Kavli NeuroTechnology Center seminar

Thursday 1/12/17

January 9, 2017

Kavli NTC Seminar

Rm. 703 NWC Building, 7th floor
Thursday. 1/12/2017
2:00 pm - 3:00pm
530 West 120th St,
New York, NY 10027
Involvement of astrocytes in transcranial direct current stimulation
Speaker: Hajime Hirase
RIKEN Brain Science Institute, Wako, Japan

Abstract: In an attempt to monitor the Ca2+ dynamics of wide brain areas, we made a transgenic mouse (G7NG817) that expresses the genetic Ca2+ indicator G-CaMP7 in astrocytes and a subpopulation of neurons. Using this mouse, we explored the cortical Ca2+ dynamics during transcranial direct current stimulation (tDCS), a treatment known to ameliorate various neurological conditions and enhance memory and cognition in humans. Surprisingly, we found that tDCS induced large-amplitude astrocytic Ca2+ surges across the entire cortex with no obvious changes in cortical neuronal activity. Moreover, sensory evoked cortical responses were enhanced after tDCS, whereas this enhancement was not seen in IP3R2 (inositol trisphosphate receptor type 2) knockout mice, in which astrocytic Ca2+ surges are absent, suggesting that tDCS alters the plasticity of the cortex through astrocytic Ca2+/IP3 signaling. Together, we propose that tDCS changes the metaplasticity of the cortex through astrocytic Ca2+/IP3 signaling. Metaplasticity of the brain could be modulated astrocyte-secreted transmitters. Amongst astrocyte-secreted transmitters, glycogen-derived lactate has been shown to be important in synaptic plasticity and learning. We are currently investigating brain glycogen distribution by immunohistochemistry.