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C Baleydier

Publications and source records attributed to C Baleydier.

At least 19 recordsLinked to original sources
PubMed1997

Neurofilament architecture of superior and mesial premotor cortex in the human brain.

Monoclonal antibody (SMI-32) to neurofilament protein was used in an immunochemical study of the premotor cortex of two human brains in comparison with other architectonic techniques such as Nissi, myelin, cytochrome-oxidase and acetylcholinesterase staining in order to distinguish cortical subdivisions. SMI-32 immunoreactivity technique provides 'neurofilament architecture' patterns specific to area 4, caudal area 6 (area 6c) and rostral area 6 (area 6r). Particularly, the distinction between the two subdivisions of area 6, which is difficult to appreciate with the usual cytochemical or enzyme architectonic techniques, appears very apparent with this technique. Hence, it was possible to localize the topographic boundaries of area 6a alpha and 6a beta of the Vogts on the dorso-lateral convexity and the supplementary motor area and the presupplementary motor area on the mexial wall of the hemisphere.

Adult↗
PubMed1992

Segregated thalamocortical pathways to inferior parietal and inferotemporal cortex in macaque monkey.

Inferior parietal and inferotemporal cortex, which process different aspects of visual information through largely segregated pathways from the visual cortex, both receive thalamic afferents from the pulvinar complex. We examined the topography of pulvinar projections to these two cortical regions by placing multiple injections of different tracers (fluorescent dyes, horseradish peroxidase) in the inferotemporal and inferior parietal cortex of macaque monkeys. The patterns of label observed after injections in inferotemporal gyrus indicate that area TEO and the ventral part of area V4 receive a major input from the ventral part of the lateral pulvinar (PuLv) while area TE has strong connections with the caudal pole of the medial pulvinar (PuM) and only minor connections with PuLv. In contrast, injections in the caudal inferior parietal cortex demonstrate that area PGc, on the lateral surface of the inferior parietal gyrus, and area POa, in the ventral bank of intraparietal sulcus, receive strong projections from PuM and the adjacent fringe of the dorsal part of the lateral pulvinar (PuLd). Paired injections of two different tracers in the inferotemporal and inferior parietal cortex of the same hemisphere revealed a nearly complete segregation of the two populations of labeled neurons in the pulvinar, with only a small region of overlap in PuM, close to the PuM/PuLd border. These results demonstrate a clear separation of the thalamic afferents to the inferior parietal and inferotemporal cortex which parallels the separation of prestriate afferents to these two cortical territories (Morel & Bullier, 1990).

Afferent Pathways↗
PubMed1990

Macaque accessory optic system: I. Definition of the medial terminal nucleus.

The organization of the accessory optic system (AOS) has been studied in the macaque monkey following intravitreal injections of tritiated amino acids in one eye. Retinal projections to the dorsal (DTN) and the lateral (LTN) terminal nuclei are identical to those previously described in other primate species. We observed an additional group of retinorecipient cells of the AOS, located between the cerebral peduncle and the substantia nigra, which we define as the interstitial nucleus of the superior fasiculus, medial fibers. In this report, we focus our attention on the medial terminal nucleus (MTN). Although a ventral division of this nucleus (MTNv) was not observed in the macaque, the retina projects to a group of cells in the midbrain reticular formation (MRF), which we argue to be homologous to the dorsal division of the MTN (MTNd). To provide evidence in support of this homology, the retinal projection to the MTNv and MTNd was also examined in 21 additional species from 11 orders of mammals including carnivores, marsupials, lagomorphs, rodents, bats, insectivores, tree shrews, hyraxes, pholidotes, edentates, and five additional species of primates. Whereas the retina projects to both ventral and dorsal divisions in all species studied, in haplorhine primates only the projection to the MTNd is conserved. The relative topological position of the MTNd in the MRF, dorsomedial to the substantia nigra and ventrolateral to the red nucleus, remains constant throughout the mammals. The trajectory of fiber paths innervating the MTNd is also similar in all species. In addition, the MTNd has comparable afferent and efferent connections with retina, pretectum, and vestibular nuclei in all species thus far studied. These results support the unequivocal conclusion that the MTNd is an unvarying feature of the mammalian AOS.

Animals↗
PubMed1990

Macaque accessory optic system: II. Connections with the pretectum.

Connections of the accessory optic system (AOS) with the pretectum are described in the macaque monkey. Injections of tritiated amino acids in the pretectum demonstrate a major contralateral projection to the dorsal (DTN), lateral (LTN), and medial (MTN) terminal nuclei of the AOS and a sparser projection to the ipsilateral LTN. Injections of retrograde tracers, Fast Blue (FB), or wheat germ agglutinin horseradish peroxidase (WGA-HRP) plus nonconjugated horseradish peroxidase (HRP) in the LTN show that the pretectal-LTN projection originates from two nuclei. The main source of pretectal efferents to the LTN is from the pretectal olivary nucleus (OPN) and is entirely contralateral. This projection, which appears unique to primates, originates from the large multipolar cells of the OPN. In addition to this projection, the nucleus of the optic tract (NOT) projects to the ipsilateral LTN, as in nonprimates. Injection of WGA-HRP in the pretectum shows a reciprocal predominantely ipsilateral projection from the LTN to the pretectum. Retinas were observed after injection of FB in the LTN. The retinal ganglion cells projecting to the AOS are mainly distributed near the fovea and in the nasal region of the contralateral eye, suggesting a nasotemporal pattern of decussation. The demonstration of a direct connection between LTN and OPN forces to a reconsideration of the functional role of the AOS. Previous descriptions of luminance responsive cells in the LTN support a possible participation of this nucleus in the control of the pupillary light reflex.

Amidines↗
PubMed1987

Network organization of the connectivity between parietal area 7, posterior cingulate cortex and medial pulvinar nucleus: a double fluorescent tracer study in monkey.

The topographic distribution of medial pulvinar neuronal populations projecting to area 7a and to posterior cingulate gyrus (area 23) was investigated with retrograde axonal transport of fluorescent dyes. In an initial stage, separate injections of fast blue and diamidino-yellow were placed in area 7a. Two segregated backfilled cell populations were observed in the cingulate gyrus revealing a topographic distribution of cortico-cortical connections. In a second stage, the two dyes were injected in area 7a and in the posterior cingulate gyrus. After injections in two cortical sub-areas previously shown to be in topographic correspondence, the two projecting populations observed in the medial pulvinar overlapped extensively. In the case of injections in two regions not topographically correspondent, the two medial pulvinar populations were found to be segregated. These findings reveal that within both posterior parietal cortex and posterior cingulate gyrus, sub-areas which are in topographic correspondence receive projections from a common region of the medial pulvinar.

Amidines↗
PubMed1986

[Place of the thalamus in the network of interconnections between the association and limbic cortices in the monkey].

Anatomophysiological criteria underlying the definition of associative cortex as well as limbic cortex include some imprecise data. The original notion of "cortical association spheres" (Flechsig) with no connections with the thalamus has rightly been abandoned, and that of the macroscopic "large limbic lobe" (Broca) fails to stand up to histologic or hodologic findings. However, the concept of cortical areas implicated specifically in multiple sensorial integration, sensory-motor coupling and control of behavior lasts due to necessity. In the monkey, the posterior parietal cortex of area 7 (PG area), the cortex of the upper slope of the superior temporal sulcus (STS) and the prefrontal cortex anterior to the sulcus arcuatus exchange direct corticocortical connections, receive afferents from sensory cortex and are not connected to specific thalamic relays. The term "associative" in its widest sense applies more particularly therefore to these cortical areas organized in networks. On the internal surface of the hemisphere, the cingular gyrus, retrosplenial cortex and parahippocampic gyrus (TF and TH areas) which occupy the major part of the limbic lobe, participate in the formation of this network and exchange direct cortico-cortical connections with the associative cortex defined above. The use of anterograde (labelled aminoacids) and retrograde (peroxidases) markers and of fluorescent dyes, allowing double retrograde labelling, demonstrates that the median pulvinar nucleus is connected with the knots of the associative cortical network. This thalamic nucleus, of a relatively increased size from phylogenetic evolution, is therefore excluded from the classification opposing specific and diffuse projection nuclei. In contrast to the thalamic reticular nucleus, which lacks cortical projections, and to the nuclei of the internal medullary band, which have the striatum as main target, the median pulvinar is a thalamic structure connected directly and specifically with each of the cortical areas, lesions of which result in negligence behavior.

Animals↗
PubMed1985

Anatomical evidence for medial pulvinar connections with the posterior cingulate cortex, the retrosplenial area, and the posterior parahippocampal gyrus in monkeys.

Reciprocal connections between the medial pulvinar and the limbic neocortex in monkeys were demonstrated by means of tritiated amino acid injections in the medial pulvinar and the cingulate cortex, and HRP injections in the medial pulvinar. It appears that the medial nucleus of the pulvinar sends projection fibres to the posterior cingulate gyrus (area 23), the retrosplenial area, and the posterior parahippocampal gyrus (areas TH and TF). The labeled terminals were concentrated in two bands, one in the deeper part of layer III and in layer IV, and the other in layer I. These projections were observed to be reciprocal, and the cortical afferent fibers to the medial pulvinar were found to originate from the deep layers of the cortex. The medial nucleus of the pulvinar was already known to be connected with the prefrontal cortex and with the inferior parietal lobule. Since this nucleus is now demonstrated to be connected with the posterior limbic neocortex, it is envisaged as being the thalamic counterpart of a cortical triad (prefrontal, parietal, and limbic) involved in modulating directed attention.

Animals↗
PubMed1983

A crossed corticotectal projection from the lateral suprasylvian area in the cat.

Crossed cortical projections to the superior colliculus of the cat were demonstrated by unilateral superior colliculus injections of horseradish peroxidase (HRP) and by cortical injections of radioactive amino acids. This crossed corticotectal projection originates in the lateral bank of the middle suprasylvian sulcus and in both banks of the posterior suprasylvian sulcus. The site of termination of the contralateral corticotectal projection is restricted to the anterior margin of the superior colliculus (SC) while the ipsilateral projection spreads over the whole SC. The contralateral terminal areas are restricted to the superficial tectal layers. The projection fibers reach the contralateral superior colliculus by crossing the collicular commissure. The existence of such a connection may help to explain certain electrophysiological observations.

Animals↗
PubMed1980

The duality of the cingulate gyrus in monkey. Neuroanatomical study and functional hypothesis.

According to most behavioural, electrophysiological, and clinical studies, the cingulate gyrus is widely thought to be involved in regulation of emotional life, reactivity to painful stimuli, memory processing, and attention to sensory stimuli. Anatomically the cingulate cortex is composed of two distinct areas numbered 24 and 23 in Brodmann's classification. We have investigated the connections of the cingulate gyrus in monkeys, using horseradish peroxydase and radioautographic techniques, in order to verify the hypothesis of an anatomical complementarity of these cytoarchitectonic subdivisions. The posterior cingulate gyrus (area 23) is specifically connected with the associative temporal cortex, the medial temporal and orbitofrontal cortices, and with the medial pulvinar. The anterior cingulate gyrus (area 24) is related to the intralaminar, mediodorsal, and ventral anterior thalamic nuclei, the amygdala, and the nucleus accumbens septi. The two cingulate areas were found to be interconnected and to have, in common, connections with the 'limbic' thalamic nuclei (AM, AV, LD), the caudate nucleus, the claustrum, the lateral frontal and the posterior parietal (area 7) cortices.

Afferent Pathways↗
PubMed1979

Afferent and efferent connections of the parabigeminal nucleus in cat revealed by retrograde axonal transport of horseradish peroxidase.

Afferent and efferent connections of the parabigeminal nucleus (PBG) of the cat have been demonstrated by means of horseradish peroxidase (HRP) tracing technique. Following HRP injection in the PBG, labelled cells were observed mainly in the deep layers of the ipsilateral superior colliculus (SC). The other labelled structures were the prepositus hypoglossi complex (PH), the ventral nucleus of the lateral geniculate body (LGV), the locus coeruleus, the cuneiform nucleus, the periaqueductal gray and the dorsomedial hypothalamic area. Efferent projections of the PBG were investigated by HRP injection in SC, LGV, PH, hypothalamus and in some acoustic relays, i.e. medial geniculate body and inferior colliculus. Only the PBG-SC projection appeared to be well systematized. The positive labelling of the PBG following injection of LGV and hypothalamus is discussed in terms of the specificity of the injection. The absence of afferent and efferent connections of the PGB with any acoustic relay tends to exclude this nucleus from the auditory system in contrast to previous suggestions. On the basis of the close reciprocal PBG-SC connections a possible role of the PBG within visuomotor tectal function is proposed.

Afferent Pathways↗
PubMed1978

Projections of the ascending somesthetic pathways to the cat superior colliculus visualized by the horseradish peroxidase technique.

Projections of the somesthetic ascending pathways to the superior colliculus (SC) of the cat have been demonstrated by means of the horseradish peroxidase (HRP) tracing technique. Following HRP injection in one SC, marked neurons were found in the contralateral dorsal horn and in the contralateral dorsal column nuclei, mainly the cuneate nucleus. Moreover, in the contralateral trigeminal complex, the sub-nucleus caudalis of the spinal nucleus of the Vth nerve, and the subnucleus oralis plus the main sensory trigeminal nucleus were labeled. Thus, the anterolateral system and the lemniscal system subserving face and forelimb sensation send afferent fibers to the contralateral SC.

Afferent Pathways↗
PubMed1978

["Functional and anatomical organization of associative" cortical areas 7, 21 and 22 in monkeys. A study of the cortical projections from the pulvinar by means of HRP tracing technique (author's transl)].

The thalamic projections to the parietal and temporal associative areas (Brodmann's areas 7, 21 and 22) have been revealed by means of the retrograde axonal transport of horseradish peroxidase (HRP). The medial pulvinar (PM) was found to send afferents to the three studied areas. Labelled neurones of the PM appeared to be grouped in terms of their cortical target; indeed, neurones of origin of projection fibres to areas 7, 21 and 22 were respectively localized in the dorso-lateral, ventro-lateral and ventro-medial part of the PM. Although the multimodal sensory nature of the PM has been demonstrated by electrophysiological works, the function of PM neurones and the significance of their topographical repartition remain unknown. However PM could be involved in the transmission of specific sensory informations to the three associative areas 7, 21 and 22. Such an hypothesis is discussed according to the hitherto available data.

Afferent Pathways↗
PubMed1977

Direct projections from thalamic intralaminar nuclei to extra-striate visual cortex in the cat traced with horseradish peroxidase.

Thalamic projections to the visual cortex were investigated using the Horseradish peroxidase tracing technique. Besides confirmation of a distinct origin of thalamic projections to striate and extra-striate visual cortex, afferents of the intralaminar nuclei (ILN) to visual cortex were demonstrated. These projections of ILN were shown to be specific in that they terminate in areas 18, 19 and Clare Bishop but not area 17. The coupling of these intralaminar projections on to the extra-striate visual system is considered with respect ot orientation of gaze.

Animals↗
PubMed1977

Pulvinar-latero posterior afferents to cortical area 7 in monkeys demonstrated by horseradish peroxidase tracing technique.

Pulvinar-latero posterior afferents to the parietal cortical area 7 of the monkey have been demonstrated by means of horseradish peroxidase (HRP) tracing technique. Following HRP injection of area 7, labelled neurons have been found in the pulvinar medialis and the nucleus lateralis posterior. The role of these pulvinar projection fibers is discussed with reference to the "visual neurons" of area 7 recently recorded from.

Afferent Pathways↗
PubMed1975

Epileptic activity and anatomical characteristics of different lesions in cat cortex. Ultrastructural study.

Three different types of lesions have been studied in the cortex of the cat, by means of electroencephalography and electron microscopy. These three types of lesions can be listed in order of increasing magnitude according to their capacity to induce abnormal electrical activity: 1. incision of the cortex gives paroxymal activity, 2. intracortical insertion of a resin pellet generates weak epileptic activity, 3. intracortical insertion of a colbalt resin pellet produces epileptic activity. A parallel can be drawn between electrophysiological and anatomical data: there seems to be a quantitative relationship between the degree of epileptic activity and the extent of perilesional tissue. Furthermore, in this perilesional tissue, oedema is observed, the intensity of which varies according to the type of lesion. Thus, the epileptic activity of a lesion seems to be proportional not only to the volume of the perilesional tissue but also to the development of the oedema.

Animals↗