context matters
It is crucial to disambiguate the effects of context from knowledge when interpreting cognitive and behavioral performance. In doing so, we may uncover mechanisms to accelerate learning, express latent knowledge, and treat intractable cognitive and neurological disorders.
Neural circuits for learning: unlocking hidden task knowledge during behavior
Learning does not occur in a vacuum: humans and other animals acquire and use knowledge in context. Some context-dependent responses may be maladaptive; for example, anxiety may repress the recollection of knowledge under stressful conditions. Others may be adaptive; the apparent absence of predators in a particular location may trigger animals to explore more terrain for water. Neural signals that enable learning arise from a distributed network of brain regions that relate not only sensory stimuli and valence but also context. Sensation arises from neural circuits that process the physical features of stimuli. Learning in associative tasks requires animals to associate these stimuli with reward or punishment. Contextual factors contribute to learning by modulating internal brain state and adjusting cost-benefit calculations. Identifying the neural substrates of learning, therefore, demands an experimental approach that dissociates these aspects from one another and explores their discrete contributions.
We are studying the neural circuits and dynamics that enable learning, with an emphasis on the role of context and brain state. We first aim to gain behavioral control by designing parametric behavioral assays. We then apply the modern tools of neuroscience to monitor, manipulate and model neural networks. We can monitor outputs with two-photon calcium imaging and measure synaptic inputs with whole-cell voltage clamp recordings. We manipulate networks with opto- and chemo-genetics, using pseudorabies techniques to target defined functional populations. Finally, we collaborate with theoreticians to develop testable hypotheses to constrain our interpretations of the ever-growing "big data" we collect.
natural behaviors in the echolocating bat
Bats provide an extraordinary model species to elucidate the neural circuits that enable natural behaviors. We are working in collaboration with Melville Wohlgemuth (Arizona ), Phillip Gutruf (Arizona), and Cindy Moss (JHU) to adapt optical tools, including awake two-photon imaging and wireless optogenetics, for use in the echolocating bat. One question of particular interest is whether and how the midbrain (inferior and superior colliculus) and the auditory cortex operate in concert to integrate bottom-up signals about the sensory environment with top-down control of behavioral strategies in a naturalistic context.
Social behavior
We rarely function alone. We learn from others in school, develop enduring bonds with friends and family members, and, in today's world, create a digital life through social media. How are our brains wired to enable social interactions? Why are these relationships so critical to behavior? We are designing new social behaviors to address these questions and will exploit the modern tools of neuroscience to understand the underlying neural implementations.
Alzheimer's disease
Context can influence the accessibility of knowledge. For example, in Alzheimer’s disease, a specific context can trigger periods of lucidity even for patients deep in cognitive decline. Knowledge may exist in the AD brain but is inaccessible. Can this “hidden” knowledge be unlocked? We will explore how context triggers latent knowledge in AD and whether we can target these mechanisms therapeutically to improve cognition.