title: Improved methods for chronic light-based motor mapping in mice: automated movement tracking with accelerometers, and chronic EEG recording in a bilateral thin-skull preparation.
abstract: Optogenetic stimulation of the mouse cortex can be used to generate motor maps that are similar to maps derived from electrode-based stimulation. Here we present a refined set of procedures for repeated light-based motor mapping in ChR2-expressing mice implanted with a bilateral thinned-skull chronic window and a chronically implanted electroencephalogram (EEG) electrode. Light stimulation is delivered sequentially to over 400 points across the cortex, and evoked movements are quantified on-line with a three-axis accelerometer attached to each forelimb. Bilateral maps of forelimb movement amplitude and movement direction were generated at weekly intervals after recovery from cranial window implantation. We found that light pulses of ~2 mW produced well-defined maps that were centered approximately 0.7 mm anterior and 1.6 mm lateral from bregma. Map borders were defined by sites where light stimulation evoked EEG deflections, but not movements. Motor maps were similar in size and location between mice, and maps were stable over weeks in terms of the number of responsive sites, and the direction of evoked movements. We suggest that our method may be used to chronically assess evoked motor output in mice, and may be combined with other imaging tools to assess cortical reorganization or sensory-motor integration.
authors: Department of Psychiatry, University of British Columbia Vancouver, BC, Canada ; Brain Research Centre, University of British Columbia Vancouver, BC, Canada.
authors: Gergely
authors: G
authors: Silasi
authors: Jamie D
authors: JD
authors: Boyd
authors: Jeff
authors: J
authors: Ledue
authors: Timothy H
authors: TH
authors: Murphy
mesh_terms: D061725:Accelerometry / Q000379:methods*; D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011897:Random Allocation; D012886:Skull / Q000502:physiology; D013997:Time Factors
keywords: accelerometer; chronic EEG; chronic window; cortex; motor mapping; mouse; optogenetics
references: Neuron. 2002 May 30;34(5):841-51
references: 12062029
references: Nat Methods. 2012 Dec;9(12):1171-9
references: 23169303
references: J Neurosci Methods. 2009 May 15;179(2):258-63
references: 19428535
references: J Neurophysiol. 2005 Dec;94(6):4209-23
references: 16120657
references: Can J Neurol Sci. 1991 Feb;18(1):28-38
references: 2036613
references: J Neurosci Methods. 2009 Sep 15;182(2):211-8
references: 19559049
references: Neuroscientist. 2005 Oct;11(5):471-83
references: 16151047
references: Nature. 2009 Dec 17;462(7275):920-4
references: 19946265
references: Neuron. 2012 Apr 26;74(2):397-409
references: 22542191
references: Nat Methods. 2010 Dec;7(12):981-4
references: 20966916
references: J Neurosci. 2013 Jan 30;33(5):2097-107
references: 23365246
references: Nat Protoc. 2010 Feb;5(2):247-54
references: 20134425
references: Nat Methods. 2009 Mar;6(3):219-24
references: 19219033
references: J Neurosci Methods. 2011 Mar 15;196(1):60-9
references: 21219927
references: Stroke. 2013 Feb;44(2):483-9
references: 23321442
references: Neurorehabil Neural Repair. 2013 May;27(4):381-4
references: 23161864
references: Neuroscience. 2005;130(3):601-10
references: 15590144
references: Cereb Cortex. 2011 Apr;21(4):865-76
references: 20739477
references: NeuroRx. 2006 Oct;3(4):489-96
references: 17012063
references: Biomed Opt Express. 2010 Jul 15;1(1):246-259
references: 21258462
references: Behav Brain Res. 2013 Oct 15;255:3-18
references: 23473879
references: J Neurosci. 2009 May 13;29(19):6196-206
references: 19439597
references: Nat Neurosci. 2013 Jan;16(1):64-70
references: 23143518
references: Eur J Neurosci. 2008 Jan;27(1):228-37
references: 18093166
references: J Neurophysiol. 1998 Dec;80(6):3321-5
references: 9862925