popular TMS-derived neurophysiological biomarkers such as short-interval intracortical inhibition (SICI) and long-interval intracortical inhibition (LICI). While it has become well established that corticospinal excitability and intracortical inhibition are modulated during the enactment and cancellation of actions, it has remained unclear as to whether interin idual differences in these neurophysiological markers were associated with an in idual's actual ability to restrain and cancel actions. In this study, we found that in idual differences in both SICI and LICI were positively associated with relevant performance metrics on the go/no-go task and stop-signal task. Specifically, we found that in iduals with greater resting SICI and LICI were faster to respond on go trials of the go/no-go task and were also more accurate at inhibiting their manual responses on both go/no-go and stop-signal tasks. These results are in support of findings from our earlier study and also provide new evidence for a general relationship between in idual differences in resting-state GABAergic intracortical inhibitory functioning and motor inhibition.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Research Square Platform LLC
Date: 24-07-2023
DOI: 10.21203/RS.3.RS-3122105/V1
Abstract: Healthy aging is associated with a decline in motor sequence learning. Acute cardiorespiratory exercise has emerged as a potential intervention to improve motor learning, however research in healthy older adults is limited. The current study investigated the impact of high-intensity interval exercise on a subsequent sequential motor learning task. Twenty-four older adults (aged 55–75 years) completed either 20-minutes of cycling, or an equivalent period of active rest before practicing a sequential force grip task. Skill learning was assessed during acquisition and at a 6-hour retention test. In contrast to expectation, exercise was associated with reduced accuracy during skill acquisition compared to rest, particularly for older participants. However, improvements in motor skill were retained in the exercise condition, while a reduction in skill was observed following rest. Our findings suggest the impact of high intensity exercise on motor performance varies depending on age. Importantly, our findings indicate that high-intensity exercise can facilitate early offline consolidation of a novel skill in older adults which may have implications for motor rehabilitation.
Publisher: Society for Neuroscience
Date: 13-06-2012
Publisher: Wiley
Date: 21-11-2014
DOI: 10.1002/HBM.22700
Publisher: eLife Sciences Publications, Ltd
Date: 09-04-2019
Publisher: Mary Ann Liebert Inc
Date: 06-2011
Abstract: Bimanual actions are ubiquitous in daily life. Many coordinated movements of the upper extremities rely on precise timing, which requires efficient interhemispheric communication via the corpus callosum (CC). As the CC in particular is known to be vulnerable to traumatic brain injury (TBI), furthering our understanding of its structure-function association is highly valuable for TBI diagnostics and prognosis. In this study, 21 young adults with TBI and 17 controls performed object manipulation tasks (insertion of pegs with both hands and bilateral daily life activities) and cognitive control tasks (i.e., switching maneuvers during spatially and temporally coupled bimanual circular motions). The structural organization of 7 specific subregions of the CC (prefrontal, premotor/supplementary motor, primary motor, primary sensory, parietal, temporal, and occipital) was subsequently investigated in these subjects with diffusion tensor imaging (DTI). Findings revealed that bimanual coordination was impaired in TBI patients as shown by elevated movement time values during daily life activities, a decreased number of peg insertions, and slower response times during the switching task. Furthermore, the DTI analysis demonstrated a significantly decreased fractional anisotropy and increased radial diffusivity in prefrontal, primary sensory, and parietal regions in TBI patients versus controls. Finally, multiple regression analyses showed evidence of the high specificity of callosal subregions accounting for the variance associated with performance of the different bimanual coordination tasks. Whereas disruption in commissural pathways between occipital areas played a role in performance on the clinical tests of bimanual coordination, deficits in the switching task were related to disrupted interhemispheric communication in prefrontal, sensory, and parietal regions. This study provides evidence that structural alterations of several subregional callosal fibers in adults with TBI are associated with differential behavioral manifestations of bimanual motor functioning.
Publisher: Wiley
Date: 22-03-2011
DOI: 10.1002/HBM.21257
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.NEUBIOREV.2008.08.013
Abstract: Processes that engage frontal cortex and the basal ganglia are responsible for the prevention of planned movements. Here, we review the role of primary motor cortex (M1) in this function. M1 receives and integrates input from a range of cortical and subcortical sites. It is also the final cortical processing site for voluntary motor commands, before they descend to the spinal cord. Inhibitory networks within M1 may be an important mechanism for the prevention or suppression of movement. Transcranial magnetic stimulation (TMS) has been used to evaluate corticospinal excitability and intracortical inhibition in humans, during the performance of a range of movement selection and prevention tasks. This review explores how M1 intracortical inhibition is selectively reduced to initiate desired voluntary movements, while movement prevention is associated with rapid, non-selective recruitment of inhibition within M1. The relationship between deficient intracortical inhibition and behavioural inhibition is also explored. Ex les of neuropathology are reviewed, including focal dystonia, attention deficit hyperactivity disorder and Tourette syndrome. The strengths and limitations of TMS in the study of movement prevention are also discussed. While the precise functional links between M1 neuronal populations and the fronto-basal-ganglia network activated by movement prevention have yet to be elucidated, it is clear that M1 plays a critical role in the final processing stage of response inhibition.
Publisher: Springer Science and Business Media LLC
Date: 04-06-2018
DOI: 10.1038/S41598-018-26791-W
Abstract: This study assessed the effect of interval duration on the direction and magnitude of changes in cortical excitability and inhibition when applying repeated blocks of intermittent theta burst stimulation (iTBS) over motor cortex. 15 participants received three different iTBS conditions on separate days: single iTBS repeated iTBS with a 5 minute interval (iTBS-5-iTBS) and with a 15 minute interval (iTBS-15-iTBS). Changes in cortical excitability and short-interval cortical inhibition (SICI) were assessed via motor-evoked potentials (MEPs) before and up to 60 mins following stimulation. iTBS-15-iTBS increased MEP litude for up to 60 mins post stimulation, whereas iTBS-5-iTBS decreased MEP litude. In contrast, MEP litude was not altered by single iTBS. Despite the group level findings, only 53% of in iduals showed facilitated MEPs following iTBS-15-iTBS, and only 40% inhibited MEPs following iTBS-5-iTBS. Modulation of SICI did not differ between conditions. These results suggest interval duration between spaced iTBS plays an important role in determining the direction of plasticity on excitatory, but not inhibitory circuits in human motor cortex. While repeated iTBS can increase the magnitude of MEP facilitation/inhibition in some in iduals compared to single iTBS, the response to repeated iTBS appears variable between in iduals in this small s le.
Publisher: Elsevier BV
Date: 03-2009
Publisher: Wiley
Date: 02-08-2013
DOI: 10.1002/HBM.22341
Publisher: Oxford University Press (OUP)
Date: 08-2014
Abstract: In young adults, canceling an initiated action depends on the right inferior frontal cortex (IFC), presupplementary motor area (preSMA), and the basal ganglia. Older adults show response inhibition deficits, but how this relates to functional brain activation remains unclear. Using event-related functional magnetic resonance imaging, we tested whether older adults (N = 20) exhibit overactivation during stop-signal inhibition as shown for attentional control tasks, or reduced activity compared with young adults (N = 20). We used a modified stop-signal task involving coupled bimanual responses and manipulated whether both or just one hand was cued to stop. Stop-task difficulty was matched across groups. We found a group by condition interaction in supramarginal gyrus, anterior insula, rIFC, and preSMA, with activation increasing for successful Stop versus Go trials in the young adults only. Comparing the groups on Stop trials revealed preSMA and striatum hypoactivity for older adults. White matter tracts connecting rIFC, preSMA, and the subthalamic nuclei were associated with stronger activation of preSMA in older adults, suggesting that maintenance of the brain's structure has positive implications for brain function.
Publisher: Oxford University Press
Date: 16-12-2010
Publisher: Wiley
Date: 16-07-2010
DOI: 10.1002/HBM.20943
Publisher: Springer Science and Business Media LLC
Date: 27-07-2023
DOI: 10.1038/S41380-023-02187-9
Abstract: Deficits in effective executive function, including inhibitory control are associated with risk for a number of psychiatric disorders and significantly impact everyday functioning. These complex traits have been proposed to serve as endophenotypes, however, their genetic architecture is not yet well understood. To identify the common genetic variation associated with inhibitory control in the general population we performed the first trans-ancestry genome wide association study (GWAS) combining data across 8 sites and four ancestries ( N = 14,877) using cognitive traits derived from the stop-signal task, namely – go reaction time (GoRT), go reaction time variability (GoRT SD) and stop signal reaction time (SSRT). Although we did not identify genome wide significant associations for any of the three traits, GoRT SD and SSRT demonstrated significant and similar SNP heritability of 8.2%, indicative of an influence of genetic factors. Power analyses demonstrated that the number of common causal variants contributing to the heritability of these phenotypes is relatively high and larger s le sizes are necessary to robustly identify associations. In Europeans, the polygenic risk for ADHD was significantly associated with GoRT SD and the polygenic risk for schizophrenia was associated with GoRT, while in East Asians polygenic risk for schizophrenia was associated with SSRT. These results support the potential of executive function measures as endophenotypes of neuropsychiatric disorders. Together these findings provide the first evidence indicating the influence of common genetic variation in the genetic architecture of inhibitory control quantified using objective behavioural traits derived from the stop-signal task.
Publisher: Oxford University Press (OUP)
Date: 04-02-2014
Abstract: It has been established that bimanual coordination with augmented feedback (FB) versus no augmented feedback (NFB) is associated with activity in different brain regions. It is unclear however, whether this distinction remains after practice comprising both these conditions. Functional magnetic resonance imaging was used in humans to compare visual FB versus NFB conditions for a bimanual tracking task, and their differential evolution across learning. Scanning occurred before (Pre) and after 2 weeks (Post) of mixed FB and NFB training using an event-related design, allowing differentiation between the planning and execution phase of the task. Activations at the whole-brain level initially differed for FB versus NFB movements but this differentiation diminished with training for the movement execution phase. Specifically, in right dorsal premotor cortex and right dorsolateral prefrontal cortex activation increased for NFB and decreased for FB trials to converge toward the end of practice. This suggests that learning led to a decreased need to adjust the ongoing movement on the basis of FB, whereas online monitoring became more pronounced in NFB trials as discrepancies between the required and the produced motor output were detected more accurately after training, due to a generic internal reference of correctness supporting movement control under varying conditions.
Publisher: Wiley
Date: 10-05-2018
DOI: 10.1113/JP276193
Publisher: Springer Science and Business Media LLC
Date: 02-09-2016
DOI: 10.1007/S00221-016-4767-5
Abstract: Aerobic exercise can enhance neuroplasticity although presently the neural mechanisms underpinning these benefits remain unclear. One possible mechanism is through effects on primary motor cortex (M1) function via down-regulation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The aim of the present study was to examine how corticomotor excitability (CME) and M1 intracortical inhibition are modulated in response to a single bout of moderate intensity aerobic exercise. Ten healthy right-handed adults were participants. Single- and paired-pulse transcranial magnetic stimulation was applied over left M1 to obtain motor-evoked potentials in the right flexor pollicis brevis. We examined CME, cortical silent period (SP) duration, short- and long-interval intracortical inhibition (SICI, LICI), and late cortical disinhibition (LCD), before and after acute aerobic exercise (exercise session) or an equivalent duration without exercise (control session). Aerobic exercise was performed on a cycle ergometer for 30 min at a workload equivalent to 60 % of maximal cardiorespiratory fitness (VO
Publisher: American Physiological Society
Date: 07-2007
Abstract: Coincident hand and foot movements are more reliably performed in the same direction than in opposite directions. Using transcranial magnetic stimulation (TMS) to assess motor cortex function, we examined the physiological basis of these movements across three novel experiments. Experiment 1 demonstrated that upper limb corticomotor excitability changed in a way that facilitated isodirectional movements of the hand and foot, during phasic and isometric muscle activation conditions. Experiment 2 demonstrated that motor cortex inhibition was modified with active, but not passive, foot movement in a manner that facilitated hand movement in the direction of foot movement. Together, these findings demonstrate that the coupling between motor representations within motor cortex is activity dependent. Because there are no known connections between hand and foot areas within primary motor cortex, experiment 3 used a dual-coil paired-pulse TMS protocol to examine functional connectivity between secondary and primary motor areas during active ankle dorsiflexion and plantarflexion. Dorsal premotor cortex (PMd) and supplementary motor area (SMA) conditioning, but not ventral premotor cortex (PMv) conditioning, produced distinct phases of task-dependent modulation of excitability of forearm representations within primary motor cortex (M1). Networks involving PMd–M1 facilitate isodirectional movements of hand and foot, whereas networks involving SMA–M1 facilitate corticomotor pathways nonspecifically, which may help to stabilize posture during interlimb coordination. These results may have implications for targeted neurorehabilitation after stroke.
Publisher: Wiley
Date: 05-03-2021
DOI: 10.1113/JP280966
Abstract: TMS is commonly used to study excitatory/inhibitory neurotransmission in cortical circuits. Changes in cortical excitability following TMS are typically measured from hand (using EMG limited to motor cortex) or scalp (using EEG) however, it is unclear whether these two measures represent the same activity when assessing motor cortex. We found that TMS‐EMG and TMS‐EEG measures of motor cortex excitability are differentially affected by sensory confounds at different time points, masking any actual relationship between them in the time domain. In the frequency domain, local high‐frequency oscillations in EEG recordings were minimally confounded by sensory artefacts and demonstrated strong correlations with EMG measures of cortical excitability across time, regardless of TMS intensity or waveform. Therefore, despite the effects of sensory artefacts, the two measures of motor cortex excitability share a response component, suggesting that they index a similar cortical activity and perhaps the same neuronal population. Transcranial magnetic stimulation (TMS) is a powerful tool for investigating cortical circuits. Changes in cortical excitability following TMS are typically assessed by measuring changes in either conditioned motor‐evoked potentials (MEPs) following paired‐pulse TMS over motor cortex or evoked potentials measured with electroencephalography following single‐pulse TMS (TEPs). However, it is unclear whether these two measures of cortical excitability index the same cortical response. Twenty‐four healthy participants received local and interhemispheric paired‐pulse TMS over motor cortex with eight inter‐pulse intervals, sub‐ and suprathreshold conditioning intensities, and two different pulse waveforms, while MEPs were recorded from a hand muscle. TEPs were also recorded in response to single‐pulse TMS using the conditioning pulse alone. The relationships between TEPs and conditioned‐MEPs were evaluated using metrics sensitive to both their magnitude at each time point and their overall shape across time. The impacts of undesired sensory potentials resulting from TMS pulse and muscle contractions were also assessed on both measures. Both conditioned‐MEPs and TEPs were sensitive to re‐afferent somatosensory activity following motor‐evoked responses, but over different post‐stimulus time points. Moreover, the litude of low‐frequency oscillations in TEPs was strongly correlated with the sensory potentials, whereas early and local high‐frequency responses showed minimal relationships. Accordingly, conditioned‐MEPs did not correlate with TEPs in the time domain but showed high shape similarity with the litude of high‐frequency oscillations in TEPs. Therefore, despite the effects of sensory confounds, the TEP and MEP measures share a response component, suggesting that they index a similar cortical response and perhaps the same neuronal populations.
Publisher: Cold Spring Harbor Laboratory
Date: 03-09-2023
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.CORTEX.2013.10.009
Abstract: Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, le evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus. To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions. Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit.
Publisher: American Physiological Society
Date: 03-2007
Abstract: In studies of volitional inhibition, successful task performance usually requires the prevention of all movement. In reality, movements are selectively prevented in the presence of global motor output. The aim of this study was to investigate the ability to prevent one movement while concurrently executing another, referred to as selective inhibition. In two experiments, participants released switches with either their index and middle fingers (unimanual) or their left and right index fingers (bimanual) to stop two moving indicators at a fixed target (Go trials). Stop trials occurred when either one or both indicators automatically stopped before reaching the target, signaling that prevention of the prepared movement was required. Stop All and selective Stop trials were randomly interspersed among more frequently occurring Go trials. We found that selective inhibition is harder to perform than nonselective inhibition, for both unimanual and bimanual task contexts. During selective inhibition trials, lift time of the responding digit was delayed in both experiments by ≤100 ms, demonstrating the generality of the result. A nonselective neural inhibitory pathway may temporarily “brake” the required response, followed by selective excitation of the to-be-moved digit's cortical representation. After selective inhibition trials, there were persistent asynchronies between finger lift times of subsequent Go trials. The persistent effects reflect the behavioral consequences of nonspecific neural inhibition combined with selective neural disinhibition.
Publisher: Oxford University Press (OUP)
Date: 15-01-2010
Abstract: Structural and neurochemical changes in frontostriatal circuits are thought to underlie age-related behavioral deficits on cognitive tasks. Here, we test the hypothesis that age-related motor switching deficits are associated with reduced basal ganglia (BG) function. Right-handed volunteers (15 Old, and 15 Young) made spatially and temporally coupled bimanual circular motions during event-related FMRI. A visual cue signaled the right hand to Switch or Continue its circling direction. Switching from mirror symmetric to asymmetric (SW»ASYMM) took longer and resulted in more contralateral (left-) hand disruptions than vice versa. These effects were more pronounced in the elderly, showing that the ability to suppress and flexibly adapt motor behavior (agility) declines with age. For both groups, switching activated the BG and a typical network for task-set implementation, including dorsal anterior cingulate cortex/supplementary motor area (pre-SMA, SMA-proper) and anterior insula/inferior frontal gyrus. A region of interest analysis revealed significantly reduced SW»ASYMM activation in bilateral subthalamic nucleus and right globus pallidus, only in the elderly. Age-related behavioral deficits may be related to inefficient recruitment of cortico-BG loops to suppress undesired movements. The elderly may use an alternative strategy to select the required movement pattern as indicated by increased activation of prefrontal cortex.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2019.03.014
Abstract: Responsiveness to suggestions while hypnotized is termed hypnotic susceptibility. An association between reaction time and hypnotic susceptibility has been demonstrated, but whether distinct changes in brain activity accompany this relationship remains unclear. We investigated the effect of hypnotic susceptibility on the speed of information processing and motor cortical preparatory activity. Twenty-one "low" (Low
Publisher: American Physiological Society
Date: 12-2014
Abstract: The sudden cancellation of a motor action, known as response inhibition (RI), is fundamental to human motor behavior. The behavioral selectivity of RI can be studied by cueing cancellation of only a subset of a planned response, which markedly delays the remaining executed components. The present study examined neurophysiological mechanisms that may contribute to these delays. In two experiments, human participants received single- and paired-pulse transcranial magnetic stimulation while performing a bimanual anticipatory response task. Participants performed most trials bimanually (Go trials) and were sometimes cued to cancel the response with one hand while responding with the other (Partial trials). Motor evoked potentials were recorded from left first dorsal interosseous (FDI) as a measure of corticomotor excitability (CME) during Go and Partial trials. CME was temporally modulated during Partial trials in a manner that reflected anticipation, suppression, and subsequent initiation of a reprogrammed response. There was an initial increase in CME, followed by suppression 175 ms after the stop signal, even though the left hand was not cued to stop. A second increase in excitability occurred prior to the (delayed) response. We propose an activation threshold model to account for nonselective RI. To investigate the inhibitory component of our model, we investigated short-latency intracortical inhibition (sICI), but results indicated that sICI cannot fully explain the observed temporal modulation of CME. These neurophysiological and behavioural results indicate that the default mode for reactive partial cancellation is suppression of a unitary response, followed by response reinitiation with an inevitable time delay.
Publisher: Oxford University Press (OUP)
Date: 21-11-2006
DOI: 10.1093/BRAIN/AWL333
Abstract: Determining whether a person with stroke has reached their full potential for recovery is difficult. While techniques such as transcranial magnetic stimulation (TMS) and MRI have some prognostic value, their role in rehabilitation is undefined. This study used TMS and MRI to determine which factors predict functional potential, defined as an in idual's capacity for further functional improvement at least 6 months following stroke. We studied 21 chronic stroke patients with upper limb impairment. The functional integrity of the corticospinal tracts (CSTs) was assessed using TMS and functional MRI. The presence or absence of motor-evoked responses (MEPs) to TMS in the affected upper limb, and the lateralization of cortical activity during affected hand use were determined. The structural integrity of the CST was assessed using MRI, and diffusion tensor imaging was used to measure the asymmetry in fractional anisotropy (FA) of the internal capsules. A multiple linear regression analysis was performed, to predict both clinical score at inception and change in clinical score for 17 patients who completed a 30 day programme of motor practice with the affected upper limb. The main findings were that in patients with MEPs, meaningful gains were still possible 3 years after stroke, although the capacity for improvement declined with time. In patients without MEPs, functional potential declines with increasing CST disruption, with no meaningful gains possible if FA asymmetry exceeds a value of 0.25. This study is the first to demonstrate the complementary nature of TMS and MRI techniques in predicting functional potential in chronic stroke patients. An algorithm is proposed for the selection of in idualized rehabilitation strategies, based on the prediction of functional potential. These strategies could include neuromodulation using a range of emerging techniques, to prime the motor system for a plastic response to rehabilitation.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.BANDC.2018.09.002
Abstract: This study aimed to evaluate the 'inhibitory deficit' hypothesis of developmental coordination disorder (DCD). We adopted a multifaceted approach, investigating two distinct, yet complimentary facets of motor inhibition: action restraint and action cancellation. This was achieved using carefully constructed versions of the 'Go/No-go' and 'Stop-signal' tasks, respectively. The s le comprised 11 young adults with DCD aged between 18 and 30 years of age and 11 typically developing, age-matched controls. Participants completed both the 'Go/No-go' and 'Stop-signal' tasks to assess action restraint and action cancellation respectively. In iduals with DCD were less efficient than their typically developing peers at performing both action restraint and action cancellation, indicated by significantly reduced action restraint efficiency index scores on the 'Go/No-go' task and a trend towards longer stop-signal reaction times on the 'Stop-signal' task. This work clarifies disparate evidence speaking to the integrity of action restraint in DCD and provides the first account of action cancellation in DCD using a purpose-built measure. In support of the inhibitory deficit hypothesis of DCD, our results suggest that young adults with DCD experience broad difficulties with engaging inhibitory mechanisms during motor behaviour.
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.NEUROBIOLAGING.2019.05.017
Abstract: Transcranial magnetic stimulation may represent an effective means for improving motor function in the elderly. The aim of this study was therefore to investigate the effects of paired associative stimulation (PAS a plasticity-inducing transcranial magnetic stimulation paradigm) on acquisition of a novel visuomotor task in young and older adults. Fourteen young (20.4 ± 0.6 years) and 13 older (69.0 ± 1.6 years) adults participated in 3 experimental sessions during which training was preceded (primed) by PAS. Within each session, the interstimulus interval used for PAS was set at either the N20 latency plus 5 ms (PAS
Publisher: Elsevier BV
Date: 05-2022
Publisher: Wiley
Date: 30-01-2012
DOI: 10.1002/HBM.21508
Abstract: The ability to suppress and flexibly adapt motor behavior is a fundamental mechanism of cognitive control, which is impaired in traumatic brain injury (TBI). Here, we used a combination of functional magnetic resonance imaging and diffusion weighted imaging tractography to study changes in brain function and structure associated with motor switching performance in TBI. Twenty‐three young adults with moderate‐severe TBI and twenty‐six healthy controls made spatially and temporally coupled bimanual circular movements. A visual cue signaled the right hand to switch or continue its circling direction. The time to initiate the switch (switch response time) was longer and more variable in the TBI group and TBI patients exhibited a higher incidence of complete contralateral (left hand) movement disruptions. Both groups activated the basal ganglia and a previously described network for task‐set implementation, including the supplementary motor complex and bilateral inferior frontal cortex (IFC). Relative to controls, patients had significantly increased activation in the presupplementary motor area (preSMA) and left IFC, and showed underactivation of the subthalamic nucleus (STN) region. This altered functional engagement was related to the white matter microstructural properties of the tracts connecting preSMA, IFC, and STN. Both functional activity in preSMA, IFC, and STN, and the integrity of the connections between them were associated with behavioral performance across patients and controls. We suggest that damage to these key pathways within the motor switching network because of TBI, shifts the patients toward the lower end of the existing structure‐function‐behavior spectrum. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Publisher: Springer Science and Business Media LLC
Date: 30-12-2012
Publisher: MIT Press - Journals
Date: 07-2016
DOI: 10.1162/JOCN_A_00946
Abstract: Dopamine agonists can impair inhibitory control and cause impulse control disorders for those with Parkinson disease (PD), although mechanistically this is not well understood. In this study, we hypothesized that the extent of such drug effects on impulse control is related to specific dopamine gene polymorphisms. This double-blind, placebo-controlled study aimed to examine the effect of single doses of 0.5 and 1.0 mg of the dopamine agonist ropinirole on impulse control in healthy adults of typical age for PD onset. Impulse control was measured by stop signal RT on a response inhibition task and by an index of impulsive decision-making on the Balloon Analogue Risk Task. A dopamine genetic risk score quantified basal dopamine neurotransmission from the influence of five genes: catechol-O-methyltransferase, dopamine transporter, and those encoding receptors D1, D2, and D3. With placebo, impulse control was better for the high versus low genetic risk score groups. Ropinirole modulated impulse control in a manner dependent on genetic risk score. For the lower score group, both doses improved response inhibition (decreased stop signal RT) whereas the lower dose reduced impulsiveness in decision-making. Conversely, the higher score group showed a trend for worsened response inhibition on the lower dose whereas both doses increased impulsiveness in decision-making. The implications of the present findings are that genotyping can be used to predict impulse control and whether it will improve or worsen with the administration of dopamine agonists.
Publisher: Wiley
Date: 06-2017
DOI: 10.1111/EJN.13590
Abstract: Response inhibition is an important executive process studied by clinical and experimental psychologists, neurophysiologists and cognitive neuroscientists alike. Stop-signal paradigms are popular because they are grounded in a theory that provides methods to estimate the latency of an unobservable process: the stop-signal reaction time (SSRT). Critically, SSRT estimates can be biased by skew of the response time distribution and gradual slowing over the course of the experiment. Here, we present a series of experiments that directly compare three common stop-signal paradigms that differ in the distribution of response times. The results show that the widely used choice response (CR) and simple response (SR) time versions of the stop-signal paradigm are particularly susceptible to skew of the response time distribution and response slowing, and that using the anticipated response (AR) paradigm based on the Slater-Hammel task offers a viable alternative to obtain more reliable SSRT estimates.
Publisher: Public Library of Science (PLoS)
Date: 27-03-2015
Publisher: Public Library of Science (PLoS)
Date: 13-01-2017
Publisher: MIT Press - Journals
Date: 04-2017
DOI: 10.1162/JOCN_A_01078
Abstract: Gamma-aminobutyric acid (GABA) inhibition shapes motor cortex output, gates synaptic plasticity in the form of long-term potentiation, and plays an important role in motor learning. Remarkably, recent studies have shown that acute cardiovascular exercise can improve motor memory, but the cortical mechanisms are not completely understood. We investigated whether an acute bout of lower-limb high-intensity interval (HIT) exercise could promote motor memory formation in humans through changes in cortical inhibition within the hand region of the primary motor cortex. We used TMS to assess the input–output relationship, along with inhibition involving GABAA and GABAB receptors. Measures were obtained before and after a 20-min session of HIT cycling (exercise group) or rest (control group). We then had the same participants learn a new visuomotor skill and perform a retention test 5 hr later in the absence of sleep. No differences were found in corticomotor excitability or GABAB inhibition however, synaptic GABAA inhibition was significantly reduced for the exercise group but not the control group. HIT exercise was found to enhance motor skill consolidation. These findings link modification of GABA to improved motor memory consolidation after HIT exercise and suggest that the beneficial effects of exercise on consolidation might not be dependent on sleep.
Publisher: Oxford University Press (OUP)
Date: 28-10-2010
Abstract: Sensory information is critical to correct performance errors online during the execution of complex tasks and can be complemented by augmented feedback (FB). Here, 2 groups of participants acquired a new bimanual coordination pattern under different augmented FB conditions: 1) visual input reflecting coordination between the 2 hands and 2) auditory pacing integrating the timing of both hands into a single temporal structure. Behavioral findings revealed that the visual group became dependent on this augmented FB for performance, whereas the auditory group performed equally well with or without augmented FB by the end of practice. Functional magnetic resonance imaging (fMRI) results corroborated these behavioral findings: the visual group showed neural activity increases in sensory-specific areas during practice, supporting increased reliance on augmented FB. Conversely, the auditory group showed a neural activity decrease, specifically in areas associated with cognitive/sensory monitoring of motor task performance, supporting the development of a control mode that was less reliant on augmented FB sources. Finally, some remnants of brain activity in sensory-specific areas in the absence of augmented FB were found for the visual group only, illustrating ongoing reliance on these areas. These findings provide the first neural account for the "guidance hypothesis of information FB," extensively supported by behavioral research.
Publisher: Wiley
Date: 04-08-2016
DOI: 10.1002/HBM.23338
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.NEUBIOREV.2017.09.023
Abstract: The aetiology of various psychiatric and neurological disorders may be partially attributable to impairments in neuroplasticity. Developing novel methods of stimulating neuroplasticity is a promising treatment approach to counterbalance these maladaptive influences and alleviate symptomologies. Two non-pharmacological approaches with significant and direct impacts on neuroplasticity are aerobic exercise and repetitive transcranial magnetic stimulation. Aerobic exercise is associated with the promotion of numerous neurotrophic mechanisms at a molecular and cellular level, which have a broad influence on neuroplasticity. Transcranial magnetic stimulation is a form of non-invasive brain stimulation with the capacity to modulate the synaptic efficacy and connectivity of particular brain networks. This review synthesises extant literature to explore the complementary physiological mechanisms targeted by aerobic exercise and repetitive transcranial magnetic stimulation, and to substantiate the hypothesis that the use of these techniques in tandem may result in synergistic impact on neural mechanisms to achieve a more efficacious therapeutic approach for mental disorders.
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2011.04.016
Abstract: Depending on task combination, dual-tasking can either be performed successfully or can lead to performance decrements in one or both tasks. Interference is believed to be caused by limitations in central processing, i.e. structural interference between the neural activation patterns associated with each task. In the present study, single- and dual-task effects were addressed in the context of aging. Increasing evidence from research on motor and cognitive tasks has shown that aging is associated with an expansion of brain activation and an increased BOLD-signal. This may result in increased structural interference and higher dual-task interference in older adults. Functional magnetic resonance imaging was used to measure the BOLD-response in 20 old and 20 young healthy adults while performing tasks separately, or combined. Single tasks consisted of mental arithmetic cued by auditory tones, and a visuomotor task, drawing a circular shape with spatiotemporal constraints. Age-related brain activation increases were only apparent during performance of the visuomotor task. Elderly showed higher BOLD-responses in a frontoparietal network, pointing to an increased reliance on sensory feedback processing. However, no increased structural interference was found for the elderly during performance of the dual-task. Region of interest analysis involving a functional cluster within the (pre-) supplementary motor area, active during performance of both single-tasks, revealed that both groups were able to upregulate their brain activity for dual-as compared to single-task performance. We assume that this allowed both groups to maintain performance under dual-task conditions, leading to minimal dual-task interference.
Start Date: 2018
End Date: 12-2021
Amount: $378,870.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2024
End Date: 12-2027
Amount: $985,272.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2020
End Date: 12-2024
Amount: $543,500.00
Funder: Australian Research Council
View Funded Activity