Gating at early cortical processing stages is associated with changes in behavioural performance on a sensory conflict task

A History of Concussion Affects Relevancy-Based Modulation of Cortical Responses to Tactile Stimuli

“…There was a trend toward a significant interaction effect between group, attention, and stimulus type ( F (1,25) = 2.97, p = 0.07) but no other interaction effects reached significance. The significant main effect of stimulus type was explored by conducting a two-way repeated-measures ANOVA of the N140 amplitudes collected from the concussion history participants for comparison with the control group statistics published previously (Adams et al, 2017 ). When each group was examined individually, there was no significant interaction between attention and stimulus type in either group and a trend toward a significant main effect of attention in both the control group ( F (1,60) = 3.60, p = 0.06) and the group with a history of concussion ( F (1,39) = 2.96, p = 0.09).…”

“…The relevance of a stimulus to the task at hand is a contributor to how the stimulus is processed, with more relevant stimuli eliciting more robust cortical responses. Previous work by our lab demonstrated that the somatosensory-evoked N70 potential is enhanced when the evoking stimulus is task-relevant and attenuated when the evoking stimulus is irrelevant during a sensory grading task (Adams et al, 2017(Adams et al, , 2019. When the ability to downregulate cortical excitability to irrelevant distractor stimuli was disrupted using cTBS applied to the prefrontal cortex, these distractors exerted a greater behavioral cost during the sensory grading task (Adams et al, 2019).…”

“…No restrictions were placed on the maximum number of concussions, time since the most recent concussion, recovery time, or age at the time of injury for those in the concussion group, ensuring that the participant group reflected the heterogeneity of the wider population of those who have recovered from concussion and consistent with other published studies (Thériault et al, 2009 , 2011 ; Dalecki et al, 2016 ; Hurtubise et al, 2016 ); see Table 1 for participant characteristics. Control participant data have been examined and published previously (Adams et al, 2017 ). Participants had no history of substance abuse, psychoactive drug treatment, or neurological disease or impairment, other than a concussion(s) for those in the concussion history group.…”

“…Data sets were tested for normality to validate the use of parametric tests, and transformed when necessary to uphold the assumptions of the ANOVA model. Since N70 amplitudes are modulated by attention in the control group (Adams et al, 2017 ), pre-planned contrasts were conducted on the N70 potential in the post-concussion group. Specifically, contrasts tested the hypotheses that the modulation of N70 amplitude by task-relevance which was seen in the control group would not be replicated in the group with concussion history and that the presentation of a task-irrelevant visual distractor would significantly decrease the tactile-evoked N70 amplitude in the concussion history group.…”

“…The present study was designed to investigate how a history of concussion affected the tactile-evoked N70 ERP, which we have shown to be a cortical correlate of task relevance and distractibility in two separate groups of participants (Adams et al, 2017 , 2019 ). The first hypothesis of the present experiment was that relevancy-based sensory gating would be impaired in participants with a history of concussion, resulting in less suppression of N70 cortical responses to task-irrelevant stimuli.…”