Amygdala ensembles encode behavioral states

Abstract

Internal states, including affective or homeostatic states, are important behavioral motivators. The amygdala regulates motivated behaviors, yet how distinct states are represented in amygdala circuits is unknown. By longitudinally imaging neural calcium dynamics in freely moving mice across different environments, we identified opponent changes in activity levels of two major, nonoverlapping populations of basal amygdala principal neurons. This population signature does not report global anxiety but predicts switches between exploratory and nonexploratory, defensive states. Moreover, the amygdala separately processes external stimuli and internal states and broadcasts state information via several output pathways to larger brain networks. Our findings extend the concept of thalamocortical “brain-state” coding to include affective and exploratory states and provide an entry point into the state dependency of brain function and behavior in defined circuits.

Altered theta / beta frequency synchrony links abnormal anxiety-related behavior to synaptic inhibition in Neuroligin-2 knockout mice

“…No significant changes were observed in the BLA, although there was a trend for an increase in beta power, and in the mPFC, LFP power was reduced in the gamma frequency band. However, despite the fact that all of these brain regions have been prominently implicated in anxiety processing (1,4,5,(19)(20)(21)(22)(23)(24)(25)(26)(27)40), only weak correlations were observed with time spent in the center of the OF as a measure of anxiety behavior ( Figure S3). Instead, OF center time correlated most strongly with the synchrony between brain regions, and particularly with the ratio of theta/beta frequency synchrony, resulting from a reduction in theta frequency synchrony and a marked increase in synchrony in the beta frequency range.…”

“…To address this question, we performed simultaneous local field potential (LFP) recordings in multiple brain regions in wildtype (WT) and Nlgn2 KO mice under anxiogenic conditions in an open field (OF) paradigm. Specifically, we focused on five brain regions known to be essential for anxiety processing and the context-dependent regulation of anxietyrelated behaviors, including the basolateral amygdala (BLA), centromedial amygdala (CeM), ventral hippocampus (vHPC), medial prefrontal cortex (mPFC) and bed nucleus of stria terminalis (BNST) (4,(19)(20)(21)(22)(23)(24)(25)(26)(27). Our data indicate that disruptions in synaptic inhibition due to loss of Nlgn2 result in a fundamental change in the mechanisms by which anxiety-related behaviors are encoded in the anxiety network.…”

Independent representations of reward-predicting cues and reward history in frontal cortical neurons

“…First, licking information was simultaneously represented with the reward-predicting cue or the past and/or current reward information in 22-62% of the neurons in the four frontal cortical areas. This mixed representation of behavior-related and taskrelated information was also detected in the visual cortex, amygdala, and dopamine neurons in the ventral tegmental area(Engelhard et al, 2019;Gründemann et al, 2019;Stringer et al, 2019). It may be a general principle that ongoing movements affect the neuronal activity in a proportion of individual neurons during sensory processing.…”

Model-based decoupling of evoked and spontaneous neural activity in calcium imaging data

“…Even a primary sensory area like the optic tectum or visual cortex receives converging inputs from other brain regions that can make it highly active in the absence of sensory inputs [26,33,34]. Recently, several studies reported brain-wide activity correlated with behaviour [2,5,35]. For example, Stringer et al analysed calcium imaging data from 10, 000 neurons in the mouse primary visual cortex and found that locomotor variables such as pupil diameter and running speed accounted for ∼ 20% of the total variance of the population activity [2].…”