Biomedical subjects

Y Ben-Uriah

Publications and source records attributed to Y Ben-Uriah.

9 recordsLinked to original sources

PubMed1983

Lexical decision time as a function of visual field and stimulus probability.

Two experiments were performed to study lexical decision time to word and non-word Hebrew trigrams as a function of stimulus probability, visual hemifield and responding hand. The results indicate that lexical decision time to words is shorter than to non-words. In addition, although decision time to words is significantly shorter with right hemifield stimulation than with left hemifield stimulation, decision time to non-words is the same whether they are presented to the right or left hemifield. Decision time to non-words decreases almost linearly as stimulus probability increases from 0.25 to 0.75, whereas decision time to words decreases in a concave manner apparently approaching an asymptote at a stimulus probability of 0.75. Responding hand is not significant as a main effect or in any interaction with any other variable. The data are discussed in terms of several models of hemispheric linguistic superiority.

Decision Making↗

PubMed1981

Iron deficiency-induced circadian rhythm reversal of dopaminergic-mediated behaviours and thermoregulation in rats.

An iron-free diet for 28 days caused a reduced level of iron in the blood. Iron deficient rats exhibited a lower level of motor activity and reversed circadian rhythms of thermoregulation and motor activity. The hypothermic effect of d-amphetamine was significantly reduced in iron deficient rats, and the magnitude of this effect was correlated with the decrease in the blood and brain. The hypermotility effect of d-amphetamine was also significantly reduced. Apomorphine-induced stereotyped behaviour was greater during the light period in contrast to that of control rats. The results of this study indicate that iron plays a major role in the normal function of the monoaminergic system in the brain, particularly in the dopaminergic system, via modification of dopaminergic receptors.

Animals↗

PubMed1981

Vasoconstriction and d-amphetamine-induced hypothermia.

The hypothermic effect of d-amphetamine was investigated in rats in which vasoconstriction or vasodilation was induced by pharmacological agents: aramine as vasoconstrictor and neprasol as vasodilator. The d-amphetamine-induced hypothermia was enhanced by both drugs among rats kept at 4 degrees C, and both drugs were unable to modify the d-amphetamine-induced hypothermia. These results indicate that although vasoconstriction and vasodilation play a major role in thermoregulation, d-amphetamine-induced hypothermia is not mediated peripherally by vasoconstriction. Since changes in basal metabolic rate, motor activity, food intake and vasoconstriction are not the peripheral mechanisms by which d-amphetamine induced hypothermia, the mechanisms is still unknown.

Animals↗

PubMed1981

Physiological evidence (hypothermia) for central effects of beta-blocker agents.

In recent studies carried out during the last decade, it has been found that beta-blocker agents have many central effects. These findings raise the question how beta-blocker agents act when they influence central effects. In spite of intensive research efforts on this subject, no answer has been offered so far. Several studies indicate that the effect of beta-blocker agents on the dopaminergic receptors in the brain is very similar to their effect on beta-adrenergic receptors. In a set of experiments we checked the effect of two beta-blocker agents: oxprenolol and dl-propranolol, and the effect of d-propranolol on hypothermia induced by d-amphetamine and apomorphine at an ambient temperature of 4 degrees C. It was found that the two beta-blockers and the d-propranolol significantly potentiated the effect of hypothermia induced by d-amphetamine and apomorphine, an effect which is mediated by the central dopaminergic system. However, the activity of the beta-blockers was agonistic. Furthermore, the influence of d-propranolol on hypothermia shows that this dopaminergic agonistic activity of the beta-blockers is not related to peripheral or central beta-receptor blockage.

Animals↗

PubMed1981

Effects of d-amphetamine on colonic and skin temperatures of rats kept at various ambient temperatures.

d-Amphetamine-treated rats (15 mg/kg) were compared with untreated controls at various ambient temperatures. Colonic and skin temperatures were recorded and their ratio analyzed as a function of ambient temperature. The interaction of the peripheral receptor system (skin) with the central thermoregulatory mechanisms is discussed. The possible utility of this index as a simpler expression of the functional relationship which neither requires nor contradicts the concept of a "set point" is proposed.

Animals↗

PubMed1981

Personality type, life events and sudden cerebrovascular attack.

The severity of cerebrovascular attack (CVA) in patients having no known history of cardiovascular problems tends to be influenced by two factors: (a) recent life events; and (b) "type A" personality. It was found that the higher the frequency of life events reported by the CVA patients, the more severe were the CVAs. The percentage of CVA patients having no known history of cardiovascular disorders who were of type A personality was much higher among the more severe CVA patients. The results of this study indicate the importance of these factors in precipitating CVA.

Cerebrovascular Disorders↗

PubMed1981

A comparison of the hypothermic effects of methylphenidate and d-amphetamine.

Methylphenidate is a central nervous system stimulant with a spectrum of action similar to the effects of d-amphetamine. d-Amphetamine-induced hypothermia is mediated via release of dopamine in the DA mesolimbic pathway. Methylphenidate causes hypothermia among rats kept at 4 degrees C, but d-amphetamine is twice as potent as methylphenidate. Dose-response relationship of methylphenidate thermal effects exhibits a U-shape curve. The hypothermic effects of 5-15 mg/kg methylphenidate are mediated by central dopaminergic neurons, as pretreatment with haloperidol inhibits these effects. The hypothermia produced by larger doses of methylphenidate is not blocked by pretreatment with haloperidol and hypothermia induced by d-amphetamine is blocked by pretreatment with haloperidol.

Animals↗

PubMed1980

Grammatical decision time and visual hemifield stimulation.

An experiment was performed to study grammatical decision time to three-letter Hebrew verbs and nouns presented to the right or to the left visual hemifield. Decision time was measured by the subject's manual response involving the movement of the index finger from the middle one of three electronic contact keys, to the right key to indicate the appearance of a verb, and to the left key to indicate the appearance of a noun. A comparison was also made of two response conditions, right hand responding versus left hand responding. The results indicate a greater number of errors in responding to verbs than to nouns, but no difference in accuracy between right visual field (RVF) stimulation and left visual field (LVF) stimulation. In contrast, the results indicate that grammatical decision time to Hebrew verbs is shorter than to nouns for all conditions of stimulation and response. Decision time to verbs appearing in the right visual field (RVF) is shorter than to verbs appearing in the left visual field (LVF). Consequently, the difference in decision time between verbs and nouns is greater for RVF stimulation than for LVF stimulation. There is no difference in decision time for stimulation of the RVF or LVF by nouns. Responding hand also does not affect grammatical decision time to either verbs or nouns in either RVF or LVF stimulation.

Choice Behavior↗

PubMed1980

Chronic lithium treatment and dopamine-mediated behavior.

The effect of 3--4 weeks of chronic lithium (Li) treatment in food on amphetamine-induced stereotypy, hyperactivity, and hypothermia was examined. The long-term Li treatment failed to inhibit these behaviors and even resulted in small but statistically significant potentiation of stereotypy and hypothermia. The absence of an inhibitory effect of Le on these dopaminergic processes is consistent with Li's lack of antischizophrenic properties. Previous studies reporting conflicting results, including lithium inhibition of amphetamine-induced hyperactivity, used acute or very short-term lithium administration and/or did not verify serum lithium levels to be at therapeutically equivalent levels.

Animals↗