Evoked potentials

Further examinations have been made on the sleep-wakefulness cycle of aluminum-exposed cats. The amount of time spent in slow-wave sleep went from 58% prior to injection, to 63% on day 12, and 72% on day 15 post-injection. Conversely, rapid eye movement (REM) sleep went from 13% pre-injection to 14% on day 12, and only 7% on day 15 post-injection. 

Transcallosal stimulated evoked responses have also been examined in the cat. There is a progressive decline in the surface negative wave after day 7 post-injection that then reversed polarity and was replaced by a large surface positive wave 24-72 h prior to the onset of status epilepticus. The late, 120 ms peak latency, surface positive wave also reversed polcirity in the later stages of encephalopathy. 

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Stewart RD, Fisher TN, Hosko MJ, et al Experimental human exposure to methylene chloride. Arch Environ Health 25 342-348, 1972 Substance Abuse and Mental Health Services Administration Preliminary Estimates from the 1995 National Household Survey on Drug Abuse. Rockville, MD, U.S. Department of Health and Human Services, 1996 Tenenbein M, PillayN Sensory evoked potentials in inhalant (volatile solvent) abuse. J Paediatr Child Health 29 206-208, 1993... 

Recently, there has been a growth of interest in the development of in vitro methods for measuring toxic effects of chemicals on the central nervous system. One approach has been to conduct electrophysiological measurements on slices of the hippocampus and other brain tissues (Noraberg 2004, Kohling et al. 2005). An example of this approach is the extracellular recording of evoked potentials from neocortical slices of rodents and humans (Kohling et al. 2005). This method, which employs a three-dimensional microelectrode array, can demonstrate a loss of evoked potential after treatment of brain tissue with the neurotoxin trimethyltin. Apart from the potential of in vitro methods such as this as biomarkers, there is considerable interest in the use of them as alternative methods in the risk assessment of chemicals, a point that will be returned to in Section 16.8. 

Vajda, A. Schmid, H., and Groll-Knapp, E. et al. (1974). EEC changes in evoked potentials caused by insecticides. Electroencephalography and Clinical Neurophysiology 37, 442. 

Rothwell, J. C. 1993 Evoked potentials, magnetic stimulation studies and event-related potentials. Curr. Opin. Neurol. 6, 715-723. 

Berman NE, Marcario JK, Yong C et al (1999) Microglial activation and neurological symptoms in the SIV model of NeuroAIDS association of MHC-II and MMP-9 expression with behavioral deficits and evoked potential changes. Neurobiol Dis 6 486 98 Biber K, Zuurman MW, Dijkstra IM et al (2002) Chemokines in the brain neuroimmunology and beyond. Curr Opin Pharmacol 2 63-68... 

Altered flash evoked potentials were not observed in rats exposed to 250 ppm. 

An increased level of exploratory activity immediately after exposure, attributed to reduced anxiety on the part of the rats, was also observed in this study. Decreased avoidance was observed in rats exposed to 125 ppm trichloroethylene 4 hours per day, 5 days per week for 30 days (Goldberg et al. 1964a). Changes in visually evoked potentials (Blain et al. 1992) and electroretinal responses to flash stimulation (Blain et al. 1994) were seen in rabbits exposed to 350 ppm trichloroethylene for 12 weeks (4 days/week, 4 hours/day). The study authors suggested that binding of trichloroethanol to blood proteins may enable it to reach the visual cortex. 

Arezzo JC, Simson R, Brennan NE. 1985. Evoked potentials in the assessment of neurotoxicity in humans. Neurobehav Toxicol Teratol 7 229-304. 

Barret MD, Garrel S, Danel V, et al. 1987. Chronic trichloroethylene intoxication A new approach by trigeminal-evoked potentials. Arch Environ Health 42 297-302. 

Blain L, Lachapelle P, Molotchnikoff S. 1992. Evoked potentials are modified by long term exposure to trichloroethylene. Neurotoxicology 13 203-206. 

Dogui M, Mrizak N, Yacoubi M, et al. 1991. Trigeminal somatosensory evoked potentials in workers handling trichloroethylene. Neurophysiol Clin 21 95-103. 

Rebert CS, Day VL, Matteucci MJ, et al. 1991. Sensory-evoked potentials in rats chronically exposed to trichloroethylene Predominant auditory dysfimction. Neirrotoxicol Teratol 13 83-90. 

Liles, S.L. Cortico-striatal evoked potentials in eats. Electroencephalogr Clin Neurophysiol 35 277-285, 1973. 

MacLeod N. and Reinhardt W. (1983). An electrophysiological study of the accessory olfactory bulb in rabbit — I. Analysis of electrical evoked potential fields. Neuroscience 10, 119-129. 

Dissemination in space by MRI evidence of nine or more T2-weighted brain lesions, or two or more cord lesions, or four to eight brain and one cord lesion, or positive visual evoked potentials with four to eight MRI lesions, or positive visual evoked potentials with less than four brain lesions plus one cord lesion. 

Evoked potential testing A procedure in which sensory nerve pathways are stimulated and the time lapse to electrical response in the corresponding area of the brain is measured. 

NS (children, environmental exposure) Neurological Blood lead correlated with alterations in visual evoked potentials range, 1.4-17.4 Altmann et al. 1998 Winneke et al. 1994... 

NS (general population) Neurological Altered auditory evoked potential latency and decreased hearing acuity in children 4-60 Holdstein et al. 1986 Robinson et al. 1985 Schwartz and Otto 1987... 

Brainstem auditory evoked potential (BAEP) latency (Holdstein et al. 1986 Otto et al. 1985 Robinson et... 

Ewert T, Beginn U, Winneke G, et al. 1986. [Sensory nerve conduction and visual and somatosensory evoked potential in children exposed to lead.] Nervenarzt 57 465-471. (German)... 

Holdstein Y, Pratt H, Goldsher M, et al. 1986. Auditory brain stem evoked potentials in asymptomatic lead-exposed subjects. J Laryng Otol 100 1031-1036. 

Lasky RE, Maier MM, Snodgrass EB, et al. 1995. The effects of lead on otoacoustic emissions and auditory evoked potentials in monkeys. Neurotoxicol Teratol 17 633-644. 

Lilienthal H, Winneke G. 1996. Lead effects on the brain stem auditory evoked potentials in monkeys during and after the treatment phase. Neurotoxicol Teratol 18 17-32. 

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