The Japanese journal of neuropsychology

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ArticleTitle	The function of medial parieto-occipital cortex and three cases report of its lesion
Language	J
AuthorList	Michitaka Funayama
Affiliation	Department of Neuropsychiatry, Ashikaga Red Cross Hospital
Publication	Japanese Journal of Neuropsychology: 26 (1), 65-76, 2010
Received
Accepted
Abstract	The medial parieto-occipital cortex has traditionally received little study, except for retrosplenial cortex. However, the modern era of neuroimaging has recently made it possible to explore the functional aspects of the medial parietal cortex, precuneus and posterior cingulate cortex. The precuneus is involved in a wide spectrum of highly integrated tasks, including visuo-spatial imagery, episodic memory retrieval and self-processing operations. The posterior cingulate cortex subserves evaluative functions such as monitoring sensory events and the organism's own behavior in the service of spatial orientation and memory. Imaging studies have also shown that hypometabolism in early-stage Alzheimer's disease is localized to the precuneus and posterior cingulate cortex and disorientation in Alzheimer's disease is correlated with the glucose hypometalobism in the posterior cingulate cortex. We report three patients with lesions involving the medial parietal cortex, who exhibited sudden disorientation characterized with an intriguing complain, "What am I doing right now?" while attending a goal-oriented task. The mechanism of this sudden disorientation was discussed in the light of the default-mode network, recently disclosed brain system.
Keywords	medial parietal lobe, precuneus, posterior cingulate cortex, disorientation, default mode network