PubMed Health⌕ Search

Biomedical subjects

F Klingberg

Publications and source records attributed to F Klingberg.

At least 19 recordsLinked to original sources
PubMed1995

Behavior-dependent and drug-induced changes of rat visual evoked potential: relation to the EEG spectral power.

The relation between EEG spectral power and alterations of the visual evoked potential (VEP) during different behavioral states and after intraperitoneal application of neuroactive drugs have been investigated in Long-Evans rats. FFT power and field potential maps were made in five behavioral states of the unrestrained rat: exploratory sniffing, face washing, relaxed waking immobility, slow wave sleep, and during cortical high-voltage spindling. Fourteen epidural electrodes were implanted in the bulbus olfactorius, in the frontal areas Fr2 and Fr1, in the visual areas 18 and 17, and in the cerebellum of the right hemisphere. Two regions in the investigated cortex were found to be the probable origins of slow delta and theta waves: the frontal cortex and the anterior area 18. Area 17 does not express prominent EEG frequencies that contribute to the cortical EEG in any of the investigated behavioral states. The VEP was found to originate in area 17. The neural activity of the occipital cortex is reflected in the VEP whereas the occipital EEG possibly reflects the hippocampal activity in some behavioral states. This may be a reason for partly independent changes of VEP and EEG during different behavioral states and after application of neuroactive drugs.

Animals↗
PubMed1994

Nucleus cuneiformis lesion increases high-voltage spindle incidence in unrestrained rat neocortex.

The effects of bilateral electrolytical lesions of the mesencephalic nucleus cuneiformis (CU) on both the high-voltage splindle (HVS) activity and the spontaneous behaviour of unrestrained rats have been investigated. In control experiments, EEG spectral power mapping indicated different HVS rhythms in frontal and occipital cortices. The main lesion effect was a strong significant increase of the HVS incidence in the frontal cortex. However, the CU lesion did not affect the incidence of relaxed waking immobility which is specifically related to HVS generation. Furthermore, CU lesion did not alter the power spectra of the frontal cortical EEG during different behavioural states. The results indicate that CU exerts inhibitory influences on the generation of HVSs, which probable correlates with facilitation of the sensory information transfer through the thalamus.

Animals↗
PubMed1993

Lesions in four parts of the basal forebrain change basic behaviour in rats.

Subdivisions of the basal forebrain (BF) are postulated to be differently involved in the regulation of behavioural functions. We compared 16 parameters of rat open field behaviour before, 10 days and 60 days after lesions in four BF subdivisions, the anterior and the posterior nucleus basalis magnocellularis (NBMa, NBMp), the vertical and the horizontal diagonal band nucleus (VDB, HDB) with sham-operated control rats. Every lesion type caused a significantly different pattern of significant behavioural changes. VDB and NBMp lesions both produced different patterns of ambulatory and exploratory hyperactivity, whereas NBMa lesions caused hypoactivity. Changes after HDB lesions were relatively small. The rate of habituation also shared changes that differed according to the lesion site. These changes in basic unlearned behaviour are likely to interact with more complex functions such as cognitive processes, learning and memory.

Animals↗
PubMed1991

Depth distribution of frontal cortical field potential to acoustic stimulation in unrestrained non-anaesthetized rats.

Intracortical depth profiles of acoustically evoked potentials (AEP) through the frontal cortex were studied with moveable electrodes in 5 freely behaving rats to identify the generators of the AEP components with current source-density analysis in pharmacologically uninfluenced relaxed wakefulness. The main negative AEP components (N21 and N38) which change their polarity across the cortical depth are generated by extracellular current sinks within the V cortical lamina. Since both components were polarity reversed in different cortical depths and have their current sources in different laminae, the participation of different generation modi are assumed for both AEP components.

Acoustic Stimulation↗
PubMed1991

Reaction time prolongation in the early stage of presenile onset Alzheimer's disease.

Simple reaction times (RT) to clicks, flashes and numerical signals were measured in four groups of subjects: 21 patients with mild presenile onset dementia of the Alzheimer type (PDAT, mean age 56 years), 14 patients with chronic cardiovascular disease and incipient cognitive deficit (mean age 55 years), 15 healthy older controls (mean age 53 years) and 16 younger controls (mean age 23 years). Both patient groups had significantly prolonged RTs, the PDAT group especially to the numerical signal (149%), compared with the age-matched controls.

Adult↗
PubMed1991

Impaired eye tracking performance in patients with presenile onset dementia.

Smooth pursuit eye movements, saccades and eye blinks were electrooculographically recorded from 26 healthy subjects of different age and 35 patients with presumptive presenile onset dementia (mean age 54), who had to track a light spot which oscillated with different speeds. Older subjects (mean age 51) performed the eye tracking with less accuracy and more saccades than younger ones (mean age 22). 16 patients with stage CDR 1 according to Washington University Clinical Dementia Rating performed smooth pursuit eye movements significantly worse with increased saccade numbers than the healthy older subjects and lost attention significantly more often which was measured by omitted trackings to presented target oscillations. Their number of eye blinks was partly increased. The test is found suitable for early diagnosis of dementia onset, supporting clinical findings and presumptive diagnosis by objective parameters.

Aging↗
PubMed1991

Duration of EEG alpha wave blockade by tone stimulation is prolonged in early stage of presenile onset dementia of the Alzheimer type.

The EEG alpha rhythm suppression by sudden unexpected tones in a relaxed wakefulness state (Berger response) was measured in four groups of patients and healthy control subjects. One patient group with early cognitive deficits probably caused by a mild stage of presenile onset primary degenerative dementia of the Alzheimer type (DAT), a second patient group with cardiovascular disease and a stage of questionable dementia, an age-matched group of older healthy control subjects and a younger control group. Only half of the DAT group in the mild stage had significantly prolonged Berger responses and a retarded or disturbed habituation. In agreement with other data of their cognitive deficits this indicated a weakening in focussing attention and selective inhibition.

Acoustic Stimulation↗
PubMed1991

Systemically applied thyrotropin-releasing hormone (TRH) modifies spontaneous behaviour of rats.

The effect of TRH and its analogon "RGH 2022" (Gedeon Richter, Budapest) on parameters of open field (OF) behaviour, wheel running (WR) and sleep-wakefulness cycles was recorded after intraperitoneal injections of the drugs in two dosages, 1 microgram/kg and 10 micrograms/kg, and compared with the control group. The lower TRH dose enhanced exploratory activity in the OF to 130%, WR to 150%, but reduced the entrance to central fields in the OF to 50%. The higher TRH dose reduced the locomotor activity in the OF to 53% and the entrance to central fields to 15% but enhanced the exploratory index to 190%. The analogon RGH 2022 had less effects in its lower dose and mimicked the TRH effect in its higher dose. The amount of all waking states increased after TRH to 120%. Single periods of relaxed wakefulness and sleep phases (slow wave sleep and paradoxical sleep) were 15-20% prolonged after 10 micrograms/kg TRH on account of phase frequency. There was, however, a maximum of sleep phase frequency and duration between the 35th and 55th min after TRH application.

Animals↗
PubMed1991

Systemically applied luteinizing hormone-releasing hormone (LHRH) reduces behavioural activity in rats and increases sleep activity.

Groups of each 8 male Long-Evans rats were treated with 1 or 10 micrograms/kg LHRH intraperitoneally and compared with control rats which received the vehicle fluid (NaCl-solution). Ambulatory activity in an open field (OF), entrance to central fields and the mobility index were significantly decreased by both doses. Correspondingly, wheel running and movement velocity were significantly decreased. A further group of 8 rats with chronically implanted electrodes which was habituated to sessions showed an increase of slow-wave sleep and a significant reduction of waking and active states with maximal expression 45 min after ip application of 10 micrograms/kg LHRH. Paradoxical sleep was slightly reduced. Sleep-wakefulness cyclograms showed increase of a sleep phase duration to 175% and of single slow wave sleep phase duration to 140% after LHRH. Phases of drowsiness were also prolonged.

Activity Cycles↗
PubMed1991

Lesion of pontine micturition area in rat causes a severe kidney syndrome.

Bilateral symmetric lesions of a small strip in the dorsal pontine reticular formation between the locus coeruleus and the laterodorsal tegmental nucleus caused a severe disturbance of kidney and urinary bladder function beginning with haematuria, micturition paralysis and incontinence on the second postoperative day. Thirteen rats with these lesions were killed on the sixth postoperative day, dissectioned and their kidneys were pathomorphologically investigated. Their urinary bladders were extremely expanded and filled with bloody urine. All kidneys showed a picture of hydronephrosis and were enlarged from 15 mm preoperatively to 30 mm in their longitudinal axis and from 9 to 15 mm in their transverse axis. In seven further rats with partial or asymmetric lesions of this pontine micturition area the micturition cessation and the haematuria disappeared between the 4th and 8th postoperative days: kidney enlargement and hydronephrosis were still found on the 20th postoperative day.

Animals↗
PubMed1991

Disturbance of brightness discrimination and active avoidance learning after lesions of nucleus reticularis tegmenti pontis (NRTP) of rats are related to impairment of goal-directed behaviour.

Long-Evans hooded rats were not able neither to reach criterion of active avoidance tasks in a Y-maze and in a jump test, nor in brightness discrimination after lesions of the NRTP without preoperative experience in these tests. After preoperative consolidation of active avoidance, the retention of Y-maze avoidance performance was zero and of jump test avoidance at 25%. The Y-maze avoidance was again relearned except in the task with 2:2 alternation of goals whereas retention of brightness discrimination was not affected. In the jump test, avoidance relearning was evidently retarded. Ambulatory and exploratory behaviour in the open field were significantly reduced after NRTP lesions. The NRTP is evidently involved in the establishment and control of goal-directed behaviour.

Animals↗
PubMed1991

Incisor growth acceleration after lesions in the lateral pontine reticular formation of rats.

The length of upper and lower incisors of Long-Evans hooded rats between gingiva and top were measured before and after small bilateral symmetric electrolytic lesions of the pontine reticular formation between the ventromedial parabrachial nucleus and the motor trigeminal nucleus. Ten days after lesions of this region 8.5 mm posterior to bregma the length of upper incisors was 13.4 +/- 0.7 mm compared with 6.1 +/- 0.2 mm before lesion (p less than 0.01) and the length of the lower incisors 17.1 +/- 0.4 mm compared with 10.2 +/- 0.2 mm before lesion (p less than 0.01). A second group with a smaller lesion of this region 9.0 mm posterior to bregma reached upper incisor length of 13.2 +/- 0.4 mm (p less than 0.05) and lower incisor length of 14.7 +/- 0.5 mm (p less than 0.05) at the 20th postoperative day. Sham-operated controls had no tooth growth acceleration.

Animals↗
PubMed1990

Labyrinth learning impairment in patients with early symptoms of presenile dementia.

21 patients (54 +/- 7 years old) with early cognitive deficit (ECD) during the presenile stage of presumptive primary degenerative dementia (mild stage) and 14 patients (54 +/- 4 years old) with early cognitive deficit with a background of cardiovascular disease (CVD) were examined in a labyrinth learning test of Milner (modified by Roth). 15 patients in the ECD group made 3 times more errors to negative fields (p less than 0.01), about 10 times more errors to positive fields (p less than 0.01) and needed treble the amount of time for passing through the labyrinth (p less than 0.01) compared with a healthy control group (51 +/- 4 years). A further 6 patients of the ECD group had no success in performing the labyrinth test. The CVD group was not different from the control group in making errors, but slower (p less than 0.05). The labyrinth test is found suitable for a more precise diagnosis of early cognitive deficit in the early stage of a primary degenerative dementia of the Alzheimer type.

Cognition Disorders↗
PubMed1990

Acoustically evoked potentials of the basal forebrain and the nucleus cuneiformis of the freely moving rat.

Acoustically evoked potentials (AEP) were recorded and analysed in the basal forebrain (bf, nucleus basalis magnocellularis) and in the mesencephalic parabrachial nucleus cuneiformis (Cnf) of freely moving rats and the modulatory effects of electrical single stimulations within both cholinergic regions on these AEP are described. Bipolar electrodes were implanted in both regions for stimulation and AEP recording. Electrical single impulses with increasing intensities were applied 100 ms before or simultaneously with the clicks. The AEP of the bf as well as the Cnf varied their configuration in dependence on the behavioural state. During grooming, amplitude reductions of certain components of both AEP were found in in comparison to relaxed wakefulness. Electrical stimulation of the bf had no effect on the early component of the Cnf-AEP, which is likely generated within the Cnf. However, a later component of the Cnf-AEP whose generation locus within the mesencephalon is unknown was modulated by bf stimulation. This indicates that the bf is only able to modulate secondary acoustic information processing in the mesencephalon. Cnf stimulation caused reductions of the amplitudes and of the peak times of the bf-AEP. This modulation of the bf-AEP takes place likely within the acoustic pathway.

Animals↗
PubMed1990

Correlation of photically evoked afterdischarge parameters to the respiration rate and their modulation by basal forebrain and nucleus cuneiformis stimulation in the freely moving rat.

On 29 freely moving Long-Evans rats the correlations of various parameters of photically evoked afterdischarges (PhAD) with respiration rate were observed and statistically evaluated. Increasing respiration rate is related with PhAD of reduced amplitude, higher number per flash and increased frequency. PhAD show their best appearance at frequencies around 6.2 PhAD/s. At frequencies below 5.9 and above 6.4/s PhAD number and amplitude decreased. Electrical single impulse stimulation of the nucleus cuneiformis (Cnf) decreased PhAD trigger rate significantly stronger than basal forebrain (Bf) stimulation from 10 rats. The Cnf stimulation effects on PhAD continued longer than Bf stimulation effects which is also recognizable on the different modulations of the PhAD amplitude and frequency. After the desynchronizing stimulation effects, more synchronized PhAD were found, which indicates a desynchronization-synchronization sequence of the PhAD modulation after Bf and Cnf stimulation.

Animals↗
PubMed1990

Different laminar distribution of flash evoked potentials in cortical areas 17 and 18 b of freely moving rats.

The laminar distribution of flash evoked field potential (VEP) was investigated in the visual cortical areas 17 and 18 b in freely moving rats. Averaged VEPs were recorded during stable relaxed wakefulness characterized behaviorally and polygraphically. The depth profiles of the main VEP components displayed polarity reversals in lamina V in every electrode track through area 17 while no polarity reversal was observed in any track through area 18 b. The primary negative component (N30) had an amplitude maximum in lamina IV in both areas. Current source-density analysis (CSD) in connection with amplitude depth profiles indicated that the surface-negative component N30 is generated mainly by the synaptic excitatory inputs in lamina IV. The negative peak of the flash-evoked afterdischarges in area 17 are generated the same way. The data imply a more concentrated field generator in area 17 with densely packed cellular elements responding synchronously to the flash. In area 18 b, either the anatomical distribution or the temporal relationship of the responding elements seems to be different.

Animals↗