The Journal of Neuroscience, February 25, 2009, 29(8):2486-2495; doi:10.1523/JNEUROSCI.3898-08.2009
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Behavioral/Systems/Cognitive
Distinct Subtypes of Basolateral Amygdala Taste Neurons Reflect Palatability and Reward
Alfredo Fontanini,4 *
Stephen E. Grossman,1,3 *
Joshua A. Figueroa,2 and
Donald B. Katz1,2,3
1Volen National Center for Complex Systems, 2Department of Psychology, and 3Program in Neuroscience, Brandeis University, Waltham, Massachusetts 02454, and 4Department of Neurobiology and Behavior, State University of New York at Stony Brook, Stony Brook, New York 11794
Correspondence should be addressed to Donald B. Katz, Volen National Center for Complex Systems, Brandeis University, MS 013, 415 South Street, Waltham, MA 02454. Email: dbkatz{at}brandeis.edu
The amygdala processes multiple, dissociable properties of sensory stimuli. Given its central location within a dense network of reciprocally connected regions, it is reasonable to expect that basolateral amygdala (BLA) neurons should produce a rich repertoire of dynamical responses to taste stimuli. Here, we examined single BLA neuron taste responses in awake rats and report the existence of two distinct subgroups of BLA taste neurons operating simultaneously during perceptual processing. One neuron type produced long, protracted responses with dynamics that were strikingly similar to those previously observed in gustatory cortex. These responses reflect cooperation between amygdala and cortex for the purposes of processing palatability. A second type of BLA taste neuron may be part of the system often described as being responsible for reward learning: these neurons produced very brief, short-latency responses to rewarding stimuli; when the rat participated in procuring the taste by pressing a lever in response to a tone, however, those phasic taste responses vanished, phasic responses to the tone appearing instead. Our data provide strong evidence that the neural handling of taste is actually a distributed set of processes and that BLA is a nexus of these multiple processes. These results offer new insights into how amygdala imbues naturalistic sensory stimuli with value.
Key words: hedonics; sensory processing; single unit; multielectrode; electrophysiology; temporal coding
Received Aug. 15, 2008;
revised Jan. 5, 2009;
accepted Jan. 14, 2009.
Correspondence should be addressed to Donald B. Katz, Volen National Center for Complex Systems, Brandeis University, MS 013, 415 South Street, Waltham, MA 02454. Email: dbkatz{at}brandeis.edu