title: Negative hemodynamic response without neuronal inhibition investigated by combining optical imaging and electrophysiological recording.
abstract: Understanding the mechanisms underlying negative hemodynamic responses is critical for the interpretation of functional brain imaging signals. Negative imaging signals have been found in the visual, somatosensory and motor cortices in functional magnetic resonance imaging (fMRI) and intrinsic signal optical imaging (ISOI) studies. However, the origin of negative imaging signals is still controversial. The present study investigated the visual cortical responses to peripheral grating stimuli using multi-wavelength ISOI and electrophysiological recording. We found an increased cerebral blood volume (CBV) in the stimulus-induced regions and a decreased CBV in the adjacent regions in the visual cortex. Nevertheless, there was no significant change in blood oxygenation in the negative CBV regions. Furthermore, by combining the planar and laminar electrophysiological recordings, we did not observe significantly decreased neuronal activity in the negative CBV regions. Our results suggest that the negative hemodynamic response does not necessarily originate in decreased neuronal activity. Therefore, caution should be taken when interpreting a negative hemodynamic response as neuronal inhibition.
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China; School of Biomedical Engineering, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China.
authors.forename: Zengguang
authors.initials: Z
authors.lastname: Ma
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China.
authors.forename: Pengjia
authors.initials: P
authors.lastname: Cao
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Sun
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China.
authors.forename: Zhuofan
authors.initials: Z
authors.lastname: Lu
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China.
authors.forename: Liming
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China. Electronic address: yao.chen@sjtu.edu.cn.
authors.forename: Yao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Minhang District, Shanghai 200240, PR China. Electronic address: xychai@sjtu.edu.cn.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Chai
mesh_terms: D000818:Animals; D001931:Brain Mapping / Q000379:methods; D002415:Cats; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D055724:Electrophysiological Phenomena / Q000502:physiology*; D059907:Functional Neuroimaging / Q000379:methods; D006439:Hemodynamics; D008279:Magnetic Resonance Imaging / Q000379:methods; D009474:Neurons / Q000502:physiology*; D061848:Optical Imaging / Q000379:methods; D010100:Oxygen / Q000097:blood; D014793:Visual Cortex / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: Laminar electrophysiological recording; Negative hemodynamic response; Optical imaging; Planar electrophysiological recording