# Encoding of odor information and reward anticipation in anterior cortical amygdaloid nucleus

## TL;DR

This study explores how the anterior cortical amygdaloid nucleus processes odor information and reward anticipation during a task involving water reward.

## Contribution

The paper identifies two types of neurons in the ACo with distinct reward anticipation patterns and their role in behavioral learning.

## Key findings

- ACo neurons show go cue-preferred activity during late-phase nose-poking.
- Two types of ACo neurons exhibit either gradual or phasic reward anticipation.
- Phasic-type neurons also respond to go cues, linking odor information with reward anticipation.

## Abstract

Olfactory information directly reaches the amygdala through the olfactory cortex, without the involvement of thalamic areas, unlike other sensory systems. The anterior cortical amygdaloid nucleus (ACo) is one of the olfactory cortices that receives olfactory sensory input and is part of the olfactory cortical amygdala, which relays olfactory information to the amygdala. To examine its electrophysiological features, we recorded individual ACo neurons during the odor-guided go/no-go task to obtain a water reward. Many ACo neurons exhibited odor-evoked go cue-preferred activity during the late phase of nose-poking supporting the population dynamics that differentiate go/no-go responses before executing the odor-evoked behaviors. We observed two types of neurons with different anticipation signals: one neuron type exhibited gradual increases of activity toward reward delivery, while another type exhibited a phasic go cue-preferred activity during nose-poking as well as another phasic anticipatory activity for rewards. These results suggest that the ACo may be involved in reward-related behavioral learning by associating the olfactory information with reward anticipation.

•Late-phase nose-poking activity reveals go cue-preferred responses in ACo neurons•Population dynamics in the ACo distinguish go versus no-go actions before behavior•ACo neurons comprise two types that show gradual or phasic reward anticipation•Phasic-type ACo neurons that anticipate rewards also respond to go cues

Late-phase nose-poking activity reveals go cue-preferred responses in ACo neurons

Population dynamics in the ACo distinguish go versus no-go actions before behavior

ACo neurons comprise two types that show gradual or phasic reward anticipation

Phasic-type ACo neurons that anticipate rewards also respond to go cues

Behavioral neuroscience; sensory neuroscience