Voltage compartmentalization in dendritic spines in vivo

• Published in: Science (American Association for the Advancement of Science) Vol. 375; no. 6576; pp. 82 - 86
• Main Authors: Cornejo, Victor Hugo, Ofer, Netanel, Yuste, Rafael
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 07.01.2022
• Subjects: Action Potentials; Anatomy; Animals; Brain; Central nervous system; Cerebral cortex; Compartments; Dendrites; Dendritic plasticity; Dendritic spines; Dendritic Spines - physiology; Dendritic structure; Depolarization; Electrical properties; Genetic code; Membrane Potentials; Mice; Neocortex; Nervous system; Neurons; Neurotransmission; Optogenetics; Patch-Clamp Techniques; Photons; Pyramidal cells; Pyramidal Cells - physiology; Sensory stimulation; Somatosensory cortex; Somatosensory Cortex - cytology; Somatosensory Cortex - physiology; Spine; Synapses - physiology; Synaptic plasticity; Synaptic Potentials; Synaptic strength; Voltage; Voltage indicators
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.abg0501

Dendritic spines are small protrusions that cover the dendrites of most neurons in the brain. Their electrical properties are still controversially discussed. Cornejo et al . used an array of techniques to investigate the degree of voltage attenuation by dendritic spine necks in pyramidal neurons of the mouse neocortex. Spines not only synchronously depolarized in response to backpropagating action potentials, but local and transient depolarization also occurred. Isolated depolarization in individual spines reflected localized synaptic activation. A significant voltage gradient between dendritic spine and dendrite indicated that spines may constitute elementary electric compartments. The spine neck resistance is thus not negligible and may substantially contribute to the regulation of synaptic efficacy in the central nervous system. —PRS Dendritic spines in mouse pyramidal neurons are elementary voltage compartments. Dendritic spines mediate most excitatory neurotransmission in the nervous system, so their function must be critical for the brain. Spines are biochemical compartments but might also electrically modify synaptic potentials. Using two-photon microscopy and a genetically encoded voltage indicator, we measured membrane potentials in spines and dendrites from pyramidal neurons in the somatosensory cortex of mice during spontaneous activity and sensory stimulation. Spines and dendrites were depolarized together during action potentials, but, during subthreshold and resting potentials, spines often experienced different voltages than parent dendrites, even activating independently. Spine voltages remained compartmentalized after two-photon optogenetic activation of individual spine heads. We conclude that spines are elementary voltage compartments. The regulation of voltage compartmentalization could be important for synaptic function and plasticity, dendritic integration, and disease states.