Affective disorders, such as bipolar disorder, schizophrenia and PTSD, as well as drug and alcohol addiction, are increasingly being understood as dysfunctions of specific brain circuits. In order to develop new, rational therapeutic approaches to these illnesses, it is necessary to understand the normal function of the disrupted circuits, and how they are altered in a given disorder. Central to this objective is the use of molecular genetic-based tools, in the mouse, to mark, map and manipulate neural circuitry. In this application, we propose to develop new, genetically based, techniques for mapping the connectivity of neurons that are activated by a specific stimulus or during a specific behavior. Specifically, our goal is to fill two lacunae in the current """"""""toolkit"""""""" for genetic mapping of neuronal circuits in mice: a conditional, viral-based method for anterograde trans-neuronal tracing;and a method to stably and efficiently mark neurons that have been transiently activated.
In Specific Aim I, we will develop recombinant variants of the Herpesvirus strain H129, which is transported trans-neuronally in the anterograde direction, using a homologous recombination-based method we have developed. These variants will be dependent on Cre recombinase for expression of a marker and/or replication. We will test these recombinant strains in several lines of Cre-expressing mice, in both the peripheral and central nervous system.
In Specific Aim II, we will develop and test two methods for stable, activity-dependent marking (SADM) of neurons, both of which are based on the expression of Cre recombinase. These methods are based on the combined use of transgenic mice and stereotaxically injected, Cre-dependent recombinant viruses. They allow, in principle, the expression of any marker or effector gene in transiently activated neurons.
In Specific Aim III, we will combine the technologies of Aims I and II, to achieve activity-dependent retrograde and anterograde trans-neuronal tracing of neural circuits. Finally, in Specific Aim IV, we will modify the methods of Aim II, to permit selective stable, activity-dependent marking of GABAergic neurons (SADM-GAD). This will permit the visualization of active inhibitory networks in the brain, and will open the way to marking and manipulating them in an activity-dependent manner. The methods described in this application will make available to the community a new set of tools that should have wide applications in neuronal circuit tracing, in both normal mice and disease models.

Public Health Relevance

The development of new treatments for psychiatric disorders, such as depression, schizophrenia and post-traumatic stress disorder (PTSD), as well as for drug and alcohol addiction, will require a better understanding of the brain circuits whose functions are disrupted in these disorders. The present application is aimed at developing new, molecular genetically based, methods for marking, mapping and manipulating neural circuits in the mouse, the best genetically accessible system for modeling such disorders. These methods should have wide applicability in furthering our understanding of the neural circuit basis of affective disorders and addiction in this important model system, and may identify new cellular targets for the development of novel therapeutics.

National Institute of Health (NIH)
National Institute of Mental Health (NIMH)
Research Project (R01)
Project #
Application #
Study Section
Molecular Neurogenetics Study Section (MNG)
Program Officer
Freund, Michelle
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
California Institute of Technology
Schools of Arts and Sciences
United States
Zip Code
Zelikowsky, Moriel; Hui, May; Karigo, Tomomi et al. (2018) The Neuropeptide Tac2 Controls a Distributed Brain State Induced by Chronic Social Isolation Stress. Cell 173:1265-1279.e19
Remedios, Ryan; Kennedy, Ann; Zelikowsky, Moriel et al. (2017) Social behaviour shapes hypothalamic neural ensemble representations of conspecific sex. Nature 550:388-392
Kunwar, Prabhat S; Zelikowsky, Moriel; Remedios, Ryan et al. (2015) Ventromedial hypothalamic neurons control a defensive emotion state. Elife 4:
Kennedy, Ann; Asahina, Kenta; Hoopfer, Eric et al. (2014) Internal States and Behavioral Decision-Making: Toward an Integration of Emotion and Cognition. Cold Spring Harb Symp Quant Biol 79:199-210
Cai, Haijiang; Haubensak, Wulf; Anthony, Todd E et al. (2014) Central amygdala PKC-?(+) neurons mediate the influence of multiple anorexigenic signals. Nat Neurosci 17:1240-8
Hong, Weizhe; Kim, Dong-Wook; Anderson, David J (2014) Antagonistic control of social versus repetitive self-grooming behaviors by separable amygdala neuronal subsets. Cell 158:1348-1361
Anthony, Todd E; Dee, Nick; Bernard, Amy et al. (2014) Control of stress-induced persistent anxiety by an extra-amygdala septohypothalamic circuit. Cell 156:522-36
Lee, Hyosang; Kim, Dong-Wook; Remedios, Ryan et al. (2014) Scalable control of mounting and attack by Esr1+ neurons in the ventromedial hypothalamus. Nature 509:627-32
Lo, Liching; Anderson, David J (2011) A Cre-dependent, anterograde transsynaptic viral tracer for mapping output pathways of genetically marked neurons. Neuron 72:938-50