title: Assessment of neurovascular dynamics during transient ischemic attack by the novel integration of micro-electrocorticography electrode array with functional photoacoustic microscopy.
abstract: This study developed a novel system combining a 16-channel micro-electrocorticography (μECoG) electrode array and functional photoacoustic microscopy (fPAM) to examine changes in neurovascular functions following transient ischemic attack (TIA) in rats. To mimic the pathophysiology of TIA, a modified photothrombotic ischemic model was developed by using 3 min illumination of 5 mW continuous-wave (CW) green laser light focusing on a distal branch of the middle cerebral artery (MCA). Cerebral blood volume (CBV), hemoglobin oxygen saturation (SO2), somatosensory evoked potentials (SSEPs) and alpha-to-delta ratio (ADR) were measured pre- and post-ischemia over a focal cortical region (i.e., 1.5×1.5 mm(2)). Unexpectedly, the SO2, peak-to-peak amplitude (PPA) of SSEPs and ADR recovered and achieved levels greater than the baseline values at the 4th hour post-ischemia induction without any intervention, whereas the CBV value only partially recovered. In other words, transient ischemia led to increased neural activity when the relative CBV was reduced, which may further compromise neural integrity or lead to subsequent vascular disease. This novel μECoG-fPAM system complements currently available imaging techniques and represents a promising technology for studying neurovascular coupling in animal models.
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Department of Electrical and Computer Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore.
authors.forename: Yu-Hang
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35 Keyan Road., Zhunan, Miaoli, Taiwan. Electronic address: gs336.tw@gmail.com.
authors.forename: Lun-De
authors.initials: LD
authors.lastname: Liao
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore.
authors.forename: Stacey Sze Hui
authors.initials: SSH
authors.lastname: Tan
authors.affiliation: Department of Electrical and Computer Engineering, Michigan State University, 428 S Shaw Ln, RM 2120 Engineering Building, MI 48824, USA.
authors.forename: Ki Yong
authors.initials: KY
authors.lastname: Kwon
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Department of Neurosurgery, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433, Singapore; SingHealth Duke-NUS Neuroscience Academic Clinical Program, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433 Singapore.
authors.forename: Ji Min
authors.initials: JM
authors.lastname: Ling
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Department of Biomedical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore.
authors.forename: Aishwarya
authors.initials: A
authors.lastname: Bandla
authors.affiliation: Department of Neurology, University of North Carolina at Chapel Hill, 170 Manning Drive, Chapel Hill, NC 27599, USA.
authors.forename: Yen-Yu Ian
authors.initials: YI
authors.lastname: Shih
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Department of Neurosurgery, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433, Singapore; SingHealth Duke-NUS Neuroscience Academic Clinical Program, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433 Singapore.
authors.forename: Eddie Tung Wee
authors.initials: ETW
authors.lastname: Tan
authors.affiliation: Department of Electrical and Computer Engineering, Michigan State University, 428 S Shaw Ln, RM 2120 Engineering Building, MI 48824, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433, Singapore; SingHealth Duke-NUS Neuroscience Academic Clinical Program, National Neuroscience Institute (NNI), 11 Jalan Tan Tock Seng, 308433 Singapore.
authors.forename: Wai Hoe
authors.initials: WH
authors.lastname: Ng
authors.affiliation: Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, No. 268, Kaixuan Road, Hangzhou, Zhejiang 310027, China.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Lai
authors.affiliation: Department of Biomedical Engineering, National Yang Ming University, No. 155, Sec. 2, Linong St., Taipei 112, Taiwan, ROC.
authors.forename: You-Yin
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, 117456, Singapore; Department of Electrical and Computer Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore; Department of Biomedical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore; Department of Biomedical Engineering, Johns Hopkins University, Traylor 701/720 Rutland Ave, Baltimore, MD 21205, USA.
authors.forename: Nitish V
authors.initials: NV
authors.lastname: Thakor
mesh_terms: D000513:Alpha Rhythm; D000818:Animals; D001810:Blood Volume; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003700:Delta Rhythm; D004195:Disease Models, Animal; D004558:Electric Stimulation; D000069280:Electrocorticography / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D004867:Equipment Design; D005073:Evoked Potentials, Somatosensory; D002546:Ischemic Attack, Transient / Q000473:pathology / Q000503:physiopathology*; D007834:Lasers; D008297:Male; D033401:Microscopy, Acoustic / Q000295:instrumentation / Q000379:methods*; D020768:Middle Cerebral Artery; D061088:Photoacoustic Techniques / Q000295:instrumentation / Q000379:methods*; D017207:Rats, Sprague-Dawley; D013997:Time Factors
keywords: Functional photoacoustic microscopy (fPAM); Micro-electrocorticography (μECoG); Neurovascular function; Photothrombotic ischemia; Transient ischemic attack (TIA)