Biology subjects

Hinder, M.

Publications and source records attributed to Hinder, M..

4 recordsLinked to original sources

bioRxiv2025

The Stop Signal Stepping Task: how action cancellation commands disrupt step initiation in young and healthy older adults

Action cancellation - the ability to rapidly cancel an initiated movement in response to unexpected events - has been extensively studied in the upper limb using the stop signal task (SST). During gait, action cancellation is needed to stop and modify steps to avoid hazards and prevent falls. By adapting the SST to step initiation, this study investigated how the anticipatory postural adjustment (APA) and foot-lift phases of forward stepping were affected by action cancellation commands, and whether this changed with healthy ageing. The SST was performed in stepping, foot tap, and finger button conditions in 27 young (Mage = 28.7 years) and 29 healthy older adults (Mage = 70.1 years). Across conditions, older adults exhibited slower response speed compared to young adults and greater proactive slowing of responses when stop cues were anticipated. However, there was no significant difference in stopping speed between young and older adults. Stopping speed was fastest in the finger tap condition, and slowest in the step condition. When an APA was initiated in a step cancellation trial, the magnitude of the weight shift toward the step leg did not differ between successful and unsuccessful foot-lift cancellations. Foot-lift could be cancelled when stop cues were presented at similar phases of step preparation for young and older adults. These results suggest that the initial loading of the step leg is a ballistic process, however as weight is shifted toward the stance leg, action cancellation commands responding to external stimuli can decouple the APA and foot-lift step phases. Key PointsO_LIThe stop signal task (SST) - which allows an estimation of stopping speed independently of response speed - was applied to voluntary stepping in young and older adults. C_LIO_LIWhile response speed was slower for older than young adults, stopping speed was not significantly different between age groups in the upper limb, lower limb when seated, and during forward stepping. C_LIO_LIWhen stop cues were introduced, response speed slowed more in older than young adults, and more in the upper than the lower limb (i.e., Foot Tap and Step conditions). C_LIO_LIThe initial preparatory weight shift toward the stepping foot was not significantly different between successfully cancelled steps and normal steps, highlighting the ballistic nature of the early phase of step preparation. C_LIO_LIPrior to foot-lift, action cancellation commands could decouple the preparatory weight shift phase from foot-lift at similar stages of step initiation in young and healthy older adults. C_LI

neuroscience↗

bioRxiv2022

Dissociating Attentional Capture from Action Cancellation in the Stop Signal Task

Inhibiting ongoing responses when environmental demands change is a critical component of human motor control. Experimentally, the stop signal task (SST) represents the gold standard response inhibition paradigm. However, an emerging body of evidence suggests that the SST conflates two dissociable sources of inhibition, namely an involuntarily pause associated with attentional capture and the (subsequent) voluntary cancellation of action. The extent to which these processes also occur in other response tasks is unknown. 24 younger (20-35 years) and 23 older (60-85 years) adults completed a series of tasks involving rapid unimanual or bimanual responses to a visual stimulus. A subset of trials required cancellation of one component of an initial bimanual response (i.e., selective stop task; stop left response, continue with right response) or enacting an additional response (e.g., press left button as well as right button). Critically, both tasks involved some infrequent stimuli which bore no behavioural imperative (i.e., they had to be ignored). EMG recordings of voluntary responses during the stopping tasks revealed bimanual covert responses (i.e., muscle activation which was suppressed before a button press ensued), consistent with a pause process, following both stop and ignore stimuli, before the required response was subsequently enacted. Critically, we also observed the behavioural consequences of a similar involuntary pause in trials where action cancellation was not part of the response set (i.e., when the additional stimulus required additional action or ignoring, but not inhibition). The findings shed new light on the mechanisms of inhibition and their generalisability to other task contexts.

neuroscience↗

bioRxiv2021

Low intensity repetitive transcranial magnetic stimulation drives structural synaptic plasticity in the young and aged motor cortex.

BackgroundRepetitive transcranial magnetic stimulation (rTMS) is a non-invasive tool commonly used to drive neural plasticity in the young adult and aged brain. Recent data from mouse models have shown that even at subthreshold intensities (0.12 Tesla), rTMS can drive neuronal and glial plasticity in the motor cortex. However, the physiological mechanisms underlying subthreshold rTMS induced plasticity and whether these are altered with normal ageing are unclear. ObjectiveTo assess the effect of subthreshold rTMS, using the intermittent theta burst stimulation (iTBS) protocol on structural synaptic plasticity in the mouse motor cortex of young and aged mice. MethodsLongitudinal in vivo 2-photon microscopy was used to measure changes to the structural plasticity of pyramidal neuron dendritic spines in the motor cortex following a single train of subthreshold rTMS (in young adult and aged animals) or the same rTMS train administered on 4 consecutive days (in young adult animals only). Data were analysed with Bayesian hierarchical generalized linear regression models and interpreted with the aid of Bayes Factors (BF). ResultsWe found strong evidence (BF>10) that subthreshold rTMS altered the rate of dendritic spine losses and gains, dependent on the number of stimulation sessions and that a single session of subthreshold rTMS was effective in driving structural synaptic plasticity in both young adult and aged mice. ConclusionThese findings provide further evidence that rTMS drives synaptic plasticity in the brain and uncovers structural synaptic plasticity as a key mechanism of subthreshold rTMS induced plasticity.

neuroscience↗

bioRxiv2018

A data-driven approach to reduce gender disparity in invited speaker programs at scientific meetings

We present a data-driven approach that uses established metrics of scientific quality to select invited speakers; this approach enables gender parity in conference programs while ensuring high scientific standards. Gender disparity continues to be an issue in STEM, with progress requiring consistent and focused efforts. Here, we present a data-driven approach to promote high quality, gender balanced invited speaker selection for neuroscience conferences. We have targeted invited speaker opportunities because underrepresentation of female speakers at international neuroscience conferences remains a major problem, and such opportunities are critical for career development. First, we audited the top ten neuroscience journals (indexed by SCImago Journal and Country Rank; SJR), identifying (1) highly cited papers, (2) gender of first and last authors, and (3) field-weighted citation impact and total publications of first and last authors. Second, we used these data to establish a database of high quality scientists that could be used to select speakers for conferences. We found that research quality (as indexed by field-weighted citation impact and total publications) of authors of highly cited publications in the top 10 neuroscience journals did not differ significantly for females and males. The comparison between the gender base rate in neuroscience and authors publishing highly cited papers in high-quality neuroscience journals shows that female representation, particularly at last author level, is less than the estimated base rate for neuroscience. In summary, we present a data-driven approach to invited speaker selection that would facilitate gender balanced conference programs while maintaining the highest of scientific standards. This approach minimizes the influence of implicit gender bias in speaker selection decisions by using scientific quality metrics that STEM researchers are familiar with, and indeed use to evaluate their own performance. Having an immediate effect on reducing gender disparity in conference programs, our approach would generate a positive spiral for more long-term reduction of gender disparity in STEM.

scientific communication and education↗