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Biomedical subjects

A Isseroff

Publications and source records attributed to A Isseroff.

12 recordsLinked to original sources
PubMed1985

An inexpensive microcomputer-based image-analysis system: novel applications to quantitative autoradiography.

We describe a relatively inexpensive, yet versatile and powerful microcomputer-based image-analysis system, and its applications to processing of deoxyglucose autoradiographic data. Images are acquired via a video camera mounted on a light microscope or a light box, and digitized in 40 ms to 512 X 512 picture elements with 8-bit resolution (256 gray levels). The bit-mapped image analysis hardware can provide up to 256 colors for pseudo-color coding, and virtually instantaneous readout of brightness values for densitometry. The system is controlled by an 8-bit S-100 bus microcomputer, providing flexibility and ease of expansion. In addition to pseudo-color coding and densitometry, we have developed programs for averaging of successive sections, image subtraction and quantitative reconstruction of different planes of section from serial autoradiograms.

Animals↗
PubMed1984

Columnar organization of callosal and associational projections from rat frontal cortex.

Autoradiography and HRP histochemistry were used to study the laminar and columnar distribution of callosal and associational connections of areas 6 and 10 of Krieg in the rat frontal cortex. In coronal sections through homotopic contralateral areas and ipsilateral somatosensory cortex, terminations of projections arising in frontal cortex formed discrete vertical columns; these were 250-750 micron wide and alternated with unlabeled or poorly labeled areas of approximately equal width. In reconstructions from serial coronal sections through these areas, the terminal fields formed a series of bands. The location of retrogradely labeled neurons tended to reciprocate the distribution of terminal label, although the boundaries of terminal and cell label were not always in precise register. These findings indicate that in the rat, both association and callosal projections exhibit a terminal organization remarkably similar in width and spacing to that observed in primates. Thus, a columnar mode of termination of cortico-cortical fibers may be an organizational feature common to mammalian neocortex.

Animals↗
PubMed1983

Monocular stimulation increases deoxyglucose uptake in ipsilateral primary optic centers of the rat.

We present data from autoradiography of 2-deoxyglucose (2-DG), which indicate that despite the limited uncrossed optic innervation of the rat, monocular stimulation produces considerable activation of ipsilateral primary visual centers. Compared to binocularly occluded rats, intact, monocularly occluded ones showed substantial and statistically significant increases in 2-DG uptake throughout the dorsal lateral geniculate nucleus and superficial layers of the superior colliculus ipsilateral to the stimulated eye, as well as larger increases in contralateral areas. In contrast, stimulation of mono-enucleated rats did not produce observable increases in 2-DG uptake in ipsilateral optic centers, confirming previous results. This effect may be due to functional depression in the denervated areas.

Animals↗
PubMed1982

Spatial memory impairments following damage to the mediodorsal nucleus of the thalamus in rhesus monkeys.

The present study assessed whether the mediodorsal nucleus (MD) of the primate thalamus subserves some of the same learning and memory functions mediated by its prefrontal cortical projection areas. Behavioral effects of MD lesions were evaluated in 14 young adult rhesus monkeys, using tests known to be sensitive to damage in different regions of the prefrontal cortex. Performance on a spatial delayed alternation task was significantly (P less than 0.01) impaired by MD lesions, and this impairment was significantly correlated (rs = 0.52) with damage to the posterior half of the mediodorsal nucleus. Such damage was also correlated significantly (rs = 0.51) with performance on another spatial memory task, delayed response; monkeys that sustained the largest lesions of the posterior mediodorsal nucleus were significantly (P less than 0.05) impaired on this task relative to operated animals suffering the least posterior MD damage. In contrast to their performance on spatial memory tasks, operated animals were not impaired on tests of object reversal or visual pattern discrimination. These results indicate that lesions of the mediodorsal nucleus can elicit a specific syndrome of spatial memory loss qualitatively similar to that observed after damage to the dorsolateral prefrontal cortex.

Animals↗
PubMed1980

Facilitation of delayed spontaneous alternation behavior in adult rats following early hydroxyzine treatment: differential sensitivity in late infancy.

When tested in adulthood, male rats that had been treated daily with 50 mg/kg hydroxyzine HCl SC at 10--29 or 23--29 days of age were significantly facilitated in performance of delayed spontaneous alternation relative to saline-injected rats. Treatment at 10--16 days of age did not produce significant facilitation in the delay task, nor were there any significant differences between groups in spontaneous alternation with no intertrial delay. The facilitative effect may be attributable to anomalies in areas, such as the limbic system, that continue to develop postnatally and mature in late infancy.

Aging↗