Parietal lobes

Compared to the Category Test, SSP and SRT results show a relatively mixed performance profile. This profile is indicative of temporal lobe impairment and may explain the idiosyncratic character of PCP-induced brain dysfunction. Other HRB subtest data suggest that parietal lobe-mediated functions are less influenced by PCP abuse, since approximately 30 percent of this sample had error-free performances on a test sensitive to finger agnosia. 

Named for the bones of the cranium under which they lie, the lobes are conspicuously defined by prominent sulci of the cortex, which have a relatively constant position in human brains. Each lobe is specialized for different activities (see Figure 6.3). Located in the anterior portions of the hemispheres, the frontal lobes are responsible for voluntary motor activity, speaking ability, and higher intellectual activities. The parietal lobes, which are posterior to the frontal lobes, process and integrate sensory information. The occipital lobes, located in the posterior-most aspects of the cerebrum, process visual information, and the temporal lobes, located laterally, process auditory information. 

The sensory receptors and spinal tracts that convey these sensations are multiple, and the sensations often reach consciousness, in the parietal lobe, as blends of the primary components. Because of the number of receptors and hence of distinct tactile feelings and blends, they are best lumped together. 

Durazzo et al. (2006) 14 11 NA NR NR Over 1 month of abstinence from alcohol, recovering alcoholics showed significant increases of NAA and Cho in frontal and parietal lobes. These increases appeared to be driven by data from nonsmokers. 

Mehta, M.A., Owen, A.M., Sahaklan, B.J., Mavaddat, N., Pickard, J.D., and Robbins, T.W. (2000) Methylphenldate enhances working memory by modulating discrete frontal and parietal lobe regions in the human brain. / Neurosci 20 RC651-RC656. 

The medial and caudal portions of the midbody of the CC contain interhemispheric projections from the auditory cortices, posterior cingulate, retrosplenial cortex, and insula, and somatosensory and visual cortices to a lesser extent. It also includes connections from the inferior parietal lobe to the contralateral superior temporal sulcus, cingulate, and parahippocampal gyrus (Pandya and Seltzer, 1986). Several of the regions with interhemispheric projections through the medial and caudal portions of the midbody of the CC are involved in the processing of emotional stimuli and various memory functions—core disturbances frequently observed in children with a history of early trauma. 

Kowatch et al., 1999 7 MDD 7 NC 13-18 Tc HMPAO hrain SPECT MDD > NC rCBF temporal lobe subregions MDD < NC rCBF anterior thalamus, left parietal lobe, right caudate... 

The parietal lobes are responsible for integrating the sensory input from touch, taste, smell, etc. The complex organization of this section of the brain allows us to recognize patterns in our experience, maintain physical orientation and stability, and perform more intricate intellectual tasks such as math and chemistry. 

A. This is not known for sure but from the subjective and behavioral effects it can be surmised that salvinorin is almost certainly affecting the limbic system, and may be affecting somatosensory (parietal lobe), cerebellar and vestibular function as well. 

In inferior MCA trunk occlusion infarctions of the lateral surface of the temporal lobe and the inferior parietal lobe may occur (Olsen 1991 Ringelstein et al. 1992). Motor or sensory deficits may not be severe, but visual field deficit and sensory aphasia in left sided infarctions and constructional apraxia in right sided lesions occur (Geschwind 1975 Spinazzola et al. 2003). Right temporal lesions cause agitation and confusion resembling an organic psychosis (Ferro 2001). 

The watershed areas (see Chap. 15) are particularly sensitive to ischemia in cardiac arrest, especially in the parietal lobe area in the borderzone between anterior, posterior and middle cerebral artery territories. 

---