Abstract
Modulating cortical excitability based on a stimulus’ relevance to the task at hand is a component of sensory gating, and serves to protect higher cortical centers from being overwhelmed with irrelevant information (McIlroy et al., 2003; Kumar et al., 2005; Wasaka et al., 2005). This study examined relevancy-based modulation of cortical excitability, and corresponding behavioral responses, in the face of distracting stimuli in participants with and without a history of concussion (mean age 22 ± 3 SD years; most recent concussion 39.1 ± 30 SD months). Participants were required to make a scaled motor response to the amplitudes of visual and tactile stimuli presented individually or concurrently. Task relevance was manipulated, and stimuli were occasionally presented with irrelevant distractors. Electroencephalography (EEG) and task accuracy data were collected from participants with and without a history of concussion. The somatosensory-evoked N70 event-related potential (ERP) was significantly modulated by task relevance in the control group but not in those with a history of concussion, and there was a significantly greater cost to task accuracy in the concussion history group when relevant stimuli were presented with an irrelevant distractor. This study demonstrated that relevancy-based modulation of electrophysiological responses and behavioral correlates of sensory gating differ in people with and without a history of concussion, even after patients were symptom-free and considered recovered from their injuries.
Highlights
We are surrounded by multiple competing stimuli at all times during daily life, but not all stimuli need to elicit equivalent cortical responses
This study demonstrated that relevancybased modulation of electrophysiological responses and behavioral correlates of sensory gating differ in people with and without a history of concussion, even after patients were symptom-free and considered recovered from their injuries
Since the tactile-evoked N70 potential had been shown to have relevancy effects in two separate groups of healthy young adults, and these relevancy effects could be linked to performance accuracy on our sensory grading task, we sought to examine relevancy-based sensory gating in a group of people with a history of concussion
Summary
We are surrounded by multiple competing stimuli at all times during daily life, but not all stimuli need to elicit equivalent cortical responses. Patients frequently report difficulties sustaining attention, in complex environments with multiple competing sensory stimuli, such as grocery stores or noisy rooms (Arciniegas et al, 1999; Halterman et al, 2006). We hypothesized that these concussion sequelae may be related to impairments in the cortical processes related to gating irrelevant stimuli out of the processing stream. Our objective was to explore differences in cortical and behavioral responses in a group of people who had recovered from concussions
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