Tuning of synaptic integration in the medial entorhinal cortex to the organization of grid cell firing fields.
Neurons important for cognitive function are often classified by their morphology and integrative properties. However, it is unclear if within a single class of neuron these properties tune synaptic responses to the salient features of the information that each neuron represents. We demonstrate that for stellate neurons in layer II of the medial entorhinal cortex, the waveform of postsynaptic potentials, the time window for detection of coincident inputs, and responsiveness to gamma frequency inputs follow a dorsal-ventral gradient similar to the topographical organization of grid-like spatial firing fields of neurons in this area. We provide evidence that these differences are due to a membrane conductance gradient mediated by HCN and leak potassium channels. These findings suggest key roles for synaptic integration in computations carried out within the medial entorhinal cortex and imply that tuning of neural information processing by membrane ion channels is important for normal cognitive function.
Garden
Derek L F
DL
Centre for Neuroscience Research and Centre for Integrative Physiology, R(D)SVS, University of Edinburgh, Hugh Robson Building, Edinburgh, EH8 9XD, Scotland, UK.
Dodson
Paul D
PD
O'Donnell
Cian
C
White
Melanie D
MD
Nolan
Matthew F
MF
D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D001931:Brain Mapping; D048429:Cell Size; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000037:antagonists & inhibitors; D004558:Electric Stimulation / Q000379:methods; D018728:Entorhinal Cortex / Q000166:cytology* / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D051379:Mice; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009474:Neurons / Q000145:classification / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011743:Pyrimidines / Q000494:pharmacology; D011802:Quinidine / Q000494:pharmacology; D013569:Synapses / Q000502:physiology*
D017609:Barium Compounds; D002712:Chlorides; D054815:Cyclic Nucleotide-Gated Cation Channels; D018727:Muscarinic Antagonists; D011743:Pyrimidines; C024986:barium chloride; C082246:ICI D2788; D002586:Cesium; C028019:cesium chloride; D011802:Quinidine