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F Klingberg

Publications and source records attributed to F Klingberg.

At least 73 records · Page 4Linked to original sources
PubMed1985

Correlation between peak times of visually evoked potentials and an amplitude coefficient of acoustically evoked potentials in the superior colliculus on the freely moving rat.

Components of VEP and AEP of 27 male hooded rats with chronically implanted electrodes in the anterior medial superior colliculus (CS) were measured and compared during relaxed wakefulness. Peak times of the VEP are correlated to the log of the quotient II/I of amplitudes P20-N32 (II) and P5-N10 (I) of AEP on the same recording point. The conclusion is drawn that the configuration of the collicular EP strongly depends on the distribution of neuronal elements around the electrode tip.

Animals↗
PubMed1984

The effect of lesions in the mesencephalic reticular formation upon conditioned avoidance responses in rat. II. Lesions of the area cuneiformis.

Hooded rats of the Long-Evans strain were not able to acquire a conditioned avoidance response (CAR) in a jump test when they were injured by bilateral symmetric lesions in the area cuneiformis (CU) of the mesencephalic reticular formation. The acquisition of a simple CAR in a Y-maze was not impaired irrespective of the size of the lesion. However, lesioned rats ran significantly slowlier to the maze exit in simple and discrimination tasks and displayed more erroneous runs in dark-light discrimination sessions. These deficits were not observed when rats with small lesions in the anterior CU (CU-1 group) had preoperatively learnt the dark-light discrimination, but they were observed when preoperatively trained rats were injured by caudally extended lesions (CU-2 group). After preoperative training CU-1 rats had a great retention deficit in the jump test compared with no deficit in a sham-operated group. They were unable to relearn the task, whereas rats with dorsally extended lesions including the nucleus commissurae posterioris (NCP-CU group) had less deficit and relearnt the CAR in the jump test. Animals of this group performed an enhanced number of intertrial responses and showed increased arrest reactions with goal-directed attention evoked by the conditioned stimulus. The results indicate - together with the observed behavioural syndrome of disturbed locomotion, reduced orienting responses and exploratory behaviour - that the CU is an important structure for the integration of goal-directed behaviour.

Animals↗
PubMed1984

Cortical tooth pulp evoked potentials in freely moving rat.

The paper deals with the method of chronic implantation of electrodes for tooth pulp stimulation (TPS) in the upper incisor of rats, which enables investigations of tooth pulp evoked potentials (TPEP) under conditions of unrestrained behavior during several weeks. The most favorable point for recording TPEPs in the somatosensory cortex was 1 mm anterior of the bregma and lateral 3 mm below the crest of the skull. Here, TPEPs had amplitudes between 1000 and 2000 mikroV. TPEPs with amplitudes lower than 400 mikroV were recorded in other neocortical areas. The amplitudes of the primary components with peak times of 6 ms for positive and 12 ms for negative peaks were dependent on the behavioral state. The position of and distance between stimulation electrodes influence the TPEP. With increasing stimulus intensity TPEP amplitudes rised in an s-shaped curve. Current spread to alveolar nerve tested in acute experiments and was too small to evoke sufficiently large EPs of other origin.

Animals↗
PubMed1984

The effect of lesions in the mesencephalic reticular formation upon conditioned avoidance responses in rat: I. Lesions of the nucleus commissurae posterioris.

After bilateral symmetric lesions of the n. commissurae posterioris (NCP) hooded rats of the Long-Evans strain did not acquire the conditioned avoidance response (CAR) in a jumping test. The NCP rats were rather unable to find out the escape possibility on the rod hanging in the middle of the apparatus. They did not learn the context between the conditioned stimulus (CS), the unconditioned stimulus (UCS) and the jump. In an Y-maze formation of CAR was even better in NCP rats than in sham-operated controls because of their shorter reaction times and their higher running speed. Their brightness discrimination, on the other hand, was significantly impaired and erroneous runs were only reduced to a low insignificant amount after more than 100 trials. Lesions in the NCP had no severe effects upon preoperatively learnt CARs, but brightness discrimination was still impaired. From these results it may be concluded that NCP plays a role in the formation of goal-directed behaviour depending on external cues and in actual visually guided behaviour.

Animals↗
PubMed1983

Open field behaviour of rats after various mesencephalic lesions.

Hooded rats of the Long-Evans strain with small bilateral symmetric lesions of the pretectum (PR, n = 10), the nucleus commissurae posterioris (NCP, n = 14), area cuneiformis (CU, n = 10), area subcuneiformis (CUS, n = 11) and with combined lesions of CU and NCP (n = 6) were compared in an open field (OF) situation with sham-operated controls (C, n = 8). All lesioned rats showed significantly decreased crossing of 15 cm squares in the OF, which were controlled by infra-red beams. This decrease was stronger after dorsal lesions (55% of controls) than after ventral ones (80% of controls). In all lesioned groups with exception of CUS rats the duration of immobility was significantly prolonged, maximally after NCP lesions (980%). When NCP rats moved, they had a higher rate of crossings per second (150%) whereas CUS rats moved more slowly (71% crossings per second related to controls). The stay on peripheral fields was prolonged in PR rats and reduced in NCP rats. The number of rearings in all lesioned animals was less than 25% of control values. This was closely correlated with a strong reduction of climbings at the walls except after PR lesions. The third parameter of exploratory behaviour - the duration of sniffing - was significantly diminished except in CUS rats, in which sniffing was significantly enhanced compared with controls. Lesioned rats had shorter grooming latencies with a minimum in CUS rats (23% of controls) and prolonged grooming durations with a maximum in NCP-CU rats (267%). The results demonstrate that relatively small lesions in the anterior mesencephalic reticular formation (MRF) lead to remarkable changes in the spontaneous behaviour of rats with widely differing patterns of behavioural parameters depending on the locus of bilateral symmetric lesions. The data suggest in contrast to the hypothesis of an unspecific modulating function of the MRF, that their different parts play a specific role in the integration of various behavioural patterns.

Animals↗
PubMed1983

Wheel-running of rats in combination with a simple self-stimulation procedure.

LONG EVANS hooded rats with chronically implanted electrodes in the Area hypothalamica lateralis (AHL, group 1), the Nucleus linearis rostralis (LR, group 2) and the Nucleus centralis superior (CES, group 3) were offered the possibility to spontaneously perform wheel-running for one hour per session. The number of wheel revolutions per ten minutes and per hour were counted automatically. The rats were connected with a square wave generator by a smooth flexible cable and received stimulus series (50 imp./s; 0.5 ms imp. duration; 0.5 s series duration; 0-3 V intensity) triggered by each complete revolution of the wheel. The sessions took always place at the same time of the day and under the same experimental conditions -- except the change of stimulus intensity. The results with 0 V served as controls. The method has the following advantages: 1. Self-stimulation is induced spontaneously in the first stimulation session. 2. Negative emotional effects can be quantified by the decrease of the wheelrunning activity. -- AHL stimulation caused an increase in the wheel-running activity amounting to 300-350% with a maximum at 3 V. LR stimulation brought about an ambivalent effect with increase to 200% at 1-2 V and decrease to 56% at 3 V. During CES stimulation an increase to 166-240% with its maximum at 2 V was observed. Stimulation with the same parameters did not evoked locomotion in an open field situation.

Animals↗
PubMed1982

Behaviour-dependent changes of visually evoked potentials and their correlation to the respiration rate in freely moving rats.

The variability of visually evoked potentials (VEP) during spontaneous changes of behavioural activity was investigated in freely moving rats with electrodes in the visual and frontal cortex, olfactory bulb and other brain structures. Averaged VEP were recorded and compared during periods of characteristic behaviour types like drowsiness, relaxed wakefulness, attentiveness, grooming and exploratory behaviour. These behavioural patterns, which are clearly distinguishable by observation, were characterized by a certain degree of visually evoked afterdischarges, recorded movements, EEG-patterns and mean respiration rate. The evaluation of early components of the VEP from single recorded samples and of the correspondent momentary respiration rate (respiration intervals) revealed strongly negative correlations. In general, the increasing behavioural activity is characterized by a decrease in the amplitudes of VEP-components, inversely correlated to the log of momentary respiration rate. During drowsiness and enhanced attentiveness, certain components are increased. During strong movements and distraction of attention (e.g. intensive scratching and licking) the VEP-components were decreased stronger. The negative complex around 62 ms increased during certain forms of behavioural activation and locomotion. The VEP-component N31, the respiration rate, and the quotient N31: N61 were found suitable parameters to characterize certain types of behaviour in comparison to relaxed wakefulness.

Animals↗
PubMed1982

Participation of thalamic nuclei in the elaboration of conditioned avoidance reflexes of rats. VIII. Lesions of the nucleus posterior.

Bilateral symmetric lesions of the posterior thalamic nucleus reduced the preoperatively learnt avoidance responses in Long-Evans hooded rats strongly. Postoperative acquisition of conditioned avoidance reflexes was rather low in each rat in a simple runway and impossible in an alternation task. Thresholds of reactions to pain (withdrawal of paws from the grid floor) were significantly increased. The lesioned rats had trouble to find the way out, as if they had difficulties to localize the source of punishment or to associate pain information with any other cues.

Animals↗
PubMed1982

Visual post-stimulus excitability changes in freely moving rats indicated by amplitude and peak time of evoked potentials.

Visual post-stimulus excitability changes (visual recovery cycles = VRC) were investigated in 25 freely moving hooded rats by means of double-flash stimuli with varying intervals in 10 ranks from 25 to 400 ms. The amplitudes and peak times of visually evoked potentials (VEP)-components were evaluated from averaged double-flash responses of the visual cortex under conditions of stationary spontaneous behaviour during the averaging time. The amplitudes of component N 31 showed the slowest increase: still below 60% after 400 ms flash interval during relaxed wakefulness, but approximately 85% during exploratory behaviour. P 45 was equalized after 150 ms and component N 49 never decreased but increased. All components of the test VEP were influenced by oscillating excitability changes in the course of the photically evoked afterdischarges triggered by the first flash. The peaks of all test VEP components were delayed by about 15-25 ms with a maximum at the 50 ms intervals and an exponential course of normalization with the prolongation of flash intervals to 300-400 ms. The results demonstrate that rather complicated neuronal interactions take place in the post-stimulus period, which is expressed by the dynamic changes of different test VEP components.

Animals↗
PubMed1982

Participation of thalamic nuclei in the acquisition of conditioned avoidance reflexes in rats. IX. Lesions of the nucleus reticularis.

Bilateral symmetric lesions of the anterior part of the nucleus reticularis thalami (RET) strongly reduced the preoperatively learnt avoidance responses in Long-Evans hooded rats. A great retention loss, significantly prolonged reaction times and slow incorrect escape reactions in the first postoperative session in a simple runway task were corrected in the relearning period. The relearning of directional change and of a 2:2 alternation schedule in the Y-maze was rather difficult; it delayed and remained on a lower performance level with a not correctable side preference. A great retention loss in the pole-climbing test was not compensated in the relearning period. The experimental data suggest that the RET plays an important role in the inhibition of incorrect responses.

Animals↗
PubMed1981

The effect of anterior thalamic nuclei lesions upon conditioned avoidance responses in rat.

Three groups each of 7 hooded rats had bilateral symmetric lesions of the n. anterior ventralis the n. anterior medialis and n. anterior dorsalis and were compared to two groups of 7 nonoperated control rats. After the lesions no changes in spontaneous behavior, sensory or motor functions, body weight, reaction type and thresholds to painful footshocks were observed. The postoperative acquisition of a one-way conditioned avoidance response in a simple runway task was significantly retarded in ventral and medial rats and impossible in dorsal rats. While escape reactions were not impaired, lesioned rats had troubles passing the start door early after the onset of the conditioned stimulus. During alternation training of avoidance responses, the ventral and the medial rats preferred one side of the Y-maze. When they learned to run to the illuminated exit as a high-probability stimulus after several sessions, the entire stereotype became more unstable and the percentage of avoidance responses decreased. None of the lesioned rats escaped shock in a pole-climbing test, which was characterized by very low probability of correct response in the first session. These anterior thalamic nuclei are part of the Papez circuit which may be the main substrate for learning and retrieval of problems with low probability.

Animals↗
PubMed1981

Acoustically evoked potentials in the visual cortex and superior coliculus of the freely moving rat and their variability.

Hooded rats of the Long-Evans strain with chronically implanted electrodes in the visual cortex (VC, area 17), superior colliculus (CS), olfactory bulb (BO) and the prefrontal cortex (FC) were stimulated by series of 20 clicks (0.4 per s) during spontaneous behaviour. Different behavioural patterns were identified and classified by observation, recorded movement patterns, respiration rate and EEG patterns. Averaged acoustically evoked potentials in the visual system showed reproducible changes of all their components in correlation to behavioural patterns. Components N10 and N32 in the CS, resp. N14 and N32 in the VC changed differently during behavioural activation. The early negative component did not decrease while the later ones became significantly smaller during progressive activation, except during attentive behaviour in which they were facilitated. From the results can be concluded that a great number of neurons in the visual system of the rat should be involved in heteromodal information processing which is modified in correlation to the changing behavioural pattern.

Acoustic Stimulation↗
PubMed1980

Participation of thalamic nuclei in the elaboration of conditioned avoidance reflexes of rats. VI. Lesions of the nucleus lateralis anterior.

Bilateral lesions of the nucleus lateralis anterior thalami (LA) did not change sensory or motor functions of hooded rats. Postoperative retention of conditioned avoidance response (CAR) preoperatively learnt in a jumping test, was decreased insignificantly, relearning slowed somewhat down, the variance of individual reaction times (CAR latencies) increased. Postoperative acquisition of CAR revealed some uncertainty and delay, but criterion was reached. Preoperative experience influenced the type of errors in a discrimination task (go/no go): After preoperative acquisition of CAR go-responses, after postoperative acquisition of CAR no-go-responses dominated. In these experiments the memory processes may be influenced by changes of some limbic regulatory processes in which LA plays a role.

Animals↗
PubMed1980

Participation of thalamic nuclei in the elaboration of conditioned avoidance reflexes of rats. VII. Lesions of the nucleus lateralis posterior.

Bilateral lesions of the nucleus laterials posterior thalami (LP) scarcely changed preoperatively learnt conditioned avoidance responses (CAR) in a runway and the Y-maze. Postoperative elaboration of CAR showed some difficulties in the runway which were increased during alternation training in the Y-maze. All rats with LP lesions had severe disturbances of spatial orientation in new situations, which could be overcome by training.

Animals↗
PubMed1979

[On the influence of thiocyanates on the delayed immune response in intact and epinephrectomised guinea pigs (author's transl)].

Daily application of 32 mg/kg sodium thiocynate from 1--11th respectively 12th--21st experimental day causes in epinephrectomised guinea pigs at the 26th experimental day an inhibition of cell-mediated immune response (sensitization was induced by intraperitoneal injection of horse serum at the 5th and 7th experimental day). The inhibition of cell-mediated immune response could be demonstrated by means of migration inhibition of spleen cells. Epinephrectomy was performed by operation procedures twice a week. Gluco- and mineralocorticoids were applied supplementary. -- Also other proved thiocyanates respectively compounds with thiocyanate groups such as potassium thiocyanate, ammonium thiocyanate and d,1-2-imino-3.4-dimethyl-5-phenyl-thiacolidinhydrothiocyanate showed the same effect. The results are only pointed out in intact animals, but distinct in epinephrectomised guinea pigs. Finally a significant weaker effect, but of the same kind was observed by potassium- and sodium iodate. Every used dose of prednisolone and cyclophosphamide suppress the migration inhibition. The influence of 2-iminothiacolidin-4-carbon acid and desoxycorticosteronacetat on the migration inhibition is different and depends on the antigen dose applied for sensitization. -- Simulated daily injections undertaken in form of stitches and application of aqua destillata are inefficacious.

Adrenal Glands↗
PubMed1978

[Involvement of thalamic nuclei in the formation of conditional avoidance reflexes in rats. II. Lesions of the midline nuclei].

Lesions of the habenular-paraventricularis-anterior complex of the thalamus caused a total impairment of conditioned avoidance response of hooded rats (Long-Evans-strain) in a jumping test, but not in a simple runway. The change of stereotyped avoidance reactions could be attained very slowly. Running speed was lower and the number of errors much higher using an alternation schedule. Lesions of the nucleus centralis medialis and partly of its surrounding caused less deficits. From the results may be suggested that regulatory interactions between general behavioural activation originating from the brain stem, motivational processes and the analyzer systems are disrupted.

Animals↗