title: Optogenetic spatial and temporal control of cortical circuits on a columnar scale.
abstract: Many circuits in the mammalian brain are organized in a topographic or columnar manner. These circuits could be activated-in ways that reveal circuit function or restore function after disease-by an artificial stimulation system that is capable of independently driving local groups of neurons. Here we present a simple custom microscope called ProjectorScope 1 that incorporates off-the-shelf parts and a liquid crystal display (LCD) projector to stimulate surface brain regions that express channelrhodopsin-2 (ChR2). In principle, local optogenetic stimulation of the brain surface with optical projection systems might not produce local activation of a highly interconnected network like the cortex, because of potential stimulation of axons of passage or extended dendritic trees. However, here we demonstrate that the combination of virally mediated ChR2 expression levels and the light intensity of ProjectorScope 1 is capable of producing local spatial activation with a resolution of ∼200-300 μm. We use the system to examine the role of cortical activity in the experience-dependent emergence of motion selectivity in immature ferret visual cortex. We find that optogenetic cortical activation alone-without visual stimulation-is sufficient to produce increases in motion selectivity, suggesting the presence of a sharpening mechanism that does not require precise spatiotemporal activation of the visual system. These results demonstrate that optogenetic stimulation can sculpt the developing brain.
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
authors.forename: Arani
authors.initials: A
authors.lastname: Roy
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Osik
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Ritter
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
authors.forename: Shen
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts;
authors.forename: James T
authors.initials: JT
authors.lastname: Shaw
authors.affiliation: Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts; Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts; and Department of Cognitive Sciences, Central European University, Budapest, Hungary.
authors.forename: József
authors.initials: J
authors.lastname: Fiser
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts; Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts; Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University, Waltham, Massachusetts; and vanhooser@brandeis.edu.
authors.forename: Stephen D
authors.identifier: http://orcid.org/0000-0002-1112-5832
authors.initials: SD
authors.lastname: Van Hooser
mesh_terms: D000818:Animals; D005289:Ferrets; D055495:Neurogenesis; D062308:Optogenetics / Q000295:instrumentation / Q000379:methods*; D012243:Rhodopsin / Q000235:genetics / Q000378:metabolism; D014793:Visual Cortex / Q000166:cytology / Q000254:growth & development / Q000502:physiology*
chemical_list: D012243:Rhodopsin
keywords: activity-dependent plasticity; direction selectivity; optogenetics