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PubMed1984

Thalamic connections of the insula in the rhesus monkey and comments on the paralimbic connectivity of the medial pulvinar nucleus.

Thalamic connections of the insula in the rhesus monkey were studied with axonal transport methods. Tritiated amino acid injections limited to the insula revealed autoradiographic label in the principal and parvicellular components of the ventroposterior medial nucleus, the ventroposterior inferior nucleus, the oral and medial pulvinar nuclei, the nucleus reuniens, the parvicellular and magnocellular components of the medial dorsal nucleus, the centromedian-parafasicularis nuclei, and the reticular nucleus. In additional animals, tritiated amino acids and horseradish perioxidase injections were made within different regions of the insula. Although the injection sites in these additional cases may have included minor extensions into claustrum and adjacent structures, several tentative conclusions emerged with respect to the antero-posterior gradient in insulothalamic connectivity. The anterior insula appears to have a more extensive relationship with the ventroposterior medial complex, the medial dorsal nucleus, the centromedian-parafasicularis nuclei and with some midline nuclei. In contrast, the posterior insula is more extensively connected with the ventroposterior inferior nucleus, the oral and medial pulvinar nuclei, and the suprageniculate nucleus. The patterns of insulothalamic connections support conclusions derived from observations on the cortical connectivity of the primate insular cortex indicating that the anterior insula is related to olfactory, gustatory, and viscero-autonomic behavior, whereas the posterior insula is related to auditory-somesthetic-skeletomotor function (Mesulam and Mufson, '82b). The medial pulvinar nucleus has extensive connections with many paralimbic cortical regions including the insula as well as with high order polymodal association cortex. These findings suggest that the medial pulvinar may provide a region for the convergence of multisensory association input with limbic information.

Animals↗
PubMed1980

Brain stem projections in the pulvinar-lateralis posterior complex of the cat.

The present experiments were undertaken to define the areas of projection of pretectum and superior colliculus to the pulvinar and n. lateralis posterior, respectively, and to define other brain stem structures projecting to these thalamic nuclei in cats. For this purpose of technique of retrograde transport of horseradish peroxidase (HRP) has been used. After injection of the enzyme in the pulvinar, neurons were labeled in all subdivisions of the pretectal area. The majority of the labeled cells were located in the n pretectalis anterior pars compacta and area pretectalis medialis. Neurons projecting to the pulvinar were also found in the periaqueductal gray, reticular formation and locus coeruleus. When HRP was injected in the n. lateralis posterior, labeled neurons were present in the II and III subdivisions of the second layer of the superior colliculus. The location of these cells shifted from medial to lateral as the injections were shifted from posterior to anterior within the lateralis posterior. Neurons projecting to this nucleus were also present in the intermediate layers of the superior colliculus, lateral hypothalamus and parabigeminal nucleus. The possible role of the pretectal area and superior colliculus in mediating somesthetic input to the pulvinar and lateralis posterior, respectively, and the role of these structures in the control of ocular movements, are discussed.

Animals↗
PubMed1979

Functional properties of pulvinar-lateral posterior neurons which receive input from the superior colliculus.

Focal electrical stimulation of the superior colliculus induced short latency responses and/or a long duration suppression of spontaneous activity in single cells isolated in the pulvinar and lateral posterior (LP) nuclei of the cat. Cells which responded with one or more spikes at short latencies were relatively few in number, and these tended to be encountered in or near the principal tectorecipient zone of LP. In contrast, a suppression response was observed in many more cells which were widely distributed throughout the pulvinar-LP complex. Stimulation of the superficial layers of the colliculus was more effective in driving or suppressing pulvinar-LP cells than that of intermediate and deep layers. There was also an indication of a coarse topography in this projection. On the basis of their sensory response properties the cells responsive to tectal stimulation, at short latency or with a suppression, could not be differentiated from the overall sample of pulvinar-LP neurons.

Animals↗
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↗
PubMed1987

The postnatal development of thalamocortical projections from the pulvinar in the cat.

The postnatal development of thalamocortical projections from the pulvinar to an association cortex of the cat, the crown of the middle suprasylvian gyrus, was studied by using both HRP and evoked field potentials. From birth onward, the pulvinar sends dense fibres to this cortical area, but the cortical laminar distribution of the afferents was found to change markedly with aging. An orthograde HRP study showed that at birth and up to 2 weeks of age, the terminals are distributed mainly in layer I, whereas in adult cats and kittens older than 1 month, the terminals are found largely in and around layer IV and only sparsely in layer I. After HRP injections exclusively into layer I of the crown, numerous thalamic neurones were retrogradely labelled in both the ventroanterior-ventrolateral complex (VA-VL) and the pulvinar in 5-day-old kittens, but in the VA-VL alone in 2-month-old kittens. In agreement with these anatomical findings, stimulation of the pulvinar elicited a surface-negative, depth-positive potential in 1-week-old kittens, indicating the existence of a large current sink in layer I; however, it induced a surface-positive, depth-negative potential in 1-month-old kittens, reflecting the presence of a strong current sink in the deep cortical layers.

Afferent Pathways↗
PubMed1977

A retino-pulvinar projection in the cat.

Injections of tritiated amino acids were made in one eye of Siamese and common cats including young kittens. After survival periods of 1--7 days axoplasmically transported label accumulated in a portion of the pulvinar nucleus as well as in the other known sites of termination of the retinofugal pathway. The retino-pulvinar projection is present at birth; it is bilateral and approximately symmetrical in common cats but the ipsilateral component is markedly reduced in Siamese animals. Labeled terminal ramifications of the retinal fibers in the pulvinar take the form of a thin, interrupted sheet oriented dorsoventrally and lying at the extreme lateral edge of the pulvinar nucleus. It appears to be continuous caudally with the medial interlaminar nucleus of the lateral geniculate complex, but the cells about which the grains cluster are clearly different from those of the medial interlaminar nucleus.

Animals↗
PubMed1978

Visuotopic organization of the cebus pulvinar: a double representation the contralateral hemifield.

The projection of the visual field in the pulvinar nucleus was studied in 17 Cebus monkeys using electrophysiological techniques. Visual space is represented in two regions of the pulvinar; (1) the ventrolateral group, Pvlg, comprising nuclei P delta, P delta, P gamma, P eta and P mu 1; and (2) P mu. In the first group, which corresponds to the pulvinar inferior and ventral part of the pulvinar lateralis, we observed a greater respresentation of the central part of the visual field. Approximately 58% of the volume of the ventrolateral group is concerned with the visual space within 10 degrees of the fovea. This portion of the visual field is represented at its lateral aspects, mainly close to the level of the caudal pole of the lateral geniculate nucleus (LGN). Projection of the vertical meridian runs along its lateral border while that of the horizontal one is found running from the dorsal third of the LGN's hilus to the medial border of the ventro-lateral group. The lower quadrant is represented at its dorsal portion while the upper quadrant is represented at the ventral one. In Pmu the representation is rotated 90 degrees clockwise around the rostrocaudal axis: the vertical meridian is found at the ventromedial border of this nucleus. Thus, the lower quadrant is represented at the later portion of Pmu and the upper at its medial portion. Both projections are restricted to the contralateral hemifield.

Animals↗
PubMed1981

Selective synaptic antagonism by atropine and alpha-aminoadipate of pulvinar and cortical afferents to the suprasylvian visual area (Clare-Bishop area).

The synaptic excitations of cells of the Clare-Bishop cortical region produced by electrical stimulation of the pulvinar and ipsilateral cortex, have been shown to be differentially antagonized by iontophoretically applied antagonists. Atropine attenuated the responses evoked by pulvinar stimulation without having an appreciable effect against either iontophoretically applied aspartate or cortically evoked responses. alpha-Aminoadipate antagonized aspartate elicited excitations and those obtained with cortical stimulation while leaving unaffected acetylcholine and pulvinar evoked responses. The results are supportive of the view that acetylcholine and aspartate, or a similar excitatory amino acid, act as synaptic transmitters of some afferents from the pulvinar and ipsilateral cerebral cortex, respectively.

2-Aminoadipic Acid↗
PubMed1983

Visual activation of neurons in the primate pulvinar depends on cortex but not colliculus.

Superior colliculus lesions had little effect on the visual response of neurons in the monkey inferior pulvinar. By contrast, striate cortex lesions eliminated the visual response of all inferior pulvinar neurons for a period of 3 weeks after the lesion. At longer survival times, a few pulvinar neurons responded to small light spots, but sensitivity to orientation and direction of movement never returned. Thus striate cortex, rather than the colliculus, appears to be responsible for the visual properties of pulvinar cells.

Animals↗
PubMed1983

The organization of connections between the pulvinar and visual area MT in the macaque monkey.

Injections of horseradish peroxidase were placed in visual area MT which is located in the superior temporal sulcus of the macaque monkey occipital cortex. Overlapping retrogradely filled cells and anterogradely transported terminal grains were found to be located only within a crescent shaped region which traverses the brachium of the superior colliculus to include the inferior pulvinar and dorsal overlying lateral pulvinar. The connections between MT and the pulvinar crescent are reciprocal and topographically organized, with the lower visual field represented dorsally and the upper visual field represented ventrally. There is an expanded representation of central vision located caudally within the crescent while peripheral vision is represented rostrally. These findings indicate that any functional properties derived from the visual thalamus must arise from this crescent shaped region of the pulvinar.

Animals↗
PubMed1984

Cerebellar projections to the lateral posterior-pulvinar thalamic complex in the cat.

Stereotaxic injections of horseradish peroxidase in the subdivisions of the lateral posterior-pulvinar thalamic complex were made in adult cats. Labeled neurons were found in the ventrolateral part of the contralateral lateral cerebellar nucleus. Cerebellar-positive neurons were more abundant after injections situated in the lateralis intermedius oralis, lateralis intermedius caudalis and rostral pulvinar nuclei, while they were scarce or absent when the injections were located in the extra-geniculate visual subdivision of the lateral posterior-pulvinar complex (lateralis posterior lateralis and lateralis posterior medialis nuclei). These projections give an anatomical substrate to support the cerebellar modulation of the lateral posterior-pulvinar complex motor activities as well as its dinamogenic cortical functions.

Animals↗
PubMed1996

Motion sensitivity and stimulus interactions in the striate-recipient zone of the cat's lateral posterior-pulvinar complex.

The cat's lateral posterior-pulvinar complex (LP-pulvinar) establishes reciprocal connections with the anterior ectosylvian visual (AEV) and lateral suprasylvian (LS) cortices; two regions which are believed to be involved in motion analysis. We have investigated the motion sensitivity of neurons in the LP-pulvinar complex by: (1) studying the responses properties of cells in the striate-recipient zone of the LP nucleus (LPI) to the drift of a two-dimensional texture pattern (visual noise); and (2) determining the extent to which the latter stimulus can modify the spatial frequency tuning function of LPI cells. Experiments were carried out on anesthetized normal adult cats. Almost all LPI cells (55 out of 63, 87%) responded to the motion of visual noise. For most units (39 out of 55, 71%), responses varied as a function of the direction of motion (bandwidth of 49 degrees). One-third of the LPI units did not exhibit any preference for drift direction of noise. For practically all LPI cells, responses to noise varied as a function of drift velocity. Optimal velocities were distributed from 2 to 35 degrees/s with a mean value of 27.5 degrees/s (means bandwidth of 2.5 octaves). The influence of visual noise on the spatial frequency tuning function of 22 LPI cells was also studied. For half of LPI cells, responses at all spatial frequencies were reduced when the grating and the texture pattern were moving in opposite directions (anti phase condition). This masking effect of noise was rarely observed when both stimuli were drifted in the same direction (in phase condition). These results suggest that the LP-pulvinar complex may be part of extrageniculate pathways involved in the analysis of motion of visual targets and/or the analysis of the relative movement between an object and its surrounding environment.

Animals↗
PubMedDate not supplied

The spatial distribution of pulvinar neurons that project to two subregions of the inferior parietal lobule in the macaque.

The distribution of pulvinar neurons that project to the lateral intraparietal area (LIP) and area 7a, two subregions of the inferior parietal lobule in monkeys, was determined using small injections of retrogradely transported fluorescent dyes. Both LIP and 7a received the majority of their thalamic input from contiguous but distinct zones within the medial pulvinar nucleus. Thalamocortical cell bodies that projected to LIP were arranged in a dense, horizontally oriented cluster that was sandwiched between two similar clusters of neurons that projected to 7a. There was minimal overlap of the respective clusters. LIP also received an appreciable input from the dorsal half of the lateral pulvinar nucleus, but tracer placements in 7a resulted in only occasional labeled neurons in the lateral pulvinar.

Amidines↗
PubMed1979

Cross-correlation analysis of the lateral pulvinar and scalp EEG in man.

Cross-correlation analysis of the EEG between the lateral pulvinar and various cortical regions was made after EEG was recorded during stereotactic pulvinectomy. Cross-correlation analysis of the alpha-waves between the lateral pulvinar and the scalp EEG showed that the lateral pulvinar has the highest degree of functional connection with the pre-central area, diminishing in degree with the parietal and frontal areas, and has poor functional connections with the occipital area. From these results, it might be concluded that the lateral pulvinar may be related to motor function by functional connections with the pre-central area rather than the parietal area.

Alpha Rhythm↗
PubMed1991

[Electrophysiologic study of influences of the Pulvinar stimulation on the caudate nucleus neurons responding to visual stimulation].

Responses of caudate neurons to electrical stimulation of the afferent input from the thalamic nucleus pulvinar and to visual stimuli of various orientations were studied extracellularly in awake chronic cats. Activation responses dominated among reactions of these neurons. The response latencies have ranged from 4 to 85 ms for units with primary activation and from 20 to 150 ms for inhibited ones, the values are indicative of both rapidly and slowly conducting afferent pathways. A possibility of monosynaptic transmission in the pulvinar-caudate projections is also revealed. Stimulation of pulvinar is found to be efficient for the significant (more than 50%) number of caudate neurons responding to visual stimuli including orientation-selective cells. The mode of influences from other structures of the visual system (optic tract, area 17, the Clare-Bishop area) on caudate neurons, responding to pulvinar stimulation is described. The obtained data are discussed in the aspect of the possible role of cortical and subcortical projections of the visual system in the creation of sensory specific responses of the caudate nucleus.

Animals↗
PubMed1990

Positron emission tomographic measurements of pulvinar activity during an attention task.

Positron emission tomographic scans were recorded from human subjects following an object-identification task, one version of which required attentional selection and the other version of which did not. In one experimental session, the attention-demanding displays were presented in the left visual field and the nonattention displays were presented in the right visual field. In a second session, the sides of the displays were reversed. Analysis of the scans indicated that, averaged across the 2 sessions, the pulvinar showed greater glucose uptake when it was contralateral to the display of the selective attention task than when it was contralateral to the display of the nonattention task. The pattern of the data indicated that the degree of the attention task effect on pulvinar glucose uptake may differ between the hemispheres. In view of known connections between the pulvinar and cortical areas that mediate object identification, the present finding suggests that the pulvinar operates interactively with these cortical structures when an identification process demands selective attention.

Adult↗
PubMed1986

Lateral-posterior (LP) and pulvinar unit activity related to intentional upper limb movements directed to spatially separated targets, in behaving Macaca nemestrina monkeys.

We have showed in a previous paper that the pulvinar extracellular unit activity in behaving monkeys was dependent on the attention the animal paid to the stimulus, or on its behavioral significance or on the intentional movements the animal performed. Several groups of pulvinar cells quantitatively studied in the behavioral tasks the monkeys performed were described. "Projection and hand manipulation" neurons belong to a group of pulvinar cells that increased their activity when the animal made an intentional movement of the limb towards an object that attracted his attention. Some of these cells showed temporal patterns of discharge as well as peak rates of activity that frequently differed for reaching movements to spatially separated targets. This suggested that the overall pattern of discharge of these population of cells differ for different directions of arm movements. We give here a description of the observations made in three behaving Macaca Nemestrina monkeys trained to project there hands and arms to four spatially separated targets situated on a panel in front of them and at arm's reach. The extracellular unit activity in the LP-pulvinar was simultaneously recorded during the execution of the behavioral task. Statistical analysis were applied to objectively quantify the electrophysiological data. In 39 microelectrode penetrations, 362 neurons were recorded. 50 cells, a 13 p. 100, showed significative changes in their discharge during the execution of the task. Neurons of this class were activated when the monkey made an intentional movement with his upper limb towards something that attracted his attention. They were driven very poorly, and in a not easily reproducible way by passive manipulation of the limb.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Retino-pulvinar pathway of the cat brain].

Peculiarities on axonal distribution and termination of the retinal ganglionar cells within the limits of the thalamic pulvinar nuclei have been studied in 10 cats by means of the radioautography method combined with silver nitrate impregnation (Fink--Heimer technique). The ganglionar cells have projections on two pulvinar nuclei -- the lateral and the inferior. The medial pulvinar nucleus has no similar connections. The retinal projections in the pulvinar nuclear complex are bilateral and nearly symmetrical, the contralateral projections of the pathway somewhat predominate.

Animals↗