Abstract:
Sensory gating is the process by which the neural responses to repeated stimuli are decreased. This phenomenon has been widely studied in the auditory domain by examining the amplitude decrement of auditory evoked potentials, primarily P1 and N1. Paradigms used to study gating have employed various tasks, stimuli, repetition rates and stimulus presentation methods (e.g. pairs or trains of stimuli). Theories for gating implicate areas such as auditory cortex and frontal regions (Boutros et al., 2011). However, it is uncertain what mechanisms underlie gating and whether it is a refractory-like process within the auditory cortex or an inhibition process from outside the auditory cortex. The current study uses a target detection task, with stimuli presented in pairs (experiment 1) and trains of 5 (experiment 2). Targets were located predictably in the first position for experiment 1 or the fifth position for experiment 2. Stimuli were presented at four stimulus onset asynchronies (SOA; 200, 400, 600 and 800 ms) with three pitch interval conditions between stimuli (same note, half octave apart, or full octave apart). Participants were either musicians or non-musicians. In general, more gating was observed for shorter SOAs and more physically similar pitch intervals. The results support a refractory-like process underlying gating that is modulated by higher level controls based on endogenous attention control settings (Ishigami et al., 2011) related to the target detection task. Musicians showed stronger task-related effects than non-musicians for experiment 2. The presentation method (pairs or trains) also affected results, demonstrating that these paradigms are not entirely equivalent.