Biomedical subjects

F Klingberg

Publications and source records attributed to F Klingberg.

At least 91 records · Page 5Linked to original sources

PubMed1978

[The involvement of thalamic nuclei in the formation of conditional avoidance reflexes in rats. I. Lesions in the anterior part of the nucleus ventralis lateralis].

Hooded rats (Long-Evans-strain) were not able to elaborate conditioned avoidance responses in a simple runway respectively in a jumping test after bilateral lesions of the anterior part of the nucleus ventralis lateralis thalami. When the number of the CS-US-combinations was increased from 10 to 25 per session, then during the last ten combinations the punishing electrical foot shocks were correctly avoided, but the animals showed no retention in their long-term memory.

Animals↗

PubMed1978

[Involvement of thalamic nuclei in the formation of conditioned avoidance responses in rats. III. Lesions of the nucleus ventralis medialis].

Bilateral lesions of the nucleus ventralis medialis thalami (VM) did not change the reactivity to sensory and painful stimuli, the preoperatively fixed motor patterns and the preoperatively elaborated conditioned avoidance response (CAR, jumping test) in hooded rats (Long-Evans-strain). The postoperative acquisition of a CAR in a runway was attained as in controls, but with significantly higher running speed. During continuation of the training in a Y-maze using a 2:2-alternation schedule the CAR decreased gradually to zero as a consequences of increasing reaction times (time from onset of the acoustic conditioned signal to the onset of running). At least the lesioned animals only started with the onset of the painful reinforcement. In spite of the non-avoidance these animals learned to escape correctly through the illuminated floor (dark-light-discrimination). The results are discussed as a consequence of a deficit in conditioning of locomotor programs.

Animals↗

PubMed1978

[Participation of thalamic nuclei in the elaboration of conditioned avoidance reflexes of rats. IV. Lesions of the nucleus reuniens].

The elaboration of conditioned avoidance reflexes in a Y-maze and in the jumping test was scarcely influenced by lesion of the n. reuniens of the thalamus in hooded rats. The increase of intertrialreactions in the jumping test after such lesions in contrast to the control group indicates changes in the regulation of motivational processes. After additional lesion of the n. rhomboideus neither the conditioned avoidance nor the unconditioned escape reaction were elaborated in the jumping test.

Animals↗

PubMed1978

Participation of thalamic nuclei in the elaboration of conditioned avoidance reflexes of rats. V. Lesions of the nucleus mediodorsalis.

Hooded rats of the Long-Evans strain with isolated bilateral lesions of the nucleus mediodorsalis thalami (MD) were not able to avoid foot-shocks in a simple runway and in the jumping test. They even did not move and showed no emotional reactions during the conditioned stimulus. The lesions did not change spontaneous behaviour, motor patterns or the thresholds of pain reactivity. The animals displayed less spontaneous and goal-directed orienting responses. The possible participation of MD in a functional system realizing certain kinds of prognosis is discussed.

Animals↗

PubMed1975

[Photic evoked responses in the brain stem of the rat].

The appearance of photic evoked responses in various structures of the reticular formation (RF) and the thalamus was investigated in freely moving rats. Photic evoked potentials (PhEP) were recorded in all the nuclei tested. The PhEP are different in shape, amplitude and latency; they can be classified as a "primary type" with small amplitudes and without latency differences from the PhEP of the visual cortex (VC) and as a "secondary type" with large amplitudes and latency differences from the PhEP of the VC. The "primary type" was observed in thalamic, pontine and bulbar structures but the "secondary type" in posterior-thalamic and mesencephalic structures. Photic afterdischarges (PhNE) and photic recruitment (PhR) were recorded in most of the nuclei tested. These PhNE and PhR have a correlation in their frequency and peak-latency to the PhNE and PhR of the VC. It is discussed that a great part of visual information is transferred to the brain stem through the Corpus geniculatum laterale (CGL) and the VC.

Animals↗

PubMed1975