The two specific goals of this project are to understand how amygdala contributes to taste processing in gustatory cortex, and to understand how inactivation of amygdala affects taste responses during learning. Work towards both of these goals will advance our current understanding of basic taste processing. To accomplish the first goal, taste-responsive neurons in primary taste cortex (GC) will be recorded while basal lateral nucleus (BLA;another brain region known to be involved in the perception of tastes) is temporarily inactivated using muscimol in awake rats receiving a range of taste solutions that vary in palatability. The responses of ensembles of neurons to each taste will be compared in order to evaluate the effect of BLA on taste information and to test current theories of how these regions may interact during taste processing. To accomplish the second goal, this taste-evoked activity in 'normal'rats from the first goal will be compared to that in rats who have undergone taste learning known as conditioned taste aversion (CTA). Since learning reliably increases BLA influence on GC, when BLA in inactivated as before, CTA induced changes normally seen with learning should predictably be inhibited. The results of these experiments will shed light on how much the GC taste response is influenced by input from BLA during taste learning.
This project adds to our understanding of how interconnected brain regions imbue sensory responses with emotional relevance based on personal learning experiences. This basic knowledge is of general interest as cancer patients undergoing chemotherapy often form unwanted aversions to comforting foods and environments following treatment. Further, the National Comorbidity Survey has estimated that the lifetime prevalence of post-traumatic stress disorder-a severe anxiety disorder that can develop after exposure to any traumatic event- among adult Americans is 7.8% and rising.
|Piette, Caitlin E; Baez-Santiago, Madelyn A; Reid, Emily E et al. (2012) Inactivation of basolateral amygdala specifically eliminates palatability-related information in cortical sensory responses. J Neurosci 32:9981-91|