The photically evoked afterdischarge: Current concepts and potential applications

Shearer, Donald E.; Creel, Donnell J.

doi:10.3758/bf03326741

Cited by 23 publications

(11 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…sensitivity of this portion of the FEP to alteration by solvents (Herr et al, 1992;Dyer et al, 1988;Rebert et al, 1989b,c) and because it may be influenced by the behavioral state of the test subject, possibly reflecting processes related to habituation and/or sensitization (Dyer, 1989;Herr et al, 1991Herr et al, , 1994. It should be noted that although other portions of the FEP may also be affected by the test paradigm (Herr et al, 1991(Herr et al, , 1994(Herr et al, , 1996, the most dramatic changes associated with the animal's behavioral state are usually associated with peak N ]6 o and the photic afterdischarge (Bigler, 1977;Dyer, 1989;Herr et al, 1991Herr et al, , 1994Joseph el al.. 1981;Shearer and Creel, 1978).…”

Section: Methodsmentioning

confidence: 99%

A Comparison of the Acute Neuroactive Effects of Dichloromethane, 1,3-Dichloropropane, and 1,2-Dichlorobenzene on Rat Flash Evoked Potentials (FEPs)

Herr

Boyes

1997

Toxicol Sci

View full text Add to dashboard Cite

Previous research showed that acute exposure to dichloromethane (DCM) produced a selective reduction in peak N i0 of flash evoked potentials (FEPs) in rats. In contrast, acute exposures to p-xylene or toluene selectively reduced FEP peak N 160 . The present experiments compared the effects of DCM (log P = 1.25; oihwater partition coefficient), 1,3-dichloropropane (DCP; log P = 2.00), and 1,2-dichlorobenzene (DCB; log P = 3.38) on FEPs recorded from adult Long-Evans rats. Before administration of test compounds, FEPs were recorded for five daily sessions to develop FEP peak N m . Test compounds were dissolved in corn oil and administered ip at doses based on proportions of their LD50 values. The doses were: DCM, 0, 57.5, 115, 230, or 460 mg/kg; DCP, 0, 86, 172, 343, or 686 mg/kg; and DCB, 0, 53, 105, 210, or 420 mg/kg. Testing times after dosing varied among compounds and were based on pilot studies to measure both the times of peak effect and recovery. Each solvent produced significant changes in the latency and amplitude of multiple components of the FEP waveforms. However, the predominant effect of DCM was to reduce the amplitude of peak JV 30 (ED50 = 326.3 mg/kg), that of DCP was to reduce both peaks N 30 (ED50 = 231.0 mg/kg) and N 160 (ED50 = 136.8 mg/kg), and that of DCB was to reduce peak iVi6o (ED50 = 151.6 mg/kg). There was no consistent relationship between log P values and the potency of the compounds to alter 1 Portions of this report were presented as posters at the 30th and 31 st annual meetings of the Society

show abstract

Section: Methodsmentioning

confidence: 99%

A Comparison of the Acute Neuroactive Effects of Dichloromethane, 1,3-Dichloropropane, and 1,2-Dichlorobenzene on Rat Flash Evoked Potentials (FEPs)

Herr

Boyes

1997

Toxicol Sci

View full text Add to dashboard Cite

show abstract

“…Both regions of the brain are necessary for the for mation of late components of the VEP (latencies > 100 ms) [Shearer and Creel, 1978;Allison et al. 1977], and would therefore have to reflect an activation of the GABA system due to valproate on the VEP.…”

Section: Discussionmentioning

confidence: 99%

“…Although differences in the structure and function of the visual system are known for different species, a comparative electrophysiological characterization of components of the 'primary' and 'sec ondary' complex of the VEP of rats and man appears to be possible [Borhely, 1973], In particular, psychopharma ceuticals and behavioural changes (e.g. excitation) exert a similar, species-independent action on the 'secondary complex' of the VEP [Shearer and Creel, 1978], Ampli tude reductions of the late components of SEP in schizo phrenics after the administration of haloperidol have been described by Saletu et al [1971]; in this connection it should be borne in mind that haloperidol besides blocking dopamine receptors also gives rise to an inhibi tion of the cellular GABA uptake, and thus to a potentia tion of the GABA action on synapses [Iversen and John ston, 1971], Interrelations between haloperidol and val proate have been studied by Walters et al [1979] on the nigrostriatal dopamine system; in this process valproate inhibits the new synthesis of dopamine induced by halo peridol without influencing the excitability of dopamin ergic neurons. There have been no such investigations on the more complex thalamocortical neuronal circuits in volved in the formation of late components of the VEP.…”

Section: Discussionmentioning

confidence: 99%

Effects of a GABA-Mimetic Drug (Sodium Valproate) on Visually Evoked Potentials in Chronic Schizophrenics

Kausen¹,

Zimmermann²,

Fünfgeld³

et al. 1984

Neuropsychobiology

View full text Add to dashboard Cite

Data were obtained from 14 chronically schizophrenic women (age 40–59) living in the same ward of a psychiatric hospital (Marburg, FRG), and having been treated with clozapine (450–600 mg/day) during the last 2 years. The uncontrolled study was initiated by the addition of sodium valproate (900 mg/day) for 3 months. The observation commenced after the discontinuation of the valproate medication with the evaluation of the symptoms (Brief Psychiatric Rating Scale, BPRS) and the visually evoked potentials (VEP). The VEP were recorded after 3, 12 and 30 days and the rating was repeated after 4 weeks. No significant changes in symptomatology were obtained with the BPRS in patients under combination therapy in comparison with the scores 30 days after discontinuation of the valproate medication. On the other hand, after single flash stimulation, the amplitudes of the components N₁₁₀, P₂₆₀ and N₃₀₀ of the VEP were significantly (p < 0.05) increased during the same time interval. These findings are interpreted as an expression of an inhibiting action of the GABA system on the reactivity of the visual system in chronic schizophrenics induced by the comedication of sodium valproate.

show abstract

“…Low-level mesencephalic reticular activ ity [24,25], i.e. short-term habituation [26,27] and quiet waking state of the unrestrained rat [28,29], are necessary for the increased occurrence of well-developed responses, while both increased arousal and drowsiness suppress it [30,31], From the pharmacological point of view, PEAD was proposed as a model of petit mal epilepsy [31,32] butaccording to the extensive studies reviewed by Bigler [5] it proved not to be specific for this purpose: anesthetics. adrenergic and cholinergic agents as well as ACTH or pargyline influenced it more or less and in different ways.…”

Section: Discussionmentioning

confidence: 99%

Classification of Drugs Based on Visually Evoked Responses in Rats

Sarkadi

Ambrus²,

Szporny

1993

Neuropsychobiology

View full text Add to dashboard Cite

Quantified parameters of photically evoked afterdischarge and EEG background activity of visual cortex of freely moving rats were used as variables to obtain a t profile for each drug dosage. Behavioural scores were also used. The determination of the dose/time-effect profile of a compound was based on normalization of data and on calculation of the first two factor values in comparison with pooled data of representatives of neuroleptic, anxiolytic, convulsant, petit mal anticonvulsant, antidepressant and psychostimulant drug classes. The compounds were investigated in different dosages and/or routes of administration. The model and procedure are validated for antipsychotic, anxiolytic and vigilance enhancer effect, and comprise the predictability of proconvulsive and petit mal anticonvulsive effects.

show abstract

The photically evoked afterdischarge: Current concepts and potential applications

Cited by 23 publications

References 68 publications

A Comparison of the Acute Neuroactive Effects of Dichloromethane, 1,3-Dichloropropane, and 1,2-Dichlorobenzene on Rat Flash Evoked Potentials (FEPs)

A Comparison of the Acute Neuroactive Effects of Dichloromethane, 1,3-Dichloropropane, and 1,2-Dichlorobenzene on Rat Flash Evoked Potentials (FEPs)

Effects of a GABA-Mimetic Drug (Sodium Valproate) on Visually Evoked Potentials in Chronic Schizophrenics

Classification of Drugs Based on Visually Evoked Responses in Rats

Contact Info

Product

Resources

About