The role of the infralimbic cortex in decision making processes

Infralimbic cortex plays a similar role in the punishment and extinction of instrumental behavior

Learning to stop responding is a fundamental process in instrumental learning. Animals may learn to stop responding under a variety of conditions that include punishment-where the response earns an aversive stimulus in addition to a reinforcer-and extinction-where a reinforced response now earns nothing at all. Recent research suggests that punishment and extinction may be related manifestations of a common retroactive interference process. In both paradigms, animals learn to stop performing a specific response in a specific context, suggesting direct inhibition of the response by the context. This process may depend on the infralimbic cortex (IL), which has been implicated in a variety of interference-based learning paradigms including extinction and habit learning. Despite the behavioral parallels between extinction and punishment, a corresponding role for IL in punishment has not been identified. Here we report that, in a simple arrangement where either punishment or extinction was conducted in a context that differed from the context in which the behavior was first acquired, IL inactivation reduced response suppression in the inhibitory context, but not responding when it "renewed" in the original context. In a more complex arrangement in which two responses were first trained in different contexts and then extinguished or punished in the opposite one, IL inactivation had no effect. The results advance our understanding of the effects of IL in retroactive interference and the behavioral mechanisms that can produce suppression of a response.

The interaction of membrane estradiol receptors and metabotropic glutamate receptors in adaptive and maladaptive estradiol-mediated motivated behaviors in females

Estrogen receptors were initially identified as intracellular, ligand-regulated transcription factors that result in genomic change upon ligand binding. However, rapid estrogen receptor signaling initiated outside of the nucleus was also known to occur via mechanisms that were less clear. Recent studies indicate that these traditional receptors, estrogen receptor α and estrogen receptor β, can also be trafficked to act at the surface membrane. Signaling cascades from these membrane-bound estrogen receptors (mERs) can rapidly alter cellular excitability and gene expression, particularly through the phosphorylation of CREB. A principal mechanism of neuronal mER action has been shown to occur through glutamate-independent transactivation of metabotropic glutamate receptors (mGlu), which elicits multiple signaling outcomes. The interaction of mERs with mGlu has been shown to be important in many diverse functions in females, including driving motivated behaviors. Experimental evidence suggests that a large part of estradiol-induced neuroplasticity and motivated behaviors, both adaptive and maladaptive, occurs through estradiol-dependent mER activation of mGlu. Herein we will review signaling through estrogen receptors, both "classical" nuclear receptors and membrane-bound receptors, as well as estradiol signaling through mGlu. We will focus on how the interactions of these receptors and their downstream signaling cascades are involved in driving motivated behaviors in females, discussing a representative adaptive motivated behavior (reproduction) and maladaptive motivated behavior (addiction).

The Neural Mechanism of Long-Term Motor Training Affecting Athletes’ Decision-Making Function: An Activation Likelihood Estimation Meta-Analysis

Decision-making is an advanced cognitive function that promotes information processes in complex motor situations. In recent years, many neuroimaging studies have assessed the effects of long-term motor training on athletes’ brain activity while performing decision-making tasks, but the findings have been inconsistent and a large amount of data has not been quantitatively summarized until now. Therefore, this study aimed to identify the neural mechanism of long-term motor training affecting the decision-making function of athletes by using activation likelihood estimation (ALE) meta-analysis. Altogether, 10 studies were included and comprised a total of 350 people (168 motor experts and 182 novices, 411 activation foci). The ALE meta-analysis showed that more brain regions were activated for novices including the bilateral occipital lobe, left posterior cerebellar lobe, and left middle temporal gyrus (MTG) in decision-making tasks compared to motor experts. Our results possibly suggested the association between long-term motor training and neural efficiency in athletes, which provided a reference for further understanding the neural mechanisms of motor decision-making.

Detailed mapping of behavior reveals the formation of prelimbic neural ensembles across operant learning

The prelimbic cortex (PrL) is involved in the organization of operant behaviors, but the relationship between longitudinal PrL neural activity and operant learning and performance is unknown. Here, we developed deep behavior mapping (DBM) to identify behavioral microstates in video recordings. We combined DBM with longitudinal calcium imaging to quantify behavioral tuning in PrL neurons as mice learned an operant task. We found that a subset of PrL neurons were strongly tuned to highly specific behavioral microstates, both task and non-task related. Overlapping neural ensembles were tiled across consecutive microstates in the response-reinforcer sequence, forming a continuous map. As mice learned the operant task, weakly tuned neurons were recruited into new ensembles, with a bias toward behaviors similar to their initial tuning. In summary, our data suggest that the PrL contains neural ensembles that jointly encode a map of behavioral states that is fine grained, is continuous, and grows during operant learning.