Compartmentalization of GABAergic Inhibition by Dendritic Spines

• Published in: Science (American Association for the Advancement of Science) Vol. 340; no. 6133; pp. 759 - 762
• Main Authors: Chiu, Chiayu Q., Lur, Gyorgy, Morse, Thomas M., Carnevale, Nicholas T., Ellis-Davies, Graham C. R., Higley, Michael J.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 10-05-2013; The American Association for the Advancement of Science
• Subjects: Animals; Behavioral neuroscience; Biological and medical sciences; Biophysics; Brain; Calcium; Calcium - metabolism; Channelrhodopsins; Computer Simulation; Dendrites; Dendritic spines; Dendritic Spines - physiology; Dendritic structure; Excitation; Female; Fundamental and applied biological sciences. Psychology; gamma-Aminobutyric Acid - physiology; Glutamic Acid - physiology; Imaging; Inhibition; Interneurons; Male; Mice; Mice, Inbred C57BL; Models, Neurological; Neighborhoods; Neocortex - physiology; Neural Inhibition; Neurobiology; Neurons; Neurotransmitters; Photic Stimulation; Physiological regulation; Pyramidal Cells - physiology; Signals; Spine; Stimulation; Synapses; Synapses - physiology; Vertebrates: nervous system and sense organs; Compartmentalization; Cerebral cortex; Calcium; Central nervous system; Electrophysiology; Action potential; Stimulation; Photon; Encephalon; Dendrite; Signal transduction; Synapse; Neurotransmitter; Dendritic spine; GABA; Pyramidal neuron
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1234274

γ-aminobutyric acid-mediated (GABAergic) inhibition plays a critical role in shaping neuronal activity in the neocortex. Numerous experimental investigations have examined perisomatic inhibitory synapses, which control action potential output from pyramidal neurons. However, most inhibitory synapses in the neocortex are formed onto pyramidal cell dendrites, where theoretical studies suggest they may focally regulate cellular activity. The precision of GABAergic control over dendritic electrical and biochemical signaling is unknown. By using cell type-specific optical stimulation in combination with two-photon calcium (Ca²⁺) imaging, we show that somatostatin-expressing interneurons exert compartmentalized control over postsynaptic Ca²⁺ signals within individual dendritic spines. This highly focal inhibitory action is mediated by a subset of GABAergic synapses that directly target spine heads. GABAergic inhibition thus participates in localized control of dendritic electrical and biochemical signaling.