title: Circuits for grasping: spinal dI3 interneurons mediate cutaneous control of motor behavior.
abstract: Accurate motor performance depends on the integration in spinal microcircuits of sensory feedback information. Hand grasp is a skilled motor behavior known to require cutaneous sensory feedback, but spinal microcircuits that process and relay this feedback to the motor system have not been defined. We sought to define classes of spinal interneurons involved in the cutaneous control of hand grasp in mice and to show that dI3 interneurons, a class of dorsal spinal interneurons marked by the expression of Isl1, convey input from low threshold cutaneous afferents to motoneurons. Mice in which the output of dI3 interneurons has been inactivated exhibit deficits in motor tasks that rely on cutaneous afferent input. Most strikingly, the ability to maintain grip strength in response to increasing load is lost following genetic silencing of dI3 interneuron output. Thus, spinal microcircuits that integrate cutaneous feedback crucial for paw grip rely on the intermediary role of dI3 interneurons.
authors.affiliation: Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors.forename: Tuan V
authors.initials: TV
authors.lastname: Bui
authors.forename: Turgay
authors.initials: T
authors.lastname: Akay
authors.forename: Osama
authors.initials: O
authors.lastname: Loubani
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hnasko
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jessell
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brownstone
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004558:Electric Stimulation; D056228:Feedback, Sensory / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics; D018737:Hand Strength / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008564:Membrane Potentials / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009068:Movement / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D010320:Parvalbumins / Q000378:metabolism; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D012018:Reflex / Q000502:physiology; D012867:Skin / Q000294:innervation*; D013116:Spinal Cord / Q000166:cytology*; D018800:Thy-1 Antigens / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D050599:Vesicular Glutamate Transport Protein 2 / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D060850:LIM-Homeodomain Proteins; D008164:Luminescent Proteins; D010320:Parvalbumins; D012333:RNA, Messenger; C493477:Slc17a6 protein, mouse; D018800:Thy-1 Antigens; D014157:Transcription Factors; D050599:Vesicular Glutamate Transport Protein 2; C063843:insulin gene enhancer binding protein Isl-1; C070614:neurobiotin; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins; D001710:Biotin; D002795:Choline O-Acetyltransferase