PubMed Health⌕ Search

Biomedical subjects

R Bandler

Publications and source records attributed to R Bandler.

At least 19 recordsLinked to original sources
PubMed1992

Vocalization and marked pressor effect evoked from the region of the nucleus retroambigualis in the caudal ventrolateral medulla of the cat.

It is well established that the nucleus retroambigualis (NRA) of the cat contains a population of expiratory-related neurons. We report here that in the unanesthetized, decerebrate cat, microinjections of 300-900 pmol of D,L-homocysteic acid within the NRA evoked excitation of laryngeal as well as expiratory muscles, and often pressor responses. Moreover, vocalizations, which did not sound like normal feline vocalizations (i.e., hiss, howl, mew, growl), were evoked from a restricted region of the NRA, 1-3 mm caudal to the obex. The results indicate that in addition to its role in expiration: (i) the NRA plays an important role in the control of laryngeal muscles and the production of vocalization; and (ii) that neurons in the NRA region can modulate arterial pressure.

Animals↗
PubMed1992

Anatomical evidence for segregated input from the upper cervical spinal cord to functionally distinct regions of the periaqueductal gray region of the cat.

In the cat, the caudal third of the midbrain periaqueductal gray region (PAG) mediates two distinct behavioral and cardiovascular patterns: (i) flight and hypertension from the lateral PAG and (ii) immobility and hypotension from the ventrolateral PAG. The afferent input from the upper cervical spinal cord (UCC) to these functionally distinct PAG regions was investigated using retrograde tracing techniques. The following results were obtained: (i) following tracer injections into the lateral PAG large numbers of labelled cells were found in lamina I and the lateral cervical nucleus; (ii) following tracer injections into the ventrolateral PAG large numbers of labelled cells were found in the ventral horn; (iii) both PAG regions received substantial projections from UCC cells in laminae IV and V, however, no double labelled cells were observed. Thus, functionally distinct regions of the caudal PAG are targeted by quite separate and discrete UCC neural populations. These anatomical differences likely reflect functionally distinct UCC afferent regulation of the functionally opposite PAG regions.

Animals↗
PubMed1992

Longitudinal neuronal organization of defensive reactions in the midbrain periaqueductal gray region of the rat.

In a previous study we investigated the intraspecific defensive reactions evoked by excitation of neurons in the intermediate third of the midbrain periaqueductal gray matter (PAG) of the rat. Experiments revealed that activation of neurons in this region of the PAG mediated: (i) backward defensive behavior, characterized by upright postures and backward movements, and (ii) reactive immobility ("freezing"), in which the rat remained immobile, but reacted with backward defensive behavior to investigative, non-aggressive contact initiated by the partner. In the present study, we aimed to extend our understanding of PAG mediation of defensive behavior by observing: (i) in a non-aggressive social interaction test, the behavioral effects of microinjections of low doses of kainic acid (40 pmol in 200 nl) made in the caudal third of the PAG; and (ii) the behavioral and cardiovascular effects of microinjections of D,L-homocysteic acid (5-10 nmol in 50-100 nl) made in the PAG of the unanesthetized decerebrate rat. Kainic acid injections into the area lateral to the midbrain aqueduct in the caudal third of the PAG evoked: (i) forward avoidance behavior, characterized by forward locomotion and occasional hop/jumps; (ii) reactive immobility ("freezing"), in which the rat remained immobile, but reacted with forward avoidance behavior to investigative, non-aggressive contact initiated by the partner; and (iii) 22-28 kHz ultrasonic vocalizations. These injections also evoked a dramatic increase in defensive responsiveness to tactile stimuli on the half of the body contralateral, but not ipsilateral, to the site of injection. Electroencephalographic measurements indicated that none of these effects were secondary to seizure activity. In the decerebrate rat, D,L-homocysteic acid injections in the caudal third of the PAG evoked forward running movements along with increased blood pressure and heart rate, the strongest effects being evoked from the region lateral to the midbrain aqueduct. More rostrally, sites in the intermediate PAG evoked backward "defensive" movements, which were also associated with increased blood pressure and heart rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Aggression↗
PubMed1991

Viscerotopic organization of neurons subserving hypotensive reactions within the midbrain periaqueductal grey: a correlative functional and anatomical study.

Microinjection of the excitatory amino acid D,L-homocysteic acid (40 nmol, in 200 nl) made into the ventrolateral part of the caudal half (A2.5-P1.5) of the midbrain periaqueductal gray (PAG) of the decerebrate cat evoked a hypotensive reaction associated with a slowing of the heart and a decrease in either external iliac or renal vascular resistance. The decrease in iliac vascular resistance was elicited from the pretentorial portion (A2.5-A0.6) of the PAG hypotensive area, whereas the decrease in renal vascular resistance was elicited from the subtentorial portion (A0.6-P1.5). Anatomical experiments using the method of retrograde transport of rhodamine-labelled microspheres or wheat germ agglutinin-horseradish peroxidase demonstrated topographically organized projections from the ventrolateral PAG to the subretrofacial (SRF) pressor nucleus in the rostral ventrolateral medulla. The pretentorial part of the ventrolateral PAG projected mainly to the caudal part of the SRF nucleus, which preferentially controls iliac vascular resistance. The subtentorial part of the ventrolateral PAG projected mainly to the rostral part of the SRF nucleus, which preferentially controls renal vascular resistance. Taken together, these findings suggest: (i) that neurons within the ventrolateral PAG are viscerotopically organized; and (ii) that their hypotensive function may be mediated by an inhibition of SRF pressor neurons. The results are discussed in relation to the recently described PAG hypertensive area which also is viscerotopically organized and projects to the SRF nucleus.

Amino Acids↗
PubMed1991

Control of extracranial and hindlimb blood flow by the midbrain periaqueductal grey of the cat.

Microinjections of D,L homocysteic acid (DLH, 40 nmoles) made in the lateral PAG of the unanesthetized and paralyzed decerebrate cat evoked distinct patterns of extracranial and hindlimb blood flow. One pattern, evoked from the pretentorial part of the lateral PAG (A3.3-A2.5), consisted of an extracranial vasodilation associated with an iliac vasoconstriction. Another pattern, evoked from the subtentorial part of the lateral PAG (P0.2-P0.9), consisted of an extracranial vasoconstriction associated with an iliac vasodilation. Both patterns were associated with increased arterial blood pressure. These results indicate (i) that the PAG contains neurons regulating head and hindlimb vasculature, and (ii) that these neurons are viscerotopically organized, in the sense that different representations of the head and hindlimb are found at different rostrocaudal levels. The significance of the results is discussed in the context of our previous findings that different kinds of defense reactions are evoked from these same pretentorial and subtentorial PAG regions.

Animals↗
PubMed1991

Neurobiological evidence for epilepsy-induced interictal disturbances.

It is not in the best interest of persons with epilepsy to deny the possibility that seizures could cause enduring behavioral disturbances. Rather, it is essential to pursue clinical and animal investigations in order to identify any such changes that might occur and to elucidate their mechanisms. Many testable hypotheses can be developed from existing evidence. Antiepileptic medication may produce interictal behavioral disturbances in patients with epilepsy by indirect mechanisms. Some aberrant behaviors could be due to medication-induced systemic disorders, neuroendocrine dysfunction, or REM deficit, whereas depression following successful treatment with drugs, as well as with surgery, may be related more specifically to cessation of seizures. The underlying neuropathological process also induces neurological and mental deficits, but it is not always possible to differentiate those behavioral disturbances due to destructive effects of the lesion from those due to recurrent epileptic seizures. Behavioral disturbances are associated more frequently with epileptogenic lesions in limbic structures than with those elsewhere in the brain, but a relationship between hemispheric lateralization of the epileptogenic lesion and specific interictal behavioral symptoms remains controversial. When considering the effects of seizures per se on interictal behavior, it is important to realize that some "interictal" behavioral disturbances may actually be ictal events. Prolonged affective, autonomic, and psychic disturbances can occur in clear consciousness with unilateral limbic seizures that are not associated with scalp EEG changes. When epilepsy is acquired as a result of cerebral damage, the epileptogenic process takes time to develop before spontaneous seizures appear. It is more reasonable to assume that this progressive process continues than to postulate that it stops completely at the time the first seizure occurs. Epilepsy-induced protective homeostatic mechanisms that act to terminate ictal events, prevent ictal spread, and maintain the interictal state may also disrupt interictal function. Furthermore, seizures could indirectly influence interictal behavior as a result of their effects on neuroendocrine function and sleep. Because of confounding biological factors, it is difficult to document the association of any epilepsy disorder, by itself, with progressive behavioral disturbances in humans. Secondary epileptogenesis, protective homeostatic mechanisms, and epilepsy-induced disturbances in development can be readily demonstrated, however, in experimental animal models. In experimental animals, endogenous opoids are released during seizures and mediate some postictal behaviors. A physiological dependency on high levels of endogenous opioids released during seizures could produce depression as a withdrawal symptom interictally or when seizures no longer occur as a result of successful therapy. Experimental animal models of depression exist to test hypotheses concerning pro- and antidepressant effects of epileptogenesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Flight and immobility evoked by excitatory amino acid microinjection within distinct parts of the subtentorial midbrain periaqueductal gray of the cat.

Unilateral microinjections of the excitatory amino acid, D,L-homocysteic acid (DLH) made in the lateral and ventrolateral parts of the subtentorial (A 1.0-P 1.5) midbrain periaqueductal gray (PAG) of the freely moving cat evoked two distinct patterns of coordinated somatic changes. When DLH injection (80 nmol) was made within the lateral part of the subtentorial PAG it evoked a flight reaction, characterized by strong locomotion (running) and multiple jumps. This flight reaction was quite distinct from the defensive threat display previously described following DLH microinjection in the lateral part of the pretentorial PAG. When DLH injection (80 nmol) was made in the subtentorial PAG region, ventrolateral to the aqueduct, it elicited a cessation of both spontaneous locomotion and general movements (e.g. licking, scratching, grooming, head and limb movements), a reaction termed immobility. The subtentorial PAG regions from which flight and immobility were evoked are seemingly identical to the lateral and ventrolateral subtentorial PAG regions in which hypertensive and hypotensive reactions have been evoked previously by DLH microinjection. The present results together with our previous studies suggest that: (1) the lateral PAG of the cat contains at least two, topographically separable neuronal pools, which mediate different types of defense reactions (i.e. threat display--lateral part of the pretentorial PAG; flight reaction--lateral part of the subtentorial PAG); and (2) excitation of neurons in the ventrolateral PAG alters autonomic and somatic functions, but in a direction opposite to that of lateral PAG neurons, namely decreased somatomotor activity and hypotension.

Animals↗
PubMed1989

Viscerotopic control of regional vascular beds by discrete groups of neurons within the midbrain periaqueductal gray.

It is well established that a group of bulbospinal neurons within the rostral ventrolateral medulla plays a crucial role in the tonic and phasic control of arterial pressure. In the cat, these neurons are confined to a discrete region which has been termed the subretrofacial (SRF) nucleus. Recent evidence suggests that this nucleus is viscerotopically organized with respect to its control over different vascular beds. These observations raise the question as to whether functionally different subgroups of SRF pressor neurons receive inputs from supramedullary cell groups that also exert a specific control over particular vascular beds. To answer this question retrogradely transported tracers (i.e. rhodamine or fluorescein-labelled microspheres, wheat germ agglutinin-horseradish peroxidase) were injected into physiologically identified sites within the rostral or caudal parts of the SRF nucleus of the cat. Separate groups of neurons in the midbrain periaqueductal gray region (PAG) were found to project specifically to subgroups of cells within the rostral and caudal parts of the SRF nucleus. These findings, together with the results of recent functional studies of the PAG suggest that these distinct projections from the PAG to the SRF nucleus are involved in the expression of different patterns of emotionally coupled cardiovascular responses.

Animals↗
PubMed1989

Characterization of pretentorial periaqueductal gray matter neurons mediating intraspecific defensive behaviors in the rat by microinjections of kainic acid.

Unilateral microinjections of 40 pmol of kainic acid (KA; in 0.2 microliter) within the periaqueductal gray matter (PAG) evoked intraspecific defensive postures (defensive uprights, defensive alterting, defensive sideways, backing) in rats confronted with a conspecific. These reactions, which lasted for up to 30 min, were seemingly identical to the rat's natural defensive reaction to attacks by a conspecific although they were evoked by the investigatory approach, rather than the attack, of another rat. Histological analysis revealed that the strongest defensive reactions were evoked from sites within a restricted part of the pretentorial periaqueductal gray matter. Lower doses of KA induced fewer (20 pmol) or non-significant increases (4 pmol) in defensive reactions. Higher doses (100 and 200 pmol) increased the percentage of defensive behavior and also induced oriented jumps out of the test cage. In tests with a conspecific, defensive reactions were elicited most frequently when investigation by the partner was localized to the side of the body contralateral to the injection site. This was confirmed in a sensory reactivity test in which tactile stimulation by the experimenter elicited most defensive reactions when applied on the side of the body contralateral to the injection side. This test also revealed a somatotopic gradient in the animal's reaction: tactile stimulation of the contralateral head and the forelimb evoked the strongest reactions, whereas no responses were observed upon tactile stimulation of the contralateral flank or hindlimb. Measurement of electroencephalographic activity at the cortical, hippocampal, amygdala and PAG levels indicated that the evoked defensive reactions were not secondary to epileptogenic effects. Finally, quantitative analysis of an autoradiographic study found that [3H]KA diffused within a diameter of 1.0-1.2 mm around the cannula tip. Taken together, these results indicate the existence of a population of neurons within a restricted part of the pretentorial PAG of the rat, the excitation of which produces defensive responses and demonstrate that these defensive reactions have a socially adaptive value.

Animals↗
PubMed1989

Somatic and autonomic integration in the midbrain of the unanesthetized decerebrate cat: a distinctive pattern evoked by excitation of neurones in the subtentorial portion of the midbrain periaqueductal grey.

Microinjections of the excitant amino acid D,L-homocysteic acid (DLH) made in a restricted part of the subtentorial (P0.2-P0.9) midbrain periaqueductal grey (PAG) of the unanesthetized decerebrate cat evoked a distinctive pattern of coordinated somatic and autonomic changes which was characterized by strenuous hindlimb movement and a concomitant vasodilation in the hindlimb vascular bed. The vasodilation was not secondary to movement as it could still be evoked in the paralyzed preparation. The autonomic changes also included pupillary dilation, increases in arterial pressure and heart rate, and vasoconstriction in renal and mesenteric vascular beds. This evoked response is quite different from that elicited by DLH microinjections made in a restricted part of the pretentorial PAG of the unanesthetized cat (Carrive et al., Neurosci. Lett., 81 (1987) 273-278). This latter response is characterized by a threat display which includes strong facial and vocal changes, but no strenuous hindlimb movement, and skeletal muscle vasoconstriction. The present results together with our previous research suggest that two distinct sets of neurons located in different midbrain PAG regions mediate coordinated patterns of somatic and autonomic change characteristics of different aspects of defensive behavior.

Action Potentials↗
PubMed1989

New method for quantitating yeasts in clinical specimens.

Existing methods for quantitating yeasts in clinical specimens usually rely on plate counts of sediments. A new method has been developed which uses filtration to concentrate a sample and fluorescence microscopy to facilitate counting. This method is fast and easy to perform and can be used for a wide variety of specimens including urine, mouthwash water, and vaginal fluid.

Colony Count, Microbial↗
PubMed1988

Anatomical evidence that hypertension associated with the defence reaction in the cat is mediated by a direct projection from a restricted portion of the midbrain periaqueductal grey to the subretrofacial nucleus of the medulla.

Wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injections were made at sites within a restricted portion of the midbrain periaqueductal grey region (PAG) of the cat at which microinjection of the excitant amino acid, D.L-homocysteic acid, elicits the strongest form of a defence reaction, including a hypertensive response. Among the revealed projections, significant anterograde labelling was found in a discrete region of the rostral ventrolateral medulla, the subretrofacial nucleus (SRF). In the cat, the SRF contains pressor neurones which project to the spinal preganglionic sympathetic outflow. The labelling was most marked ipsilaterally, although substantial contralateral labelling was also observed. To verify that the projection to the SRF originated from the restricted 'defence region' of the PAG, WGA-HRP or rhodamine-labelled microspheres were injected into physiologically-identified sites in the SRF. In all experiments, labelled neurones were found in the same restricted region of the PAG at which DLH injection evokes hypertension and behavioural signs of the defence reaction. The results are consistent with the hypothesis that a discrete cell group within the PAG mediates both somatic and autonomic components of the defence reaction and that the characteristic hypertensive response is mediated by a direct pathway from these PAG cells to pressor neurones in the SRF.

Animals↗
PubMed1988

Elicitation of intraspecific defence reactions in the rat from midbrain periaqueductal grey by microinjection of kainic acid, without neurotoxic effects.

Microinjection of 40 pmol of the neuroexcitotoxin, kainic acid (KA) in the midbrain periaqueductal grey region (PAG) evoked a significant increase in both defensive and immobile behaviours in rats tested in a social situation. The evoked reactions appeared identical to the rat's natural defensive reaction to attack by a conspecific, although they were evoked by the presence, rather than the attack, of another rat. The long duration and natural appearance of the KA-evoked reactions stand in contrast to the short, 'explosive' reactions evoked by injection in the PAG of other excitant amino acids. There was no behavioural evidence of a diminution in the effect of repeated injections of KA in the PAG, nor was there any histological evidence of neurotoxicity.

Animals↗
PubMed1988

Integrated defence reaction elicited by excitatory amino acid microinjection in the midbrain periaqueductal grey region of the unrestrained cat.

Unilateral microinjections (0.20 microliter) of the excitatory amino acids (EAA), L-aspartate (ASP), D,L-homocysteate (DLH) or kainate (KA) were made into the midbrain of freely moving cats. Injections of DLH (20 nmol) or ASP (200 nmol) made within the midbrain periaqueductal grey matter (PAG) consistently elicited a threat display characteristic of defensive behaviour (i.e., pupillary dilatation, piloerection, retraction of the ears, sideways backing, arching of the back, hissing, howling, growling), whereas injections of DLH or ASP made in the tegmentum bordering the PAG did not elicit such behaviour. Injections of KA (940 pmol) made within the PAG, but not the tegmentum, elicited not only a threat display but also directed attack (striking with unsheathed claws and biting). As injections of EAA depolarize cell bodies, but not axons, the results suggest that a population of neurones whose excitation elicits all of the behavioural signs of defence, including directed attack, is found within the PAG. Histology indicated that the region of the PAG from which the defence reaction was elicited was not confined to any PAG subnucleus. Rather, the 'defence region' of the PAG formed a cylindrical column lateral to the midbrain aqueduct, approximately 1.5 mm in diameter and 5.0 mm in length, the rostral end of which lay dorsal to the caudal end. Further, it was found that EAA microinjections made in different portions of the defence region of the PAG elicited defence reactions characterised by different patterns of vocalization and differing intensities of display. It was also observed following unilateral injection of KA into the PAG that defence reactions, including attack, were elicited by approach in the visual hemifield or touch of the body contralateral, but not ipsilateral, to the injection site. The asymmetry of the defence reaction was not due to any obvious ipsilateral motor impairment and thus suggests that the PAG mediation of the defence reaction, in addition to controlling the outflow to the somatic and autonomic motor systems, also affects sensory processing.

Animals↗
PubMed1987

Excitation of neurones in a restricted portion of the midbrain periaqueductal grey elicits both behavioural and cardiovascular components of the defence reaction in the unanaesthetised decerebrate cat.

Microinjections of the excitant amino acid D,L-homocysteic acid (DLH) into a restricted part of the midbrain periaqueductal grey (PAG) of unanaesthetized decerebrate cats evoked a distinctive pattern of facio-vocal and cardiovascular changes characteristic of a defence reaction, including pupillary dilatation, howling vocalization, an increase in arterial pressure and heart rate, and skeletal muscle vasoconstriction. These facio-vocal and cardiovascular responses always occurred together, and thus may arise from excitation of a common population of neurones. DLH injections within a greater extent of the PAG elicited other facio-vocal changes characteristic of defence, such as hissing or growling, but these were not accompanied by significant cardiovascular changes.

Animals↗
PubMed1987

Midbrain periaqueductal grey region in the cat has afferent and efferent connections with solitary tract nuclei.

Wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injections were made at the same sites within the midbrain periaqueductal grey region (PAG) of the cat at which microinjections of excitatory amino acids had previously elicited the set of autonomic and somatic reactions (i.e. pupil dilatation, piloerection, retraction of the ears, arching of the back, hissing, howling and growling) known as the 'defence reaction'. The WGA-HRP injections revealed that this PAG region has an extensive set of afferent and efferent connections with solitary tract nuclei (NTS). Within the NTS the majority of labelled neurons were distributed, in approximately equal numbers, in the ipsilateral medial solitary nucleus (SM) and the ipsilateral and the contralateral ventrolateral solitary nuclei (SVL). The densest anterograde labelling was found in the ipsilateral SM, with lighter anterograde labelling in the contralateral SM and bilaterally in the commissural solitary nucleus and SVL. The described connections between the defence region of the PAG and the NTS not only provide a new anatomical basis for cardiovascular and respiratory components of the reaction, but also add to the evidence that, in addition to the hypothalamus, the PAG is an important integrating center for the autonomic and somatic elements of the defence reaction.

Animals↗
PubMed1987

Ictal and enduring interictal disturbances in emotional behaviour in an animal model of temporal lobe epilepsy.

Unilateral microinjections of kainic acid (4.7 nmol) were made into the dorsal hippocampus of 17 unanesthetized freely moving cats. These injections provoked an acute period of intense seizure activity (first 48-72 h) which in 10 cats was followed by a chronic period of recurrent spontaneous complex partial seizures persisting for as long as the cats were studied (up to 4 months). During the chronic epileptic period 8 of these 10 cats demonstrated both ictal and interictal emotional behaviour disturbances. The ictal events included behaviour similar to a 'defensive rage' reaction. Interictally, each of the cats demonstrated an emotional lability. That is, although they behaved in a normal manner if handled affectionately, any mild provocation triggered an explosive defensive rage reaction. As well, the thresholds for electrical brain stimulation induced defensive rage were lowered. That the interictal emotional behaviour disturbances were related to the presence of an active epileptogenic process was suggested by the finding that during periods when no spontaneous seizures were observed for several days, the cats reverted to a less emotionally reactive state and the thresholds for stimulation-induced defence reactions returned to baseline. The results indicate that epileptogenic lesions of the temporal lobe alone can induce an enduring disturbance of emotional behaviour. They support the view that emotional disturbances in patients with epilepsy may sometimes result from pathophysiological mechanisms related to the epileptogenic process, and further suggest that such emotional disturbances might be reversed or prevented if the epileptic seizures could be controlled.

Animals↗