The functional organization of posterior parietal association cortex

Abstract

Posterior parietal cortex has traditionally been considered to be a sensory association area in which higher-order processing and intermodal integration of incoming sensory information occurs. In this paper, evidence from clinical reports and from lesion and behavioral-electrophysiological experiments using monkeys is reviewed and discussed in relation to the overall functional organization of posterior parietal association cortex, and particularly with respect to a proposed posterior parietal mechanism concerned with the initiation and control of certain classes of eye and limb movements. Preliminary data from studies of the effects of posterior parietal lesions on oculomotor control in monkeys are reported.The behavioral effects of lesions of posterior parietal cortex in monkeys have been found to be similar to those which follow analogous damage of the minor hemisphere in humans, while behavioral-electrophysiological experiments have disclosed classes of neurons in this area which have functional properties closely related to the behavioral acts that are disrupted by lesions of the area. On the basis of current data from these areas of study, it is proposed that the sensory association model of posterior parietal function is inadequate to account for the complexities of the present evidence. Instead, it now appears that many diverse neural mechanisms are locatedin partin parietal cortex, that some of these mechanisms are involved in sensory processing and perceptual functions, but that others participate in motor control, and that still others are involved in attentional, motivational, or emotional processes. It is further proposed that the elementary units of these various neural mechanisms are distributed within posterior parietal cortex according to the columnar hypothesis of Mountcastle.

Treatment with Olanzapine is Associated with Modulation of the Default Mode Network in Patients with Schizophrenia

“…This region is associated with visual processing, motor planning (Cavada and Goldman-Rakic, 1989), cognitive functions, such as motor imagery, spatial navigation (Sato et al, 2006), memory retrieval (Lundstrom et al, 2005), and also selfperception and internal mentation ). On the lateral parietal cortex, IPL which is a heteromodal association area, also has a crucial role in integrating incoming sensory information (Lynch, 1980) and in executive functions, specifically WM, sustained attention and dual task performance (Torrey, 2007). Increased connectivity of parietal regions within the DMN may be compensatory for deficits in other brain regions within the DMN, for example, pCC.…”

Cortical afferent input to the principals region of the rhesus monkey

“…On the other hand the other principalis sites also received some of their input from the inferior parietal lobule and from the medial parietal cortex, regions thought to have some role in spatial performance. 22 ' 45 ' 57 …”

Multimodal Representation of Space in the Posterior Parietal Cortex and Its Use in Planning Movements

“…Area 7a is another largely visual area that has strong cortical connections with other visual areas; it also has connections with areas of the cortex associated with the highest cognitive functions, including the parahippocampal gyrus and cingulate cortex (see Lynch 1980, Goldman-Rakic 1988, Andersen et al 1990a for review). Although adjacent to LIP, area 7a does not appear to play a direct role in saccades (Barash et al 1991a), and unlike LIP, which has relatively smaller and contralateral visual receptive fields (Blatt et al 1990), area 7a has large, bilateral fields (Motter & Mountcastle 1981).…”