CHEMOARCHITECTONICS OF AXONAL AND PERIKARYAL ACETYLCHOLINESTERASE ALONG INFORMATION-PROCESSING SYSTEMS OF THE HUMAN CEREBRAL-CORTEX

The distribution of axonal and perikaryal acetylcholinesterase (AChE) was studied in whole-brain sections. All cytoarchitectonic sectors and cortical layers of the human cerebral cortex contained AChE-rich axon s. These axons displayed multiple varicosities which appeared to come in contact with AChE-rich and AChE-poor cortical perikarya. The upper layers of cortex tended to contain the highest density of AChE-rich ax ons. The AChE-rich axons were more dense in limbic-paralimbic areas of cortex than in primary sensory-motor and association areas. Within un imodal sensory association areas, the parasensory (upstream) sectors h ad a slightly lesser density of AChE-rich axons than the downstream se ctors. Within paralimbic areas, the nonisocortical sectors displayed a distinctly higher density of AChE-rich axons than the more differenti ated isocortical sectors. These observations indicate that the distrib ution of AChE-rich axons displays orderly variations that obey the org anization of information processing systems in the cerebral cortex.