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Shivdasani, M. N.

Publications and source records attributed to Shivdasani, M. N..

2 recordsLinked to original sources

When Tagging Frequency Matters to Attention: Effects on SSVEPs, ERPs, and Cognitive Processing

Selective attention enables the prioritization of task-relevant information while managing distractors, and steady-state visual evoked potentials (SSVEPs) are widely used to track this process by tagging different visual objects at distinct flicker frequencies. However, whether the choice of tagging frequency itself influences other neural and cognitive measures remains unclear. Here, 27 participants performed detection and 1-back working memory tasks while a central target and peripheral distractors flickered at either 8.6 Hz or 12 Hz. The working memory task produced slower responses, more errors, and greater perceived difficulty than detection. Tagging frequency strongly shaped neural responses, with 8.6 Hz eliciting higher SSVEP signal-to-noise ratios than 12 Hz regardless of stimulus location. Nevertheless, stronger SSVEP responses for centrally attended stimuli were associated with fewer working memory errors and larger early visual ERP responses, while SSVEPs for attended and distractor stimuli were negatively correlated. In addition, the working memory task produced a larger P1-N1 peak-to-peak difference, and tagging frequency altered the timing and amplitude of early ERP effects. Together, these findings show that tagging frequency is not a neutral methodological parameter, but one that shapes both neural indices of attention and their relationship to cognitive performance.

neuroscience↗

Peripheral direct current for suppression of physiologically evoked nociceptive responses at the spinal cord

Electrical neuromodulation is an established non-pharmacological treatment for chronic pain. However, existing devices using pulsatile stimulation are not suitable for all types of chronic pain. Direct current stimulation is a recently developed technology which shows better selectivity for small-diameter fibres. We investigated if this selectivity could be applied to preferentially suppress nociceptive signalling. We applied direct current to the sciatic nerve of rats and compared its effects on spinal activity produced by physiological (non-electrical) stimuli delivered to the foot. Tests were performed across models of neuropathic and inflammatory pain to further clarify potential clinical applications. We found that direct current could effectively suppress activity relating to painful stimuli in both pain models tested. These findings strongly support the use of direct current neuromodulation for chronic pain relief, and suggest that it may be effective at treating a broader range of aberrant pain conditions than existing devices.

neuroscience↗