Wilbrecht Lab

Research

Developmental and experience-dependent changes in learning and decision making

The frontal regions of the neocortex show protracted development in mammals. While dendritic spines are pruned in the frontal neocortex in adolescence there is also late growth of new local and long range connections. We are interested in understanding the function of these changes and their impact on learning and decision making.

Current projects in the lab are focused on these questions:

How does experience in development alter the way the adult brain learns and makes decisions? Does experience with adversity in maternal care or food insecurity alter brain function? How does early learning experience with different statistics alter later circuit function? How does early life adversity enhance risk of substance use issues?

How does pubertal onset alter circuit function, learning and decision making?

How do cortico-basal ganglia circuits support learning and flexible decision making? How do genes x experience sculpt the computations made by these circuits.

How do different learning systems mature? How are these learning systems integrated through development? (with Anne Collins lab)

What changes in the brain support dispersal from the natal nest in rodents? Do we see any similar changes in humans and how does this inform our understanding of adolescent development?

We are also collaborating with the Markita Landry lab to develop new optical tools for neuroscience.

Approaches

In Vivo Imaging

We use in vivo imaging methods to examine the function of specific cell types during behavior. We are particularly interested in the neurons that regulate learning and flexible updating of behavior in the neocortex and basal ganglia.

Electrophysiology

We use electrophysiology to investigate the changes in neurotransmission at different developmental stages and in rodents with different experience. We also use new optical tools to measure neuromodulator release in brain slice preparations.

Behavior

We use behavioral tests to investigate learning and decision making at different stages of development and in animals with different experiences. We are particularly interested in cognitive flexibility.

Recent Publications & Preprints

Hidden state inference requires abstract contextual representations in ventral hippocampus

The ability to form and utilize subjective, latent contextual representations to influence decision making is a crucial determinant of everyday life. The hippocampus is widely hypothesized to bind together otherwise abstract combinations of stimuli to represent such latent contexts, and to allow their use to support the process of hidden state inference. Yet, direct evidence for this remains limited. Here we show that the CA1 area of the ventral hippocampus is necessary for mice to perform hidden state inference during a 2-armed bandit task. vCA1 neurons robustly differentiate between the two abstract contexts required for this strategy in a manner similar to the differentiation of spatial locations, despite the contexts being formed only from past probabilistic outcomes. These findings offer [...]

Adolescent and adult mice use both incremental reinforcement learning and short term memory when learning concurrent stimulus-action associations

Computational modeling has revealed that human research participants use both rapid working memory (WM) and incremental reinforcement learning (RL) (RL+WM) to solve a simple instrumental learning task, relying on WM when the number of stimuli is small and supplementing with RL when the number of stimuli exceeds WM capacity. Inspired by this work, we examined which learning systems and strategies are used by adolescent and adult mice when they first acquire a conditional associative learning task. In a version of the human RL+WM task translated for rodents, mice were required to associate odor stimuli (from a set of 2 or 4 odors) with a left or right port to receive reward. Using logistic regression and computational models to analyze the [...]

Goal-directed learning in adolescence: neurocognitive development and contextual influences

Adolescence is a time during which we transition to independence, explore new activities and begin pursuit of major life goals. Goal-directed learning, in which we learn to perform actions that enable us to obtain desired outcomes, is central to many of these processes. Currently, our understanding of goal-directed learning in adolescence is itself in a state of transition, with the scientific community grappling with inconsistent results. When we examine metrics of goal-directed learning through the second decade of life, we find that many studies agree there are steady gains in performance in the teenage years, but others report that adolescent goal-directed learning is already adult-like, and some find adolescents can outperform adults. To explain the current variability in results, sophisticated [...]

The interpretation of computational model parameters depends on the context

Reinforcement Learning (RL) models have revolutionized the cognitive and brain sciences, promising to explain behavior from simple conditioning to complex problem solving, to shed light on developmental and individual differences, and to anchor cognitive processes in specific brain mechanisms. However, the RL literature increasingly reveals contradictory results, which might cast doubt on these claims. We hypothesized that many contradictions arise from two commonly-held assumptions about computational model parameters that are actually often invalid: That parameters generalize between contexts (e.g. tasks, models) and that they capture interpretable (i.e. unique, distinctive) neurocognitive processes. To test this, we asked 291 participants aged 8–30 years to complete three learning tasks in one experimental session, and fitted RL models to each. We found that some [...]