The laterodorsal tegmentum is essential for burst firing of ventral tegmental area dopamine neurons
- Departments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, PA 15260
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Edited by Richard D. Palmiter, University of Washington School of Medicine, Seattle, WA, and approved February 8, 2006 (received for review December 12, 2005)
Abstract
In response to behaviorally salient stimuli, dopamine (DA) neurons fire in bursts. Burst firing induces a large transient increase in synaptic DA and is regarded as the functionally relevant mode of transmission that signals reward and modulates goal-directed behavior. DA neuron burst firing is dynamically regulated by afferent inputs, and it is not present in vitro because of severing of afferent processes. However, what afferents are requisite for burst firing in vivo is not known. Here, we show that tonic input from the laterodorsal tegmental nucleus (LDTg) is required for glutamate-elicited burst firing in ventral tegmental area DA neurons of anesthetized rats. Also, after LDTg inactivation, DA neurons fire as they do in vitro (i.e., as pacemakers); even direct glutamate application fails to cause them to burst fire under these conditions. These data show that the LDTg is critical to normal DA function, and thus, pathology within this region may lead to aberrant DA signaling.
Footnotes
- *To whom correspondence should be addressed. E-mail: lodge{at}bns.pitt.edu
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Author contributions: D.J.L. and A.A.G. designed research; D.J.L. performed research; D.J.L. and A.A.G. analyzed data; and D.J.L. and A.A.G. wrote the paper.
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Conflict of interest statement: No conflicts declared.
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This paper was submitted directly (Track II) to the PNAS office.
- Abbreviations:
- DA,
- dopamine;
- ISI,
- interspike interval;
- LDTg,
- laterodorsal tegmental nucleus;
- PPTg,
- pedunculopontine tegmental nucleus;
- VTA,
- ventral tegmental area;
- A/P,
- anterior/posterior;
- PFC,
- prefrontal cortex.
- © 2006 by The National Academy of Sciences of the USA
