Perturbation of amygdala-cortical projections reduces ensemble coherence of palatability coding in gustatory cortex.

Jian-You Lin,Donald B Katz,Max J Bernstein,Narendra Mukherjee

doi:10.7554/elife.65766

Abstract

Taste palatability is centrally involved in consumption decisions-we ingest foods that taste good and reject those that don't. Gustatory cortex (GC) and basolateral amygdala (BLA) almost certainly work together to mediate palatability-driven behavior, but the precise nature of their interplay during taste decision-making is still unknown. To probe this issue, we discretely perturbed (with optogenetics) activity in rats' BLA→GC axons during taste deliveries. This perturbation strongly altered GC taste responses, but while the perturbation itself was tonic (2.5 s), the alterations were not-changes preferentially aligned with the onset times of previously-described taste response epochs, and reduced evidence of palatability-related activity in the 'late-epoch' of the responses without reducing the amount of taste identity information available in the 'middle epoch.' Finally, BLA→GC perturbations changed behavior-linked taste response dynamics themselves, distinctively diminishing the abruptness of ensemble transitions into the late epoch. These results suggest that BLA 'organizes' behavior-related GC taste dynamics.

Highlights

A significant part of our daily lives is spent on acquiring and consuming food and drink
Our results demonstrate that this perturbation impacts gustatory cortical (GC) taste responses in an ‘epoch-wise’ manner, in that: (1) the likelihood of firing-rate changes peaks at epoch onset times, despite the perturbation itself being tonic; (2) the perturbation reduces Palatability Epoch content, without reducing Identity Epoch information; and (3) the loss of basolateral amygdala (BLA) input ‘blurs’ the onset of the Palatability Epoch by reducing the suddenness of the firing-rate transition in all neurons in the ensembles
Note the cell body staining in BLA, and the utter lack of cell body staining in GC, where expression is restricted to axon filaments

Summary

Introduction

A significant part of our daily lives is spent on acquiring and consuming food and drink. Our results demonstrate that this perturbation impacts GC taste responses in an ‘epoch-wise’ manner, in that: (1) the likelihood of firing-rate changes peaks at epoch onset times, despite the perturbation itself being tonic; (2) the perturbation reduces Palatability Epoch content, without reducing Identity Epoch information; and (3) the loss of BLA input ‘blurs’ the onset of the Palatability Epoch by reducing the suddenness of the firing-rate transition in all neurons in the ensembles These data suggest BLA to be more involved in the organization of emergent network dynamics than in the delivery of palatability information to GC per se

Results

Discussion

Materials and methods