Motivated behaviors are mediated by a neuronal circuit that includes the amygdala, prefrontal cortex and nucleus accumbens. The amygdala signals the affective significance of cues in the environment, and the prefrontal cortex and accumbens contribute to planning and selecting actions. Thus, the physiological interactions within this circuit may be neural correlates for the interface between motivation and voluntary movement. Using in vivo electrophysiological recordings, we measured the effects of amygdala activation on excitatory transmission in the prefrontal cortex-to-nucleus accumbens pathway. In the prefrontal cortex, a subset of neurons that projected to the accumbens was excited by amygdala stimulation. Prefrontal-to-accumbens projecting neurons were also excited by Pavlovian conditioned odors, suggesting a role for this pathway in the expression of conditioned fear. In neurons of the accumbens, amygdala input facilitated and shifted the latency of spikes elicited by prefrontal cortex stimulation. Facilitation was greatest when amygdala and prefrontal cortex were stimulated nearly synchronously at subthreshold intensities, suggesting that accumbens neurons integrate both the timing and strength of their afferent inputs. In additional accumbens recordings, high intensity amygdala activation induced an activity-dependent depression of prefrontally elicited spiking; thus, the amygdala is able to modulate prefrontal-to-accumbens transmission by several mechanisms. Taken together, these findings show that the amygdala can influence neuronal transmission at two critical motor-related sites in the brain. In this way, affective information may constrain and gate action, resulting in optimal behavioral responses to salient motivational stimuli.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-06162008-184056 |
| Date | 30 October 2008 |
| Creators | McGinty, Vincent Benjamin |
| Contributors | Susan R. Sesack, Ph.D., Bita Moghaddam, Ph.D., Anthony A. Grace, Ph.D., Peter L. Strick, Ph.D., Germán Barrionuevo, M.D., Joel P. Gallagher, Ph.D. |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-06162008-184056/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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