High-speed imaging of local population activity in mouse visual cortex

Abstract

Event Abstract Back to Event High-speed imaging of local population activity in mouse visual cortex A fundamental goal in systems neuroscience is to understand how local populations of neurons coordinate their firing to encode external events and to generate internal states. Much of what is known on the subject has been inferred from multi-electrode recordings which can only sparsely sample neural populations. Recently, two-photon calcium imaging has made it possible to measure spiking from a large number of neurons in a local region. Two-photon calcium imaging is an optical microscopic technique that allows visualization and simultaneous measurement of the activity of nearly every neuron in a local plane or volume of the living brain. Spiking activity induces large calcium influxes into the cell body which can be measured by loading a fluorescent calcium indicator into the cell and exciting the indicator with high intensity infrared laser pulses. While two-photon calcium imaging routinely yields high-resolution activity maps, it has remained a challenge to use it to study how neural responses evolve as a function of time, or how they vary from one trial to the next. In theory, its temporal resolution should only depend on the time course of the calcium influx, limited by diffusion, which has a rise time of a few tens of milliseconds. In practice, two-photon imaging is limited by both the ability to scan the sample quickly and also by signal-to-noise. Scan speed is affected by the technology used to deflect the laser. Signal-to-noise is primarily affected by the number of collected photons since this type of imaging works at low light levels where shot noise dominates. To address these problems we have developed a two-photon microscope which uses a high-speed resonant galvanometer and an optimized excitation and collection light path which increases photon flux. We can continuously image large populations (up to several hundreds of neurons) in the living brain at rates of >30 Hz with high signal-to-noise. We find that we can reliably detect the presence or absence spontaneous and stimulus-evoked calcium transients, and that we can measure their onset of with a temporal resolution of ~30 milliseconds. This yields the ability to analyze trial-to-trial responses of a large population of neurons. We are examining how populations of neurons in visual cortex respond to repeated presentation of visual stimuli. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). High-speed imaging of local population activity in mouse visual cortex. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.239 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Feb 2009; Published Online: 03 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.