Immunohistochemical evidence for a possible somatostatin-containing amygdalostriatal pathway in normal and Alzheimer\u27s disease brain

Somatostatin (SOM) immunohistochemistry was used to map SOM-containing fibers, perikarya and terminal-like structures in the human forebrain of 8 control and 8 Alzheimer\u27s diseased patients. Immunohistochemically processed tissue revealed a somatostatin-immunoreactive amygdalostriatal fiber pathway apparently originating from SOM-positive neurons of the central amygdaloid nucleus. This pathway coursed dorsomedially between the optic tract and the internal segment of the globus pallidus within the ansa peduncularis-ventral amygdalofugal fiber system en route to the substantia innominata-nucleus basalis complex, the bed nucleus of the stria terminalis, the medial preoptic hypothalamic area, the nucleus accumbens and the olfactory tubercle. Somatostatin fibers associated with this pathway appeared as coarse heavily stained \u27wooly fibers\u27. At the light microscopic level, there was no apparent difference in this somatostatin containing amygdalostriatal pathway between neurologically normal and Alzheimer\u27s diseased brains. © 1988