ORCID Profile
0000-0001-8243-9540
Current Organisations
University of Western Australia
,
University of Oxford
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.
Publisher: Frontiers Media SA
Date: 14-06-2022
DOI: 10.3389/FNINS.2022.903977
Abstract: Non-invasive brain stimulation is a growing field with potentially wide-ranging clinical and basic science applications due to its ability to transiently and safely change brain excitability. In this study we include two types of stimulation: repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS). Single session stimulations with either technique have previously been reported to induce changes in attention. To better understand and compare the effectiveness of each technique and the basis of their effects on cognition we assessed changes to both temporal and visuospatial attention using an attentional blink task and a line bisection task following offline stimulation with an intermittent theta burst (iTBS) rTMS protocol or 10 Hz tACS. Additionally, we included a novel rTMS stimulation technique, low-intensity (LI-)rTMS, also using an iTBS protocol, which uses stimulation intensities an order of magnitude below conventional rTMS. Animal models show that low-intensity rTMS modulates cortical excitability despite sub-action potential threshold stimulation. Stimulation was delivered in healthy participants over the right posterior parietal cortex (rPPC) using a within-subjects design ( n = 24). Analyses showed no evidence for an effect of any stimulation technique on spatial biases in the line bisection task or on magnitude of the attentional blink. Our results suggests that rTMS and LI-rTMS using iTBS protocol and 10 Hz tACS over rPPC do not modulate performance in tasks assessing visuospatial or temporal attention.
Publisher: Springer Science and Business Media LLC
Date: 12-2022
DOI: 10.1007/S00213-022-06281-8
Abstract: There is an urgent need to identify behaviours in animals that can provide insight into the aetiology and potential treatment of depression in humans. This study aimed to validate a repeated measures cognitive affective bias (CAB) test in a rat model of chronic stress and compare CAB with forced swim test (FST) measures. Male and female Sprague Dawley rats were trained to associate large and small rewards with scent, spatial, and tactile cues, and their response to an ambiguous tactile stimulus tested. Rats underwent weekly CAB testing for 4 weeks with no intervention, or for 2 weeks of chronic restraint stress (CRS), followed by 2 weeks of fluoxetine, vehicle, or no treatment. CRS rats also underwent the FST at selected timepoints. In control rats, CAB was positive and remained stable over the 4-week period. In CRS-fluoxetine and CRS-vehicle groups, CAB was initially positive, became negative during chronic restraint stress, and returned to positive by 2 weeks after treatment. However, in the CRS-no treatment group, CAB was variable at the outset and unstable over time. Behaviour in the FST was not affected by treatment, and there was no correlation between CAB and FST outcomes. Instability in the CRS-no treatment group precluded interpretation of the impact of fluoxetine on CAB post-CRS. Our results suggest that behaviour in the FST does not reflect or alter affective state and support the use of CAB tests as part of the behavioural testing repertoire for preclinical animal models of affective disorders.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.NEUINT.2019.104546
Abstract: Repetitive Transcranial Magnetic Stimulation (rTMS) is a form of non-invasive brain stimulation that has shown therapeutic potential for various nervous system disorders. In addition to its modulatory effects on neuronal excitability, rTMS is capable of altering neurotransmitter (e.g., glutamate, GABA, dopamine and serotonin) concentrations in cortical and subcortical brain regions. Here we used a modified liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) to quantify changes in 27 free amino acids and the monoamines: dopamine (DA), serotonin (5HT) and their metabolites (DOPAC, HVA 5HIAA) in the mouse brain. Awake C57BL/6 J mice (either sex, 8-12 weeks old) received 10 Hz rTMS using two devices that can deliver low (LI- 12 mT custom built) or high (Fo8- 1.2 T MagVenture) intensity rTMS. Sham (unstimulated) mice were used as controls. S les were collected immediately following a single session of rTMS or sham and processed for LC-MS/MS. The modified LC-MS/MS method used to detect DA, 5-HT and their metabolites showed good accuracy and precision with regression coefficients greater than 0.999, and an intra- and inter-day reproducibility with values < 13%. Fo8-rTMS induced a significant reduction in cortical 5-HT turnover rates, hippoc al DOPAC and an increase in striatal DOPAC concentrations. Fo8-rTMS also reduced concentrations of hippoc al α-aminoadipic acid, and striatal serine, threonine, sarcosine, aspartate and glutamate. There were no changes in the level of any compounds following LI-rTMS as compared to sham. The rapid change in monoamine turnover and amino acid concentrations following Fo8-rTMS but not LI-rTMS suggests that different stimulation parameters recruit different cellular mechanisms related to rTMS-induced plasticity. The described method can be used for the characterisation of trace levels of neurotransmitters and amino acids in brain tissue homogenates, providing a useful and precise tool to investigate localised neurotransmitter changes in animal models of health and disease.
Publisher: Frontiers Media SA
Date: 06-03-2020
Publisher: Springer Science and Business Media LLC
Date: 29-11-2022
DOI: 10.1038/S41598-022-24934-8
Abstract: Repetitive transcranial magnetic stimulation (rTMS) induces action potentials to induce plastic changes in the brain with increasing evidence for the therapeutic importance of brain-wide functional network effects of rTMS however, the influence of sub-action potential threshold (low-intensity LI-) rTMS on neuronal activity is largely unknown. We investigated whether LI-rTMS modulates neuronal activity and functional connectivity and also specifically assessed modulation of parvalbumin interneuron activity. We conducted a brain-wide analysis of c-Fos, a marker for neuronal activity, in mice that received LI-rTMS to visual cortex. Mice received single or multiple sessions of excitatory 10 Hz LI-rTMS with custom rodent coils or were sham controls. We assessed changes to c-Fos positive cell densities and c-Fos arvalbumin co-expression. Peak c-Fos expression corresponded with activity during rTMS. We also assessed functional connectivity changes using brain-wide c-Fos-based network analysis. LI-rTMS modulated c-Fos expression in cortical and subcortical regions. c-Fos density changes were most prevalent with acute stimulation, however chronic stimulation decreased parvalbumin interneuron activity, most prominently in the amygdala and striatum. LI-rTMS also increased anti-correlated functional connectivity, with the most prominent effects also in the amygdala and striatum following chronic stimulation. LI-rTMS induces changes in c-Fos expression that suggest modulation of neuronal activity and functional connectivity throughout the brain. Our results suggest that LI-rTMS promotes anticorrelated functional connectivity, possibly due to decreased parvalbumin interneuron activation induced by chronic stimulation. These changes may underpin therapeutic rTMS effects, therefore modulation of subcortical activity supports rTMS for treatment of disorders involving subcortical dysregulation.
Publisher: Elsevier BV
Date: 2022
Publisher: Cold Spring Harbor Laboratory
Date: 13-08-2022
DOI: 10.1101/2022.08.13.503840
Abstract: Repetitive transcranial magnetic stimulation (rTMS) induces action potentials to induce plastic changes in the brain with increasing evidence for the therapeutic importance of brain-wide functional network effects of rTMS however, the influence of sub-action potential threshold (low-intensity LI-) rTMS on neuronal activity is largely unknown. We investigated whether LI-rTMS modulates neuronal activity and functional connectivity. We also specifically assessed modulation of parvalbumin interneuron activity. We conducted a brain-wide analysis of c-Fos, a marker for neuronal activity, in mice that received LI-rTMS to visual cortex. Mice received single or multiple sessions of excitatory 10Hz LI-rTMS with custom rodent coils or were sham controls. We assessed changes to c-Fos positive cell densities and c-Fos arvalbumin co-expression. Peak c-Fos expression corresponded with activity during rTMS. We also assessed functional connectivity changes using brain-wide c-Fos-based network analysis. LI-rTMS modulated c-Fos expression in cortical and subcortical regions. c-Fos density changes were most prevalent with acute stimulation, however chronic stimulation decreased parvalbumin interneuron activity, most prominently in the amygdala and striatum. LI-rTMS also increased anti-correlated functional connectivity, with the most prominent effects also in the amygdala and striatum following chronic stimulation. LI-rTMS induces changes in c-Fos expression that suggest modulation of neuronal activity and functional connectivity throughout the brain. Our results suggest that LI-rTMS promotes anticorrelated functional connectivity, possibly due to decreased parvalbumin interneuron activation induced by chronic stimulation. These changes may underpin therapeutic rTMS effects, therefore modulation of subcortical activity supports rTMS for treatment of disorders involving subcortical dysregulation. - Low-intensity rTMS increases brain-wide anti-correlated functional connectivity - Acute excitatory LI-rTMS modulates cortical and subcortical neuronal activity - Decreased parvalbumin interneuron activity may promote anti-correlated activity - Striatum and amygdala show prominent modulation with LI-rTMS
Publisher: Frontiers Media SA
Date: 15-06-2023
DOI: 10.3389/FNCIR.2023.1179096
Abstract: Overreliance on habit is linked with disorders, such as drug addiction and obsessive-compulsive disorder, and there is increasing interest in the use of repetitive transcranial magnetic stimulation (rTMS) to alter neuronal activity in the relevant pathways and for therapeutic outcomes. In this study, we researched the brains of ephrin-A2A5 −/− mice, which previously showed perseverative behavior in progressive-ratio tasks, associated with low cellular activity in the nucleus accumbens. We investigated whether rTMS treatment had altered the activity of the dorsal striatum in a way that suggested altered hierarchical recruitment of brain regions from the ventral striatum to the dorsal striatum, which is linked to abnormal habit formation. Brain sections from a limited number of mice that underwent training and performance on a progressive ratio task with and without low-intensity rTMS (LI-rTMS) were taken from a previous study. We took advantage of the previous characterization of perseverative behavior to investigate the contribution of different neuronal subtypes and striatal regions within this limited s le. Striatal regions were stained for c-Fos as a correlate of neuronal activation for DARPP32 to identify medium spiny neurons (MSNs) and for GAD67 to identify GABA-ergic interneurons. Contrary to our hypothesis, we found that neuronal activity in ephrin-A2A5 −/− mice still reflected the typical organization of goal-directed behavior. There was a significant difference in the proportion of neuronal activity across the striatum between experimental groups and control but no significant effects identifying a specific regional change. However, there was a significant group by treatment interaction which suggests that MSN activity is altered in the dorsomedial striatum and a trend suggesting that rTMS increases ephrin-A2A5 −/− MSN activity in the DMS. Although preliminary and inconclusive, the analysis of this archival data suggests that investigating circuit-based changes in striatal regions may provide insight into chronic rTMS mechanisms that could be relevant to treating disorders associated with perseverative behavior.
Publisher: Elsevier BV
Date: 02-2021
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jessica Moretti.