Disconnection of basolateral amygdala and insular cortex disrupts conditioned approach in Pavlovian lever autoshaping

Abstract

Previously established individual differences in appetitive approach and devaluation sensitivity observed in goal- and sign-trackers may be attributed to differences in the acquisition, modification, or use of associative information in basolateral amygdala (BLA) pathways. Here, we sought to determine the extent to which communication of associative information between BLA and anterior portions of insular cortex (IC) supports ongoing Pavlovian conditioned approach behaviors in sign- and goal-tracking rats, in the absence of manipulations to outcome value. We hypothesized that the BLA mediates goal-, but not sign- tracking approach through interactions with the IC, a brain region involved in supporting flexible behavior. We first trained rats in Pavlovian lever autoshaping to determine their sign- or goal-tracking tendency. During alternating test sessions, we gave unilateral intracranial injections of vehicle or a cocktail of gamma-aminobutyric acid (GABA) receptor agonists, baclofen and muscimol, unilaterally into the BLA and contralaterally or ipsilaterally into the IC prior to reinforced lever autoshaping sessions. Consistent with our hypothesis we found that contralateral inactivation of BLA and IC increased the latency to approach the food cup and decreased the number of food cup contacts in goal-trackers. While contralateral inactivation of BLA and IC did not affect the total number of lever contacts in sign-trackers, this manipulation increased the latency to approach the lever. Ipsilateral inactivation of BLA and IC did not impact approach behaviors in Pavlovian lever autoshaping. These findings, contrary to our hypothesis, suggest that communication between BLA and IC maintains a representation of initially learned appetitive associations that commonly support the initiation of Pavlovian conditioned approach behavior regardless of whether it is directed at the cue or the location of reward delivery.

Overt Attention toward Appetitive Cues Enhances Their Subjective Value, Independent of Orbitofrontal Cortex Activity

“…By this logic, we predict that neurons in vmPFC should exhibit stronger correlations with conditioned licking than neurons in OFC. Apart from the VS and vmPFC (which are specifically implicated in oromotor responses), other potential regions of interest include the amygdala and insular cortex, owing to their involvement in other forms of conditioned appetitive behavior, such as autoshaping (Cardinal et al, 2002; Nasser et al, 2018), and the anterior cingulate cortex, owing to its role in motivation more generally (Cohen et al, 1999; Darby et al, 2018).…”

Basolateral amygdala to insular cortex activity makes sign-tracking behavior insensitive to outcome value

“…Previously, we observed that BLA-aIC communication is necessary for full expression of sign- and goal-tracking behaviors (Nasser et al, 2018). Contralateral disconnection of the BLA and aIC with baclofen/muscimol decreased food cup approach (in GT rats) and increased the latency to contact both the food cup (in GT rats) and lever (in ST rats), seemingly disrupting both goal- and sign-tracking behaviors.…”

“…Unlike our prior study, disrupting communication between BLA and aIC did not disrupt sign- and goal-tracking. Our prior BLA-aIC inactivation study (Nasser et al, 2018) disrupted bidirectional communication between the BLA and aIC during a reinforced lever autoshaping test. In contrast, the current test was under extinction conditions and inhibited direct communication from BLA to aIC, while leaving communication from the aIC to BLA intact.…”

Instrumental and Pavlovian Mechanisms in Alcohol Use Disorder

“…Preclinical work suggests largely overlapping neural circuits are involved in Pavlovian learning processes, including OFC [132], dorsolateral PFC [97], nucleus accumbens (NAcc) [133], subthalamic nucleus [134], amygdala [135][136][137][138][139][140], hippocampus [139], and insula [138], which are widely preserved across species [141,142]. Recent work has shown the relevance of adrenergic, cannabinoid receptor, and NMDA signaling for Pavlovian conditioning [99,[143][144][145][146].…”