Papers by Richard Staines
BMC Neuroscience, Sep 7, 2010
BMC sports science, medicine & rehabilitation, Jun 21, 2014
Neurorehabilitation and Neural Repair, Sep 10, 2008
Multiple sclerosis journal, experimental, translational and clinical, Jun 1, 2015
Experimental Brain Research, Jun 10, 2021
Brain Research, Nov 1, 2009
Assessing linear time-invariance in human primary somatosensory cortex with BOLD fMRI using vibrotactile stimuli
Magnetic Resonance in Medicine, 2005
The assumption of linear time‐invariance (LTI) in the human primary somatosensory cortex (SI) is ... more The assumption of linear time‐invariance (LTI) in the human primary somatosensory cortex (SI) is assessed for fMRI signals generated by variable‐duration vibrotactile stimuli. Predictions based on time‐shifted summation (TSS) of responses to 2 s stimuli overestimate observed BOLD signal amplitudes in response to longer‐duration stimuli, in agreement with previous findings in other primary sensory cortices. To interpret these results, we undertook an alternative approach for LTI assessment by characterizing BOLD signals using two biophysical models. The first model assumes that the input stimulus envelope is proportional to neural activity. The second assumes that neural activity exhibits both transient and steady‐state components, consistent with extensive electrophysiological data, and fits the experimental data better. Although nonlinearity remains evident for short stimulus durations, the latter model shows that the TSS procedure to assess LTI overestimates the BOLD signal because the temporal characteristics of neural activity have not been considered adequately. Further research to investigate the BOLD response to time‐varying neural activity is required. Magn Reson Med 53:304–311, 2005. © 2005 Wiley‐Liss, Inc.
Brain, 2019
Cognitive dysfunction affects 40–80% of patients with multiple sclerosis. Smoking cannabis may ad... more Cognitive dysfunction affects 40–80% of patients with multiple sclerosis. Smoking cannabis may add to these deficits. It is unclear whether coming off cannabis results in cognitive improvement. To address this question, 40 patients with multiple sclerosis who started using cannabis after the onset of multiple sclerosis and who used it for at least 4 days a week over many years were divided by odd-even number selection into two groups: cannabis continuation and cannabis withdrawal. Assessments took place at baseline and after 28 days and included serial versions of the Brief Repeatable Neuropsychological Battery for multiple sclerosis containing tests of verbal and visual memory, processing speed and executive function; structural and functional MRI, the latter entailing a compatible version of the Symbol Digit Modalities Test; urine for cannabinoid metabolites to detect compliance with abstinence. Only those participants deemed globally impaired at baseline (failure on at least two ...
Journal of Stroke and Cerebrovascular Diseases, 2017
Differential effects of continuous theta burst stimulation (cTBS) over left premotor cortex (PMC) and right prefrontal cortex (PFC) on modulating upper limb somatosensory input
NeuroImage, Jan 27, 2015
Somatosensory evoked potentials (SEPs) represent somatosensory processing in non-primary motor ar... more Somatosensory evoked potentials (SEPs) represent somatosensory processing in non-primary motor areas (i.e. frontal N30 and N60) and somatosensory cortices (i.e. parietal P50). It is well-known that the premotor cortex (PMC) and prefrontal cortex (PFC) are involved in the preparation and planning of upper limb movements but it is currently unclear how they modulate somatosensory processing for upper limb motor control. In the current study, two experiments examined SEP modulations after continuous theta burst stimulation (cTBS) was used to transiently disrupt the left PMC (Experiment 1) and right PFC (Experiment 2). Both Experiment 1 (n=15) and Experiment 2 (n=16) used pre-post experimental designs. In both experiments participants performed a task requiring detection of varying amplitudes of attended vibrotactile (VibT) stimuli to the left index finger (D2) and execution of a pre-matched finger sequence with the right (contralateral) hand to specific VibT targets. During the task, S...
NeuroImage: Clinical, 2015
Behavioural brain research, Jan 15, 2015
Neuroimaging research has shown that acute bouts of moderate intensity aerobic exercise can enhan... more Neuroimaging research has shown that acute bouts of moderate intensity aerobic exercise can enhance attention-based neuronal activity in frontal brain regions, namely in the prefrontal cortex (PFC), as well as improve cognitive performance. The circuitry of the PFC is complex with extensive reciprocal corticocortical and thalamocortical connections, yet it remains unclear if aerobic exercise can also assist attentional control over modality-specific sensory cortices. To test this, we used a tactile discrimination task to compare tactile event-related potentials (ERPs) prior to and following an acute bout of moderate intensity aerobic exercise. We hypothesized that exercise preceding performance of the task would result in more efficient sensory gating of irrelevant/non-attended and enhancement of relevant/attended sensory information, respectively. Participants received vibrotactile stimulation to the second and fifth digit on the left hand and reported target stimuli on one digit o...
Clinical Neurophysiology, 2015
Progress in Neurobiology, 1997
CyberPsychology & Behavior, 2003
Modulation of H reflexes in human tibialis anterior muscle with passive movement
Brain Research, 1997
Significant movement-induced gain changes in H reflexes have been observed in soleus muscle follo... more Significant movement-induced gain changes in H reflexes have been observed in soleus muscle following passive movement of the lower limb. Hypotheses from these concepts were tested on magnitudes of H reflexes in tonically contracted tibialis anterior. From eleven subjects at rates of 20 and 60 r.p.m. passive leg movement, statistically significant attenuation from controls and phasic modulation occurred. The results make more general the conclusions from soleus H reflexes. However, the functional effect should be much smaller, as tibialis anterior H reflexes are smaller compared to those in soleus.
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Papers by Richard Staines