Monitor Neural Activity

Abstract The

ABSTRACT The neurotransmitter acetylcholine is widely distributed in the central nervous system and brain, and is a key signaling molecule involved in neural function. Current measurements of this important signaling molecule rely on implanted electrodes or sampling techniques, which often trade temporal or spatial resolution for chemical specificity, or vice versa.

The development of minimally invasive direct readouts of neural activity is one of the greatest challenges facing neuroscience today. Our laboratory is leading efforts to enable high resolution functional magnetic reso- nance imaging (fMRI) of molecular-level phenomena using MRI contrast agents sensitive to hallmarks of neu- ral activity. Calcium-sensitive fMRI is of outstanding interest.

Conditionally silencing the activity of specific neural ensembles is a powerful approach for mapping brain circuits responsible for specific behaviors. While microbial opsin- based tools exist to silence neural activity with light, these tools have significant limitations that make them unsuitable for persistent silencing over the course of minutes or hours.

Project Summary A longstanding goal in neuroscience is to understand the brain at the level of individual neurons. Existing techniques involve inserting electrodes that heavily damage the area that they are recording. Due to the damage it has also been very difficult to combine electrophysiology techniques with imaging the same neurons after the fact. We have developed novel carbon fiber electrode arrays, with individual elements that are 8 μm in diameter, smaller than most neuron cell bodies.

PROJECT SUMMARY Understanding how information is processed in the mammalian neocortex has been a longstanding question in neuroscience. While the action potential is the fundamental bit of information, how these spikes encode representations and drive behavior remains unclear. In order to adequately address this problem, it has become apparent that experiments are needed in which activity from large numbers of neurons can be measured in a detailed and comprehensive manner across multiple timescales. Direct measurements of action potentials have primarily been achieved by electrophysiology.

PROJECT SUMMARY This proposal aims to record and store neural activity into DNA/RNA strands with high spatial and temporal resolution, enabling neural activity recording densely within local circuits, yet broadly across large scale neural circuits, and potentially across the entire brain. Current technologies require tradeoffs in coverage, spatial resolution, or temporal resolution.

TITLE kHz-rate in vivo imaging of neural activity throughout the living brain SUMMARY The overarching challenge in neuroscience today is how to monitor the neural signaling events in intact brains of behaving animals at synaptic or cellular spatial resolution and millisecond time resolution. Multiphoton fluorescence microscopy stands out among the existing brain imaging methods because of its ability to visualize the neuronal signals in optically opaque brains at sub-micron spatial resolution. However, hampered by the fundamental speed limitation of the gold-standard mechanical scanning mir

Project Summary/Abstract A major goal of the BRAIN Initiative is in creating new systems for being able to record and modulate neuronal activity across wide areas of cortex and at the scale of small ensembles and even individual neurons.

Project summary  Currently,  no  technology  exists  that  has  been  specifically  designed  to  allow  high  precision  noninvasive  neuromodulation and neuroimaging in awake animals. Ultrasound is an ideal modality to fill this void since it has  been  used  (1)  directly  for  neuromodulation,  (2)  for  functional  imaging  of  cerebral  blood  flow,&nbsp