Date of Award


Degree Name

Doctor of Philosophy


Biological Sciences


Arshad M. Khan


Rodent models are invaluable for understanding the foundations of motivatedbehaviors. One major obstacle faced by these efforts is the lack of a 'wiring diagram' or a 'parts list' of structures that support motivated behaviors. Here, I present work that advances our knowledge of the structural organization of connections and chemoarchitecture of the diencephalon. Chapter 1 aims to clarify a wiring diagram of the medial prefrontal cortex (mPFC) following a recent demonstration of cortically-evoked feeding through this region. Chapter 2 clarifies the distributions of a subpopulation of tyrosine hydroxylase (TH) neurons in the hypothalamus. These disparate datasets were analyzed and interpreted using a Nissl-based mapping approach and nomenclature system that facilitates construction of a spatial model for motivated behaviors. Using this methodology, I describe widespread and topographically organized reciprocal connectivity between mPFC and thalamus as well as subregion-specific connectivity with the hypothalamus. I also demonstrate heterogeneity among hypothalamic TH neurons on the basis of their co-expression of the vesicular GABA transporter. Taken together, this work describes a general principle of mPFC connections with thalamus that has been overlooked, and it contributes important insights toward a comprehensive wiring diagram and parts list for feeding and other motivated behaviors.




Recieved from ProQuest

File Size


File Format


Rights Holder

Kenichiro Negishi