Tonic excitation and inhibition of neurons: ambient transmitter sources and computational consequences.
Tonic activation of excitatory and inhibitory receptors, by the ambient concentration of neurotransmitters in the extracellular space of the brain, has been suggested to underlie phenomena as diverse as relapse to cocaine use by reward pathways in the striatum, sparse coding of motor information in the cerebellum, and control of the development of the cerebral and cerebellar cortices. Here we assess the mechanisms which may determine the ambient levels of excitatory and inhibitory neurotransmitters, and consider their likely effect on information processing.
Cavelier
Pauline
P
Department of Physiology, University College London, Gower Street, London WC1E 6BT, UK.
Hamann
Martine
M
Rossi
David
D
Mobbs
Peter
P
Attwell
David
D
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002490:Central Nervous System / Q000254:growth & development / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology / Q000502:physiology; D006801:Humans; D008606:Mental Processes / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology*; D018091:Receptors, AMPA / Q000187:drug effects / Q000502:physiology; D011963:Receptors, GABA-A / Q000502:physiology; D018092:Kainic Acid Receptors / Q000187:drug effects / Q000502:physiology; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology
D018698:Glutamic Acid; D018377:Neurotransmitter Agents; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D018092:Kainic Acid Receptors; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate