Edward Gruberg - Academia.edu (original) (raw)

Papers by Edward Gruberg

Neuroscience Letters, 2016

We used physiological and anatomical methods to elucidate how the visual field is represented in ... more We used physiological and anatomical methods to elucidate how the visual field is represented in the part of the dorsal anterior thalamus of the leopard frog that receives direct retinal projections. We recorded extracellularly while presenting visual stimuli, and characterized a physiologically defined region that encompasses the retinal projections as well as an extended zone beyond them. We probed the area systematically to determine if the zone is organized in a visuotopic map: we found that it is not. We found that units in this region respond only to stimuli in the contralateral half of the visual field, which is similar to what is seen in the dorsal lateral geniculate nucleus in mammals. When we backfilled retinal ganglion cells from application of HRP to the anterior thalamus, we found labeled cells only in those parts of the retina corresponding to the contralateral hemifield, confirming our physiological observations.

J Morphol, 1973

... concentrations BW284C51 (Burroughs-Wellcome) selectively inhibits acetylcholin-esterase witho... more ... concentrations BW284C51 (Burroughs-Wellcome) selectively inhibits acetylcholin-esterase without significantly inhibiting butyrylcholinesterase (Bayliss and Tod-rick, '56). ... Enucleated tiger sala-manders were allowed to survive post-operatively for 16, 18, 21 and 25 days at 15 ...

Experimental Neurology, Apr 30, 1995

We studied the effect of optic chiasm midline transection on visually guided behavior and retinot... more We studied the effect of optic chiasm midline transection on visually guided behavior and retinotectal fiber regrowth in frogs. After complete tr ansection, frogs do not respond to visually presented prey and looming stimuli. Beginning about 2 months later there is recovery of visual function. However, unlike recovery after optic nerve transection, animals respond as if the stimulus were not at its actual position, but at the symmetric position in the contralateral field. For instance, if a prey stimulus is located 5 cm away from the recovered frog at an eccentricity of 40" to the left of the midline, the animal will respond as if the stimulus were 5 cm away at 40" right. Further, these animals typically respond to looming stimuli not by jumping away from the stimulus, but by either colliding with the stimulus or jumping toward the side from which the stimulus approaches. These behaviors persist throughout the testing period, up to 17.5 months postlesion. Electrophysiological recordings reveal that visual activity in the optic tectum is retinotopically organized but driven primarily by stimuli to the ipsilateral eye. BBP histochemistry reveals that some regenerated retinal fibers are found to cross at the midline of the chiasm. Thus, the midline is not impenetrable to crossing retinal fibers. Frogs with cut of 8/r of the chiasm respond normally to prey stimuli initially but later respond as if the stimuli are at mirror image locations. In these animals most retinotectal fibers project to the ipsilateral tectum despite the presence of intact contralaterally projecting retinotectal fibers during the recovery period.

Visual Neuroscience, 1996

Visuomotor Coordination, 1989

Journal für Hirnforschung

Visual Neuroscience, 2005

The superficial layers of the frog optic tectum receive a projection from the contralateral eye t... more The superficial layers of the frog optic tectum receive a projection from the contralateral eye that forms a point-to-point map of the visual field. The monocular part of the visual field of the contralateral eye is represented in the caudolateral region of the tectum while the binocular part of the visual field is represented in the rostromedial tectum. Within the representation of the binocular field (rostromedial tectum), the maps of visual space from each eye are aligned. The tectal representation of the binocular visual field of the ipsilateral eye is mediated through a crossed projection from the midbrain nucleus isthmi. This isthmotectal projection also terminates in the caudolateral region of the optic tectum, yet there has been no indication that it forms a functional connection. By extracellular recording in intermediate layer 7 of the caudolateral tectum, we have discovered electrical activity driven by visual stimulation in the monocular visual field of the ipsilateral e...

Neuroscience Letters, 1985

Neuroscience Letters, 54 (1985) 307-312 Elsevier Scientific Publishers Ireland Ltd. NSL 03178 ABL... more Neuroscience Letters, 54 (1985) 307-312 Elsevier Scientific Publishers Ireland Ltd. NSL 03178 ABLATION OF NUCLEUS ISTHMI LEADS TO LOSS OF SPECIFIC VISUALLY ELICITED BERAVIORS IN THE FROG RANA PIP/ENS HANAN S. CAlNE* and EDWARD R. GRUBERG Biology ...

Journal of Morphology, 1978

After hemisection of the spinal cord and medulla oblongata, a projection has been traced to the i... more After hemisection of the spinal cord and medulla oblongata, a projection has been traced to the inner half of the tectal white of the tiger salamander, using Fink-Heimer degeneration staining. By microelectrode recording it was found that the tectal projection forms a topographic somatosensory map of the contralateral half of the body. This map is in register with the overlying retino-tectal visual projection. Using the Falck-Hillarp technique, it was found that the somatosensory tectal input is associated with yellow-fluorescing 5-hydroxytryptamine fibers.

Journal of Comparative Physiology A, 2010

The frog nucleus isthmi (parabigeminal nucleus in mammals) is a visually responsive, cholinergic ... more The frog nucleus isthmi (parabigeminal nucleus in mammals) is a visually responsive, cholinergic and anatomically well-defined group of neurons in the midbrain. It shares reciprocal topographic projections with the ipsilateral optic tectum (superior colliculus in mammals) and strongly influences visual processing. Anatomical and biochemical information indicates the existence of distinct neural populations within the frog nucleus isthmi, which raises the question: are there electrophysiological distinctions between neurons that are putatively classified by their anatomical and biochemical properties? To address this question, we measured frog nucleus isthmi neuron cellular properties in vitro and visual response properties in vivo. No evidence for distinct electrophysiological classes of neurons was found. We thus conclude that, despite the anatomical and biochemical differences, the cells of the frog NI respond homogeneously to both current injections and simple visual stimuli.

Brain, Behavior and Evolution, 1998

When given the option between a ground-level prey presented in front and another prey presented 9... more When given the option between a ground-level prey presented in front and another prey presented 90 degrees to the side, leopard frogs have a front preference. When given a choice between prey objects presented at the left and right sides, some individual leopard frogs have a side preference. Repeated prey object presentations at one side predispose leopard frogs to respond to the opposite side when presented with prey objects at both sides. The phenomenon is preserved through a half minute delay between single prey presentations (biasing) and two prey presentations (testing) but not through a three-minute delay between biasing and testing. Ten biasing presentations on a side are sufficient to induce opposite side preference, while three biasing presentations are insufficient. Attempts to permanently modify preferences by completely exhausting responsiveness to a single side were unsuccessful. A neural model for the effect of biasing on behavior is shown.

Brain, Behavior and Evolution, 2004

Anurans have independent systems for detecting moving stimuli and stationary opaque objects. We h... more Anurans have independent systems for detecting moving stimuli and stationary opaque objects. We have discovered that leopard frogs will also orient to, and spontaneously and accurately jump through, circular apertures in overhead transparent covers. When given a choice between one large aperture of 3.8 cm diameter, and three apertures of smaller but equal diameter (2.5 cm diameter, 1.9 cm diameter, or 1.3 cm diameter) they choose the larger diameter aperture at a frequency (64, 87 and 97%, respectively) that is statistically greater than chance. In only 1 of 255 attempts was there a jump to the overhead cover that was not directed at an aperture. Atectal frogs are still able to detect and jump accurately through transparent apertures. Frogs cannot distinguish between two apertures of equal diameter if one aperture is covered with clear plastic with high light transmissibility (92% of transmissibility of air). However, if the plastic covering of the aperture has a residue which reduces light through the cover from 92 to 87% of the transmissibility of air, frogs will jump to the uncovered aperture at a frequency that is statistically greater than chance. Our results show that leopard frogs have an extremely well developed ability to detect overhead apertures just as they can vertical obstacles. They are able to jump towards such openings with a small margin of error independent of the tectal visual system.

Brain Research, 1987

An immunohistochemical method for choline acetyltransferase (CHAT) identifies presumably choliner... more An immunohistochemical method for choline acetyltransferase (CHAT) identifies presumably cholinergic axons in two retino-receptive laminae in the optic tectum of the frog Rana pipiens. Following eye enucleation there is no loss of immunoreactive axons in the optic tectum. Following unilateral ablation of the nucleus isthmi there is a near-total loss of ChAT-positive axons in the superficial cholinergic lamina contralaterally and in the deeper cholinergic lamina ipsilaterally. Thus, the cholinergic innervation of the tectum appears to derive from the nucleus isthmi. However, ChAT-positive staining of the basal optic nucleus does depend upon an intact retinal input and could derive from either retinal axons or some system trophically dependent on them.

Brain Research, 1974

With the use of tetrazolium salt the distribution of succinic semialdehyde dehydrogenase, the fin... more With the use of tetrazolium salt the distribution of succinic semialdehyde dehydrogenase, the final enzyme in the degradative pathway of GABA, was investigated in the brain and retina of the tiger salamander. In the brain it was found in discrete neural areas, including the neuropil of the acoustico-lateral area, the magnocellular area of the medulla, the neuropil of the cerebellum, the mesencephalic V nucleus, the third nerve nucleus, the epiphysis, the subcommissural organ, the fasciculus retroflexus, and the neuropil of the habenula. In addition there was a diffuse distribution due to ependymal cells. In the retina the enzyme was seen in M/Jller cells, ellipsoid bodies and possibly Landolt club processes.

Behavioral and Brain Sciences, 1987

Neuroscience Letters, 1998

We loaded adult leopard frog optic nerves with the calcium-sensitive dye Calcium Green-1 3000 mw ... more We loaded adult leopard frog optic nerves with the calcium-sensitive dye Calcium Green-1 3000 mw dextran conjugate. The dye was transported to the optic tectum in approximately 6 days and selectively labeled optic nerve terminals as seen with confocal microscopy. Viewed with an intensified CCD system, electrical stimulation of the optic nerve in vitro increases Calcium Green-1 fluorescence significantly. With

Visual neuroscience

The retina of the leopard frog projects topographically to the superficial neuropil of the entire... more The retina of the leopard frog projects topographically to the superficial neuropil of the entire contralateral tectum. In the rostromedial neuropil of the tectum, there is a map of the binocular region of the visual field seen from the ipsilateral eye that is in register with the map of the binocular region of the visual field seen from the contralateral eye. The ipsilateral eye projects indirectly to the tectum through nucleus isthmi (n. isthmi), a midbrain tegmental structure. N. isthmi receives input from the ipsilateral optic tectum and sends projections bilaterally that cover both tectal lobes. Previous workers have not been able to find visual activity from the ipsilateral eye in the caudolateral optic tectum, representing the monocular visual field of the contralateral eye. We show electrophysiologically that across the entire extent of n. isthmi there are two superimposed maps, one map representing the entire visual field of the contralateral eye, the other map representing...

Brain Res, 1980

Key words: frog visual system --binocular system --frog tectum --horseradish peroxidase --tectal ... more Key words: frog visual system --binocular system --frog tectum --horseradish peroxidase --tectal units SUMMARY The locations of tectal neurons projecting to nucleus isthmi (n. isthmi) were found by iontophoretic injection of horseradish peroxidase (HRP) into n. isthmi. After retrograde transport, stained tectal somata are found to lie almost exclusively in layer 6 and below of the ipsilateral tectum. Many cells are colored throughout the extent of their dendrites into the fine rami, giving the appearance of a Golgi stain. Nucleus isthmi receives projections from the ipsilateral rectum and from no other region.