Publications
89 results found
Ahmad H, Arshad Q, Patel M, et al., 2015, ACQUIRED PENDULAR NYSTAGMUS IN STARGARDT'S SYNDROME SUPPRESSED BY ALCOHOL, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Ahmad H, Roberts R, Arshad QA, et al., 2015, USING TRANSCRANIAL MAGNETIC STIMULATION (TMS) TO PROBE EFFECTS OF VISUAL MOTION ADAPTATION ON PRIMARY VISUAL CORTEX (V1) EXCITABILITY IN BILATERAL VESTIBULAR FAILURE (BVF) PATIENTS, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Bronstein AM, Arshad Q, Siddiqui S, et al., 2015, Right hemisphere dominance directly predicts both baseline V1 cortical excitability and the degree of top-down modulation exerted over low-level brain structures, Neuroscience, Vol: 311, Pages: 484-489, ISSN: 0306-4522
Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals. This dominance has been attributed to both an anatomically larger right fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstrated that interhemispheric conflict, which induces left hemisphere inhibition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular–ocular reflex (VOR) via top-down control mechanisms. However to date, it remains unknown whether the degree of an individual’s right hemisphere dominance for visuospatial function can influence, (i) the baseline excitability of the visual cortex and (ii) the extent to which the right hemisphere can exert top-down modulation. We directly tested this by correlating line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability measured using phosphene perception elicited via single-pulse occipital trans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, following left hemisphere inhibition. We found that those individuals with greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppression following left hemisphere cathodal tDCS. To conclude, our results provide the first demonstration that individual differences in right hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation exerted over them.
Ahmad H, Roberts RE, Arshad Q, et al., 2015, Probing effects of visual motion adaptation on primary visual cortex (V1) excitability using Tms in Bilateral Vestibular Failure (Bvf) patients, JOURNAL OF THE NEUROLOGICAL SCIENCES, Vol: 357, Pages: E172-E172, ISSN: 0022-510X
Arshad Q, Cerchiai N, Goga U, et al., 2015, ELECTROCORTICAL THERAPY FOR MOTION SICKNESS, Neurology, Vol: 85, Pages: 1257-1259, ISSN: 0028-3878
Patel M, Roberts RE, Riyaz MU, et al., 2015, Locomotor adaptation is modulated by observing the actions of others, Journal of Neurophysiology, Vol: 114, Pages: 1538-1544, ISSN: 1522-1598
Observing the motor actions of another person could facilitate compensatory motor behavior in the passive observer. Here we explored whether action observation alone can induce automatic locomotor adaptation in humans. To explore this possibility, we used the “broken escalator” paradigm. Conventionally this involves stepping upon a stationary sled after having previously experienced it actually moving (Moving trials). This history of motion produces a locomotor aftereffect when subsequently stepping onto a stationary sled. We found that viewing an actor perform the Moving trials was sufficient to generate a locomotor aftereffect in the observer, the size of which was significantly correlated with the size of the movement (postural sway) observed. Crucially, the effect is specific to watching the task being performed, as no motor adaptation occurs after simply viewing the sled move in isolation. These findings demonstrate that locomotor adaptation in humans can be driven purely by action observation, with the brain adapting motor plans in response to the size of the observed individual's motion. This mechanism may be mediated by a mirror neuron system that automatically adapts behavior to minimize movement errors and improve motor skills through social cues, although further neurophysiological studies are required to support this theory. These data suggest that merely observing the gait of another person in a challenging environment is sufficient to generate appropriate postural countermeasures, implying the existence of an automatic mechanism for adapting locomotor behavior.
Patel M, Roberts RE, Arshad Q, et al., 2015, Galvanic Vestibular Stimulation Induces a Spatial Bias in Whole-body Position Estimates, Brain Stimulation, Vol: 8, Pages: 981-983, ISSN: 1935-861X
Ahmad H, Roberts R, Patel M, et al., 2015, Using transcranial magnetic stimulation (TMS) to probe effects of visual motion adaptation on primary visual cortex (V1) excitability in bilateral vestibular failure patients, 1st Congress of the European-Academy-of-Neurology, Publisher: WILEY, Pages: 51-51, ISSN: 1351-5101
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- Citations: 1
Cousins S, Kaski D, Cutfield N, et al., 2015, Clinical recovery after acute vestibular neuritis, 1st Congress of the European-Academy-of-Neurology, Publisher: WILEY, Pages: 364-364, ISSN: 1351-5101
Murdin L, Chamberlain F, Cheema S, et al., 2015, Motion sickness in migraine and vestibular disorders, JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY, Vol: 86, Pages: 585-+, ISSN: 0022-3050
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- Citations: 54
Nigmatullina Y, Arshad Q, Wu K, et al., 2015, HOW IMAGERY CHANGES SELF-MOTION PERCEPTION, NEUROSCIENCE, Vol: 291, Pages: 46-52, ISSN: 0306-4522
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- Citations: 12
Arshad Q, Patel M, Goga U, et al., 2015, Role of handedness-related vestibular cortical dominance upon the vestibular-ocular reflex, Journal of Neurology, Vol: 262, Pages: 1069-1071, ISSN: 0340-5354
Rimmer J, Patel M, Agarwal K, et al., 2015, Peripheral Vestibular Dysfunction in Patients With Primary Ciliary Dyskinesia: Abnormal Otoconial Development?, OTOLOGY & NEUROTOLOGY, Vol: 36, Pages: 662-669, ISSN: 1531-7129
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- Citations: 4
Bronstein AM, Patel M, Arshad Q, 2015, A brief review of the clinical anatomy of the vestibular-ocular connections-how much do we know?, EYE, Vol: 29, Pages: 163-170, ISSN: 0950-222X
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- Citations: 30
Seemungal BM, Arshad Q, Paine H, et al., 2015, What is post-concussion dizziness? Expert neuro-otological assessment in acute Traumatic Brain Injury (TBI), Pages: 52-52
Ahmad H, Arshad Q, Siddiqui S, et al., 2014, Applications of neuromodulation to explore vestibular cortical processing; new insights into the effects of direct current cortical modulation upon pursuit, VOR and VOR suppression, JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION, Vol: 24, Pages: 453-458, ISSN: 0957-4271
Ahmad H, Patel M, Arshad Q, et al., 2014, Cortical modulation of vestibulo-ocular reflexes as revealed with tDCS (transcranial direct current stimulation), Joint Congress of European Neurology, Publisher: SPRINGER HEIDELBERG, Pages: S188-S188, ISSN: 0340-5354
Ahmad H, Patel M, Arshad Q, et al., 2014, Cortical modulation of vestibulo-ocular reflexes as revealed with tDCS (transcranial direct current stimulation), Joint Congress of European Neurology, Publisher: WILEY-BLACKWELL, Pages: 274-274, ISSN: 1351-5101
Arshad Q, Nigmatullina Y, Bronstein AM, 2014, Unidirectional visual motion adaptation induces reciprocal inhibition of human early visual cortex excitability, CLINICAL NEUROPHYSIOLOGY, Vol: 125, Pages: 798-804, ISSN: 1388-2457
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- Citations: 6
Papachatzaki MM, Ali N, Arshad Q, et al., 2013, Progressive ataxia with oculo-palatal tremor and optic atrophy, JOURNAL OF NEUROLOGY, Vol: 260, Pages: 2903-2905, ISSN: 0340-5354
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- Citations: 4
Arshad Q, Nigmatullina Y, Bhrugubanda V, et al., 2013, Separate attentional components modulate early visual cortex excitability, CORTEX, Vol: 49, Pages: 2938-2940, ISSN: 0010-9452
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- Citations: 11
Arshad Q, Nigmatullina Y, Roberts RE, et al., 2013, Left Cathodal Trans-Cranial Direct Current Stimulation of the Parietal Cortex Leads to an Asymmetrical Modulation of the Vestibular-Ocular Reflex, BRAIN STIMULATION, Vol: 7, Pages: 85-91, ISSN: 1935-861X
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- Citations: 31
Murdin L, Chamberlain F, Cheema S, et al., 2013, The role of motion sickness susceptibility in vestibular disorders and migraine, JOURNAL OF NEUROLOGY, Vol: 260, Pages: S27-S28, ISSN: 0340-5354
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- Citations: 1
Naushahi MJ, Khan AN, Arshad Q, et al., 2013, Effects of subthalamic nucleus (STN) and pedunculopontine nucleus (PPN)-deep brain stimulation (DBS) on saccades in advanced Parkinson's disease (PD), Publisher: WILEY-BLACKWELL, Pages: S456-S456, ISSN: 0885-3185
Naushahi MJ, Khan AN, Arshad Q, et al., 2013, Different combinations of subthalamic nucleus (STN) and pedunculopontine nucleus (PPN) deep brain stimulation (DBS) lead to variable effects in saccades and antisaccades in advanced Parkinson's disease (PD), Publisher: WILEY-BLACKWELL, Pages: S446-S446, ISSN: 0885-3185
Arshad Q, Nigmatullina Y, Bronstein AM, 2013, Handedness-Related Cortical Modulation of the Vestibular-Ocular Reflex, JOURNAL OF NEUROSCIENCE, Vol: 33, Pages: 3221-3227, ISSN: 0270-6474
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- Citations: 44
Seemungal B, Guzman-Lopez J, Arshad Q, et al., 2012, VESTIBULAR ACTIVATION DIFFERENTIALLY MODULATES HUMAN EARLY VISUAL CORTEX AND V5/MT EXCITABILITY AND RESPONSE ENTROPY, Annual Meeting of the Association-of-British-Neurologists, Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
Seemungal BM, Guzman-Lopez J, Arshad Q, et al., 2012, Vestibular Activation Differentially Modulates Excitability and Response Entropy in Human V5/MT and Early Visual Cortex., Cerebral Cortex, Vol: 23, Pages: 12-19, ISSN: 1047-3211
Head movement imposes the additional burdens on the visual system of maintaining visual-acuity and determining the origin of retinal image motion (i.e. self-motion versus object-motion). Although maintaining visual acuity during self-motion is effected by minimising retinal slip via the brainstem vestibular-ocular reflex, higher-order visuo-vestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher-order mechanisms and a cortical visuo-vestibular reciprocal antagonism is propounded. Hence one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased Early Visual Cortex (EVC) excitability, during vestibular activation. In order to exclude non-specific effects (e.g. arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a non-specific effect at EVC.
Arshad Q, Kaski D, Buckwell D, et al., 2012, A New Device to Quantify Ocular Counterroll Using Retinal Afterimages, AUDIOLOGY AND NEURO-OTOLOGY, Vol: 17, Pages: 20-24, ISSN: 1420-3030
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- Citations: 5
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