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Biomedical subjects

I Bodis-Wollner

Publications and source records attributed to I Bodis-Wollner.

At least 55 records · Page 3Linked to original sources
PubMed1993

Animal models of Alzheimer's Parkinson's and Huntington's disease. A minireview.

Animal studies have contributed significantly to deeper understanding of several neurodegenerative disorders but fully developed models are lacking. The best models to study motor, sensory and cognitive changes and the effects of therapeutic attempts are rodents and non-human primates. This review describes neuropharmacologic, neuroanatomic and behavioral features of animal models of Alzheimer's, Parkinson's and Huntington's disease.

Alzheimer Disease↗
PubMed1993

Visual and visual perceptual disorders in neurodegenerative diseases.

Optic neuropathy is reported to occur in 10-30% of patients, while retinopathy is characteristic of type III OPCA. The use of visual and visual electrophysiological tests in early diagnosis and classification is promising. The relationship between visual impairment and other manifestations of these diseases has not been explored.

Brain Diseases↗
PubMed1993

Retinal periphlebitis in multiple sclerosis.

BACKGROUND: The ocular and visual manifestations of multiple sclerosis are varied. The most uncommon is sheathing of the veins, periphlebitis. METHODS: A 39-year-old white female presented with primary visual complaints of contrast problems on a computer terminal. The patient was lost to follow up for 4 years, however, upon return a clinical diagnosis of multiple sclerosis was confirmed. Six years after the initial presentation, ophthalmoscopic exam of both eyes revealed marked focal sheathing of the retinal veins in the periphery, and associated hemorrhages in the right eye. RESULTS: During follow-up, the left eye became further involved developing hemorrhages and a retinal hole, which was treated. The visual consequence of the multiple sclerosis as a result of further exacerbations were bilateral centrocecal scotomas and midly reduced visual acuity. CONCLUSIONS: Multiple sclerosis should be considered in the differential diagnosis of patients with retinal periphlebitis.

Adult↗
PubMed1992

Evidence for two distinct nonlinear components in the human pattern ERG.

We obtained the electroretinogram (PERG) in three observers to a 4.6 c/deg grating pattern with a sinusoidal luminance profile which was modulated in time simultaneously with two sinusoidal temporal frequencies (f1 and f2), or at a single frequency (either f1 or f2). Input temporal frequency ranged from 2.4 to 7.5 Hz. A pattern modulated in the counterphase mode with a single frequency produces a response containing only even harmonics of that frequency. However, when the pattern is counterphase modulated with both f1 and f2, the PERG contains second order response frequencies corresponding to intermodulation components (sums and differences) between the two fundamental frequencies. Such frequencies do not exist in the stimulus--they can only be generated by nonlinear neural interactions. Our results provide evidence for at least two nonsaturating nonlinear response mechanisms in the human retina.

Adult↗
PubMed1992

Sensory evoked potentials: PERG, VEP, and SEP.

The review summarizes current developments in pattern electroretinography practice and theory: generator sources and clinical applications. This is particularly relevant to neuronal disease of the central nervous system (CNS). Visual evoked potentials (VEPs) are discussed in reference to the evolution and follow up of multiple sclerosis (MS) and in conjunction with magnetic resonance imaging (MRI) demonstrated abnormalities. These reveal that the techniques are complementary. Sensory evoked potentials (SEPs) in conjunction with MRI studies are highlighted as quantitatively comparable in spinal cord disorders.

Central Nervous System Diseases↗
PubMed1991

Acetyl-levo-carnitine protects against MPTP-induced parkinsonism in primates.

Acetyl-levo-carnitine (ALC) protects against 1-methyl, 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity in the nonhuman primate. ALC pretreated monkeys do not show signs of parkinsonism or electroretinographic changes typical of dopaminergic deficiency when given MPTP. In addition, pilot neurochemical and morphological data confirm a partial protection effect. While MAO-B inhibitors, like L-Deprenyl, are thought to protect dopaminergic neurons from MPTP-induced cell death by preventing the conversion of MPTP to its toxic metabolite MPP+, ALC is not known to have MAO-B affinity. Converging evidence suggests that ALC may affect directly mitochondrial respiration, which is known to be the target of MPP+ and affected in human neurodegenerative diseases, including Parkinson's disease. The results of this study point to new therapeutic avenues for the treatment of these nosologic entities.

Acetylcarnitine↗
PubMed1991

Evidence for two systems mediating perceived contrast.

We report psychophysical evidence for a categorical dichotomy in the perception of contrast. Observers were required to rate the contrast of sinusoidal gratings (2.3 c/d) with contrast varying over a given range relative to two standards. One standard was designated "high" contrast and the other was designated "low." There was a boundary effect: contrast judgment depended upon whether the tested ranges included 10-15% contrast and discrimination was sharpest at the boundary between 10 and 15% contrast. These results are consistent with the existence of two systems underlying perceived contrast; one primarily sensitive below 10%, and the other primarily sensitive above 15% contrast.

Adult↗
PubMed1990

The auditory P 300 correlates with specific cognitive deficits in Parkinson's disease.

An abnormally prolonged latency of the P 300 event-related potential has been reported in several types of dementing illnesses, including Parkinson's disease (PD). While some PD patients have dementia, a significant number of PD patients have less severe cognitive impairments. We examined the relationship between the auditory P 300 and a neuropsychological battery of 11 tasks in 43 PD patients. The quantitative relationship between the individual neuropsychological measures and the P 300 was examined using partial correlation and analysis of covariance techniques which controlled for age, education, and illness duration. The strongest correlations were between P 300 and both short-term memory and visual perception. Global cognitive deficits do not appear to relate to the abnormal P 300 responses in PD: instead, specific aspects of cognitive decline accounted for the electrophysiological abnormalities. An abnormally long or absent P 300 correlated with deficits on select cognitive tasks: those involving memory, visual perception, and abstract reasoning. The interactions between anatomical and neurochemical abnormalities in PD are discussed in light of the pattern of deficits seen in this study.

Adult↗
PubMed1990

Visual deficits related to dopamine deficiency in experimental animals and Parkinson's disease patients.

In patients affected by Parkinson's disease, and in the monkey model of this disease, visual defects have been shown using psychophysical and electrophysiological measures of spatial and temporal contrast sensitivity. These studies imply an essential role for dopamine in primate vision. There is electrophysiological and neurochemical evidence to suggest that at least part of the problem is impaired retinal processing caused by systemic dopaminergic deficiency. Some of the deficits that have been demonstrated, consistent with physiological studies, suggest that center-surround interaction of neurons may suffer as a consequence of dopaminergic deficiency. The role of the regulation of retinal dopamine (D1 and D2) receptors in primate vision and of the balance of these receptors in presynaptic dopaminergic deficiency is not yet determined. Using sinusoidal grating stimuli in cognitively loaded tasks may increase understanding of the behavioral consequences of visual deficits seen in dopamine deficiency syndromes.

Animals↗
PubMed1990

Visuospatial orientation in Parkinson's disease.

Visuospatial functioning in patients with Parkinson's disease was investigated using neuropsychological measures of basic visual perception, complex perceptual discrimination, and spatial orientation. Three subgroups of patients were described: (a) those with broadly impaired visuospatial abilities, (b) those with generally intact abilities, and (c) those whose performance on a task of spatial orientation was lower than their performance on a task of complex perceptual discrimination. These subgroup differences were also concordant with three other variables: age, duration of disease, and degree of dementia. It is suggested that decreases in spatial orientation functioning in Parkinson's disease may reflect the speed of progression of this disease.

Adult↗
PubMed1990

Physiological effects of acetyl-levo-carnitine in the central nervous system.

Acetyl-levo-carnitine (ALC) is a neuroactive agent. Some studies demonstrate that it modifies cortical electrophysiological responses in animals and man. Foremost, neuronal synchrony appears to be affected. It is thought that ALC is involved in cholinergic neurotransmission although some of its effects may be more complex. Electrophysiological processes involved in cognition may be influenced by ALC: in particular P300, an event-related potential, can be modified. Recent research data in man and monkeys concerning presumed ALC effects on P300 and cognition are summarized.

Acetylcarnitine↗
PubMed1989

The effect of intraocular 6-hydroxydopamine on retinal processing of primates.

In previous studies, we showed that in the monkey, systemically administered N-methyl, 4-phenyl, 1-2-3-6 tetrahydropyridine (MPTP) produces a chronic parkinsonian syndrome accompanied by spatial frequency-dependent abnormalities in both the pattern electroretinogram and visual evoked potential. We describe the effect of intravitreally administered 6-hydroxydopamine (6-OH-DA) on the pattern electroretinogram and pattern visual evoked potential of 3 aphakic monkeys. Because of the aphake condition, several complexities of intravitreal injection of 6-OH-DA could be avoided. Nevertheless, following 6-OH-DA treatment, both the phase and the amplitude of pattern electroretinogram and pattern visual evoked potential became abnormal. This abnormality was most pronounced for the higher spatial frequencies (2.5 and 3.5 cycles per degree), whereas lower spatial frequencies (0.5 and 1.2 cycles per degree) were less impaired. The effects of systemically administered MPTP on pattern electroretinogram and pattern visual evoked potential are similar to the effects of intravitreal injections of 6-OH-DA, suggesting that a retinal catecholaminergic system plays an important role in pattern vision of primates.

Animals↗