Hierarchical effects of choice related activity and neural encoding during feature selective attention

Selective attention is necessary to sift through, form a coherent percept of, and make behavioral decisions on the vast amount of information present in most sensory environments. How and where selective attention is employed in cortex and how this perceptual information then informs the relevant behavioral decisions is still not well understood. Studies probing selective attention and decision making in visual cortex have been enlightening as to how sensory attention might work in that modality; whether or not similar mechanisms are employed in auditory attention is not yet clear. Therefore, we trained rhesus macaques on a feature selective attention task, where they switched between reporting changes in temporal (amplitude modulation, AM) and spectral (carrier bandwidth) features of a broadband noise stimulus. We investigated how the encoding of these features by single neurons in primary (A1) and secondary (lateral belt, ML) auditory cortex were affected by the different attention conditions. We found that neurons in A1 and ML showed mixed-selectivity to the sound and task features. We found no difference in AM encoding between the attention conditions. We found that choice-related activity in both A1 and ML neurons shifts between attentional conditions. This finding suggests that choice-related activity in auditory cortex does not simply reflect motor preparation or action, and supports the relationship between reported choice-related activity and the decision and perceptual process. New & NoteworthyWe recorded from primary and secondary auditory cortex while monkeys performed a non-spatial feature attention task. Both areas exhibited rate-based choice-related activity. The manifestation of choice-related activity was attention-dependent, suggesting that choice-related activity in auditory cortex does not simply reflect arousal or motor influences, but relates to the specific perceptual choice. The lack of temporal-based choice activity is consistent with growing evidence that subcortical, but not cortical, single neurons inform decisions through temporal envelope following.