Effect of Modality-Specific Sensory Load on Novel Auditory Evoked Responses

Attentional systems must be able to identify non-salient sensory input so as to allocate appropriate neural resources. Auditory stimuli delivered high repetition rates may represent a background barrage of noncritical information. Scalp electrode recordings were obtained from human subjects in response to a train of tone-pips played at high repetition rates under conditions where sensory load and attentional focus were experimentally manipulated. Sensory load affected both the amplitude of evoked waveforms and the latency of individual peaks while attentional focus had no significant effect. These data support the hypothesis that non-salient information reaches cortical levels despite increased sensory processing requirements