title: Study of the origin of short- and long-latency SSEP during recovery from brain ischemia in a rat model.
abstract: Somatosensory evoked potentials (SSEPs) have been established as an electrophysiological tool for the prognostication of neurological outcome in patients with hypoxic-ischemic brain injury. The early and late responses in SSEPs reflect the sequential activation of neural structures along the somatosensory pathway. This study reports that the SSEP can be separated into early (short-latency, SL) and late (long-latency, LL) responses using independent component analysis (ICA), based on the assumption that these components are generated from different neural sources. Moreover, this source separation into the SL and LL components allows analysis of electrophysiological response to brain injury, even when the SSEPs are severely distorted and SL and LL components get mixed. With the help of ICA decomposition and corrected peak estimation, the latency of LL-SSEP is shown to be predictive of long-term neurological outcome. Further, it is shown that the recovery processes of SL- and LL-SSEPs follow different dynamics, with the SL-SSEP restored earlier than LL-SSEP. We predict that the SL- and LL-SSEPs reflect the timing of the progression of evoked response through the thalamocortical pathway and as such respond differently depending upon injury and recovery of the thalamic and cortical regions, respectively.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Bezerianos
authors.initials: B
authors.lastname: Anastassios
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.forename: Jai
authors.initials: J
authors.lastname: Madhok
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Jia
authors.forename: Nitish V
authors.initials: NV
authors.lastname: Thakor
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D002545:Brain Ischemia / Q000150:complications / Q000503:physiopathology*; D004567:Electrodes, Implanted; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006323:Heart Arrest / Q000150:complications; D008297:Male; D009422:Nervous System Diseases / Q000209:etiology; D009434:Neural Pathways / Q000502:physiology; D025341:Principal Component Analysis; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000502:physiology
references.citation: Resuscitation. 2008 Mar;76(3):431-42
references.pmid: 17936492
references.citation: J Neurophysiol. 2002 Oct;88(4):1924-32
references.pmid: 12364518
references.citation: Mov Disord. 2000;15 Suppl 1:14-21
references.pmid: 10755267
references.citation: Clin Neurophysiol. 2000 Oct;111(10):1779-87
references.pmid: 11018492
references.citation: Neurology. 2006 Jul 25;67(2):203-10
references.pmid: 16864809
references.citation: Neuroscience. 1994 Dec;63(3):711-24
references.pmid: 7898672
references.citation: Proc Natl Acad Sci U S A. 2003 May 13;100(10):6174-9
references.pmid: 12719546
references.citation: Lancet. 1993 Apr 3;341(8849):855-8
references.pmid: 8096562
references.citation: Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):803-10
references.pmid: 9448244
references.citation: J Cereb Blood Flow Metab. 1995 Nov;15(6):1032-9
references.pmid: 7593335
references.citation: Neurosci Lett. 2001 Apr 20;302(2-3):137-40
references.pmid: 11290406
references.citation: J Neurosci Methods. 2004 Mar 15;134(1):9-21
references.pmid: 15102499
references.citation: Neuroscience. 2002;115(3):917-29
references.pmid: 12435429
references.citation: Neural Comput. 1995 Nov;7(6):1129-59
references.pmid: 7584893
references.citation: Clin Neurophysiol. 2008 May;119(5):1051-61
references.pmid: 18343719
references.citation: Neurourol Urodyn. 2009;28(4):320-4
references.pmid: 19090588
references.citation: AJNR Am J Neuroradiol. 1998 Apr;19(4):648-52
references.pmid: 9576649
references.citation: Vision Res. 1997 Dec;37(23):3327-38
references.pmid: 9425547
references.citation: Neural Netw. 2000 May-Jun;13(4-5):411-30
references.pmid: 10946390
references.citation: Brain Res. 2006 Sep 21;1111(1):166-75
references.pmid: 16919609
references.citation: Trends Neurosci. 2001 Oct;24(10):595-601
references.pmid: 11576674
references.citation: Proc Natl Acad Sci U S A. 1997 Sep 30;94(20):10979-84
references.pmid: 9380745
references.citation: Crit Care Med. 1996 Apr;24(4):672-8
references.pmid: 8612421
references.citation: J Comp Neurol. 1990 Sep 8;299(2):133-50
references.pmid: 2172324
references.citation: J Clin Neurophysiol. 2009 Aug;26(4):227-35
references.pmid: 19584750
references.citation: J Neurotrauma. 2008 Nov;25(11):1323-34
references.pmid: 18976168