What are the underlying anatomical substrates that might mediate learning in the ventral striatum?

Leaders: Suzanne Haber and Scott Zahm.


ABSTRACT:

The anatomy focus group section includes a summary section containing fundamental information on the ventral parts of the basal ganglia, extended amygdala and magnocellular basal forebrain complex and an exposition of some current areas of interest and/or controversy among neuroanatomists working with these structures. These issues focus on general questions that concern the function of the ventral striatum and related structures and their combined role in plasticity and learning.

Summary of the field. The ventral striatopallidal complex in rat and monkey is covered in sections on its general, connectional and neurochemical organization. There is an extensive review of the intrinsic organization of the ventral striatum. Its boundaries and relationships to the prefrontal cortex, particularly the recently described medial and orbital prefrontocortical networks, are covered in some detail. There is a brief section on the synaptic relationships in the rat of prefrontal cortex with dopamine neurons, and an introductory description of the extended amygdala and magnocellular basal forebrain complex.

Issues for Discussion. These include, but are not intended to be limited to, (1) separation of the dorsal from ventral parts of the basal ganglia; (2) separation of different parts of the ventral basal ganglia from each other and from extended amygdala, (3) the fundamental cellular and connectional organization of basal ganglia, extended amygdala and magnocellular basal forebrain, (4) brainstem relationships of extended amygdala vs. ventral parts of the basal ganglia, (5) the implications of the small-celled interface islands for function in the ventral basal ganglia and extended amygdala, and (6) feed-forward pathways vs. parallel segregated circuits in the basal ganglia. It is hoped that an increased appreciation of macrosystemic neuroanatomical substrates subserving cortico-subcortical interactions devoted to the synthesis and plasticity of neural processing related to motivation will emerge from discussions elicited by these preparatory ruminations.

Members: Martin Cassell, Lennart Heimer, Gloria Meredith, Joseph Price, and Susan Seasack.