Simultaneous two-photon imaging and wireless EEG recording in mice

Bowon Kim; Weihua Ding; Liuyue Yang; Qian Chen; Jianren Mao; Guoping Feng; Jee Hyun Choi; Shiqian Shen

doi:10.1016/j.heliyon.2024.e25910

Simultaneous two-photon imaging and wireless EEG recording in mice

Heliyon. 2024 Feb 9;10(5):e25910. doi: 10.1016/j.heliyon.2024.e25910. eCollection 2024 Mar 15.

Authors

Bowon Kim^{1

2}, Weihua Ding¹, Liuyue Yang¹, Qian Chen^{3

4}, Jianren Mao¹, Guoping Feng³, Jee Hyun Choi², Shiqian Shen¹

Affiliations

¹ Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA.
² Center for Neuroscience, Korea Institute of Science and Technology, Seoul, Republic of Korea.
³ McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge MA, USA.
⁴ Current address: Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.

Abstract

Background: In vivo two-photon imaging is a reliable method with high spatial resolution that allows observation of individual neuron and dendritic activity longitudinally. Neurons in local brain regions can be influenced by global brain states such as levels of arousal and attention that change over relatively short time scales, such as minutes. As such, the scientific rigor of investigating regional neuronal activities could be enhanced by considering the global brain state.

New method: In order to assess the global brain state during in vivo two-photon imaging, CBRAIN (collective brain research platform aided by illuminating neural activity), a wireless EEG collecting and labeling device, was controlled by the same computer of two-photon microscope. In an experiment to explore neuronal responses to isoflurane anesthesia through two-photon imaging, we investigated whether the response of individual cells correlated with concurrent EEG changes induced by anesthesia.

Results: In two-photon imaging, calcium activities of the excitatory neurons in the primary somatosensory cortex disappeared in about 30s after to the initiation of isoflurane anesthesia. The simultaneously recorded EEG showed various transitional activity for about 7 min from the initiation of anesthesia and continued with burst and suppression alternating pattern thereafter. As such, there was a dissociation between excitatory neuron activity of the primary somatosensory cortex and the global brain activity under anesthesia.

Comparison with existing methods: Existing methods to combine two-photon and EEG recording used wired EEG recording. In this study, wireless EEG was used in conjunction with two-photon imaging, facilitated by CBRAIN. More importantly, built-in algorithms of the CBRAIN can automatically detect brain state such as sleep. The codes used for EEG classification are easy to use, with no prior experience required.

Conclusion: Simultaneous recording of wireless EEG and two-photon imaging provides a practical way to capture individual neuronal activities with respect to global brain state in an experimental set-up.

Keywords: Anesthesia; Electroencephalogram (EEG); Global brain state; Isoflurane; Multi-dimensional brain activity; Two-photon.