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P V Hoogland

Publications and source records attributed to P V Hoogland.

At least 19 recordsLinked to original sources
PubMed2003

Misrouted olfactory fibres and ectopic olfactory glomeruli in normal humans and in Parkinson and Alzheimer patients.

The presence and distribution of misrouted (MR) olfactory projection fibres were studied in the olfactory bulbs of control human brains and in the brains of people who had suffered from Parkinson's and Alzheimer's disease. It appeared that MR fibres, that is, fibres that terminate deep into the glomerular layer, are a common phenomenon in the bulbs of aged people. In all but one of the bulbs studied, MR fibres are present. The amount of MR fibres is not related to age. With a few exceptions, the MR fibres are restricted to the external plexiform layer (EPL). Only in Parkinson bulbs the MR fibres occasionally form glomerulus-like structures. These pseudo glomeruli are located in the EPL. It is concluded that MR olfactory projection fibres are a normal phenomenon in the human olfactory bulb. In nonhuman mammalians, MR fibres have only been observed in foetal and neonatal olfactory bulbs. Possibly, the age-related loss of mitral cells, which are the natural synaptic targets for the olfactory projection fibres, may play a role in the aberrant behaviour of the MR olfactory receptor cell axons. The ectopic glomerulus-like structures in Parkinson bulbs share some characteristics with normal rat glomeruli that are not observed in normal human olfactory glomeruli. This may refer to possible changes in the genetic content of olfactory structures in Parkinson patients.

Aged↗
PubMed1999

Human radicular veins: regulation of venous reflux in the absence of valves.

In the literature it is generally assumed that venous reflux within the radicular veins is prevented by the presence of bicuspid valves and narrowing of the transdural part of these vessels. Recently, we performed a human cadaver study of the internal vertebral venous plexus. Surprisingly, a large number of radicular and perimedullary veins appeared to be filled with Araldite CY 221 mixture, after injection of this material into the vertebral venous system, implicating reflux via the radicular veins and suggesting insufficiency of the presumed anti-reflux mechanism. Therefore, it was decided to study the radicular veins in order to determine and to investigate the presence or absence of anti-reflux mechanisms within this system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. After polymerization, all cadavers were dissected and the spinal nerve sheaths, including nerve roots, radicular veins and epidural veins, were excised as a whole. After macroscopical examination, serial sections (40 microm) were cut on a freezing microtome and stained in Von Gieson medium. Every third section was stained immunohistochemically with smooth muscle antigen (SMA), to visualize smooth muscle cells. In all cadavers, a number of intradural radicular veins was filled with Araldite. Employing microscopical examination, no bicuspid valves were found. However, four structures were encountered that might serve as ananti-reflux-mechanism: 1) intravenous dural folds, 2) meandrous configuration, and 3) narrowing of the radicular veins at the point of penetration of the dura mater, and 4) varying numbers of smooth muscle fibers in the walls of the intradural and extradural parts of the radicular veins. Reflux via the radicular veins seems to be a physiological phenomenon. Structural valves have not been encountered during this study. Intravenous dural folds, meandrous configuration and narrowing of the transdural part of the radicular veins, and the presence of large numbers of smooth muscle cells in the radicular venous walls suggest the existence of a dynamic reflux-regulating system that has the ability to increase the intravascular resistance under conditions of venous hyperpression, in order to protect the spinal cord from venous pressure waves. Possibly, venous reflux via the radicular veins has a role in selective cooling of the spinal cord.

Actins↗
PubMed1999

Tyrosine hydroxylase immunoreactive structures in the aged human olfactory bulb and olfactory peduncle.

We studied the anatomical distribution of dopaminergic structures in the normal, aged, human olfactory bulb and olfactory peduncle with a monoclonal antibody against tyrosine hydroxylase. Three different tyrosine hydroxylase containing cell groups are present in the olfactory bulbs: (1) a group of round, medium-sized cells within and around the glomeruli; (2) cells in the external plexiform layer; and (3) cells that are scattered in the stratum album. Occasionally, a few labeled neurons can be observed in the granule cell layer. In the olfactory peduncle a few labeled cells are present in the superficial layers just underneath the pia. Tyrosine hydroxylase containing terminal-like structures are present in the glomerular layer and the external plexiform layer. In a few cases dense terminal labeling is also observed in the cell groups that constitute the anterior olfactory nucleus. In the olfactory peduncle scattered labeled fibers are present. In addition, the present study makes clear that quantitative differences exist between the individual cases for which no explanation could be found.

Aged↗
PubMed1999

Species-specific differences in the corticohypothalamic connections of lizards.

In lizards, information from the various senses is relayed to the hypothalamus via the cortico-septo-hypothalamic pathway. It appears that the anatomical organization of the incoming fibres in the medial cortex differs considerably between the various lizard species. In the present account it is shown that it is the location of the termination of the incoming fibres in the medial cortex that determines what kind of sensory information will reach the hypothalamic centres that are responsible for sexual and feeding behaviour.

Animals↗
PubMed1998

Septal complex of the telencephalon of lizards: III. Efferent connections and general discussion.

The projections of the septum of the lizard Podarcis hispanica (Lacertidae) were studied by combining retrograde and anterograde neuroanatomical tracing. The results confirm the classification of septal nuclei into three main divisions. The nuclei composing the central septal division (anterior, lateral, medial, dorsolateral, and ventrolateral nuclei) displayed differential projections to the basal telencephalon, preoptic and anterior hypothalamus, lateral hypothalamic area, dorsal hypothalamus, mammillary complex, dorsomedial anterior thalamus, ventral tegmental area, interpeduncular nucleus, raphe nucleus, torus semicircularis pars laminaris, reptilian A8 nucleus/substantia nigra and central gray. For instance, only the medial septal nucleus projected substantially to the thalamus whereas the anterior septum was the only nucleus projecting to the caudal midbrain including the central gray. The anterior and lateral septal nuclei also differ in the way in which their projection to the preoptic hypothalamus terminated. The midline septal division is composed of the dorsal septal nucleus, nucleus septalis impar and nucleus of the posterior pallial commissure. The latter two nuclei projected to the lateral habenula and, at least the nucleus of the posterior pallial commissure, to the mammillary complex. The dorsal septal nucleus projected to the preoptic and periventricular hypothalamus and the anterior thalamus, but its central part seemed to project to the caudal midbrain (up to the midbrain central gray). Finally, the ventromedial septal division (ventromedial septal nucleus) showed a massive projection to the anterior and the lateral tuberomammillary hypothalamus. Data on the connections of the septum of P. hispanica and Gecko gekko are discussed from a comparative point of view and used for better understanding of the functional anatomy of the tetrapodian septum.

Animals↗
PubMed1998

Convergence of thalamic and cholinergic projections in the 'dentate area' of lizards.

The small-celled part of the medial cortex (Cxms) in lizards is comparable to the hippocampal area dentata in mammals. As in mammals, most of the afferents to this cortical area are arranged in sharply delimited laminae. In reptiles this lamination pattern is species-specific. In the lizard Tupinambis nigropunctatus projections from the multisensory dorsolateral thalamic nucleus (Dla) terminate in the middle one-third of the outer plexiform layer throughout the whole rostrocaudal extent of Cxms. In Podarcis hispanica the thalamic projections terminate not only in the middle one-third of Cxms but also in the inner plexiform layer. To find out whether the species-related variation of thalamic projections to Cxms is a solitary phenomenon or is related to variations of other afferents of Cxms, we studied the relationships between the thalamic and cholinergic projections from the basal telencephalon in the medial cortex of three lizard families: the Lacertidae, the Teiidae and the Gekkonidae. In the gekkonid lizards Gekko gecko and Eublepharius macularius, Dla projections were studied with the anterograde tracer Phaseolus vulgaris-leucoagglutinin. Projections were found in only the rostral one-third of Cxms where the fibers terminate in the superficial half of the outer plexiform layer and in the deep half of the inner plexiform layer. From acetylcholinesterase staining in the Cxms of representatives of these three lizard families, it appeared that the main cholinergic afferents terminate in the same subregions and the same laminae as the Dla projections. Therefore, there seems to be a close association between thalamic and cholinergic afferents in the Cxms of lizards, irrespective of their precise location in the cortex of the various species. This suggests a functional relationship between these two afferents of the dentate area in lizards.

Acetylcholinesterase↗
PubMed1997

Septal complex of the telencephalon of the lizard Podarcis hispanica. II. Afferent connections.

The afferent connections to the septal complex were studied in the lizard Podarcis hispanica (Lacertidae) by means of a combination of retrograde and anterograde tracing. The results of these experiments allow us to classify the septal nuclei into three main divisions. The central septal division (anterior, lateral, dorsolateral, ventrolateral, and medial septal nuclei plus the nucleus of the posterior pallial commissure) receives a massive, topographically organized, cortical projection (medial, dorsal, and ventral areas) and widespread afferents from the tuberomammillary hypothalamus and the basal telencephalon. Moreover, it receives discrete projections from the dorsomedial anterior thalamus, the ventral tegmentum, the midbrain raphe, and the locus coeruleus. The ventromedial septal division (ventromedial septal nucleus) receives a massive projection from the anterior hypothalamus, dense serotonergic innervation, and a faint amygdalohypothalamic projection, but it is devoid of direct cortical input. The midline septal division (nucleus septalis impar and dorsal septal nucleus) receives a nontopographic cortical projection (dorsomedial and dorsal cortices) and afferents from the preoptic hypothalamus, the dorsomedial anterior thalamus, the midbrain central gray, and the reptilian A8 nucleus/substantia nigra. Our results indicate that the cortex provides a physiologically complex, massive input to the septum that terminates over the whole dendritic tree of septal cells. In contrast, most of the ascending afferents make axosomatic contacts by means of pericellular nests. The chemical nature of the main septal afferents and the comparative implications of the available hodological data on the organization of the septal complex of tetrapod vertebrates are discussed.

Afferent Pathways↗
PubMed1997

Morphology of the human internal vertebral venous plexus: a cadaver study after intravenous Araldite CY 221 injection.

Reviewing the literature on the vascular anatomy of the spinal epidural space, it appeared that the knowledge of the internal vertebral venous plexus is limited. Injection studies of the entire internal vertebral venous plexus after application of modern techniques, to the best of our knowledge, have never been performed. Based on the clinical importance of these structures, it was decided to study the human vertebral venous system after Araldite CY 221 injection, in order to update the morphological characteristics of the internal vertebral venous system. The vertebral venous systems of ten fresh human cadavers, between 64 and 93 years of age, were injected with Araldite CY 221 mixture. All cadavers were dissected and the posterior and anterior internal vertebral venous plexuses were studied in detail. The anterior part of the internal vertebral venous plexus is fairly constant. On the contrary, the posterior internal vertebral venous plexus showed a striking segmental and interindividual variability. In the thoracic area, two types of traversing veins are observed. Both types show a somewhat symmetrical "inversed V" configuration. No anatomical valves were observed. Nevertheless, anterograde flushing (via the femoral veins) of the vertebral venous system appeared to proceed much faster than retrograde flushing (via the superior vena cava). The classical picture of the internal vertebral venous plexus appears a simplification of the actual situation. Especially in the posterior part, segmental and interindividual differences are prominent. The preferential direction of the flow during flushing suggests the presence of functional valves, which are probably located in the thoracic part of the posterior internal vertebral venous plexus, resulting from the typical shape of the veins in this area. This might explain the difficulties with imaging of the posterior part of the internal vertebral venous plexus in vitro as well as in vivo. Further study is needed to determine whether the configuration of the posterior internal vertebral venous plexus in younger individuals is different, compared with the presently studied aged subjects.

Aged↗
PubMed1995

The septal complex of the telencephalon of the lizard Podarcis hispanica. I. Chemoarchitectonical organization.

In this paper we study the septal complex architecture in the lizard Podarcis hispanica (Lacertidae). Histochemical and immunohistochemical techniques were used to define the distribution of zinc (Timm stain), acetyl cholinesterase (AChase), gamma-aminobutyric acid (GABA), tyrosine hydroxylase (TH), dopamine (DA), serotonin (5-HT), and two neuropeptides: leu-enkephalin (L-ENK) and substance P (SP). These reactions delineate a coherent map of nine septal nuclei that are named with a topographical nomenclature: anterior, lateral, ventromedial, medial, dorsolateral, ventrolateral, and dorsal septal nuclei, nucleus septalis impar, and nucleus of the posterior pallial commissure. The anterior septal nucleus is characterized by intense reaction for zinc and the presence of fibers immunoreactive for GABA, 5-HT, and L-ENK, which form pericellular nests. The lateral septal nucelus shows intense reaction for zinc, a high density of GABA-immunoreactive cells, and L-ENK-immunoreactive fibers forming basketlike figures around unstained somata. The ventromedial septal nucleus shows intense AChase reactivity, a dense network of 5-HT-immunoreactive fibers, and virtually no labeling for the other histochemical stains. The medial septal nucleus is defined by heavy reactivity for zinc, dense DA/TH and L-ENK innervations, and the presence of L-ENK-immunoreactive cells. The dorsolateral septal nucleus shows intense AChase staining in the neuropile and a dense network of fibers immunoreactive for 5-HT and DA/TH, but it shows low staining for zinc. The ventrolateral septal nucleus shows L-ENK-immunoreactive cells and a dense L-ENK innervation, but low reactivity for zinc. The dorsal septal nucleus, intermingled with the fimbrial fibers, shows a dense population of GABA-immunoreactive cells and terminals, but it is unreactive for zinc. Two subdivisions can be established in this dorsal septal nucleus: the dorsal part, intensely reactive for AChase and innervated by 5-HT fibers, and the central part, which shows L-ENK-immunoreactive neurons and fibers without reactivity for either AChase or 5-HT. The nucleus septalis impar, traversed by the fibers of the anterior pallial commissure (mildly reactive for zinc), shows reaction for AChase but low (if present) reactivity for the remaining markers. The nucleus of the posterior pallial commissure shows a generally low reactivity for the histochemical reactions employed. The distribution of these markers is similar to that found in other squamate reptiles and allows for a direct comparison with the septal formation of mammals. Such a comparison reinforces the view that the limbic system has undergone a conservative evolution within vertebrates.

Acetylcholinesterase↗
PubMed1995

Efferent connections of the lateral cortex of the lizard Gekko gecko: evidence for separate origins of medial and lateral pathways from the lateral cortex to the hypothalamus.

The lateral cortex of the lizard Gekko gecko is composed of three parts: a dorsal and ventral part located rostrally and a posterior part located caudally. In order to obtain detailed information about the efferent connections of these lateral cortex subdivisions, iontophoretic injections of the anterograde tracers Phaseolus vulgaris leucoagglutinin and biotinylated dextran were made in the various parts. The main projection from the dorsal part terminates in the caudal part of the medial cortex. Other cortical projections were noted to the ipsi- and contralateral lateral cortex, the large-celled part of the medial cortex, and the dorsal cortex. Additional fibers were found bilaterally in the anterior olfactory nucleus and the external amygdaloid nucleus. The ventral part of the lateral cortex projects mainly to the ipsilateral, posterior part of the dorsal ventricular ridge and the external amygdaloid nucleus. Minor contralateral projections to these nuclei were also found. Other projections were observed to travel to the caudal part of the medial cortex, to the nucleus sphericus, and bilaterally to the lateral cortex and the anterior olfactory nucleus. The posterior part of the lateral cortex has similar efferent connections as the dorsal part and should be regarded as the caudal continuation of the dorsal part. Because previous studies have shown that the medial cortex and the amygdaloid complex project to different hypothalamic areas, we conclude that the dorsal and ventral parts of the lateral cortex transmit olfactory information to separate hypothalamic areas that are probably involved with different types of behavior.

Animals↗
PubMed1994

Are rostral and caudal parts of the hippocampus of the lizard Gekko gecko related to different types of behaviour?

Spatial orientation is an important function of the hippocampus. In reptiles the medial cortex is the equivalent of the mammalian hippocampus. In this study we compared the structure and connections of the hippocampus of ground-dwelling lizards with those of gekkonid lizards which are able to walk on vertical walls as well as on the ceiling. This last type of locomotor behaviour makes high demands on spatial orientation. It appeared that, in contrast to the ground-dwelling lizards, in geckos the small-celled part of the medial cortex can be divided into a rostral and a caudal part. The rostral part receives visual, auditory, vestibular and proprioceptive information from the dorsolateral thalamic nucleus. The caudal part is connected with the lateral cortex which is the recipient of olfactory information from the main olfactory bulb. Also the efferent connections of the rostral and caudal part of the small-celled part of the medial cortex to the septum, and via the septum to the preoptic and hypothalamic areas remain strictly separated. Since different behavioural aspects are localized in different preoptic and hypothalamic subdivisions it seems likely that the two parts of the hippocampus in gekkonid lizards serve different behavioural functions.

Animals↗
PubMed1993

Medial cortex of the lizard Gekko gecko: a hodological study with emphasis on regional specialization.

There is increasing evidence that the archicortex in mammals and reptiles is not a homogeneous structure. However, little is known about the regional specialization of this cortical area in reptiles. Therefore, the efferent connections of the medial cortex of the lizard Gekko gecko were studied with the anterograde tracer Phaseolus vulgaris-leucoagglutinin. The small-celled part of the medial cortex (Cxms) projects to various parts of the septum in a topological way: the rostral part projects to the anterior septal nucleus, whereas the caudal part projects to the lateral septal nucleus and the nucleus septi impar. In addition, Cxms projects to the large-celled part of the medial cortex (Cxml). Axons that originate from the dorsal part of Cxms terminate at the proximal parts of the apical and basal dendrites of the neurons of Cxml caudal to the injection site. In contrast, fibers originating from the ventral part terminate on more distal parts of the dendrites of neurons of Cxml rostral to the injection site. Other projections from Cxms to the dorsal cortex (Cxd) and the external amygdaloid nucleus were found. The Cxml projects bilaterally to Cxms. These projections terminate in the superficial and deep plexiform layers. In addition, projections to the cell plate of Unger, Cxd, and to the lateral septal nucleus were found. It appears, on the basis of the efferent connections, that Cxms can be divided into a rostral and caudal part, while hodological differences also exist between the dorsal and ventral parts of Cxms. The results of the present study do not suggest a subdivision of Cxml. The regional variations of the medial cortex in the lizard Gekko gecko differ from the regional variations described in other reptilian species.

Animals↗
PubMed1993

Distribution of choline acetyltransferase immunoreactivity in the brain of the lizard Gallotia galloti.

The aim of the present study is to provide a complete description of the distribution of choline acetyltransferase (ChAT) immunoreactivity (i) in the brain of the lizard Gallotia galloti, on the basis of two different primary antisera: rat anti-ChAT and rabbit anti-chicken ChAT. Considering that the brain is a segmented structure, we have analysed our data with respect to transverse segmental domains (or neuromeres), which have been previously described by several authors in the brain of vertebrates. In the telencephalon, ChATi neurons are seen in the cortex, anterior dorsal ventricular ridge, basal ganglia, diagonal band, and bed nucleus of the stria terminalis. Further caudally, ChATi cell bodies are located in the preoptic area, hypothalamus, habenula, isthmus, and all motor efferent centers of the brainstem and spinal cord. Plexuses of ChATi fibers are observed in the areas containing cholinergic cell bodies. In addition, distinct plexuses are found in the cortex, the posterior dorsal ventricular ridge, the neuropiles of all primary visual centers of the diencephalon and mesencephalon, and several non-visual nuclei of the brainstem. The distribution of ChAT immunoreactivity in the brain of G. galloti resembles in many respects that of other vertebrates, and differences are mainly observed in the pretectum and midbrain tectum. Transverse segmental domains were identified in the brainstem and forebrain of Gallotia when the cranial nerve roots and fiber tracts were used as a reference, and most cranial motor nuclei were found to occupy the same segmental positions as have been reported in the chick.

Animals↗
PubMed1991

Differences in the regulation of acetylcholine release upon D2 dopamine and N-methyl-D-aspartate receptor activation between the striatal complex of reptiles and the neostriatum of rats.

Activation of the N-methyl-D-aspartate (NMDA) receptor increases and that of the D2 dopamine (DA) receptor inhibits the release of acetylcholine (ACh) from mammalian neostriatal tissue. Similar effects have been described in the ventral striatum of the rat, however, in the caudomedial part of the nucleus accumbens, D2 receptor activation does not inhibit the release of ACh. Likewise, the NMDA-induced stimulation of the release of ACh in this part of the striatum is much smaller. In the present study we demonstrated that in the striatal complex or striatum of reptiles D2 receptor activation did not result in an inhibition of the release of ACh, whereas the release of DA could be inhibited to a significant extent. These findings indicate that, although D2 receptors are present in the striatum of reptiles, these receptors do not regulate the release of ACh in this brain structure. We observed in the striatum of reptiles a potassium induced and calcium-dependent release of [3H]D-aspartate indicating a neurotransmitter role for aspartate or glutamate (GLU). However GLU and NMDA have only a marginal effect on the release of ACh in the striatum of the reptiles as compared to the effects in the neostriatum of the rat. It is concluded that with respect to the effects of D2 and NMDA receptor activation on the release of ACh, the striatum of reptiles bears most similarity to the caudomedial part of the nucleus accumbens.

Acetylcholine↗
PubMed1991

Ultrastructure of giant and small thalamic terminals of cortical origin: a study of the projections from the barrel cortex in mice using Phaseolus vulgaris leuco-agglutinin (PHA-L).

By means of tracing with the lectin Phaseolus-vulgaris leucoagglutinin (PHA-L), we examined in the thalamus of the mouse, the axon terminals of fibers originating in the barrel cortex. Vibratome sections of the brain were subjected to PHA-L immunocytochemistry and processed for light and electron microscopy. We observed small (0.5-0.8 microns in diameter) varicosities of labeled fibers in the nucleus ventrobasalis (VB) and the nucleus posterior (PO) as well as labeled giant terminals (3-5 microns in diameter) in PO. The analysis involved examination of serial sections and computer-aided reconstruction of several terminals. The small varicosities in VB appear to be small axon terminals forming distinct asymmetric synapses with small dendritic profiles. Some labeled terminals are apposed to, but not synaptically related with, the cell bodies of neurons in VB that are retrogradely labeled with PHA-L. The small varicosities seen with the light microscope in PO are terminals forming asymmetric synapses with dendritic shafts. The giant terminals in PO appear as large, vesicle-filled profiles forming part of synaptic glomeruli, i.e. complexes of one corticothalamic terminal engulfing several excrescences of a single dendrite. A giant terminal forms several asymmetric synapses (about 8) with these excrescences, as well as numerous (up to 15) puncta adhaerentia. The glomeruli are enveloped in glial lamellae, and they are often found at the bifurcations of primary dendritic segments. We suggest that the small terminals in VB are in the service of feedback signalling from the barrel cortex to its principal thalamic relay nucleus; the functional importance of this projection may reside in increased spatio-temporal discrimination. We interpret the giant terminals in PO as elements serving feed-forward processing, allowing the barrel cortex to influence, via PO, parts of the motor pathway modulating the animal's ongoing behavior.

Animals↗
PubMed1990

Distribution of choline acetyltransferase immunoreactivity in the telencephalon of the lizard Gekko gecko.

The presumptive cholinergic elements in the telencephalon of the lizard Gekko gecko were demonstrated with the AB8 anti-choline acetyltransferase (ChAT) antibody. Somata positive for ChAT were observed in the striatum, nucleus accumbens, the dorsal ventricular ridge, nucleus olfactorius anterior, tuberculum olfactorium, diagonal band of Broca, septum, bed nucleus of the medial forebrain bundle and lateral preoptic area. Staining of the neuropil was most conspicuous in the striatum but also occurred in the medial cortex and nucleus septi impar. The results indicate that the distribution of ChAT-positive somata in the telencephalon in reptiles is comparable to that in mammals; however, the relation of cholinergic somata and ChAT-positive neuropil seen in the striatum of G. gecko is different from that in mammals.

Animals↗