Task-Related Activation of Auditory Cortex

Abstract

Theoretical concepts of audition in conjunction with modified auditory and heterogeneous nonauditory activities found in auditory cortex during task performance point to its role as a semantic processor. Notably, these activities during each task trial reflect not only identification of auditory target features but also in many details the associations formed with other information for behavioral execution of the task. In this way the behavioral meaning of the sounds seems to be determined locally, namely what to do with a sound in a task-specific fashion. Even though many details of activation changes and activation states during a task trial need clarification, the available evidence suggests that it might be possible to recognize from these activities which basic types of logical operations were involved, for example, detection, discrimination, or categorization of sounds. Also motivational aspects related to approach or avoidance, prediction of events, and reinforcements as well as prediction errors seem to be discriminable from the activities. It is obvious that these facets of a task cannot be deduced by auditory cortex alone but only in cooperation with numerous other cortical and subcortical brain areas. Recent evidence suggests that the necessary anatomical connections are available even for primary auditory cortex but become functional only during engagement in auditory tasks. This new view on auditory cortex implies that hierarchical concepts of brain organization reserving cognitive functions to ``higher order'' cortices must be modified. The information flow from sensory cortex to such cortical areas is undebatable but they seem to feed information back to sensory cortex for local cognitive processing.