Search PubMed⌕ Search

Biomedical subjects

M Glickstein

Publications and source records attributed to M Glickstein.

At least 55 records · Page 3Linked to original sources
PubMed1981

Corticopontine projections of the lateral suprasylvian cortex: de-emphasis of the central visual field.

Layer V pyramidal cells of the cat lateral suprasylvian visual areas project to the pontine nuclei. Although all 6 of the suprasylvian visual areas project to the pons, the densest projections are from 3 areas: anterior medial lateral suprasylvian (AMLS), posterior medial lateral suprasylvian (PMSL) and ventral lateral suprasylvian (VLS). The organization of the corticopontine pathway from one of these areas (PMLS) suggests a disproportionate representation of the peripheral visual fields. This pattern of projection would serve to de-emphasize the central visual field.

Animals↗
PubMed1980

Corticopontine visual projections in macaque monkeys.

These experiments were designed to study the projections to the pons from visual and visual association cortex of monkeys by degeneration staining and horseradish peroxidase (HRP) methods. When lesions were made in these cortical visual areas, degenerated fibers were found in the rostral dorsolateral area of the pontine nuclei. When HRP was injected among visually responsive cells in this region of the pons, layer V cortical pyramidal cells were labeled. These labeled cells were concentrated most heavily on both banks of the superior temporal and intraparietal fissures, and on the rostral bank of the parieto-occipital fissure. The efferent targets and receptive field properties of these cortical regions are consistent with their possible role in visual guidance of movement.

Animals↗
PubMed1980

Visual pontocerebellar projections in the cat.

1. Projections of pontine visual cells onto the cat cerebellar cortex were studied by antidromic activation and by the retrograde transport of horseradish peroxidase (HRP). 2. Cells in the medial pontine visual area, which receive visual cortex projections, were activated antidromically principally from the contralateral cerebellar hemisphere. Cells in the dorsolateral pontine visual area, which receive an input from the superior colliculus, were activated principally from the vermis and ipsilateral hemisphere. There is some overlap in the projections of these two different populations of pontine cells, which probably occurs by way of bifurcated axons. 3. The HRP technique confirmed that there is a major difference in the pattern of projections from these two pontine visual regions. Many cells in the rostral-medial portion of the pontine nuclei, which receive their input from visual cortex, were labeled following HRP injections in the contralateral cerebellar hemisphere. Far fewer of these cells were labeled following vermal injection. Cells in the dorsolateral pontine nucleus, which receive visual input from the superior colliculus, were labeled following an HRP injection in the vermis or the ipsilateral hemisphere. Cells in the region of pontine nuclei that receive input from the ventral lateral geniculate nucleus were also labeled after a vermian injection. 4. If the vermis is related to the control of whole-body movements and the hemisphere to control of ipsilateral limbs, these results suggest that the corticopontocerebellar and the tectopontocerebellar pathways may be involved in different classes of visually guided movement.

Animals↗
PubMed1979

Tectopontine pathway in the cat: laminar distribution of cells of origin and visual properties of target cells in dorsolateral pontine nucleus.

1. The superior colliculus projects to the dorsolateral nucleus of the pons. Retrograde transport of horseradish peroxidase (HRP) revealed that cells in the superior colliculus, which send their axons to the pons, lie in both superficial (III) and deep (IV--VII) layers. Superficial cells outnumbered deep cells. The inferior colliculus also projects heavily to the dorsolateral pontine nucleus. 2. Dorsolateral pontine visual cells were activated only by visual stimulation. Cells responsive to somatic or auditory stimulation were also found in the dorsolateral nucleus, and they too responded to only one sense modality. 3. Of the dorsolateral pontine visual cells, 69% were directionally selective. 4. Dorsolateral pontine visual cells were responsive to moving targets over a wide range of stimulus velocities. Velocities between 25 and 100 degrees/s were the most effective. No cells responded to a stationary stimulus. 5. Single-spot targets were the most effective stimuli. Stimulus size was a more important parameter than stimulus configuration. Many cells had inhibitory regions outside of their excitatory fields. 6. The excitatory receptive fields of dorsolateral pontine cells were very large (median, 1,100 deg2). 7. Nearly all receptive fields were centered in the contralateral visual hemifield, and 91% of the dorsolateral visual cells were activated from either eye. 8. We conclude that the visual cells in the dorsolateral nucleus have receptive-field properties that are similar to those of cells in the superior colliculus. The preference of dorsolateral cells for single-spot targets contrasts strongly with the multiple-spot preference of medial pontine cells, which receive their input from visual cortex.

Animals↗
PubMed1978

Corticopontine cells in area 18 of the cat.

1. Area 18 projects to the rostral pontine nuclei. The visual response properties of rostral pontine cells differ greatly from those that have been reported for area 18 cells. We identified and studied corticopontine cells in area 18 and compared their receptive-field properties to those of other area 18 cells and to pontine visual cells. 2. We first located the visual area in the rostral pons by microelectrode recording and placed stimulating electrodes at the same site. Anti-dromically invaded cells were then recorded in area 18. The antidromic invasion of each cell was verified by orthodromic-antidromic spike collision. 3. Fifty-seven well-isolated corticopontine cells were studied in detail. We also recorded 466 unitary antidromic potentials with a mean invasion latency of 3.5 ms and recorded from 40 additional area 18 units to serve as a comparison group for the corticopontine cells. The comparison group cells were located in the same area in the visual field as the corticopontine cells. 4. The average receptive-field area for corticopontine cells (485 deg2) was much larger than the comparison cells (59 deg2). Forty percent of the corticopontine cells responded preferentially to multiple-spot target. Properly oriented gratings, slits, or edges were the most effective stimuli for the comparison cells. Eighty-two percent of the corticopontine cells showed clear directional preferences to moving-spot stimuli, and downward movements were most commonly preferred. Fifty-five percent of the area 18 comparison cells showed some directional preference, but no particular direction was preferred. The optimal stimulus speeds for corticopontine cells were higher than those for the comparison cells. 5. The response properties of the area 18 corticopontine cells are similar to the response properties of rostral pontine visual cells, except for a somewhat higher selectivity for orientation in the corticopontine cells. 6. We conclude that most response properties of rostral pontine visual cells are already present in a subset of area 18 cortical cells which project to the pons. The corticopontine cells are sensitive to multiple-spot targets moving in particular directions over large portions of the visual field, such properties are consistent with a visuomotor function for the corticopontocerebellar pathway.

Anesthesia↗
PubMed1976

Visual cells in the pontine nuclei of the cat.

Two hundred and thirty-two visually activated neurones were recorded in a small area of the rostral pontine nuclei of cats. The location of visually activated neurones was coextensive with the input from visual areas of cat's cortex as determined by degeneration studies. 2. Pontine visual cells could only be driven by visual stimuli. Cells responsive to somatosensory or auditory stimuli were also found in different regions in rostral pontine nuclei. They too responded to only one modality. 3. 96% of the cells were directionally selective. 4. Pontine visual cells were responsive to a wide range of stimulus speeds. Some cells responded to targets moving as fast as 1000 degrees/sec without losing directional selectivity. No pontine visual cells gave a clearly sustained response to a stationary stimulus. 5. Exact stimulus configurations were not critical. Large fields containing many spots were the most effective stimuli for 50% of the cells. Inhibition of responses depending upon stimulus dimensions, direction of movement, or location in the visual field was found for many cells. 6. Receptive field dimensions were large, ranging in size from 3 degrees X 4 degrees to more than an entire hemifield. 7. 94% of the cells had receptive fields which were centred in the contralateral hemifield. 8. 98% of the cells could be driven from both eyes. 9. The properties of the pontine visual cells suggest a corticopontocerebellar pathway sensitive to a wide range of speeds and directions of movement, but not sensitive to precise form.

Action Potentials↗
PubMed1972

Visual input to the pontine nuclei.

Visual input to the pons was studied by anatomical and physiological methods. Cortical area 18 sends a dense projection to the rostral pons. Pontine cells respond best to targets moving in a preferred direction over a large receptive field, which usually includes the center of gaze. The results suggest a role for pontocerebellar pathways in visual control of movement.

Action Potentials↗
PubMed1971

The ankle sprain.

Explore the source record for details and available documents.

Ankle Injuries↗