Biomedical subjects

F Klingberg

Publications and source records attributed to F Klingberg.

At least 55 records · Page 3Linked to original sources

PubMed1988

Substantia nigra pars reticulata modulates spontaneous and goal-directed behaviour of rat.

Spontaneous and active avoidance behaviour was compared pre- and postoperatively on 11 six month old male hooded rats of the Long-Evans strain. Seven of them with small bilateral symmetric lesions only in the ventromedial part of substantia nigra pars reticulata (SNR) were characterized by a strong decrease of exploratory parameters except rearings, without differences of ambulatory activity in the open field (OF) test. The SNR group showed a significant retention loss, increased reaction times and run durations in three variants of preoperatively consolidated Y-maze performance and weakened brightness discrimination. They were unable to relearn the tasks and to reduce errors to the preoperative level which was zero. Postoperative acquisition of a new active avoidance stereotype in the jump test box was impossible. They ignored the hanging rod in this box and did not find the escape possibility. Prevailing flexor tonus of trunk and forelegs after SNR lesions was no sufficient reason for these changes, because inborn and automated programs were far less concerned than learnt or operative programs and the accuracy of goal-directed behaviour.

Animals↗

PubMed1988

Sensory interaction in the superior colliculus of freely moving rat indicated by evoked potentials.

Sensory monomodal and bimodal interaction was compared in the anterior medial superior colliculus (CS) of freely moving Long-Evans rats with chronically implanted electrodes using pairs of click and flash stimuli separated by intervals of 100 ms. The amplitudes and peak times of first and second evoked potentials were statistically evaluated and compared with the uninfluenced control values of visually and acoustically evoked potentials (VEP and AEP) on the back-ground of relatively constant relaxed wakefulness. Heteromodal interactions were characterized by only very small and in most cases insignificant changes, compared with very striking depressions of component amplitudes of the second EP in monomodal paired stimulation. Significant differences of AEP and VEP amplitude and peak time changes in superficial and in deep layers of the CS indicated that the sensory interaction is different, corresponding to the functional structure of CS layers. The amplitude of the second negativity N32 in AEP 100 ms after flash is significantly influenced in the superficial layers, but not in the deeper ones. The VEP peak times are prolonged after click only in the deeper layers.

Acoustic Stimulation↗

PubMed1987

Long-term effects on behaviour after postnatal treatment with monosodium-L-glutamate.

22 rats of the Long-Evans strain (11 males and 11 females) were treated from the first to the eleventh postnatal day (pd) with daily subcutaneous injections of 4 mg/g body weight monosodium-L-glutamate (MSG) in aqua dest. Further 11 males and 7 females were used as controls and received isotonic NaCl-solution on the same days. The neurological investigation after 1 month revealed no difference between MSG-treated or untreated controls. All MSG treated rats were retarded in growth and body weight development. None of them died from the treatment. During 10 min exposure in a 60 x 75 x 22 cm open field (OF) we found higher rates of infrared beam crossing on pd 12-14, more rearing on pd 12, 16 and 32 and less immobility of MSG rats. Latencies of immobility and grooming were significantly prolonged versus controls. We found no essential differences of MSG effects between males and females. At the age of 4 months the ability for active avoidance was tested. When they could find the escape possibility, then the escape velocity was like in controls. But MSG rats had troubles to find this possibility at the beginning of a Y-maze training and during alternation of the goal (brightness discrimination). They never found the escape and avoidance possibility in a vertical jump test.

Animals↗

PubMed1987

Arginine-vasopressin and lysine-vasopressin have different effects on spontaneous behaviour of rats.

Two groups of each 8 adult male hooded rats of the Long-Evans strain received single subcutaneous injections of 1 microgram/kg arginine-vasopressin (AVP) or 1 microgram/kg lysine-vasopressin (LVP) 15 min before investigation in an open field (OF) and 30 min before investigation of locomotion in a wheel (W). The behavioural parameters were statistically compared with two control groups. AVP significantly increased infrared beam crossings in the OF, wheel-running and the mobility of the rats in both tests. LVP had a strong just opposite effect. LVP facilitated habituation and AVP weakened it. AVP facilitated rearing, whereas LVP suppressed it. The duration of immobility was strongly enhanced after LVP in both tests (380% in the OF and 920% in the W) but AVP had no prolonging effect. The latency of the first immobility phase in the OF was increased to 250% after AVP and decreased to 45% after LVP. Grooming was not influenced by AVP, whereas LVP strongly reduced the grooming duration and prolonged the grooming latency in the OF. The contrary effects of AVP and LVP are highly significant. They may be summarized as activating effect on motor behaviour and exploration by AVP and inhibitory action of LVP.

Animals↗

PubMed1987

Early postnatal development of open field behaviour is changed by single doses of fenfluramine or p-chloroamphetamine.

Three groups of 8 male hooded rats were treated with 50 mumol/kg fenfluramine (FF) or 50 mumol/kg p-chloroamphetamine (PCA) or the same amount of vehicle solution (NaCl) i.p. on postnatal day 8. Each rat was exposed to a 60 X 75 X 22 cm open field (OF) for 30 min from the 10th to the 30th postnatal day (pd) at the same time. FF and PCA enhanced the ambulatory activity on 11-14th pd between 200 and 1000%. Several parameters of the exploratory activity and grooming were also significantly increased in this period (p less than 0.01). Habituation to the OF was weakened. The differences disappeared during eye opening. Exploratory activity was significantly diminished in the fourth week. Most of the changes were similar after both drugs, some of them point to different actions of FF and PCA. The timing of the qualitative behavioral development was influenced by both drugs. The results demonstrate the important role of the serotoninergic system in behaviour development. Serotoninergic neurons are postulated to participate in certain forms of response inhibition. Some of the deficits may be compensated during early development.

Amphetamines↗

PubMed1987

The postnatal development of open field behaviour of the visually deprived rat.

The postnatal development of open field (OF) behaviour of two groups of each 8 male hooded rats (Long-Evans strain) was compared after bilateral eye bulb removal on the seventh postnatal day (pd) in one group and sham-operation on the same day in the other group. Ambulatory activity of the deprived group was much increased (p less than 0.01) in all sessions from the 10th to the 30th pd. Their habituation of responses to the OF was stabilized with delay only on the 21st pd. The deprived rats immediately entered central fields whereas sham-operated controls began this on the 23rd pd. Exploratory behaviour as measured by groups of horizontal head and body turnings, sniffing periods, rearings and wall climbings was significantly enhanced in deprived rats during certain phases of the postnatal development. The timing of the phases was rather identical with those of the sham-operated group and with untreated controls. Grooming activity was enhanced, too. The results indicate a rather quantitative than qualitative difference to rats which can develop visually guided behaviour. The changed OF behaviour of visually deprived rats is hardly explainable in terms of changed emotionality or tendencies to reinstate social contact and attempts to evade predation or any other ethological hypothesis of OF behaviour, but may be related to the role of visual input in the development of goal-directed behaviour.

Animals↗

PubMed1987

Behaviour-dependent variability of potentials in the somatosensory cortex evoked by stimulation of the trigeminal nuclei in freely moving rats.

Nine hooded rats with chronically implanted epidural recording electrodes on the right primary somatosensory cortex, the olfactory bulb and bipolar stimulating electrodes in the left ponto-mesencephalic trigeminal nuclei and parabrachial region were investigated during different patterns of spontaneous behaviour. The early positive-negative component of the TNEP with peak times P5 and NII (ms) appeared about 1 ms earlier than after tooth pulp stimulation. The amplitude P5-N11 was slightly increased during drowsiness, decreased during slow wave sleep and was strongly decreased in behavioural patterns with movements, always compared with relaxed wakefulness. The behaviour-dependent changes of cortical EP to stimulation of trigeminal nuclei (TNEP) were analogous to those after tooth pulp stimulation.

Animals↗

PubMed1987

Reduced behavioural inhibition after lesions in the dorsomedial pontine reticular formation of rats.

Male hooded rats of the Long-Evans strain were investigated in an open field (OF), in an Y-maze and in a pole-climbing (jump) test before and after small bilateral symmetric lesions of the dorsomedial pontine reticular formation, medial from the locus coeruleus including lateral parts of the central gray. Postoperative values of ambulatory activity were increased above 300%. This hyperactivity in the OF was characterized by weakened habituation in the OF, increased locomotor speed, increased climbing rate, whereas horizontal exploratory activity was significantly decreased. The preoperatively learnt Y-maze avoidance tasks were correctly performed after lesions without any retention deficit and without errors in brightness-discrimination. The postoperative acquisition of a jump test avoidance task was impossible because the lesioned rats did not find the escape possibility in spite of a great number of variant jumps. They never showed tendencies of arrest behaviour ("learned helplessness"). The syndrome is characterized by weakened behavioural inhibition of incorrect or redundant responses.

Animals↗

PubMed1986

Postnatal development of open field behaviour of male and female rats.

In a longitudinal study of postnatal behavioural development each 8 male and female Long-Evans hooded rats were exposed daily to an 60 X 75 X 22 cm open field beginning from the 4th postnatal day (pd) for 30 min. The number of infrared beam crossings, of rearings, climbings, sniffing and grooming periods, of grooming duration, of entering and stay in central fields and of defecation were counted and measured in 5 min periods. All parameters increased continuously or in phases with significant peaks until the 27th pd. Females significantly predominated in the second and the third week in ambulatory activity, in entering central fields and in the frequency of grooming periods and in the third and fourth week also in grooming duration. Males clearly predominated in the development of exploratory activity. Every significant peak in the curves represents the appearance of a new behavioural element which is exercised several times and then integrated in a behavioural stereotype, which becomes more and more enriched. Each peak is followed by a significant minimum. Thus, peaks and minima are highly reproducible in their postoperative timing and express the physiological development of functional systems and stereotypes. The data are a useful and important basis for the study of experimental models of perinatal or early postnatal injury.

Animals↗

PubMed1986

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

Two groups of 6 month old male hooded rats of the Long-Evans strain with bilateral symmetrical lesions in the anterior part of the mesencephalic area subcuneiformis (CUS) were compared with two sham-operated control groups (each group n = 8). CUS rats were absolutely unable to acquire a conditioned avoidance response (CAR) in a jump test; they even did not find out the escape possibility. Postoperative CAR acquisition of CUS rats in a horizontal alley was not different from controls, but their running speed was decreased (p less than 0.005). Lesioned rat's postoperative acquisition of brightness-discrimination was evidently disturbed and their error rate was still enhanced after 120 trials (p less than 0.005). Their reaction times of leaving the start box, however, were significantly lowered. The postoperative retention of preoperatively learnt CAR was very low. Relearning was possible in the Y-maze at lower level, but impossible in the jump test. The error rate decreased very slowly in the postoperative testing, whereas controls performed the brightness discrimination without errors as before. The unconditioned escape, however, was performed as correctly by CUS rats in the jump test as in the preoperative trials but rather slowly. The pattern of the behavioural syndrome after CUS lesions and the deficits in avoidance learning are possibly caused by a loss in sensory-motor coupling and a weakened ability to select visual, olfactory or painful stimuli which are important for the regulation of certain forms of behaviour.

Animals↗

PubMed1986

The pretectal region of the rat participates in the regulation of goal-directed behaviour.

Two groups of each 6 male hooded rats with bilateral symmetrical lesions in the anterior dorsolateral tegmentum including parts of the anterior and posterior pretectal nuclei and two sham-operated control groups were compared in different avoidance paradigms. The acquisition of conditioned avoidance responses (CAR) in a Y-maze was significantly retarded in lesioned rats and remained definitely on a lower performance level. Their reaction times (RTs) were significantly prolonged. Brightness discrimination was severely impaired. They had evidently troubles to correct their erroneous runs. After preoperative training lesioned rats had no retention deficit in the Y-maze performance, neither different RTs nor changes of running speed, but a deficit in brightness discrimination. Postoperative acquisition of CAR in a jump test was impossible. Retention of preoperatively learnt CAR in the jump test was zero, relearning was impossible reaching not more than 40% CAR performance after 8 sessions. The behavioural syndrome was different from other tegmental lesion types. Impaired brightness discrimination and vertical visual orientation are main symptoms of the more complex disturbance of goal-directed behaviour.

Animals↗

PubMed1986

Tooth pulp evoked potentials in trigeminal nuclei and parabrachial region of the freely moving rat.

Twelve hooded rats with chronically implanted recording electrodes in the left ponto-mesencephalic trigeminal nuclei and parabrachial region and bipolar stimulating electrodes in the left upper incisor were investigated in different states of spontaneous behaviour. At all recording sites tooth pulp evoked potentials (TPEP) with the following main components were recorded: a small negative component with a peak time of N 2 ms, followed by a second negativity with the peak time of N 6 ms and a slow large positive-negative component with the peak time of N 28 ms. The corresponding positive peaks were: P 3 ms, P 13 ms, P 58 ms. In all rats we observed a great variability of TPEP components in different waking states. A maximal decrease of TPEPs was observed during strong grooming compared with relaxed wakefulness.

Animals↗

PubMed1986

Severe deficits of adaptive behaviour after lesions of rat's nucleus reticularis pontis oralis.

Hooded rats of the Long-Evans strain with bilateral symmetric lesions of the nucleus reticularis pontis oralis (RPO) displayed locomotor hyperactivity in the open field (OF) compared with their preoperative values. Their locomotor velocity and their climbing rate were significantly enhanced. Habituation in the OF was significantly weakened. The lesioned rats were unable to acquire any active avoidance responses in a Y-maze or a jump test. They were unable to correctly perform preoperatively learned avoidance responses and could not relearn the tasks. Reaction times to the conditioned stimulus increased and more often the rats escaped only after the onset of the punishment; even their escape responses were instable. The lesioned rats were neurologically inconspicuous. One can assume that the RPO participates in a functional system for control and recall of learned (not inborn) programs.

Animals↗

PubMed1986

Tooth pulp evoked potential in the thalamus of freely moving rats.

Eleven hooded rats with bipolar stimulating electrodes in the left upper incisor and recording electrodes in the ventral posteromedial (VPM), ventral dorsomedial (VDM) and paracentral (NPC) nuclei of the contralateral thalamus and the somatosensory cortex (SC) were investigated in different states of spontaneous behaviour. The early complex of the thalamic averaged tooth pulp evoked potentials (TPEP) consisted of two negative-positive waves, a small (N2, P4) and a larger one (N6, P14). Later components appeared with different peak times and amplitudes depending on the localization of the recording electrode. The single components of the thalamic TPEP decreased differently during behavioural activation between 20 and 80% with maximal expression during intensive grooming.

Animals↗

PubMed1986

Lesions in the mesencephalic part of pedunculopontine nuclei modify goal-directed behaviour.

Eleven Long-Evans hooded rats were preoperatively tested in an open field (OF), then trained in a Y-maze and thereafter symmetrically lesioned in the mesencephalic part of the pedunculopontine nuclei (MPPN). The OF test on the 11th postoperative day revealed no significant changes in exploratory behaviour, but a significant increase of ambulatory activity during all periods of 10 min exposure. This points to the role of the lesioned structure in response inhibition and habituation. High postoperative retention of preoperatively learnt conditioned avoidance responses (CAR) and of brightness discrimination showed no memory deficit. Reaction times were significantly decreased in the MPPN rats without symptoms of enhanced emotional activation. The escape speed from start to goal box was significantly slowed down after lesion. The formation of a new CAR stereotype in the jump test was impossible after MPPN lesions, because the rats did not find the escape possibility. The results differ from that of other mesencephalic reticular lesions.

Animals↗

PubMed1985

[Variability of cortical evoked potentials in response to tooth pulp stimulation in the freely moving rat].

Evoked potentials (EP) due to the stimulation of the upper incisor tooth pulp were recorded from the somatosensory cortex of the freely moving adult rats. Background EEG, motor activity of an animal and respiratory potentials of the olfactory bulb were recorded simultaneously. EP configurations and mean amplitudes of primary complex (P1 + N1) differed significantly during states of sleep, drowsiness, relaxed wakefulness, grooming and exploratory behaviour; primary complex amplitude during intensive motor activities was several times less than during periods without movements. Negative correlation of the EP amplitude and instant respiration rate was found during relaxed wakefulness: it was less pronounced during periods with motor activities. At the same time direct parallelism between changes in EP and respiration rate was absent: the EP depression was maximal during grooming, while the respiration rate was minimal during exploratory behaviour.

Animals↗

PubMed1985

Intensity-dependent changes of visually evoked potential components in the superior colliculus of freely moving rats.

Amplitudes and peak times of averaged visually evoked potentials (VEP) recorded in the superficial layers of the anterior medial superior colliculus were measured in 7 freely moving rats. The amplitudes of P21-N29 decreased significantly to 47% (p = 0.01), the amplitudes of components N41-P54 and P54-N64 to 29 and 32% (p = 0.01) when the flash intensity was lowered six times, whereas components N29-P36 and P74-N85 showed no significant decrease. During exploratory behaviour all the components were significantly lower than during relaxed wakefulness, except N29-P36 and P74-N85. The course of their intensity-dependent decrease was different. Peak times of both early negative components N29 and N41 increased exponentially with decreasing flash intensity during relaxed wakefulness. The peak times of later negative components N64 and N85 increased only with the lowest intensity. During exploratory behaviour peak time changes were evidently smaller. The data suggest that the different changes of components reflect the activity of different neuron types.

Animals↗

PubMed1985

Behaviour-dependent changes of visually evoked potential components in the superior colliculus of freely moving rats.

Amplitudes and peak times of visually evoked potential (VEP) components in superficial and deeper layers of the superior colliculus of 24 rats were measured during slow wave sleep (S), relaxed wakefulness (RW), grooming (G) and exploratory behaviour (E). All peaks occurred later during S than during RW, whereas only a few peak times were significantly longer in activated states compared with RW. Positive and negative peaks between 35 and 60 ms were significantly (p less than 0.01) prolonged during G and E. Corresponding peaks of the polarity reversed VEP appear 1-4 ms later than in the superficial VEP when compared in identical behavioural states. Significant amplitude decrease (p less than 0.01) of almost all components related to RW was found in G and E and of components N-39-P51 and N60-P71 in S. These changes were relatively different for each component and each behavioural state. The amplitude changes of the polarity reversed VEP were similar but not identical (as a mirror image) with superficial VEP. The different behaviour-dependent patterns of the VEP components indicate different interactions in the neuron pools of superior colliculus.

Animals↗