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J Czarkowska

Publications and source records attributed to J Czarkowska.

10 recordsLinked to original sources
PubMed1985

Factors influencing contact placing reaction times in cats.

Contact placing reaction times to stimulation of all extremities and of various surfaces of each paw were measured in cats either restrained in a hammock or held by the experimenter in a conventional way. Reaction times of contact placing elicited in a conventional way were shorter than those obtained in cats positioned in a hammock. Contact placing reaction times for the forelimbs were shorter than for the hindlimbs. In the forelimbs contact placing reaction times differed depending on the stimulated surface of the paw: they were significantly shorter to stimulation of the lateral side than of the dorsal and medial surfaces. Moreover, in a hammock, contact placing reaction times of the right fore- and left hindlimbs were significantly longer than of the opposite diagonal pair of extremities. These latter differences seem to be related to the posture developed by the animals in the experimental situation.

Animals↗
PubMed1985

Contact placing reaction times in the cat.

Cantact placing reaction times were measured in cats which were either restrained in a hammock or supported in a conventional way. The reaction times were longer, particularly for the forelimbs, when the cats were tested in the hammock as compared to the conventional procedure. In both experimental situations reaction times were longer for the hindlimbs than for the forelimbs. Data for cats restrained in the hammock have shown that forelimb reaction times differ depending on the stimulation site: they were significantly shorter to stimulation of the lateral side than of the dorsal and medial surfaces. Moreover, the reaction times of the right fore- and left hindlimbs were significantly longer than those of the diagonally opposite pair of limbs. The latter differences seem to be related to the posture of the animals in the hammock.

Animals↗
PubMed1985

A method of testing contact placing reaction in the cat.

The paper describes a device for testing contact placing in the cat which allows to control, with relatively high accuracy, the duration of tactile stimulation, its strength and the reaction time of contact placing. The apparatus can be used for testing contact placing in different experimental situations.

Animals↗
PubMed1983

Interactions between cat striate cortex neurons.

A series of simultaneous recordings from several striate cortex neurons were made in paralyzed, anesthetized cats. Recordings were obtained with one or two bundles of extra fine wires and originated from one and two cortical orientation columns. Standard PST histograms and, in some cases, response planes were used to analyse the neuronal receptive fields. Functional connectivity between neurons was assessed by cross-correlation of their spike trains. It was found that 61% of neuronal pairs found within a column shared the same input, either excitatory or inhibitory, Even if neurons in a pair belonged to two different columns separated by 1mm lateral distance, 40% of pairs still exhibited shared input coordination. This type of coordination could also encompass all combinations of simple and complex fields in the pair. Direct connections between neurons were found almost exclusively within columns: excitatory connections were found in 20% of cases and inhibitory in 8%. Direct connections were often accompanied by the other types of interactions. Only one example of excitatory and one of inhibitory direct connections were found between columns. In both cases preferred orientations were almost identical.

Animals↗
PubMed1981

Common interneurones in reflex pathways from group 1a and 1b afferents of knee flexors and extensors in the cat.

1. Input from group I afferents of knee flexors and extensors to interneurones in Rexed's laminae V-VI in the cat spinal cord was analysed by use of intracellular recording and electrical stimulation of the nerves to differentiate between group Ia and Ib synaptic actions. The aim was to find out if these interneurones may mediate synaptic actions of both group Ia and Ib afferents. 2. 28% of the forty-nine neurones analysed were excited by both group Ia and group Ib afferents; 32% were inhibited by both and 35% were excited by the one and inhibited by the other. Taking into account all of these actions, input from both subgroups of group I afferents was found in nearly 60% of neurones. Most were also excited and/or inhibited by group I afferents of ankle and toe extensors. 3. Selective (excitatory and/or inhibitory) input from Ia afferents was found in 18% and from Ib afferents in 22% of the neurones. 4. Excitation was evoked from Ia afferents of either knee flexors or extensors but not from both. In several of the neurones Ia i.p.s.p.s were, however, evoked from both posterior biceps-semitendinosus and quadriceps. 5. Intracellular staining with horseradish peroxidase revealed axonal projections of laminae V-VI interneurones to motor nuclei as well as to the intermediate zone, ipsilateral as well as contralateral. No correlation was found between patterns of input from group I afferents and axonal projections, and interneurones co-excited by Ia and Ib afferents were among these with different axonal projections.

Afferent Pathways↗
PubMed1974

Quality of stimuli and prefrontal lesions effects on reversal learning in go-no go avoidance reflex differentiation in cats.

Go – no go avoidance reflex differentiation of two acoustic stimuli has been previously established in cats. Then the signalling properties of the conditioned stimuli were reversed and the course of acquisition of a new go-no go differentiation was studied in normal cats and in cats with prefrontal lesions. The hypothesis based on stimulus intensity dynamism theory was: (i) in normal cats acquisition of the new differentiation would be easier if the more effective stimulus of the pair were used as the positive stimulus, and (ii) in prefrontal cats this effect of stimulus quality would be l a or absent. Results confirmed both predictions. The differences in rapidity of reversal learning were almost exclusively due to differences in responding to the new positive stimulus. Prefrontal cats were not deficient in comparison with normal cabs in their inhibitory abilities in spite of the fact that extinction of bar-pressing to the new negative conditioned stimulus was much slower than trader of the avoidance response to the new positive stimulus. At the beginning of reversal learning two opposite changes in responding on no-go trials were observed: (i) a decrease in the number of long-latency responses, which reflected the changed signalling value of the previously positive stimulus, and (ii) an increase in the number of short-latency responses, which was positively correlated with the increase in rate of intertrial responding. The increases in number of short-latency responses to the new negative stimulus and in rate of intertrial responding observed at the beginning of reversal learning were smaller in prefrontal than in normal cabs. Results of the experiment indicate that the "drive disinhibition hypothesis" does not account for the effects of prefrontal lesions on avoidance behavior.

Animals↗
PubMed1973

Go-no go avoidance reflex differentiation and its retention after prefrontal lesion in cats.

Cats were trained in a go-no go differentiation of two acoustic stimuli (click versus tone) using the bar-pressing avoidance method. The quality of the conditioned stimuli exerted a clear effect on the rapidity of the avoidance reflex acquisition and on the proportions of short-latency bar-pressing responses executed in positive and in inhibitory trials. Removal of the proreal and orbital gyri did not abolish differentiation, although a decrease of responding in positive trials and some impairment in further consolidation of the inhibitory reflexes were observed.

Animals↗