Calcium imaging of infrared-stimulated activity in rodent brain

• Published in: Cell calcium (Edinburgh) Vol. 55; no. 4; pp. 183 - 190
• Main Authors: Cayce, Jonathan Matthew, Bouchard, Matthew B, Chernov, Mykyta M, Chen, Brenda R, Grosberg, Lauren E, Jansen, E. Duco, Hillman, Elizabeth M.C, Mahadevan-Jansen, Anita
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.04.2014
• Subjects: 6-Cyano-7-nitroquinoxaline-2,3-dione - chemistry; 6-Cyano-7-nitroquinoxaline-2,3-dione - pharmacology; Advanced Basic Science; Animals; Astrocytes; Astrocytes - drug effects; Astrocytes - metabolism; Astrocytes - radiation effects; Brain - drug effects; Brain - metabolism; Brain - radiation effects; Calcium - metabolism; Calcium dye imaging; Calcium Signaling; Cells, Cultured; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; Cerebral Cortex - radiation effects; Electric Stimulation; Fluoroacetates - chemistry; Fluoroacetates - pharmacology; In Vitro Techniques; Infrared neural stimulation; Infrared Rays; Male; Neurons; Optical imaging; Rats; Rats, Sprague-Dawley; Somatosensory cortex; Calcium signaling; Somatosensory cortex; Infrared neural stimulation; Neurons; Astrocytes; Calcium dye imaging; Optical imaging
• ISSN: 0143-4160; 1532-1991
• DOI: 10.1016/j.ceca.2014.01.004

Abstract Infrared neural stimulation (INS) is a promising neurostimulation technique that can activate neural tissue with high spatial precision and without the need for exogenous agents. However, little is understood about how infrared light interacts with neural tissue on a cellular level, particularly within the living brain. In this study, we use calcium sensitive dye imaging on macroscopic and microscopic scales to explore the spatiotemporal effects of INS on cortical calcium dynamics. The INS-evoked calcium signal that was observed exhibited a fast and slow component suggesting activation of multiple cellular mechanisms. The slow component of the evoked signal exhibited wave-like properties suggesting network activation, and was verified to originate from astrocytes through pharmacology and 2-photon imaging. We also provide evidence that the fast calcium signal may have been evoked through modulation of glutamate transients. This study demonstrates that pulsed infrared light can induce intracellular calcium modulations in both astrocytes and neurons, providing new insights into the mechanisms of action of INS in the brain.