Related Experiment Videos
Alterations in event-related potentials (ERPs) of MPTP-treated monkeys
A Glover1, M F Ghilardi, I Bodis-Wollner
1Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029.
Abstract:
Using an auditory 'oddball' paradigm and classical conditioning, we have studied auditory evoked potentials (AEPs) and P300-like potentials in monkeys pre- and post-MPTP treatment. Free-field acoustic stimuli were 500 Hz and 4000 Hz tones, which were designated as the 'frequent' and 'rare' conditions, respectively. The 4000 Hz stimuli were reinforced with mild somatosensory electrical stimulation. During the first few weeks following 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) administration, all monkeys gradually developed a parkinsonian syndrome, which partially, but not completely improved within 30-40 days in 2 animals. The amplitudes of the AEP were initially significantly decreased, but progressively returned to pretreatment magnitudes in the 2 monkeys which partially recovered. P300-like potentials were initially abolished in all animals; however, 30-40 days later P300 spontaneously re-emerged in the same 2 monkeys. Latencies of both of these signals were unaffected by MPTP. Acute administration of dopamine precursor during the first phase of neurotoxicity partially and temporarily improved depressed AEP amplitudes, but did not restore absent P300-like potentials. The relevance of these results for Parkinson's disease is discussed.
Insights
Parkinsonian syndrome induced by MPTP in monkeys impaired auditory evoked potentials (AEPs) and abolished P300-like potentials. Recovery of these potentials correlated with partial symptom improvement in some animals.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Neurotoxicology
Background:
- 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) is a neurotoxin that induces parkinsonian symptoms.
- Auditory evoked potentials (AEPs) and P300-like potentials are electrophysiological measures sensitive to neurological function.
Purpose of the Study:
- To investigate the effects of MPTP-induced parkinsonism on AEPs and P300-like potentials in monkeys.
- To assess the potential for recovery of these auditory potentials following MPTP treatment.
Main Methods:
- Monkeys were treated with MPTP to induce parkinsonism.
- Auditory oddball paradigm with frequent (500 Hz) and rare (4000 Hz) tones was used.
- Rare tones were reinforced with mild electrical stimulation.
- AEPs and P300-like potentials were recorded pre- and post-MPTP treatment.
Main Results:
- MPTP administration led to parkinsonian syndrome and decreased AEP amplitudes.
- P300-like potentials were abolished in all MPTP-treated monkeys.
- In animals with partial symptom recovery, AEP amplitudes returned to baseline, and P300-like potentials re-emerged.
- Dopamine precursor administration temporarily improved AEP amplitudes but not P300 potentials.
Conclusions:
- MPTP-induced parkinsonism significantly impacts auditory processing, affecting both basic AEPs and cognitive event-related potentials.
- The re-emergence of P300-like potentials in recovering animals suggests a potential link between dopaminergic function and these specific neural signals.
- These findings may offer insights into the neurophysiological alterations observed in Parkinson's disease.