Understanding Circuits

Project Summary. Human and nonhuman primates are highly visual animals that are predominantly active during the daylight hours. Yet our understanding of the neural mechanisms supporting spatial navigation is largely based on studies of nocturnal, burrowing rodents with poor vision. Indeed, studies of human and nonhuman primates have already demonstrated that spatial positions can be encoded in the hippocampus exclusively by visual inspection of a scene (i.e. spatial-view cells).

Abstract To survive in dynamic environments, the nervous system must be able to generate flexible behavior — seamlessly weaving together past experience with the present context to achieve future goals. Our team of experts on the neural circuits of behavior will collaborate to reveal the neural mechanisms by which a mouse engages in specific processing of one sensory modality versus another based on task demands.

Learning desired actions from experience requires evaluating alternative actions by integrating the consequences assigned to each action over time. In the real world, actions and outcomes occur in complex sequences, and a continuous stream of events must be parsed into appropriate pairs of causative action and outcome before such pairs can be evaluated. However, how the brain solves this problem, known as temporal credit assignment (TCA) is unknown.

SUMMARY Adaptive behaviors emerge from neuronal networks by dynamically regulating functional connectomes. Based on an underlying anatomical connectome, a functional connectome is the configuration of effective synaptic connections that underlies a pattern of neuronal activity during a specific behavior. Unique combinations of neurons activate specific functional connectomes, thereby generating a behavior (a combinatoric code).

Abstract Humans have a remarkable ability to flexibly interact with the environment. A compelling demonstration of this cognitive flexibility is our ability to respond correctly to novel contextual situations on the first attempt, without prior rehearsal.

An integrated single-neuronal, population-, local network- and stimulation-based prefrontal investigation of human social cognition This proposal aims to undertake a comprehensive single-cellular, population-, local circuit- and stimulation- based evaluation of the role that the dorsal prefrontal cortex plays in human social cognition. Despite ongoing progress in our understanding of basic elements of social behavior through animal models, astonishingly little is known about the single-neuronal and causal mechanisms that underlie human social cognition.

PROJECT SUMMARY Intracortical brain-computer interfaces (iBCIs) can restore lost function for people with severe speech and motor impairment (SSMI) due to neurological injury or disease. Despite tremendous recent progress, iBCI performance remains well below that of able-bodied people.

ABSTRACT Humans can skillfully control their grasp during actions as complex and dynamic as swinging a tennis racket, and as simple and static as holding a briefcase. Both tasks require the use of sensory feedback to achieve and maintain an appropriate grasp force. There is evidence that motor and somatosensory cortices communicate task-relevant information in order to enable skillful movement.

Abstract: The long-term objective of this application is to understand cortical processing of sensory to motor transformations within the human cerebral cortex. A vast number of computations must be performed to achieve sensory-guided motor control. Standing out among these computations, visual information of the goals of action must be transformed from the coordinates of the retina to the coordinates of effectors used for movement, for instance limb coordinates for reaching under visual guidance and to world coordinates for interactions in the environment.