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Brain. --- Dopamine. --- Drugs. --- Feedback. --- Receptor.

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The present investigations were undertaken to compare interspecific communicative abilities of dogs and wolves, which were socialized to humans at comparable levels. The first study demonstrated that socialized wolves were able to locate the place of hidden food indicated by the touching and, to some extent, pointing cues provided by the familiar human experimenter, but their performance remained inferior to that of dogs. In the second study, we have found that, after undergoing training to solve a simple manipulation task, dogs that are faced with an insoluble version of the same problem look/gaze at the human, while socialized wolves do not. Based on these observations, we suggest that the key difference between dog and wolf behavior is the dogs' ability to look at the human's face. Since looking behavior has an important function in initializing and maintaining communicative interaction in human communication systems, we suppose that by positive feedback processes (both evolutionary and ontogenetically) the readiness of dogs to look at the human face has lead to complex forms of dog-human communication that cannot be achieved in wolves even after extended socialization

Ability. --- Behavior. --- Canis-familiaris. --- Communication. --- Cues. --- Dog-human communication. --- Dog. --- Dogs. --- Feedback. --- Food. --- Function. --- Human. --- Humans. --- Interaction. --- Interspecific. --- Investigation. --- Level. --- Observation. --- Performance. --- Socialization. --- System. --- Systems. --- Task. --- Time. --- Training. --- Wolf. --- Wolves.

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Considerable attention has been focused on the role of corticotropin releasing factor (CRF) as well as CRF-binding protein (CRF-BP) in neuropsychiatric disorders and neurodegenerative diseases including epilepsy. Therefore, in the present study, we investigated the temporal and spatial alteration of CRF and CRF-BP in the gerbil hippocampal complex in order to characterize the possible changes and associations with different sequelae of spontaneous seizure in these animals. CRF immunoreactivity was shown in the interneurons of the hippocampal complex at 30 min following seizure. Additionally, alteration of CRF-BP immunoreactivity was restricted to the entorhinal cortex after seizure. These results indicate some factors for consideration. First, in the gerbil hippocampal complex, the delayed increase of CRF immunoreactivity, in spite of its excitatory function, may attenuate seizure activity, but may not do so in epileptogenesis. Second, in contrast to the hippocampl complex, the increase in CRF-BP immunoreactivity in the entorhinal cortex following seizure may participate in feedback inhibitory modulation. (C) 2003 Elsevier Science Ltd. All rights reserved

Activity. --- Animal. --- Animals. --- Association. --- Attention. --- Behavioral-responses. --- Brain. --- Convulsive seizures. --- Cortex. --- Corticotropin-releasing-factor. --- Crf. --- Dentate gyrus. --- Disease. --- Diseases. --- Disorder. --- Entorhinal cortex. --- Epilepsies. --- Epilepsy. --- Expression. --- Feedback. --- Function. --- Gerbil. --- Hippocampal complex. --- Hippocampal. --- Hippocampus. --- Immunoreactive neurons. --- Immunoreactivity. --- Increase. --- Kainate-elicited seizures. --- Modulation. --- Mongolian gerbil. --- Protein. --- Rat. --- Seizure. --- Somatostatin. --- Spatial. --- Spontaneous seizure. --- Subiculum. --- Synaptic connections. --- Time.

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Oxytocin secretion from the posterior pituitary gland is increased during parturition, stimulated by the uterine contractions that forcefully expel the fetuses. Since oxytocin stimulates further contractions of the uterus, which is exquisitely sensitive to oxytocin at the end of pregnancy, a positive feedback loop is activated. The neural pathway that drives oxytocin neurons via a brainstem relay has been partially characterised, and involves A2 noradrenergic cells in the brainstem. Until close to term the responsiveness of oxytocin neurons is restrained by neuroactive steroid metabolites of progesterone that potentiate GABA inhibitory mechanisms. As parturition approaches, and this inhibition fades as progesterone secretion collapses, a central opioid inhibitory mechanism is activated that restrains the excitation of oxytocin cells by brainstem inputs. This opioid restraint is the predominant damper of oxytocin cells before and during parturition, limiting stimulation by extraneous stimuli, and perhaps facilitating optimal spacing of births and economical use of the store of oxytocin accumulated during pregnancy. During parturition, oxytocin cells increase their basal activity, and hence oxytocin secretion increases. In addition, the oxytocin cells discharge a burst of action potentials as each fetus passes through the birth canal. Each burst causes the secretion of a pulse of oxytocin, which sharply increases uterine tone; these bursts depend upon auto-stimulation by oxytocin released from the dendrites of the magnocellular neurons in the supraoptic and paraventricular nuclei. With the exception of the opioid mechanism that emerges to restrain oxytocin cell responsiveness, the behavior of oxytocin cells and their inputs in pregnancy and parturition is explicable from the effects of hormones of pregnancy (relaxin, estrogen, progesterone) on pre-existing mechanisms, leading through relative quiescence at term inter alia to net increase in oxytocin storage, and re

Activation. --- Activity. --- Adaptation. --- Allopregnanolone. --- Behavior. --- Birth. --- Brainstem. --- C-fos expression. --- Dendrites. --- Dynorphin. --- Enkephalin. --- Estrogen receptors. --- Estrogen. --- Feedback. --- Fetuses. --- Firing. --- Gaba. --- Gamma-aminobutyric-acid. --- Gland. --- Hormone. --- Hormones. --- Hypothalamic paraventricular nucleus. --- Increase. --- Increases. --- Inhibition. --- Main olfactory-bulb. --- Mechanisms. --- Messenger-ribonucleic-acid. --- Milk-ejection reflex. --- Neurons in-vitro. --- Neurons. --- Nitric oxide synthase. --- Nitric-oxide synthase. --- Nucleus tractus solitarius. --- Opioid. --- Oxytocin mrna. --- Oxytocin. --- Parturition. --- Pattern. --- Patterns. --- Pituitary. --- Potentials. --- Pregnancy. --- Progesterone-receptor expression. --- Progesterone. --- Rat supraoptic nucleus. --- Response. --- Restraint. --- Review. --- Secretion. --- Steroid metabolites. --- Steroid. --- Stimulation. --- Stimuli. --- Supraoptic nucleus. --- System. --- Time. --- Uterus.