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I Divac

Publications and source records attributed to I Divac.

At least 91 records · Page 5Linked to original sources
PubMed1976

Time-discrimination performance in cats with lesions in prefrontal cortex and caudate nucleus.

Cats were trained on a time-discrimination task in which different periods of bodily confinement served as discriminanda for go-left/go-right responding. Lesions of gyrus proreus or the associated anteroventral part of nucleus caudatus impaired relearning in this situation. After reacquisition, animals with caudate lesions received proreal ablations and animals with cortical damage received caudate lesions; both additional lesions caused reappearance of the deficit. The absence of external stimuli to signal locus of reinforcement at the moment of spatial choice may have been crucial for eliciting the deficit. The data support the notion that the prefrontal cortex and the anatomically related part of the caudate nucleus participate in similar behaviors.

Animals↗
PubMed1976

Discrimination of time intervals in cats.

Fourteen cats were trained to discriminate between 5 and 20 s periods of confinement as evidenced by differential responding to two feeders. In a subsequent titration procedure the cats discriminated 5 from 10 or even 8 s. Positional mediation of correct responses was observed only in some animals. The present task may complement the classical and operant conditioning situations in which the temporal distribution of responses reflects the animals' abilities for both time discrimination and response inhibition.

Animals↗
PubMed1975

Magnocellular nuclei of the basal forebrain project to neocortex, brain stem, and olfactory bulb. Review of some functional correlates.

Horseradish peroxidase was injected into the neocortex of squirrel monkeys, rats, tree shrews and one opossum, in the brain stem of one squirrel monkey and rats, and in the olfactory bulb, the corpus vitreum or the vascular system of rats. Following the cortical, brain stem and bulbar injections labeled cells were found (predominatly ipsilaterally) in the magnocellular nuclei of the basal forebrain: nucleus of the diagonal band, the magnocellular preoptic nucleus and nucleus basalis. These nuclei may, therefore, be classified together hodologically as well as cytologically and histochemically. The number of labeled cells was proportional to the size of the injected region. It is uncertain whether the same cells project to all target regions. Large labeled cells were found scattered among pallidal and entopeduncular neurons in rats with cortical or brain stem injections. These neurons may be the equivalent to the nucleus basalis in other species.

Animals↗
PubMed1975

Emotional behavior in feral cats with ablations of prefrontal cortex and subsequent lesions in amygdala.

Bilateral ablations of gyrus proreus in 6 feral cats did not significantly alter either the intensity or the pattern of flight behavior during confrontation with a human. The scores for defense behavior were reduced in only 2 animals. Subsequent lesions in the rostral part of the basolateral nuclei of amygdala reduced flight and transiently decreased defense scores in all cats. The prefrontal cortex does not seem necessary for the flight and defense responding observed in feral cats. The role of amygdala in the regulation of these behaviors was confirmed.

Amygdala↗
PubMed1975

Dissociative effects of selective lesions in the caudate nucleus of cats and rats.

Lesions in the neostriatal region connected to the prefrontal cortex severely impaired delayed alternation in both cats and rats, whereas no such effect was found after damage to other neostriatal regions. These results indicate that the processes mediating delayed alternation are well localized in the neostriatum of both cats and rats. Two possible models of neostriatal functioning are discussed, one of functional heterogeneity, the other of functional homogeneity.

Animals↗
PubMed1972

Neostriatum and functions of prefrontal cortex.

A review of recent anatomical evidence shows that every neocortical area and many nuclei from the dorsal thalamus project to restricted neostriatal regions. The neurobehavioral literature offers many examples of the same results obtained with lesions, stimulations or recordings in a neocortical area and the associated neostriatal region. This evidence is abundant in the case of the prefrontal cortex and rostra1 neostriatum, but it is available also for other corticoneostriatal pairs. It seems possible to conclude that the function of a neostriatal region is determined by its cortical and possibly by its thalamic input. However, the possibility that the behavioral effects of lesions and stimulation of neostriatum were in fact produced by involving the fibers passing to and from the overlying cortex has not been convincingly excluded. An attempt was made to develop a simple concept about the relation between the prefrontal cortex and the region of neostriatum associated with it. A serial paradigm, suggesting that prefrontal cortex in adult monkeys and cats acts via neostriatum when mediating performance in certain behavioral tasks, seems to account for most of the available data.

Animals↗