Research Projects

High-speed volumetric imaging of dynamic neuronal activity over long periods is a challenging but essential goal in neuroscience. Conventional optical measurements of neuronal activity mostly rely on calcium signals. However, calcium imaging conveys only limited information about natural signal processing in the nervous system, and it provides little or no data on the inhibitory and excitatory signals that occur continuously in most neurons.

The objective of this project is to develop new bioanalytical methods for exploring brain chemistry dynamics in vivo. Monitoring the concentration dynamics of neurochemicals in vivo is vital for studying brain function, diseases, and treatments. A versatile approach for in vivo monitoring of brain chemistry is to couple sampling methods, such as microdialysis, to analytical measurements.

Summary Neurological and psychiatric disorders absorb one-third of the total health care expenditures; more than cancer, cardiovascular diseases, and diabetes combined. On average, approximately one in three patients fails to respond to medication treatments or has intolerable side effects. Neuromodulation, which aims to treat brain disorders at their neural source, provides a new path to effective and personalized treatments.

Abstract An outstanding challenge of brain research is to link the cross-scale functional perspectives from the cellular and molecular level to the circuit and systems level. To address this unmet need, simultaneous fMRI with electroencephalogram (EEG) recording presents a unique scheme for functional dynamic mapping that would link neuronal activity with vascular hemodynamics. But mismatching of spatial localization between EEG and MRI, and their crosstalk due to electromagnetic interference have complicated post-processing procedures and interpretation of functional dynamics.

Abstract Signals in the brain are transmitted and transformed on a millisecond timescale. The precise timing of activity can carry unique information, correlate perceptual decisions, and powerfully influence synaptic plasticity. Therefore, to understand the circuits that generate behavior and the circuit changes responsible for learning, we must interrogate signaling in vivo at millisecond timescales. Since the advent of two-photon microscopy, these signals have primarily been inferred in vivo through the use of fluorescent indicators with far slower dynamics.

PROJECT SUMMARY Achieving a detailed understanding of the neural codes of sensation, action, and cognition requires technologies that can causally perturb each of the major dimensions of population coding one at a time with extremely high precision across multiple brain areas. Existing control systems do not fully meet this challenge because they are unidirectional and have limited spatial scale, speed, or resolution.

Project Summary / Abstract IR Powered and Hermetically-Sealed Single-Unit Neural Recording Wireless Motes for Large Scale Implantation Into Nonhuman Primate Cortex In this research agenda, we propose the ReMote which is a wireless neural recording probe that utilizes near-infrared (NIR) light for both power delivery and two-way communication, 8m diameter carbon fiber electrodes that can be implanted with minimal bleeding and scarring, a new circuit architecture based on extracting spiking band power (SBP) which reduces power consumption and the communication bandwidth but nonetheless det

PROJECT SUMMARY/ABSTRACT A major obstacle to understanding how the dynamic activity of brain circuits permits the emergence of cortical function is the insufficient capability to acquire and manipulate this activity across the course of brain maturation. Neuromodulators and neural activity patterns are intimately linked in mediating this maturation. There is an urgent need to develop technology to acquire and manipulate neurophysiological signals from small, fragile, immature brains and address this gap in knowledge.

ABSTRACT Neuromodulators, such as neuropeptides and biogenic amines are produced and released by neurons to communicate with each other. They act as neurotransmitters, as well as neuromodulators, to profoundly influence the function of neural circuits, thereby regulating critical brain functions, including arousal, feeding, metabolism, social behavior, fear/anxiety, learning/memory, reward, and sexual behaviors. Dysfunction in neuromodulator signaling is associated with many neurological and neuropsychiatric disorders.

The neural circuits of animals, including humans, are the combined product of adaptation by natural selection and the evolutionary history of a species. Distinguishing which features of neural circuits represent fundamental principles of circuit design versus the quirks of a particular model species requires comparative approaches. Features of neural circuit design and architecture that have evolved independently multiple times in distantly related species indicate elements of optimal solutions to solving a particular behavioral or cognitive problem.