Neuroanatomy of Temporal Association Cortex

Abstract

The temporal lobe of the cerebrum consists of several spatially segregated functional regions. There are discrete regions of the temporal lobe where auditory (primary, secondary and tertiary), visual (motion detection and object recognition) and meta-cognitive (memory and social communication) functions are processed. The subcortical amygdala and hippocampal-complex can also be considered temporal structures. Several nomenclature systems have been promoted over the years resulting in multiple names for most individual gyri and sulci. Herein we review the historical naming systems for cerebral temporal structures and describe their relationship to the functional regions in the temporal lobe. Neuronal populations that process auditory information are located primarily in the medial region of the temporal lobe (the belt and parabelt). The object-recognition prefrontal cortical stream (the "What" pathway) projects through the rostral superior temporal gyrus while the place-related prefrontal cortical stream (the "Where" Pathway) projects through the caudal superior temporal gyrus. The dorsal part of the superior temporal sulcus receives projections from both auditory regions (superior temporal gyrus) and visual processing areas including the motion-recognition related midtemporal area (MT), the fundus of the superior temporal sulcus (FST), and the caudal inferotemporal cortex (TEO). This convergence could be related to dynamic integration of audio-visual information. The ventral part of the superior temporal sulcus also receives projections from motion-detection regions as well as object recognition areas (TE, TEO). This area could be involved in interpretation of dynamic moving objects, especially biological motion.