Functional connectomics via high-speed two-photon voltage imaging and optogenetics

The National Institute of Neurological Disorders and Stroke (part of the National Institutes of Health) awarded $361,125 to the University of California, Berkeley on September 1, 2026, under the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative (CFDA 93.372) as a project grant.

The award funds a targeted planning project to establish a functional connectomics paradigm combining ultra-fast two-photon voltage imaging (2P-FACED) with two-photon optogenetic stimulation. The system will measure, monitor, and track synaptic weights across tens of thousands of candidate synaptic connections in awake rodent brains over days to weeks to months. The approach reads both subthreshold synaptic potentials and suprathreshold spikes, enabling direct measurement of monosynaptic connectivity and its functional impact on spiking in the same neurons in vivo. The platform is designed as a general-purpose system for measuring and dynamically tracking functional connectomes throughout the brain, addressing limitations in existing connectomics approaches that operate only on post-mortem tissue, have low throughput, or sparsely sample local regions.

The period of performance runs from September 1, 2026, through August 31, 2028. Work is performed in California.

Abstract

The goal of this targeted planning project is to establish a new paradigm for "functional connectomics." existing connectomics approaches operate only on post-mortem tissue, have low throughput, or sparsely sample a local region's connectome, and none can measure the physiological strength of connections or track how they change in the living brain. Here we will combine ultra-fast two-photon voltage imaging (2P-FACED) with twophoton optogenetic stimulation to achieve high-throughput measurement and tracking of a local functional connectome in the rodent brain. Owing to the high speed and scale of 2P-FACED paired with fast single-cell optogenetic stimulation, we will build a system that can measure, monitor, and track synaptic weights across tens of thousands of candidate synaptic connections in awake animals, over days to weeks to months. Uniquely, the system will read out both subthreshold synaptic potentials and suprathreshold spikes, enabling for the first time the direct measurement of both monosynaptic connectivity and its functional impact on spiking in the same neurons in vivo. Rather than targeting a single circuit or behavior, the platform is designed as a general-purpose system for measuring and dynamically tracking functional connectomes throughout the brain.