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Biomedical subjects

G Holstege

Publications and source records attributed to G Holstege.

At least 91 records · Page 5Linked to original sources
PubMed1987

Supraspinal control of motoneurons innervating the striated muscles of the pelvic floor including urethral and anal sphincters in the cat.

The nucleus of Onuf (ON) in mammals contains motoneurons innervating the pelvic floor muscles including the external urethral and anal sphincters. Recently, direct pathways from the dorsolateral pons to the ON, probably involved in supraspinal micturition control, have been reported (Holstege et al., 1986). Since the pelvic floor muscles are involved not only in micturition but also in various other functions (e.g., coughing, vomiting, defaecation, parturition), an attempt has been made to establish whether, in the cat, there exist other direct brainstem pathways to the ON motoneurons. Our results indicate that specific projections to the ON are derived from 3 different areas: (1) the ipsilateral paraventricular hypothalamic nucleus; (2) the ipsilateral caudal pontine lateral reticular formation; and (3) the contralateral caudal nucleus retroambiguus. More diffuse projections (to all motoneuronal cell groups in the spinal cord including the ON) are derived from (1) neurons in the area of the nucleus subcoeruleus in the dorsolateral pontine reticular formation, (2) the nucleus raphe pallidus, and (3) the ventral part of the medullary medial reticular formation. Possible functional implications of these pathways are discussed.

Anal Canal↗
PubMed1986

Anatomical and physiological observations on supraspinal control of bladder and urethral sphincter muscles in the cat.

In 15 cats injections of 3H-leucine were made in the pontine tegmentum. Injections in the medial part of the dorsolateral pontine tegmentum (M-region) resulted in specific projections to the sacral intermediomedial and intermediolateral cell groups. The intermediolateral cell group contains preganglionic parasympathetic neurons that form the motor supply of the detrusor muscle of the bladder. Injections in the lateral part of the pontine tegmental field (L-region) produced labeled fibers in the nucleus of Onuf, which contains motoneurons innervating the pelvic floor including the anal and urethral sphincters. L-region projections to the sacral preganglionic parasympathetic neurons and M-region projections to the nucleus of Onuf were very limited or absent. In 12 cats physiological experiments were performed. Electrical stimulation in the L-region elicited a prompt increase in the pelvic floor EMG and urethral pressure but had little influence on the intravesical pressure. Stimulation in the M-region elicited a prompt decrease in the pelvic floor EMG and urethral pressure followed, after a delay of 2 seconds, by an increase in the intravesical pressure, so simulating normal micturition.

Animals↗
PubMed1986

Afferent projections to the orbicularis oculi motoneuronal cell group. An autoradiographical tracing study in the cat.

The motoneurons innervating the orbicularis oculi muscle from a subgroup within the facial nucleus, called the intermediate facial subnucleus. This makes it possible to study afferents to these motoneurons by means of autoradiographical tracing techniques. Many different injections were made in the brainstem and diencephalon and the afferent projections to the intermediate facial subnucleus were studied. The results indicated that these afferents were derived from the following brainstem areas: the dorsal red nucleus and the mesencephalic tegmentum dorsal to it; the olivary pretectal nucleus and/or the nucleus of the optic tract; the dorsolateral pontine tegmentum (parabrachial nuclei and nucleus of Kölliker-Fuse) and principal trigeminal nucleus; the ventrolateral pontine tegmentum at the level of the motor trigeminal nucleus; the caudal medullary medial tegmentum; the lateral tegmentum at the level of the rostral pole of the hypoglossal nucleus and the ventral part of the trigeminal nucleus and the nucleus raphe pallidus and caudal raphe magnus including the adjoining medullary tegmentum. These latter projections probably belong to a general motoneuronal control system. The mesencephalic projections are mainly contralateral, the caudal pontine and upper medullary lateral tegmental projections are mainly ipsilateral and the caudal medullary projections are bilateral. It is suggested that the different afferent pathways subserve different functions of the orbicularis oculi motoneurons. Interneurons in the dorsolateral pontine and lateral medullary tegmentum may serve as relay for cortical and limbic influences on the orbicularis oculi musculature, while interneurons in the ventrolateral pontine and caudal medullary tegmentum may take part in the neuronal organization of the blink reflex.

Afferent Pathways↗
PubMed1986

Anatomical observations on the afferent projections to the retractor bulbi motoneuronal cell group and other pathways possibly related to the blink reflex in the cat.

In the cat retractor bulbi (RB) muscle reflexively retracts the eye ball into the orbit. This reflex action is called the nictitating membrane response which, together with the reflex contraction of the orbicularis oculi muscle, constitutes the blink reflex. The retractor bulbi (RB) motoneuronal nucleus is a small cell group located in the lateral tegmentum of the caudal pons, just dorsal to the superior olivary complex. The nucleus is identical to the accessory abducens nucleus and sends its fibers through the abducens nerve. Autoradiographical tracing results indicate that the RB nucleus receives some fibers from the principal and rostral spinal trigeminal nuclei and from the dorsal red nucleus and dorsally adjoining tegmentum. The same areas project to the intermediate facial subnucleus, containing motoneurons innervating the orbicularis oculi muscle. It is suggested that the trigeminal projections take part in the anatomical framework for the R1 component of the blink reflex. Two other brainstem areas i.e.: a portion of the caudal pontine ventrolateral tegmental field and the medullary medial tegmentum at the level of the hypoglossal nucleus were also found to project to the RB motoneuronal cell group and to the intermediate facial subnucleus. These projections were much stronger than those derived from the trigeminal nuclei and red nucleus. Moreover, the medullary premotor area projects not only to the blink motoneuronal cell groups but also to the pontine premotor area. It is suggested that both areas are involved in the R2 blink reflex component. The medullary blink premotor area receives afferents especially from oculomotor control structures in the reticular formation of the brainstem while the pontine blink premotor area receives afferents from the olivary pretectal nucleus and/or the nucleus of the optic tract and from the dorsal red nucleus and its dorsally adjoining area. Because the oculomotor control structures in the reticular formation (by way of the superior colliculus) and the red nucleus receive afferents from trigeminal nuclei, they may play an important role in tactually induced reflex blinking, while the pretectum could take part in the neuronal framework of the visually induced blink reflex.

Afferent Pathways↗
PubMed1986

Anatomical evidence that the pontine lateral tegmental field projects to lamina I of the caudal spinal trigeminal nucleus and spinal cord and to the Edinger-Westphal nucleus in the cat.

Autoradiographical tracing results in the cat indicate that the lateral pontine tegmental field projects mainly contralaterally to the marginal layer of the spinal trigeminal nucleus, to laminae I and II and the lateral part of laminae V and VI of the spinal cord and the Edinger-Westphal nucleus. It is pointed out that the projections from the lateral pontine tegmentum are very similar to the ones derived from the Edinger-Westphal nucleus and that these two areas are reciprocally connected. It is postulated that both areas may play a role in supraspinal pain control.

Afferent Pathways↗
PubMed1985

Differential corticospinal projections in the cat. An autoradiographic tracing study.

An autoradiographic study of the corticospinal projections from different parts of the cat sensorimotor cortex produced the following findings. The lateral part of area 4 projects contralaterally to the lateral intermediate zone of the cervical enlargement only. The intermediate part of area 4 projects throughout the spinal cord, contralaterally to the lateral part of the intermediate zone and bilaterally to its ventromedial part. The lateral and medial part of area 3 project contralaterally to the cervical and lumbosacral dorsal horn (including laminae I and II), respectively.

Animals↗
PubMed1985

Projections of the bed nucleus of the stria terminalis to the mesencephalon, pons, and medulla oblongata in the cat.

Injections of HRP in the nucleus raphe magnus and adjoining medial reticular formation in the cat resulted in many labeled neurons in the lateral part of the bed nucleus of the stria terminalis (BNST) but not in the medial part of this nucleus. HRP injections in the nucleus raphe pallidus and in the C2-segment of the spinal cord did not result in labeled neurons in the BNST. Injections of 3H-leucine in the BNST resulted in many labeled fibers in the brain stem. Labeled fiber bundles descended by way of the medial forebrain bundle and the central tegmental field to the lateral tegmental field of pons and medulla. Dense BNST projections could be observed to the substantia nigra pars compacta, the ventral tegmental area, the nucleus of the posterior commissure, the PAG (except its dorsolateral part), the cuneiform nucleus, the nucleus raphe dorsalis, the locus coeruleus, the nucleus subcoeruleus, the medial and lateral parabrachial nuclei, the lateral tegmental field of caudal pons and medulla and the nucleus raphe magnus and adjoining medial reticular formation. Furthermore many labeled fibers were present in the solitary nucleus, and in especially the peripheral parts of the dorsal vagal nucleus. Finally some fibers could be traced in the marginal layer of the rostral part of the caudal spinal trigeminal nucleus. These projections appear to be virtually identical to the ones derived from the medial part of the central nucleus of the amygdala (Hopkins and Holstege 1978). The possibility that the BNST and the medial and central amygdaloid nuclei must be considered as one anatomical entity is discussed.

Amygdala↗
PubMed1984

Mesencephalic projections to the facial nucleus in the cat. An autoradiographical tracing study.

In 33 cats the projections of different parts of the mesencephalon to the facial nucleus were studied with the aid of the autoradiographical tracing method. The results indicate the existence of many different mesencephalo-facial pathways. The dorsomedial facial subnucleus, containing motoneurons innervating ear muscles, receives afferents from 4 different mesencephalic areas: a, the most rostral mesencephalic reticular formation; b, the nucleus of Darkschewitsch and/or the ventral part of the rostral PAG; c, the interstitial nucleus of Cajal and/or the mesencephalic tegmentum dorsomedial to the red nucleus. These areas project bilaterally by way of an ipsilateral medial tegmental pathway. The medial part of the deep tectum. This area projects bilaterally by way of the tecto-spinal tract. The lateral mesencephalic tegmentum close to the parabigeminal nucleus. This area projects mainly contralaterally by way of a separate contralateral lateral tegmental fiber bundle. The mesencephalic tegmentum just dorsolateral to the red nucleus and perhaps from the dorsolateral red nucleus itself. This area projects contralaterally by way of the rubrospinal tract. The intermediate facial subnucleus containing motoneurons innervating the muscle around the eye, receives afferents from two different mesencephalic areas: The dorsal part of the rostral as well as caudal red nucleus (but not from its caudal pole) and from the dorsally adjoining mesencephalic tegmentum including the area of the nucleus of Darkschewitsch and the interstitial nucleus of Cajal. These areas project contralaterally by way of the contralateral rubrospinal tract. The nucleus of the optic tract and/or the olivary pretectal nucleus. This area projects contralaterally by way of a contralateral medial tegmental pathway. The lateral and ventrolateral facial subnuclei containing motoneurons innervating the muscles around the mouth receive afferents from two different mesencephalic areas: The lateral part of the deep tectal layers. This area projects contralaterally by way of the tecto-spinal tract. The nucleus raphe dorsalis and perhaps the nucleus centralis superior. This area projects by way of the lateral tegmentum of caudal pons and medulla.

Animals↗
PubMed1984

Effects of neonatal and late unilateral enucleation on optokinetic responses and optic nerve projections in the rabbit.

Rabbits were unilaterally enucleated at the age of 0 or 21 days or at adult age. After survival times of 6-21 months optokinetic nystagmus (OKN) was measured and retinofugal connections were traced with anterograde transport of horseradish peroxidase or 3H leucine, injected into the eye. Non-enucleated animals served as controls. The asymmetry of monocular OKN in normal rabbits, characterized by a strong preference for pursuit of motion in the nasal (anterior) direction, was only slightly alleviated after enucleation. Responses to stimulation in the nasal direction were unchanged; responses to stimulation in the temporal direction showed modest improvements especially after enucleation at adult age and to a smaller degree after enucleation at 0 or 21 days. Redistribution of retinofugal fibers from the eye remaining after enucleation was very limited. Contralateral connections, including those to the lateral geniculate nucleus, showed a normal distribution. Of the ipsilateral connections, those to the lateral geniculate nucleus were normal in extent and density, while those to the superior colliculus were enhanced, in agreement with previous workers (Chow et al. 1973, 1981). Changes in ipsilateral pretectal projections were extremely small; particularly no connections to the nucleus of the optic tract were developed in any of the normal or enucleated animals. Of the accessory optic nuclei, the medial terminal nucleus received a very small ipsilateral projection in normal rabbits, which was markedly enhanced after enucleation especially at 0 and 21 days, but even at adult age. It is concluded that functional and anatomical plasticity of OKN circuits in the rabbit is very limited from the time of birth.

Age Factors↗
PubMed1983

Location of motoneurons innervating soft palate, pharynx and upper esophagus. Anatomical evidence for a possible swallowing center in the pontine reticular formation. An HRP and autoradiographical tracing study.

Retrograde HRP studies indicated that motoneurons innervating soft palate and pharynx are located in especially the dorsal group of the nucleus ambiguus, while motoneurons innervating upper esophagus and cricothyroid muscles are located in the retrofacial nucleus, the most rostral part of the nucleus ambiguus. Autoradiographic tracing techniques revealed that in the caudal pontine tegmentum an area is located just dorsal to the superior olivary complex, that projects contralaterally to the ventral part of the trigeminal motor nucleus, the dorsal group of the nucleus ambiguus and the ventral part of the hypoglossal nucleus. In these areas motoneurons are located innervating the mylohyoid, soft palate, pharynx and geniohyoid muscles respectively. Since these muscles are all involved in swallowing, a possible involvement of this pontine tegmental area in swallowing is discussed.

Animals↗
PubMed1982

The efferent connections of the nucleus of the optic tract and the superior colliculus in the rabbit.

3H-leucine injections were made in tectal and pretectal areas in the rabbit. After injections in the nucleus of the optic tract (NOT) labeled fibers were distributed bilaterally to the superior colliculus, the dorsal part of the medial geniculate nucleus (MGd), and the pulvinar nucleus, and ipsilaterally to the external layer of the ventral lateral geniculate nucleus (LGv), the dorsal geniculate nucleus (LGd) pars beta, the reticular thalamic nucleus, and the lateral and medial terminal nucleus (LTN, MTN). Many labeled fibers were distributed to the lateral and some to the medial parts of the pontine nuclei. more caudally, coarse labeled fiber bundles descended ipsilaterally, distributing fibers to the prepositus hypoglossi and abducens nucleus and to the caudally adjoining medial reticular formation. Many labeled fibers were also present in the inferior olive, especially ipsilaterally in the dorsal cap and the ventrally adjoining pars beta, and a few in the contralateral dorsal cap area. Contralaterally, some descending fibers terminated in the dorsal part of the facial nucleus, in which motoneurons are located innervating the orbicularis oculi muscle. The superficial layers of superior colliculus distributed fibers bilaterally to the internal layer in the ventral lateral geniculate nucleus (LGv), the LGd alpha (lateral part), the MGd, the pulvinar, and more caudally to the ipsilateral parabigeminal and lateral pontine nuclei. The deep collicular layers distributed fibers ipsilaterally to MG (internal division), pulvinar, and the internal layer of LGv. Furthermore, ascending connections were found to the suprageniculate nucleus, the zona incerta, the mediodorsal nucleus, and some intralaminar and midline nuclei. Descending fibers terminated in the mesencephalic lateral tegmentum, pontine nuclei, and ventrally in the pontine and high medullary reticular formation. Contralaterally fibers were distributed to the nucleus reticularis tegmenti pontis (NRTP), the medial reticular formation, and the inferior olive just lateral to the nucleus beta. In one case fibers were also distributed to the lateral part of the contralateral facial nucleus in which motoneurons are located innervating the upper lip muscles.

Animals↗
PubMed1978

Amygdaloid projections to the mesencephalon, pons and medulla oblongata in the cat.

Amygdalotegmental projections were studied in 26 cats after injections of horseradish peroxidase (HRP) in the diencephalon, midbrain and lower brain stem and in 6 cats after injection of 3H-leucine in the amygdala. Following HRP injections in the posterior hypothalamus, periaqueductal gray (PAG) and tegmentum many retrogradely labeled neurons were present in the central nucleus (CE) of the amygdala, primarily ipsilaterally. Injections of HRP in the posterior hypothalamus and mesencephalon also resulted in the labeling of neurons in the basal nucleus, pars magnocellularis. Following 3H-leucine injections in CE and adjacent structures autoradiographically labeled fibers were present in the stria terminalis and ventral amygdalofugal pathways. In the mesencephalon heavily labeled fiber bundles were located lateral to the red nucleus. Labeled fibers and terminals were distributed to the mesencephalic reticular formation, substantia nigra, ventral tegmental area and PAG. In the pontine and medullary tegmentum the bulk of passing fibers was located laterally in the reticular formation. Many labeled fibers and terminals were distributed to the parabrachial nuclei, locus coeruleus, nucleus subcoeruleus and lateral tegmental fields. Many terminals were also present in the solitary nucleus and dorsal motor nucleus of the vagus nerve. The location of the cells of origin and the distribution of the terminals of the amygdalotegmental projection suggest that this pathway plays an important role in the integration of somatic and autonomic responses associated with affective defense.

Amygdala↗
PubMed1977

Propriobulbar fibre connections to the trigeminal, facial and hypoglossal motor nuclei. I. An anterograde degeneration study in the cat.

The local bulbar connections to the V, VII and XII motor nuclei in the cat have been studied by means of the anterograde fibre degeneration technique in combination with the Fink-Heimer silver impregnation procedure. For this purpose electrolytic lesions were made mainly in the reticular formation of the medulla oblongata and the pons. For control purposes also, extrabulbar lesions were made in the cervical cord and the upper brain-stem and in addition, primary afferent fibres were interrupted by section of the upper cervical and trigeminal roots. The findings indicated the existence of a lateral and a medial propriobulbar fibre system, the former of which projects to the motor nuclei mainly ipsilaterally, while the latter tends to project bilaterally. Since the cells of origin of the propriobulbar fibre systems are difficult to determine by means of the anterograde degeneration technique these systems have also been investigated by means of the labelled amino-acid tracing technique. The findings thus obtained are reported in the adjoining paper.

Animals↗
PubMed1977

The organization of the bulbar fibre connections to the trigeminal, facial and hypoglossal motor nuclei. II. An autoradiographic tracing study in cat.

In 34 cats 3H-leucine was injected in the pontine and medullary tegmentum. The location of the labelled neurons and the distribution of the labelled fibres and terminals were studied autoradiographically. The findings indicate that the neurons in the bulbar lateral tegmental field (Berman, 1968) represent the main source of the propriobulbar projections to the hypoglossal, facial and motor V nuclei, while those in the medial tegmental field distribute their fibres mainly to the spinal cord. The neurons in the lateral part of the lateral tegmental field give rise to ascending and descending fibres which compose the lateral propriobulbar system, and distribute fibres mainly to ipsilateral bulbar motor nuclei. The neurons in the medial part of the lateral tegmental field compose the medial propriobulbar system, which is organized bilaterally and tends to distribute fibres to the motor nuclei bilaterally. The various neuronal cell groups which project through the medial propriobulbar system to the different motor nuclei bilaterally show relatively less spatial segregation than those which project through the lateral system to these motor nuclei.

Animals↗