Research Projects

Abstract Activity of the brain across structures is an orchestrated process that spans a broad range of time and space scales. Highly coordinated communication is what activate responses to stimuli, makes behavior possible, and generates memories. To observe exchanges of information at the cellular and synaptic level, neuroscientists have been increasingly using non-invasive imaging techniques that rely on genetically encoded indicators based on fluorescent proteins (FPs).

Abstract To understand how the brain processes information and generates behaviors, we must record neural activity of three-dimensionally distributed circuits at millisecond timescales. While current optical imaging methods successfully reached imaging rates at kHz frame rates, they are still too slow to resolve the calcium dynamics of neurons throughout an entire volume or to track large populations of neurons in interconnected regions of brain in moving animals.

A major goal of the BRAIN Initiative is to promote the development of neural activity measurement tools that bridge between spatial scales, so that the processing roles of individual neurons and microcircuits can be related to broader regional or brain-wide dynamics.

PROJECT SUMMARY/ABSTRACT A major obstacle to identifying neural network mechanisms responsible for emergence of cognitive function is insufficient capability to acquire large-scale electrophysiologic signals across the course of brain maturation. There is urgent need to develop the technology and experimental protocols to acquire large-scale, chronic neu- rophysiological signals from small, fragile, immature brains via minimally invasive implantable devices.

The rapid advance of genetically encoded functional indicators allows the scientists to visualize neuronal activities with light in the living brain at high spatiotemporal resolutions. For in vivo measurement in the mammalian brain, laser scanning two-photon fluorescence microscopy (TPM) is commonly employed to image the neurons expressing genetically encoded functional indicators. The sequential point scanning of TPM offers clean measurement without noise crosstalk and yields excellent signal-to-noise ratio.

Project Summary/Abstract Section Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. We propose the development of a novel bias-switchable row-column 2D ultrasound transducer array technology for 3D ultrasound and photoacoustic imaging of whole-brain functional activity with potential for a wearable format for awake and moving animals.

PROJECT SUMMARY Understanding the functional network in the brain is critical to the development of neural prostheses and effective treatment of neurological diseases. To that end, highly multiplexed and miniaturized probes have been developed to modulate and record neural activities in the brain. However, it remains a challenge to map the activities over a large area in the deep brain with minimal invasiveness. This proposal will leverage the advantages of two emerging technologies – multimaterial fiber-based neural interfaces developed by the PI (Dr.

Project Summary The brain’s functions are determined by its neural circuits, which consist of approximately 85 billion neuronal cells. Current brain recording technology is not sufficient to accomplish the goal of a high resolution mapping of brain activity due to the lack of a large-scale recording technology. Another vital challenge for current brain recording technology is obtaining longer lifetime for the implanted electrodes to prevent repeated surgeries.

Project Summary A multi-scale, mechanistic understanding of neural circuits that includes both local- and whole-brain interconnections still remains elusive. One of the fundamental challenges is the lack of tools for monitoring, with high spatiotemporal resolution, the activity of local neuron ensembles simultaneously in different regions of the brain in awake, freely-behaving animals. This calls for the design of ultrahigh density neural probes capable of recording from thousands of neurons with high spatiotemporal resolution.

Summary Measuring the activity of many individual neurons at once while knowing their wiring diagrams would provide exciting information on how the components of a network interact. Knowledge of wiring diagrams has rapidly improved due to advances in the field of connectomics, and capabilities for simultaneous measurement of many individual neurons has increased exponentially with large-scale recording techniques. However, it is still difficult to combine such measurements.