The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the dorsal stream of the visual system. This enables regions of the parietal cortex to map objects perceived visually into body coordinate positions.
Immediately posterior to the central sulcus, and the most anterior part of the parietal lobe, is the postcentral gyrus (Brodmann area 3), the primary somatosensory cortical area. Dividing this and the posterior parietal cortex is the postcentral sulcus.
The posterior parietal cortex can be subdivided into the superior parietal lobule (Brodmann areas 5 + 7) and the inferior parietal lobule (39 + 40), separated by the intraparietal sulcus (IP). The intraparietal sulcus and adjacent gyri are essential in guidance of limb and eye movement, and based on cytoarchitectural and functional differences is further divided into medial (MIP), lateral (LIP), ventral (VIP), and anterior (AIP) areas.
Various studies in the 1990s found that different regions of the posterior parietal cortex in Macaques represent different parts of space.
More recent fMRI studies have shown that humans have similar functional regions in and around the intraparietal sulcus and parietal-occipital junction. The human 'parietal eye fields' and 'parietal reach region', equivalent to LIP and MIP in the monkey, also appear to be organized in gaze-centered coordinates so that their goal-related activity is 'remapped' when the eyes move.
Gerstmann's syndrome is associated with lesion to the dominant (usually left) parietal lobe. Balint's syndrome is associated with bilateral lesions. The syndrome of hemispatial neglect is usually associated with large deficits of attention of the non-dominant hemisphere. Optic ataxia is associated with difficulties reaching toward objects in the visual field opposite to the side of the parietal damage. Some aspects of optic ataxia have been explained in terms of the functional organization described above.
Conversion sensory symptoms associated with parietal lobe infarct: Case report, diagnostic issues and brain mechanisms
Mar 01, 2002; This case report suggests that diagnostic difficulties and brain mechanisms related to conversion disorder associated with...