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At least 325 records · Page 18Linked to original sources
PubMed1994

Chemically defined collateral projections from the pons to the central nucleus of the amygdala and hypothalamic paraventricular nucleus in the rat.

Triple fluorescence labelling was employed to reveal the distribution of chemically identified neurons within the pontine laterodorsal tegmental nucleus and dorsal raphe nucleus which supply branching collateral input to the central nucleus of the amygdala and hypothalamic paraventricular nucleus. The chemical identity of neurons in the laterodorsal tegmental nucleus was revealed by immunocytochemical detection of choline-acetyltransferase or substance P; in the dorsal raphe nucleus, the chemical content of the neurons was revealed with antibody recognizing serotonin. The projections were defined by injections of two retrograde tracers, rhodamine- and fluorescein-labelled latex microspheres, in the central nucleus of the amygdala and paraventricular nucleus, respectively. Neurons projecting to both the central nucleus of the amygdala and the paraventricular nucleus were distributed primarily within the caudal extensions of the laterodorsal tegmental nucleus and dorsal raphe nucleus. Approximately 11% and 7% of the labelled cells in the laterodorsal tegmental nucleus and dorsal raphe nucleus projected via branching collaterals to the paraventricular nucleus and central nucleus of the amygdala. About half of these neurons in the laterodorsal tegmental nucleus were cholinergic, and one-third were substance-P-ergic; in the dorsal raphe nucleus, approximately half of the neurons containing both retrograde tracers were serotonergic. These results indicate that pontine neurons may simultaneously transmit signals to the central nucleus of the amygdala and paraventricular nucleus and that several different neuroactive substances are found in the neurons participating in these pathways. This coordinated signalling may lead to synchronized responses of the central nucleus of the amygdala and paraventricular nucleus for the maintenance of homeostasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amygdala↗
PubMed1988

[Frequency potentiation of neuronal synaptic reactions in the medial tegmentum of the medulla oblongata to microstimulation of the inhibitory point of the pons Varolii].

Synaptic responses of medial medullary neurons to single (2 pps) and repetitive (30-50 pps) stimuli delivered to the pontine inhibitory point were recorded in decerebrated cats. Firing index, inhibitory to the less extent, excitatory postsynaptic potentials usually increased when repetitive stimulation was applied. Suppression of the background impulse activity was observed in some neurons. Frequency potentiation makes a substantial contribution to functional effect of stimulation of the inhibitory point (termination of elicited locomotion).

Animals↗
PubMed1976

Gustatory neural coding in the pons.

Third-order neurons from the pontine taste area (PTA) were analyzed in accordance with the across-fiber pattern theory of gustatory neural coding. Single neuron responses, evoked by chemical stimulation of the tongue, were recorded from the PTA of acute Nembutalized rats. They reveal that PTA neurons are broadly sensitive to stimuli representing the 4 putative basic taste qualities. Of 35 neurons, 33 responded to at least 3 of the 4 quality classes. Time course analyses indicate that stimuli which are shown to be alike in behavioral studies exhibit similar temporal response sequences. Correlations between all possible pairs of response patterns indicate that like-tasting chemicals elicit similar profiles of activity across the neural population. A multidimensional analysis indicates that three underlying physico-chemical dimensions (as yet undefined) bear upon the neural responses. In certain of their response properties, PTA neurons are like those of the (second-order) solitary nucleus; in other respects they auger the characteristics seen in the (fourth-order) thalamic neurons. It is concluded that the PTA is functionally as well as anatomically intermediate between the solitary nucleus and thalamus in the taste processing chain.

Animals↗
PubMed1980

Discharge of neurons in the parabrachial pons related to the cardiac cycle: changes during different sleep-waking states.

Neuronal activity in the nucleus parabrachialis medialis (NPBM) was examined in unanesthetized, unrestrained cats during each sleep-waking state. Discharge related to the cardiac cycle was assessed by calculating cross-correlation functions between neuronal and cardiac events (using the peak of the EKG 'R' wave as a reference). Of the 60 NPBM neurons examined, the activity of 20 cells showed discharge relationships to the cardiac cycle. Firing of NPBM neurons in phase with the cardiac cycle was observed during each sleep-waking state, but was most apparent during awake (AW) and rapid eye movement (REM) sleep states. State-related changes in the correlation of NPBM neuronal discharge to the cardiac cycle included variations in the extent of rhythmic modulation of activity, and shifts in the phase relationship to the cardiac reference. The predominant phase relationship of NPBM neuronal activity to the cardiac cycle was an increased probability of discharge during a period ranging from 50 msec preceding to 50 msec following the peak of the EKG 'R' wave.

Animals↗
PubMed1980

Neurons in the dorsal rostral pons process information about changes in venous return and in arterial pressure.

To examine pathways in the brain stem that process information from cardiovascular receptors we tested, in cats anesthetized with chloralose/urethane, 76 neurons in the locus coeruleus and locus subcoeruleus for their response to hemodynamic perturbations. The experiments were designed to define processing of information from arterial baroreceptors and from atrial receptors. We have modified the activity of baroreceptors and/or atrial receptors using partial constriction of the supradiaphragmatic inferior vena cava, with and without stabilization of arterial pressure and have modified the activity of atrial receptors directly using volume pulsation of the right atrium (+/- ml, 1 Hz, 3 min). The activity of 26 neurons increased and the activity of two neurons decreased in response to constriction of the vena cava. A quantitative analysis indicates that the behavior of these neurons is related in part to changes in arterial pressure and in part to changes in other pressures, such as atrial pressure. None of the neurons stimulated by constriction of the vena cava responded to volume pulsation of the right atrium. However, 6 of 9 responsive neurons tested responded also to contriction of the vena cava during stabilization of arterial pressure. Under this condition the neurons must be responding to changes in the activity of cardiovascular receptors other than arterial baroreceptors. The results suggest strongly that neurons in the locus coeruleus and locus subcoeruleus process information about changes in venous return and in arterial pressure. It is hypothesized that the responsive neurons may mediate changes in the release of pituitary hormones and in behavioral arousal in response to hemodynamic change.

Animals↗