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Biomedical subjects

H Begleiter

Publications and source records attributed to H Begleiter.

At least 109 records · Page 6Linked to original sources
PubMed1979

Impairment of acquisition of a DRL schedule following prolonged ethanol consumption.

Two groups of male hooded rats (N = 9) were given either ethanol or sucrose solutions as their only source of fluid for six months. Thirty days after the ethanol treatment, the rats were reduced to 85% of their free-feeding weights and allowed to obtain 45 mg of food pellets on an FR 1 schedule fof five consecutive days. Subsequently, the rats were tested on four DRL schedules (6. 12, 18, 24 sec). There was no difference between the two groups on FR 1 or DRL 6 sec schedules; however, when the DRL interval was lengthened to 12, 18, and 24 sec, the ethanol group required more sessions than the sucrose group to reach criterion performance. After increases in the DRL interval, the modal interresponse time of the ethanol group shifted more slowly than that of the sucrose group.

Aging↗
PubMed1978

Alcohol self-administration in monkeys (Macaca radiata): the effects of prior alcohol exposure.

Responding by 4 monkeys was maintained under a fixed ratio 10 (FR 10) schedule for either food, intravenous sucrose or alcohol. The 20 hr sessions were divided so that food was available during hours 1, 6, 11, 16 and alcohol or sucrose during hours 2-5, 7-10, 12-15, and 17-20. All animals failed to maintain responding for isocaloric sucrose but continued to respond for food during those sessions. Responding under alcohol conditions was positively accelerated in 2 animals that were not previously exposed to alcohol, whereas prior exposure to alcohol produced maximal response rates during the first alcohol test session. The effects of alcohol in all monkeys were to suppress responding maintained by food and this suppression could not be produced with programmed infusions of isocaloric sucrose.

Alcohol Drinking↗
PubMed1977

Changes in fixed-ratio performance and blood alcohol levels in monkeys.

Three female Bonnet monkeys prepared with indwelling venous catheters were maintained on a fixed-ratio schedule of food reinforcement until response rates were stable. The animals were then intubated with alcohol (5.0 g/kg) 30 min prior to testing. Blood alcohol concentrations (BACs) were determined every 15 min throughout the 90-min session. Each alcohol intubation was separated by 3 days and on the second control day an isocaloric sucrose solution was intubated. The results show that the alcohol-induced response suppression gradually returns to baseline levels after 5 alcohol intubations, and the BACs were concomitantly decreased. The results indicate that the reversibility of alcohol induced behavioral impairments and changes in BACs develop within similar temporal intervals.

Animals↗
PubMed1977

Persistence of brain hyperexcitability following chronic alcohol exposure in rats.

Eighteen hooded Long-Evans rats were implanted with monopolar electrodes for the purpose of recording visual evoked potentials (VEP's) at the following brain sites: visual cortex, reticular formation and thalamus. Baseline VEP's were obtained to flashes for all animals, and subsequently twelve rats were intubated daily with a progression of increasing quantities of 20% (V/V) alcohol (3-8 g/kg), while the remaining six rats received an equivalent amount of water in the same fashion. Beginning 4 1/2 hours after the last dose of intubated alcohol, withdrawal VEP's were sampled every half-hour up to 8 hours, and 24-27 hours postwithdrawal. All experimental animals manifested their greatest brain hyperexcitability at visual cortex, which peaked sharply between 7-8 hours after alcohol withdrawal. Following two weeks of abstinence, half of the experimental rats (N = 6) and half of the controls (N = 3) received an alcohol challenge dose (2 g/kg i.p.), while the remaining animals received the same challenge dose after five weeks. Marked hyperexcitability was observed in the two-week challenge dose animals that had been previously subjected to alcohol; no such increase in VEP amplitude was apparent for control rats. There is also some evidence of hyperexcitability after five weeks of abstinence from alcohol at visual cortex. The data indicates that the neurophysiological responses of post-addict rats to challenge doses of alcohol are readily distinguishable from those of naive animals, even five weeks after alcohol removal. Furthermore, alcohol seems to act differently at different sites of the brain.

Alcoholism↗
PubMed1976

Response suppression on a mixed schedule of reinforcement during alcohol withdrawal.

Two groups of rats were maintained on a mixed fixed-ratio, fixed-interval schedule of food reinforcement until performance was stable. The animals were intubated daily with ascending doses of alcohol or water 30 min before each session, starting with 4.0 g/kg and increasing to the final dose of 8.0 g/kg. The results show that withdrawal from alcohol suppresses responding in all components of a mixed schedule and this suppression lasts approximately 14 hours. These results support previous reports which suggest that the duration of the behavioral aberrations produced by alcohol withdrawal are most severe 6 to 14 hours post-withdrawal.

Animals↗
PubMed1975

Evoked brain potentials as indicators of decision-making.

The effects of decision-making processes on evoked brain potentials recorded at the vertex were studied in human subjects. Significantly different visual evoked potentials to the same physical stimulus were obtained in trails that resulted in different behavioral decisions. The results suggest that certain characteristics of evoked potentials may perhaps be used as indicators of specific behavioral outcomes.

Decision Making↗
PubMed1975

Evoked potential changes during ethanol withdrawal in rats.

We have recently observed an increase in central nervous system excitability during intoxication and alcohol withdrawal in alcoholics. Our present results demonstrate a similar phenomenon in rats. The hyper-excitability caused by ethanol withdrawal is still present subsequent to the overt behavioral symptoms of withdrawal.

Animals↗
PubMed1973

Evoked potential correlates of expected stimulus intensity.

The electrophysiological responses to a flash of medium intensity have different wave shapes in trials in which the occurrence of bright stimuli or dim stimuli is expected. When a bright or dim stimulus is signaled, the potentials evoked by the medium stimulus resemble the responses evoked by a real bright or dim flash.

Electroencephalography↗
PubMed1969

Evoked potentials: modifications by classical conditioning.

Visual evoked potentials to a positive discriminative stimulus change systematically during sensory conditioning and extinction. Changes due to conditioning are manifested in the increased amplitude of the late component of the evoked response. This effect is attenuated during extinction and reappears after reconditioning.

Adult↗