ORCID Profile
0000-0001-7764-3811
Current Organisations
Alfred Health
,
St Vincent's Hospital Melbourne
,
Monash University
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Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) | Cognitive neuroscience | Cognition | Biological psychology | Cognitive Science | Psychology | Learning motivation and emotion | Decision Making
Expanding Knowledge in Psychology and Cognitive Sciences | Expanding Knowledge in the Biological Sciences |
Publisher: eLife Sciences Publications, Ltd
Date: 24-01-2020
DOI: 10.7554/ELIFE.41836
Abstract: Neocortical-hippoc al interactions support new episodic (event) memories, but there is conflicting evidence about the dependence of remote episodic memories on the hippoc us. In line with systems consolidation and computational theories of episodic memory, evidence from model organisms suggests that the cornu ammonis 3 (CA3) hippoc al subfield supports recent, but not remote, episodic retrieval. In this study, we demonstrated that recent and remote memories were susceptible to a loss of episodic detail in human participants with focal bilateral damage to CA3. Graph theoretic analyses of 7.0-Tesla resting-state fMRI data revealed that CA3 damage disrupted functional integration across the medial temporal lobe (MTL) subsystem of the default network. The loss of functional integration in MTL subsystem regions was predictive of autobiographical episodic retrieval performance. We conclude that human CA3 is necessary for the retrieval of episodic memories long after their initial acquisition and functional integration of the default network is important for autobiographical episodic memory performance.
Publisher: Public Library of Science (PLoS)
Date: 24-02-2017
Publisher: Oxford University Press (OUP)
Date: 24-01-2019
DOI: 10.1093/BRAIN/AWY341
Abstract: Disorders of motivation, such as apathy, are common in Parkinson's disease, and a key feature of such disorders is a greater aversion to effort. In humans, the experience of cognitive effort is ubiquitous, and cognitive apathy has traditionally been considered distinct and separable from other subtypes. Surprisingly, however, the neurobiology of cognitive motivation is poorly understood. In particular, although dopamine has a well-characterized role in incentivizing physically effortful behaviour, a critical, unresolved issue is whether its facilitatory role generalizes to other domains. Here, we asked how dopamine modulates the willingness of patients with Parkinson's disease to invest cognitive effort in return for reward. We tested 20 patients with idiopathic Parkinson's disease across two counterbalanced sessions-ON and OFF their usual dopaminergic medication-and compared their performance to 20 healthy age-matched controls. We applied a novel task in which we manipulated cognitive effort as the number of rapid serial visual presentation streams to which participants had to attend. After training participants to ceiling performance, we then asked them to choose between a low-effort/low-reward baseline option, and a higher-effort/higher-reward offer. Computational models of choice behaviour revealed four key results. First, patients OFF medication were significantly less cognitively motivated than controls, as manifest by steeper cognitive effort discounting functions in the former group. Second, dopaminergic therapy improved this deficit, such that choices in patients ON medication were indistinguishable from controls. Third, differences in motivation were also accompanied by independent changes in the stochasticity of in iduals' decisions, such that dopamine reduced the variability in choice behaviour. Finally, choices on our task correlated uniquely with the subscale of the Dimensional Apathy Scale that specifically indexes cognitive motivation, which suggests a close relationship between our laboratory measure of cognitive effort discounting and subjective reports of day-to-day cognitive apathy. Importantly, participants' choices were not confounded by temporal discounting, probability discounting, physical demand, or varying task performance. These results are the first to reveal the central role of dopamine in overcoming cognitive effort costs. They provide an insight into the computational mechanisms underlying cognitive apathy in Parkinson's disease, and demonstrate its amenability to dopaminergic therapy. More broadly, they offer important empirical support for prominent frameworks proposing a domain-general role for dopamine in value-based decision-making, and provide a critical link between dopamine and multidimensional theories of apathy.
Publisher: Oxford University Press
Date: 12-2013
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.PBB.2017.02.003
Abstract: Drug use is a choice with immediate positive outcomes, but long-term negative consequences. Thus, the repeated use of drugs in the face of negative consequences suggests dysfunction in the cognitive mechanisms underpinning decision-making. This cognitive dysfunction can be mapped into three stages: the formation of preferences involving valuation of decision options choice implementation including motivation, self-regulation and inhibitory processes and feedback processing implicating reinforcement learning. This article reviews behavioral studies that have examined alterations in these three stages of decision-making in people with substance use disorders. Relative to healthy in iduals, those with alcohol, cannabis, stimulant and opioid use disorders value risky options more highly during the formation of preferences have a greater appetite for superficially attractive rewards during choice implementation and are both more efficient in learning from rewards and less efficient in learning from losses during feedback processing. These observed decision-making deficits are most likely due to both premorbid factors and drug-induced effects. Because decision-making deficits have been prospectively associated with a greater risk of drug relapse, we advocate for greater research on modulating the component stages that give rise to dysfunctional decision-making in disorders of addiction.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2018
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.EURONEURO.2018.03.012
Abstract: Dopaminergic medication can induce severe addictive behaviours (e.g., pathological gambling) in susceptible Parkinson's disease (PD) patients. It is still unknown which particular neurocognitive processes become exacerbated or dysfunctional in PD patients with addictive behaviours. We sought to systematically review the relevant literature to identity potential neurocognitive correlates of medication-induced addictive behaviours in PD. We framed our review around neurocognitive processes central to four dominant accounts of substance addiction: 'aberrant learning', 'incentive sensitization', 'impulsivity to compulsivity' and 'impaired response inhibition and salience attribution'. Searches of the PubMed and Scopus databases were completed on June 23, 2017. To be included, studies were required to involve: (a) medicated PD patients, without a history of deep brain stimulation, with and without addictive behaviours (b) a reward-related or decision-making task and (c) statistical comparison of addictive and non-addictive groups' 'on' medication performance on the task(s). Studies were summarised qualitatively with statistically significant (p<.05) group differences and effect sizes (Cohen's d) highlighted. 35 studies were included. Findings showed that the extant literature is highly heterogeneous. The domains of reward and punishment learning, reflection impulsivity and disadvantageous decision-making exemplify this. More homogeneity exists in domains in which (a) neurocognitive dysfunction is not apparent (motor control, cognitive/attentional flexibility and cognitive control) or (b) typical neurocognitive processes appear exacerbated by medication (reward motivation and choice impulsivity). Future large-scale neurocognitive studies are still required to develop our scientific understanding of addictive behaviours in PD and aid their clinical treatment and prediction.
Publisher: Oxford University Press
Date: 12-2013
Publisher: Informa UK Limited
Date: 26-06-2007
Publisher: Oxford University Press (OUP)
Date: 18-09-2023
Publisher: Center for Open Science
Date: 06-04-2023
Abstract: The willingness to exert effort for reward is essential but comes at the cost of fatigue. Theories suggest fatigue increases after both physical and cognitive exertion, subsequently reducing the motivation to exert effort. Yet a mechanistic understanding of how this happens on a moment-to-moment basis, and whether mechanisms are common to both mental and physical effort, is lacking. In two studies, participants reported momentary (trial-by-trial) ratings of fatigue during an effort-based decision-making task requiring either physical (grip-force) or cognitive (mental arithmetic) effort. Using a novel computational model, we show that fatigue fluctuates from trial-to-trial as a function of exerted effort and predicts subsequent choices. This mechanism was shared across the domains. Selective to the cognitive domain, committing errors also induced momentary increases in feelings of fatigue. These findings provide insight into the computations underlying the influence of effortful exertion on fatigue and motivation, in both physical and cognitive domains.
Publisher: Proceedings of the National Academy of Sciences
Date: 31-10-2023
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.NEUROIMAGE.2007.11.030
Abstract: Our ability to recognize the actions of others is subserved by a complex network of brain areas, including the inferior frontal gyrus (IFG), inferior parietal lobe (IPL) and superior temporal sulcus (STS). An unresolved issue is whether the activity within these regions requires top-down control or whether it arises relatively automatically during passive action observation. Here we used fMRI to determine whether cortical activity associated with action observation is modulated by the strategic allocation of selective attention. Participants observed moving and stationary images of reach-to-grasp hand actions, while they performed an attentionally demanding task at the fovea. We first defined regions-of-interest (ROIs) in the IFG, IPL and STS which responded to the perception of these actions. We then probed these ROIs while participants observed the identical, but now task-irrelevant, actions and instead performed an easy (low attentional load) or difficult (high attentional load) visual discrimination task. Our data indicate that the activity of the left IFG was consistently attenuated under conditions of high attentional load, while the remaining action observation areas remained relatively unaffected by attentional manipulations. The suppression of the left IFG was unique to the observation of hand actions, and did not occur during the observation of non-biological control stimuli, in the form of coherent dot motion. We propose that the left IFG is the site at which descending inhibitory processes affect the processing of observed actions, and that the attentional modulation of this region is responsible for filtering task-irrelevant actions during ongoing behavior.
Publisher: Cold Spring Harbor Laboratory
Date: 03-09-2023
Publisher: Springer Science and Business Media LLC
Date: 02-12-2022
DOI: 10.1007/S11065-022-09567-Y
Abstract: Psychological stress is a potential modifiable risk factor for cognitive decline. However, the extent to which self-reported psychological stress is differentially associated with decline in specific cognitive domains remains unclear. Differences may be due to heterogeneity in the aspects of psychological stress investigated, for ex le, neuroticism (which is linked to vulnerability to stress), perceived stress, or exposure to stressful life events. This review aims to establish the associations between these aspects of self-reported psychological stress and cognitive decline. PsychINFO, Embase and MEDLINE were searched from database inception to September 2021. Studies were included if they were observational, prospective, and if they investigated the association between self-reported psychological stress and cognitive decline in adults with a minimum mean age of 40 years at baseline. Thirty studies satisfied the inclusion criteria, with most examining neuroticism (n = 17) as a predictor of cognitive decline. Fewer examined perceived stress (n = 7) or stressful life events (n = 6). There was evidence of an association between neuroticism and cognitive decline, particularly in the domain of memory. Similarly, across studies, perceived stress was also associated with memory decline. Research investigating the relationship between stressful life events and cognitive decline had fewer outcomes to interpret. Overall, the findings highlight that memory may be particularly susceptible to high levels of neuroticism and perceived stress. We identified a lack of research into some cognitive domains, such as executive function, which should be addressed by future studies.
Publisher: Springer Science and Business Media LLC
Date: 08-08-2018
DOI: 10.1038/S41598-018-30220-3
Abstract: Effort can be perceived both cognitively and physically, but the computational mechanisms underlying the motivation to invest effort in each domain remain unclear. In particular, it is unknown whether intensive physical training is associated with higher motivation specific to that domain, or whether it is accompanied by corresponding changes in cognitive motivation. Here, we tested a group of elite Oxford University rowers, and compared their behaviour to matched non-athletic controls. We trained participants on two tasks involving cognitive or physical effort. They then decided between a baseline low level of effort for low reward, versus higher levels of effort for higher rewards. Separate choices were made for the cognitive and physical tasks, which allowed us to computationally model motivation in each domain independently. As expected, athletes were willing to exert greater amounts of physical effort than non-athletes. Critically, however, the nature of cognitive effort-based decisions was different between groups, with a concave pattern of effort discounting for athletes but a convex pattern for non-athletes. These data suggest that the greater physical drive in athletes is accompanied by fundamentally different patterns of cognitive effort discounting, and suggests a complex relationship between motivation in the two domains.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 25-10-2023
Publisher: Wiley
Date: 05-04-2018
DOI: 10.1111/JNP.12122
Publisher: Oxford University Press (OUP)
Date: 24-07-2016
DOI: 10.1093/BRAIN/AWW188
Publisher: Wiley
Date: 03-01-2021
DOI: 10.1111/ADB.12999
Abstract: Meth hetamine use disorder involves continued use of the drug despite negative consequences. Such 'compulsivity' can be measured by reversal learning tasks, which involve participants learning action-outcome task contingencies (acquisition-contingency) and then updating their behaviour when the contingencies change (reversal). Using these paradigms, animal models suggest that people with meth hetamine use disorder (PwMUD) may struggle to avoid repeating actions that were previously rewarded but are now punished (inflexibility). However, difficulties in learning task contingencies (reinforcement learning) may offer an alternative explanation, with meaningful treatment implications. We aimed to disentangle inflexibility and reinforcement learning deficits in 35 PwMUD and 32 controls with similar sociodemographic characteristics, using novel trial-by-trial analyses on a probabilistic reversal learning task. Inflexibility was defined as (a) weaker reversal phase performance, compared with the acquisition-contingency phases, and (b) persistence with the same choice despite repeated punishments. Conversely, reinforcement learning deficits were defined as (a) poor performance across both acquisition-contingency and reversal phases and (b) inconsistent postfeedback behaviour (i.e., switching after reward). Compared with controls, PwMUD exhibited weaker learning (odds ratio [OR] = 0.69, 95% confidence interval [CI] [0.63-0.77], p < .001), though no greater accuracy reduction during reversal. Furthermore, PwMUD were more likely to switch responses after one reward unishment (OR = 0.83, 95% CI [0.77-0.89], p < .001 OR = 0.82, 95% CI [0.72-0.93], p = .002) but just as likely to switch after repeated punishments (OR = 1.03, 95% CI [0.73-1.45], p = .853). These results indicate that PwMUD's reversal learning deficits are driven by weaker reinforcement learning, not inflexibility.
Publisher: Elsevier
Date: 2016
DOI: 10.1016/BS.PBR.2016.05.007
Abstract: Disorders of diminished motivation, such as apathy, are common and prevalent across a wide range of medical conditions, including Parkinson's disease, Alzheimer's dementia, stroke, depression, and schizophrenia. Such disorders have a significant impact on morbidity and quality of life, yet their management lacks consensus and remains unsatisfactory. Here, we review laboratory and clinical evidence for the use of dopaminergic therapies in the treatment of apathy. Dopamine is a key neurotransmitter that regulates motivated decision making in humans and other species. A large corpus of evidence suggests that it plays an important role in promoting approach behavior by attributing incentive salience to reward stimuli, and facilitating the overcoming of effort costs. Furthermore, dopaminergic neurons innervate several frontostriatal structures that mediate reward-guided behavior. Based on these findings, there are a priori reasons for considering dopamine in the treatment of disorders of diminished motivation. We highlight key studies that have attempted to use dopamine to manage patients with apathy, and that collectively offer cautious evidence in favor of its efficacy. However, many of these studies are small, unblinded, and uncontrolled, and utilize subjective, questionnaire-based measures of apathy. Given the development of novel paradigms which are able to objectively dissect motivational dysfunction, we are now well positioned to quantify the effect of specific classes of dopaminergic medication on reward- and effort-based decision making in apathy. We anticipate that such paradigms will lay the foundation for future studies to evaluate new and existing treatments for disorders of motivation, using sensitive measures of apathy as primary quantifiable end points.
Publisher: Springer Science and Business Media LLC
Date: 10-04-2023
DOI: 10.3758/S13423-023-02279-1
Abstract: Contemporary models of decision-making under risk focus on estimating the final value of each alternative course of action. According to such frameworks, information that has no capacity to alter a future payoff (i.e., is “non-instrumental”) should have little effect on one’s preference for risk. Importantly, however, recent work has shown that information, despite being non-instrumental, may nevertheless exert a striking influence on behavior. Here, we tested whether the opportunity to passively observe the sequence of events following a decision could modulate risky behavior, even if that information could not possibly influence the final result. Across three experiments, 71 in iduals chose to accept or reject gambles on a five-window slot machine. If a gamble was accepted, each window was sequentially revealed prior to the outcome being declared. Critically, we informed participants about which windows would subsequently provide veridical information about the gamble outcome, should that gamble be accepted. Our analyses revealed three key findings. First, the opportunity to observe the consequences of one’s choice significantly increased the likelihood of gambling, despite that information being entirely non-instrumental. Second, this effect generalized across different stakes. Finally, choices were driven predominantly by the likelihood that information could result in an earlier resolution of uncertainty. These findings demonstrate the importance of anticipatory information to decision-making under risk. More broadly, we provide strong evidence for the utility of non-instrumental information, by demonstrating its capacity to modulate primary economic decisions that should be driven by more motivationally salient variables associated with risk and reward.
Publisher: Elsevier BV
Date: 08-2015
Publisher: Springer Science and Business Media LLC
Date: 05-10-2021
DOI: 10.1038/S41366-021-00974-4
Abstract: Obesity is associated with unhealthy food choices. Food selection is driven by the subjective valuation of available options, and the perceived and actual rewards accompanying consumption. These cognitive operations are mediated by brain regions including the ventromedial prefrontal cortex (vmPFC), dorsal anterior cingulate cortex (dACC), and ventral striatum (vStr). This study investigated the relationship between body mass index (BMI) and functional activations in the vmPFC, dACC, and vStr during food selection and consumption. After overnight fasting, 26 in iduals (BMI: 18-40 kg/m During food choice, in iduals with greater BMI had less activation in the dorsolateral prefrontal cortex when selecting a high-value option and less vmPFC activation upon its consumption. Independent of BMI, during food choice the dACC and anterior insula elicited higher activation when a less preferred beverage was selected. Activation of the dACC and a broader frontoparietal network was also observed when deciding between options more similar in value. During consumption, receipt of a more preferred beverage was associated with greater vmPFC response, and attenuation of the dACC. An in idual's preference for a food option modulates the brain activity associated with choosing and consuming it. The relationship between food preference and underlying brain activity is altered in obesity, with reduced engagement of cognition-related regions when presented with a highly valued option, but a blunted response in reward-related regions upon consumption.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 08-2018
Publisher: Oxford University Press (OUP)
Date: 17-10-2017
DOI: 10.1093/BRAIN/AWX283
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier
Date: 2016
DOI: 10.1016/BS.PBR.2016.05.002
Abstract: Motivation can be characterized as a series of cost-benefit valuations, in which we weigh the amount of effort we are willing to expend (the cost of an action) in return for particular rewards (its benefits). Human motivation has traditionally been measured with self-report and questionnaire-based tools, but an inherent limitation of these methods is that they are unable to provide a mechanistic explanation of the processes underlying motivated behavior. A major goal of current research is to quantify motivation objectively with effort-based decision-making paradigms, by drawing on a rich literature from nonhuman animals. Here, we review this approach by considering the development of these paradigms in the laboratory setting over the last three decades, and their more recent translation to understanding choice behavior in humans. A strength of this effort-based approach to motivation is that it is capable of capturing the wide range of in idual differences, and offers the potential to dissect motivation into its component elements, thus providing the basis for more accurate taxonomic classifications. Clinically, modeling approaches might provide greater sensitivity and specificity to diagnosing disorders of motivation, for ex le, in being able to detect subclinical disorders of motivation, or distinguish a disorder of motivation from related but separate syndromes, such as depression. Despite the great potential in applying effort-based paradigms to index human motivation, we discuss several caveats to interpreting current and future studies, and the challenges in translating these approaches to the clinical setting.
Publisher: eLife Sciences Publications, Ltd
Date: 26-04-2019
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2008.12.008
Abstract: Substantial evidence suggests that observed actions can engage their corresponding motor representations within the observer. It is currently believed that this process of observation-execution matching occurs relatively automatically, without the need for top-down control. In this study we tested the susceptibility of the observation-execution matching process to selective attention. We used a Go/NoGo paradigm to investigate the phenomenon of 'automatic imitation', in which participants are faster to initiate a hand movement that is congruent with a concurrently observed action, relative to one that is incongruent. First, we replicated previous findings of automatic imitation, and excluded the possibility that spatial compatibility effects might explain these results (Experiment 1). We then presented participants with the same goal-directed actions while directing their attention to an imperative stimulus that spatially overlapped, but was distinct from, the observed actions (Experiment 2). Crucially, automatic imitation no longer occurred when participants directed their attention away from the displayed actions and towards the spatially overlapping stimulus. In a final experiment, we examined whether the automatic imitation of grasp persists when participants attend to an irrelevant feature of the observed action, such as whether it is performed by a left or right hand (Experiment 3). Here we found that automatic imitation is contingent on participants attending to the feature of the observed hand that was relevant to their responses. Together these findings demonstrate the importance of selective mechanisms in the filtering of task-irrelevant actions, and indicate a role for top-down control in limiting the motoric simulation of observed actions.
Publisher: Elsevier BV
Date: 10-2008
Publisher: Elsevier BV
Date: 05-2023
Publisher: Informa UK Limited
Date: 26-06-2007
Publisher: Wiley
Date: 30-03-2022
DOI: 10.1111/ADB.13172
Abstract: People with Meth hetamine Use Disorder (PwMUD) spend substantial time and resources on substance use, which hinders their ability to explore alternate reinforcers. Gold‐standard behavioural treatments attempt to remedy this by encouraging action towards non‐drug reinforcers, but substance use often persists. We aimed to unravel the mechanistic drivers of this behaviour by applying a computational model of explore/exploit behaviour to decision‐making data (Iowa Gambling Task) from 106 PwMUD and 48 controls. We then examined the longitudinal link between explore/exploit mechanisms and changes in meth hetamine use 6 weeks later. Exploitation parameters included reinforcement sensitivity and inverse decay (i.e., number of past outcomes used to guide choices). Exploration parameters included maximum directed exploration value (i.e., value of trying novel actions). The Timeline Follow Back measured changes in meth hetamine use. Compared to controls, PwMUD showed deficits in exploitative decision‐making, characterised by reduced reinforcement sensitivity, U = 3065, p = 0.009, and less use of previous choice outcomes, U = 3062, p = 0.010. This was accompanied by a behavioural pattern of frequent shifting between choices, which appeared consistent with random exploration. Furthermore, PwMUD with greater reductions of meth hetamine use at 6 weeks had increased directed exploration ( β = 0.22, p = 0.045) greater use of past choice outcomes ( β = −0.39, p = 0.002) and greater choice consistency ( β = −0.39, p = 0.002). Therefore, limited computational exploitation and increased behavioural exploration characterise PwMUD's presentation to treatment, while increased directed exploration, use of past choice outcomes and choice consistency predict greater reductions of meth hetamine use.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Cold Spring Harbor Laboratory
Date: 09-01-2021
DOI: 10.1101/2021.01.08.425909
Abstract: Choosing how much effort to expend is a critical for everyday decisions. While effort-based decision-making is altered in common psychopathologies and many neuroimaging studies have been conducted to examine how effort is valued, it remains unclear where the brain processes effort-related costs and integrates them with rewards. Using meta-analyses of combined maps and coordinates of functional magnetic resonance imaging (fMRI) studies (total N = 22), we showed that raw effort demands consistently activated the pre-supplementary motor area (pre-SMA). In contrast, the net value of effortful reward consistently activated regions, such as the ventromedial prefrontal cortex (vmPFC) and ventral striatum (VS), that have been previously implicated in value integration in other cost domains. The opposite activation patterns of the pre-SMA and vmPFC imply a double dissociation of these two regions, in which the pre-SMA is involved in pure effort cost representation and the vmPFC in net value integration. These findings advance our understanding of the neural basis of effort-related valuation and reveal potential brain targets to treat motivation-related disorders.
Publisher: Society for Neuroscience
Date: 30-09-2015
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.NEUBIOREV.2021.10.024
Abstract: Choosing how much effort to expend is critical for everyday decisions. While several neuroimaging studies have examined effort-based decision-making, results have been highly heterogeneous, leaving unclear which brain regions process effort-related costs and integrate them with rewards. We conducted two meta-analyses of functional magnetic resonance imaging data to examine consistent neural correlates of effort demands (23 studies, 15 maps, 549 participants) and net value (15 studies, 11 maps, 428 participants). The pre-supplementary motor area (pre-SMA) scaled positively with pure effort demand, whereas the ventromedial prefrontal cortex (vmPFC) showed the opposite effect. Moreover, regions that have been previously implicated in value integration in other cost domains, such as the vmPFC and ventral striatum, were consistently involved in signaling net value. The opposite response patterns of the pre-SMA and vmPFC imply that they are differentially involved in the representation of effort costs and value integration. These findings provide conclusive evidence that the vmPFC is a central node for net value computation and reveal potential brain targets to treat motivation-related disorders.
Publisher: Future Medicine Ltd
Date: 06-2022
Abstract: Aim: In Huntington's disease (HD) and Parkinson's disease (PD), apathy is a frequently cited barrier to participation in physical activity. Current diagnostic criteria emphasize dissociable variants of apathy that differentially affect goal-directed behavior. How these dimensions present and affect physical activity in HD and PD is unknown. Methods: Using a qualitative approach, we examined the experience of apathy and its impact on physical activity in 20 people with early-manifest HD or idiopathic PD. Results: Two major themes emerged: the multidimensionality of apathy, including initiation or goal-identification difficulties, and the interplay of apathy and fatigue and facilitators of physical activity, including routines, safe environments and education. Conclusion: Physical activity interventions tailored to apathy phenotypes may maximize participant engagement.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 13-12-2021
DOI: 10.1038/S42003-021-02850-3
Abstract: Humans have a striking desire to actively seek new information, even when it is devoid of any instrumental utility. However, the mechanisms that drive in iduals’ subjective preference for information remain unclear. Here, we used fMRI to examine the processing of subjective information value, by having participants decide how much effort they were willing to trade-off for non-instrumental information. We showed that choices were best described by a model that accounted for: (1) the variability in in iduals’ estimates of uncertainty, (2) their desire to reduce that uncertainty, and (3) their subjective preference for positively valenced information. Model-based analyses revealed the anterior cingulate as a key node that encodes the subjective value of information across multiple stages of decision-making – including when information was prospectively valued, and when the outcome was definitively delivered. These findings emphasise the multidimensionality of information value, and reveal the neurocomputational mechanisms underlying the variability in in iduals’ desire to physically pursue informative outcomes.
Publisher: Springer Science and Business Media LLC
Date: 24-12-2022
Start Date: 2023
End Date: 12-2026
Amount: $875,928.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2018
End Date: 12-2020
Amount: $366,603.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2018
End Date: 12-2022
Amount: $420,717.00
Funder: Australian Research Council
View Funded Activity