title: Multiple Running Speed Signals in Medial Entorhinal Cortex.
abstract: Grid cells in medial entorhinal cortex (MEC) can be modeled using oscillatory interference or attractor dynamic mechanisms that perform path integration, a computation requiring information about running direction and speed. The two classes of computational models often use either an oscillatory frequency or a firing rate that increases as a function of running speed. Yet it is currently not known whether these are two manifestations of the same speed signal or dissociable signals with potentially different anatomical substrates. We examined coding of running speed in MEC and identified these two speed signals to be independent of each other within individual neurons. The medial septum (MS) is strongly linked to locomotor behavior, and removal of MS input resulted in strengthening of the firing rate speed signal, while decreasing the strength of the oscillatory speed signal. Thus, two speed signals are present in MEC that are differentially affected by disrupted MS input.
authors.affiliation: Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Center for Memory and Brain, Boston University, 2 Cummington Mall, Boston, MA 02215, USA. Electronic address: hinman@bu.edu.
authors.forename: James R
authors.initials: JR
authors.lastname: Hinman
authors.affiliation: Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Center for Memory and Brain, Boston University, 2 Cummington Mall, Boston, MA 02215, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Brandon
authors.affiliation: Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Center for Memory and Brain, Boston University, 2 Cummington Mall, Boston, MA 02215, USA; Graduate Program for Neuroscience, Boston University, 2 Cummington Mall, Boston, MA 02215, USA.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Climer
authors.affiliation: Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Center for Memory and Brain, Boston University, 2 Cummington Mall, Boston, MA 02215, USA.
authors.forename: G William
authors.initials: GW
authors.lastname: Chapman
authors.affiliation: Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Center for Memory and Brain, Boston University, 2 Cummington Mall, Boston, MA 02215, USA; Graduate Program for Neuroscience, Boston University, 2 Cummington Mall, Boston, MA 02215, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hasselmo
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D018728:Entorhinal Cortex / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D051381:Rats; D012420:Running / Q000502:physiology*; D012686:Septal Nuclei / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology*; D000072797:Walking Speed / Q000502:physiology*
keywords: entorhinal cortex; grid cell; medial septum; path integration; theta rhythm