Tuned responses of astrocytes and their influence on hemodynamic signals in the visual cortex.
Astrocytes have long been thought to act as a support network for neurons, with little role in information representation or processing. We used two-photon imaging of calcium signals in the ferret visual cortex in vivo to discover that astrocytes, like neurons, respond to visual stimuli, with distinct spatial receptive fields and sharp tuning to visual stimulus features including orientation and spatial frequency. The stimulus-feature preferences of astrocytes were exquisitely mapped across the cortical surface, in close register with neuronal maps. The spatially restricted stimulus-specific component of the intrinsic hemodynamic mapping signal was highly sensitive to astrocyte activation, indicating that astrocytes have a key role in coupling neuronal organization to mapping signals critical for noninvasive brain imaging. Furthermore, blocking astrocyte glutamate transporters influenced the magnitude and duration of adjacent visually driven neuronal responses.
Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
James
J
Schummers
Hongbo
H
Yu
Mriganka
M
Sur
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D001810:Blood Volume; D001931:Brain Mapping; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002560:Cerebrovascular Circulation; D005289:Ferrets; D005456:Fluorescent Dyes; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D009474:Neurons / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism; D010775:Photic Stimulation; D013569:Synapses / Q000502:physiology; D014793:Visual Cortex / Q000098:blood supply / Q000166:cytology / Q000502:physiology*
D005456:Fluorescent Dyes; D018377:Neurotransmitter Agents; C120673:benzyloxyaspartate; D001224:Aspartic Acid; D018698:Glutamic Acid; D002118:Calcium