Circumscribed changes of the cerebral cortex in neuropsychiatric disorders of later life.

The extent and distribution of biochemical abnormalities thought to reflect disorders of subpopulations of neurons have been determined in the cerebral cortex from brains of patients with Alzheimer-type dementia and depressive illness who died of natural causes. In dementia, loss of gray matter from areas of the parietal and temporal lobes is most obvious. In depression, these areas are not affected, but the pars opercularis and temporal pole are smaller than in controls. Results expressed per unit mass of total protein indicate selective reductions in both disorders of serotonin 2 recognition sites in all areas examined and of somatostatin content in only the temporal pole of the six areas examined. In dementia alone a selective loss was found of somatostatin content of the superior parietal lobule and of serotonin 1A sites and choline acetyltransferase activity in all areas examined. Results for depression expressed per entire area indicate additionally reduced somatostatin content and serotonin 1A sites in the pars opercularis and serotonin 1A sites in the temporal pole. These multiple analyses performed on each sample provide further support for a prominent disorder of pyramidal neurons in dementia as well as more evidence for alterations in cortical neurons in depression, either as a result of the disease itself or its treatment.