Age differences in dynamic measures of EEG.

Eighteen older adults and 18 younger adults were compared on two quantitative measures describing changes over time in the spatial distribution of running EEG. EEG was collected from 128 electrodes under resting eyes-open and eyes-closed conditions and during performance of a 13 minute sustained attention task. One EEG measure, the recrudescence rate, represented the number of changes in the location of the highest squared voltage per second.

Nicotine modulates nitric oxide in rat brain.

Nicotine exerts its central actions by regulating cationic fluxes through nicotinic acetylcholine receptors (nAChRs). By this effect, the drug likely also modifies events occurring beyond the nAChR, including the regulation of nitric oxide (NO) synthesis. The present study was undertaken to assess the effects of acute and chronic nicotine administration (0.

Nitric oxide synthetase inhibition hinders facilitation of active avoidance learning by nicotine in rats.

Nicotine produces dose-dependent enhancement of performance in an active avoidance test, and also increases the levels of NO2- and NO3-, which are stable metabolites of nitric oxide (NO), in various brain regions of rats. On the basis of these two observations, we hypothesized that the beneficial effect of nicotine on learning could result from increased NO in relevant brain regions. We therefore tested active avoidance performance in rats given L-Nomega-nitroarginine (L-NA) to inhibit NO synthetase (NOS) prior to nicotine administration.

The effects of melatonin on the antioxidant systems in experimental spinal injury.

Melatonin has been recently shown by various in-vivo and in-vitro studies to exert potent neutralising effects on hydroxyl radicals, stimulate glutathione peroxidase (GSH-Px) activity, and protect catalase (CAT) from the destructive activity of hydroxyl radicals in neural tissue. We aimed to investigate the possible effects of pharmacological dose of melatonin on some of the antioxidant defence systems in an in-vivo study of experimental spinal injury. Seven groups of adult male Sprague Dawley rats were used in the following scheme: Group I: Naive (n = 6), Group II: Lesion (n = 8), Group III: Melatonin (n = 5), Group IV: Melatonin + Lesion (n = 8), Group V: Placebo + Lesion (n = 5), Group VI: Sham operation (n = 5), and Group VII: Placebo (n = 5).

Increased cerebrospinal fluid and serum nitrite and nitrate levels in amyotrophic lateral sclerosis.

Abnormal glutamate metabolism is implied in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS) and cerebrospinal fluid (CSF) glutamate levels appear to be elevated. Since nitric oxide (NO) inhibits glutamate transport, excessive amounts of nitric oxide could underlie the glutamate induced neurotoxicity in ALS. Stable metabolites of NO (NO2- + NO3-) levels were determined in serum and CSF of sporadic ALS patients and control subjects.

Intersession interval affects performance in the Morris Water Maze.

We have recently reported an effect that shows a sexually dimorphic difference in cognitive style rather than ability. The preparation for potentially producing this proximal perceptual style effect is one where rats are first given 4-trial daily acquisition sessions for 12 days with the platform always in the same position, but sometimes visible (perceptual, "look-out" condition) and sometimes hidden (conceptual, "navigational" condition). On the first, probe trial of the 13th day, the platform's position is shifted to a point very close (proximal) to the rat's starting position, and made visible.

Sex difference in up-regulation of nicotinic acetylcholine receptors in rat brain.

This study tested for sex differences in the effects of chronic nicotine administration and withdrawal on nicotinic acetylcholine receptor binding in brain. Rats received nicotine (0.6 mg/kg, s.

Attention and para-attentional processing. Event-related brain potentials as tests of a model.

In 1972 when we began to analyze the vast amount of material from the laboratories of physiological psychologists, we had only a vague conceptualization of what a model of attention might look like. We began where everyone else had, with the view that everything had something to do with "arousal" but with Lacey's (1967) warning in mind that all of the dependent variables might not actually be measuring aspects of the same process. With this warning in mind, we were forced by the data to organize them into a three-systems mode.

Psychophysiological indices of cerebral maturation.

Maturation (1-21 yr) trajectories for quantitative electroencephalographic (QEEG) frequency spectra are presented for four regions of the human brain. The results show that all four regions exhibited discontinuous maturation rates: five stages were identified. The stages were synchronous across regions during the first 10 1/2 years of life.

The relationship between the Gabor elementary function and a stochastic model of the inter-spike interval distribution in the responses of visual cortex neurons.

In a previously reported study (Berger et al. 1990) we analyzed distributions of interspike intervals recorded extracellularly from cat visual cortex under four stimulus conditions. Stimuli were gratings differing in orientation and spatial frequency.

An analysis of neural spike-train distributions: determinants of the response of visual cortex neurons to changes in orientation and spatial frequency.

A previously unexploited method of examining neural spike-trains was applied to data obtained from cells in the visual cortex. Distributions of interspike intervals recorded extracellularly from cat visual cortex under four conditions were analyzed. Stimuli were gratings differing in orientation and spatial frequency.

Enhancement of opiate binding to neural membranes with an ethyl glycolate ester of phosphatidyl serine.

In order to elucidate the mechanism by which acidic lipids enhance the stereospecific high-affinity binding of opiates to neural membranes, chemical synthesis and testing of modified lipid derivatives were undertaken. Phosphatidyl serine ethyl glycolate ester was synthesized from phosphatidyl serine (PS) and ethyl diazoacetate and purified by preparative TLC on silica gel. The PS ester enhanced the specific binding of [(3)H]dihydromorphine to synaptic membranes from rat brain by 26%, while the enhancement with PS was 35% over control without added lipid.