Neural correlate of behavioral plasticity in command neurons of Pleurobranchaea

Food stimuli normally excite the command neurons of Pleurobranchaea that cause feeding. In contrast, the same food stimuli selectively inhibit these neurons in specimens that have been trained to suppress feeding and withdraw from food by means of an avoidance conditioning paradigm consisting of paired food and conditional shock. Food stimuli excite the feeding command neurons of yoked control specimens exposed to unpaired food and shock, but inhibit the feeding command neurons of untrained specimens that have been satiated with food. These results suggest that the command neurons serve as a neural locus at which an animal's behavior is modulated by past experiences. These results also establish a neural correlate of behavioral plasticity, in the form of synaptic inhibition of the command neurons.     

Lysergic acid diethylamide: dissociation of its behavioral and hyperthermic actions by DL-alpha-methyl-p-tyrosine

Rabbits treated with LSD 25 exhibit characteristic signs of hyper-excitability, increased peripheral sympathetic activity, and hyperthermia. When the rabbits received prior treatment with DL-(alpha)-methyl-p-tyrosine, the excitation and sympathetic actions of LSD 25 were abolished or attenuated, but the hyperthermia was unchanged from that of the controls. Concentrations of norepinephrine in brain stems of treated rabbits were greatly decreased. The excitation of central nervous system and sympathomimetic actions of LSD 25 in the rabbit are apparently mediated by norepinephrine, whereas the hyperthermic action functions. through a nonadrenergic mechanism.     

氯胺酮与安定在人流术中的应用

为了减少病人在人流术中的痛苦,我们于2002年开始试用氯胺酮加安定用于人工流产手术,取得了较好的效果,现报道如下.     

Evoked response correlate of symbol and significate

Changing the source and intensity of the auditory signal to six trained cats responding to meaningful auditory stimuli permits exogenous and endogenous processes in the auditory evoked potential to be separated. For short-latency exogenous processes, latency and amplitude depend on the parameters of the physical stimulus. However, the amplitude and shape of longer-latency endogenous processes are essentially independent of the location and intensity of the signal source and seem to be invariant concomitants of the significance of the signal.     

A benzodiazepine receptor antagonist decreases sleep and reverses the hypnotic actions of flurazepam

The benzodiazepine receptor antagonist 3-hydroxymethyl-beta-carboline, which blocks several of the pharmacological actions of benzodiazepines, induces a dose-dependent increase in sleep latency in the rat. Furthermore, at a low dose that by itself does not affect sleep, 3-hydroxymethyl-beta-carboline blocks sleep induction by a large dose of flurazepam. The benzodiazepine receptor may play a role in both the physiological regulation and pharmacological induction of sleep.     

Neural correlate of perceptual adaptation to gratings

Exposure of simple cells of the cat striate cortex to high-contrast drifting gratings greatly reduces the subsequent response of the cells to low-contrast gratings. This adaptation effect has an average duration of 30 seconds and shows interocular transfer and selectivity for spatial frequency and orientation. This effect is strikingly similar to the perceptual adaptation to high-contrast gratings.     

A biochemical correlate of the critical period for synaptic modification in the visual cortex

Stimulation of phosphoinositide hydrolysis by excitatory amino acids was studied in synaptoneurosomes of kitten striate cortex at several postnatal ages. Ibotenate and glutamate stimulated phosphoinositide turnover during the second and third postnatal months; N-methyl-D-aspartate and DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) were without effect. The developmental profile of ibotenate-stimulated phosphoinositide turnover parallels the postnatal changes in cortical susceptibility to visual deprivation. The transient increase in ibotenate-stimulated phosphoinositide turnover does not occur in visual cortex of kittens reared in complete darkness.     

Electrocardiographic and behavioral effects of emetine

The effects of subacute emetine poisoning on conditioning, spontaneous behavior, and the electrocardiogram of the guinea pig are reported and compared. The depression in spontaneous behavior shown by the animals does not seem to be dependent upon any psychogenic action of emetine; there appears to be a correlation between the cardiac damage and the depression caused by the drug.     

Neurochemical correlate of a spatial preference in rats

Spatial (left or right) preferences were determined for rats given foot shock in a T-maze. The animals were killed, and left and right striata were assayed separately for dopamine and left and right teldiencephalic regions were assayed for norepinephrine. Dopamine content was significantly higher (by 12 percent) in the striata contralateral to rats' side preferences than in the ipsilateral striata; there was no such difference for teldiencephalic norepinephrine. The small asymmetry in striatal dopamine content is not due to any learning- or stress-related change induced by the testing procedure but is probably inherent in normal rats. Some spatial behavior appears to be the manifestation of a normal and specific difference in the activity of left and right nigrostriatal systems.     

A behavioral measure of homosynaptic and heterosynaptic temporal summation in the self-stimulation system of rats

Bilateral stimulation of the medial forebrain bundle with pulses of varying interpulse intervals elicited a pattern of self-stimulation behavior in the rat indicative of temporal synaptic summation: the shorter the interval the greater the response. In contrast, the effectiveness of unilateral stimulation at very short intervals was limited by neuronal refractory periods. The results support the notion that there is convergence of the medial forebrain bundle self-stimulation system from the two sides of the brain and suggest ways of studying the degree of convergence. They also suggest a technique for behaviorally comparing heterosynaptic and homosynaptic mechanisms of summation.     

Localization of a stable neural correlate of associative memory

Do learning and retrieval of a memory activate the same neurons? Does the number of reactivated neurons correlate with memory strength? We developed a transgenic mouse that enables the long-lasting genetic tagging of c-fos-active neurons. We found neurons in the basolateral amygdala that are activated during Pavlovian fear conditioning and are reactivated during memory retrieval. The number of reactivated neurons correlated positively with the behavioral expression of the fear memory, indicating a stable neural correlate of associative memory. The ability to manipulate these neurons genetically should allow a more precise dissection of the molecular mechanisms of memory encoding within a distributed neuronal network.     

Epigenetic transgenerational actions of endocrine disruptors and male fertility

Transgenerational effects of environmental toxins require either a chromosomal or epigenetic alteration in the germ line. Transient exposure of a gestating female rat during the period of gonadal sex determination to the endocrine disruptors vinclozolin (an antiandrogenic compound) or methoxychlor (an estrogenic compound) induced an adult phenotype in the F1 generation of decreased spermatogenic capacity (cell number and viability) and increased incidence of male infertility. These effects were transferred through the male germ line to nearly all males of all subsequent generations examined (that is, F1 to F4). The effects on reproduction correlate with altered DNA methylation patterns in the germ line. The ability of an environmental factor (for example, endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and disease etiology.     

Visceral and behavioral responses to intraduodenal fat

Introduction of milk or corn oil into the duodenum of the cat evokes an increase in superior mesenteric blood flow (blocked by atropine), an inhibition of gastric and duodenal motility, and sedation. Cholecystokinin-pancreozymin mimics the mesenteric vascular effect of intraduodenal fat and seems to have a sedating action.     

Agriculture and behavioral science: emerging orientations

New research orientations are emerging in behavioral science approaches to agricultural development. These new orientations are the product of both experience gained during the era that followed the Green Revolution and a response to changing goals in agricultural development that now place a greater emphasis on considerations of participation and equity. They also reflect a more general concern with the relation of technology and society growing out of efforts to understand energy and environmental problems. These orientations are characterized by a shift away from a conceptual perspective emphasizing communication to one in which technology and social organization are deemed essential in understanding and promoting agricultural development. This changing conceptual perspective is being manifested in the research process from which technology develops. Use of ecological systems approaches to the study of farming systems is increasing. The importance of understanding traditional agriculture is becoming evident and technology development methodologies are beginning to simulate farm conditions at the research center and to conduct experimental research on the farm. The appreciation of technology as a variable is leading to the development of alternative technologies adapted to different socionatural situations. As these emerging orientations become elaborated, they enhance the contributions which behavioral scientists can make to agricultural development.