Integrated Ising model with global inhibition for decision-making.

Humans and other organisms make decisions choosing between different options, with the aim of maximizing the reward and minimizing the cost. The main theoretical framework for modeling the decision-making process has been based on the highly successful drift-diffusion model, which is a simple tool for explaining many aspects of this process. However, recent observations challenge this model.

Rate and noise in human amygdala drive increased exploration in aversive learning.

To cope in uncertain environments, animals must balance their actions between using current resources and searching for new ones. This exploration-exploitation dilemma has been studied extensively in paradigms involving positive outcomes, and neural correlates have been identified in frontal cortices and subcortical structures, including the amygdala. Importantly, exploration is just as essential for survival or well-being when trying to avoid negative outcomes, yet we do not know whether the single-neuron mechanisms that drive exploration are shared across positive and negative environments.

Aversive generalization in human amygdala neurons.

Generalization around aversive stimuli is a key feature of learning and adaptive decision making, but it can be maladaptive if subjects overgeneralize and respond with fear to stimuli that are only loosely similar to the original experience. Human imaging studies indicate that the amygdala, a hub of emotional learning, is involved in such overgeneralization, and studies in animal models revealed neural correlates of generalized aversive stimuli and identified changes in response properties of single neurons. Yet, it remains unclear if human neurons contribute specifically in aversive situations and, importantly, if they contribute to subsequent behavior even in a safe environment.

Integrated Ising Model with global inhibition for decision making.

Humans and other organisms make decisions choosing between different options, with the aim to maximize the reward and minimize the cost. The main theoretical framework for modeling the decision-making process has been based on the highly successful drift-diffusion model, which is a simple tool for explaining many aspects of this process. However, new observations challenge this model.

Neurons in the Nonhuman Primate Amygdala and Dorsal Anterior Cingulate Cortex Signal Aversive Memory Formation under Sedation.

Background: Anesthetics aim to prevent memory of unpleasant experiences. The amygdala and dorsal anterior cingulate cortex participate in forging emotional and valence-driven memory formation. It was hypothesized that this circuitry maintains its role under sedation.

Affective memory rehearsal with temporal sequences in amygdala neurons.

Affective learning and memory are essential for daily behavior, with both adaptive and maladaptive learning depending on stimulus-evoked activity in the amygdala circuitry. Behavioral studies further suggest that post-association offline processing contributes to memory formation. Here we investigated spike sequences across simultaneously recorded neurons while monkeys learned to discriminate between aversive and pleasant tone-odor associations.

Re-exploring Mechanisms of Exploration.

Deciding when to exploit what is already known and when to explore new possibilities is crucial for adapting to novel and dynamic environments. Using reinforcement-based decision making, Costa et al. (2019) in this issue of Neuron find that neurons in the amygdala and ventral-striatum differentially signal the benefit from exploring new options and exploiting familiar ones.