[A procedure for the recording and evaluation of evoked potentials in neurophysiology and clinical diagnostics (author's transl)].
Explore the source record for details and available documents.
Acoustic Stimulation↗
SEARCH · Search PubMed
Results for “Physical Stimulation”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Activity-dependent expression of acyl-coenzyme a-binding protein in retinal muller glial cells evoked by optokinetic stimulation.
Long-term horizontal optokinetic stimulation (HOKS) decreases the gain of the horizontal optokinetic reflex and evokes the second phase of optokinetic afternystagmus (OKAN-II). We investigated the possible molecular constituents of this adaptation. We used a differential display reverse transcriptase-PCR screen for mRNAs isolated from retinas of rabbits that received HOKS. In each rabbit, we compared mRNAs from the retina stimulated in the posterior-->anterior (preferred) direction with mRNAs from the retina stimulated in the anterior-->posterior (null) direction. Acyl-CoA-binding protein (ACBP) mRNA was one of four mRNAs selected by this screen, the proteins of which interact with GABA receptors. HOKS in the preferred direction increased ACBP mRNA transcription and ACBP protein expression. ACBP was localized to Muller glial cells by hybridization histochemistry and by immunohistochemistry. ACBP interacts with the alpha1-subunit of the GABA(A) receptor, as determined by a yeast two-hybrid technique. This interaction was confirmed by coimmunoprecipitation of ACBP and the alpha1-subunit of the GABA(A) receptor using an antibody to GABA(A)alpha1. The interaction was also confirmed by a "pull-down" assay in which histidine-tagged ACBP was used to pull down the GABA(A)alpha1. ACBP does not cross the blood-brain barrier. However, smaller truncated proteolytic fragments of ACBP do, increasing the excitability of central cortical neurons. Muller cells may secrete ACBP in the inner plexiform layer, thereby decreasing the sensitivity of GABA(A) receptors expressed on the surface of ganglion cell dendrites. Because retinal directional sensitivity is linked to GABAergic transmission, HOKS-induced expression of ACBP could provide a molecular basis for adaptation to HOKS and for the genesis of OKAN-II.
Amino Acid Sequence↗
Reward association affects neuronal responses to visual stimuli in macaque te and perirhinal cortices.
To study the roles of the perirhinal cortex (PRh) and temporal cortex (area TE) in stimulus-reward associations, we recorded spike activities of cells from PRh and TE in two monkeys performing a visually cued go/no-go task. Each visual cue indicated the required motor action as well as the availability of reward after correct completion of the trial. Eighty object images were divided into four groups, each of which was assigned to one of four motor-reward conditions. The monkeys either had to release a lever (go response) or keep pressing it (no-go response), depending on the cue. Each of the go and no-go trials could be either a rewarded or unrewarded trial. A liquid reward was provided after correct responses in rewarded trials, whereas correct responses were acknowledged only by audiovisual feedback in unrewarded trials. Several measures of the monkeys' behavior indicated that the monkeys correctly anticipated the reward availability in each trial. The dependence of neuronal activity on the reward condition was examined by comparing mean discharges to each of the 40 rewarded stimuli with those to each of the 40 unrewarded stimuli. Many cells in both areas showed significant reward dependence in their responses to the visual cues, and this was not likely attributable to differences in behavior across conditions because the variations in neuronal activity were not correlated with trial-by-trial variations in latency of go responses or anticipatory sucking strength. These results suggest the involvement of PRh and TE in associating visual stimuli with reward outcomes.
Action Potentials↗
Tactile spatial attention enhances gamma-band activity in somatosensory cortex and reduces low-frequency activity in parieto-occipital areas.
We investigated the effects of spatial-selective attention on oscillatory neuronal dynamics in a tactile delayed-match-to-sample task. Whole-head magnetoencephalography was recorded in healthy subjects while dot patterns were presented to their index fingers using Braille stimulators. The subjects' task was to report the reoccurrence of an initially presented sample pattern in a series of up to eight test stimuli that were presented unpredictably to their right or left index finger. Attention was cued to one side (finger) at the beginning of each trial, and subjects performed the task at the attended side, ignoring the unattended side. After stimulation, high-frequency gamma-band activity (60-95 Hz) in presumed primary somatosensory cortex (S1) was enhanced, whereas alpha- and beta-band activity were suppressed in somatosensory and occipital areas and then rebounded. Interestingly, despite the absence of any visual stimulation, we also found time-locked activation of medial occipital, presumably visual, cortex. Most relevant, spatial tactile attention enhanced stimulus-induced gamma-band activity in brain regions consistent with contralateral S1 and deepened and prolonged the stimulus induced suppression of beta- and alpha-band activity, maximal in parieto-occipital cortex. Additionally, the beta rebound over contralateral sensorimotor areas was suppressed. We hypothesize that spatial-selective attention enhances the saliency of sensory representations by synchronizing neuronal responses in early somatosensory cortex and thereby enhancing their impact on downstream areas and facilitating interareal processing. Furthermore, processing of tactile patterns also seems to recruit visual cortex and this even more so for attended compared with unattended stimuli.
Adult↗
Induction of labour at the start of the new millennium.
Around 20% of all deliveries are preceded by labour induction, a proportion that has not varied dramatically over recent years. Fetal death was the only indication for labour induction centuries ago, while this is now a very rare indication, with prolonged pregnancy and maternal hypertensive disorders being the major indications for the last 50-60 years. Techniques for inducing labour have also changed from dietary delicacies and verbal threats giving way to physical stimulation mainly achieved by cervical stretching and amniotomy and more recently to sophisticated pharmacological manipulation using oxytocin and prostaglandins, based on our expanding knowledge of the physiological processes involved in spontaneous parturition. Relaxin, antiprogestins, nitric oxide as well as complementary medicines have also been explored in recent years. Successful induction is, however, still not guaranteed and there has been increasing emphasis during the past decade on exploring strategies for identifying the probability of success. Measurement of fetal fibronectin in cervical mucus, maternal serum nitrite/nitrate concentrations, ultrasound delineation of cervical form and electrical impedance measurements across the cervix are all being investigated. Safety, success, and patient satisfaction continue to be the major objectives with economic evaluations now becoming a significant factor in the search for the ideal induction method.
Amnion↗
Sensitivity of spontaneously epileptic rats to external stimuli that induce seizures.
The sensitivity of spontaneously epileptic rats (SER), double homozygotes of zitter and tremor mutations, to external stimuli that induce seizures was studied in comparison with tremor (tm/tm) and zitter (zi/zi) rats, and with normal Kyo: Wistar and F 344/N rats. Touching their body, a blinking light (1200 lux, 1 sec interval) or a big sound (8 and 12 kHz, 95 dB) induced tonic extension only in the SER. The response frequency was 22 to 44% at 9 weeks of age and 75 to 100% at 13 weeks of age. Electric stimulus at 30 mA induced tonic-clonic convulsions in all Kyo: Wistar and F 344/N rats. At 20 mA the incidence of seizures decreased with age, from 100% at 5 weeks of age to 33% at 13 weeks of age in Kyo: Wistar rats and from 100 to 71% in F344/N rats. In SER, 10-mA stimuli induced tonic extension at 9 and 13 weeks of age, and 20 and 30 mA induced tonic convulsions, generalized or partial convulsions, and wild jumping or running episodes at 5, 9 and 13 weeks of age. At 30 mA, the incidence of convulsive seizures decreased with age in both tremor (tm/tm) and zitter (zi/zi) rats. Apparently external stimuli acted as simple triggers in the induction of tonic extension, since characteristic tonic extension is induced in the SER by each of the stimuli used in the present study, and induced convulsions closely resembled spontaneously occurring convulsions. The threshold of external stimuli in the induction of tonic extension became lower with aging in the SER, indicating that they are appropriate models for evaluating anticonvulsant drugs, as reported previously.
Acoustic Stimulation↗
Treatment of Meniere's disease with the low-pressure pulse generator (Meniett device).
Until recently, surgery was the only treatment option for people with disabling Meniere's disease that did not respond to adequate medical therapy. A new intermediate level treatment modality, the Meniett device, which applies low-pressure micropulses to the inner ear, has now been shown to be safe and effective. The device is portable and self-administered, requiring a 5-min three-times daily application for an indefinite period. Placement of a tympanostomy tube in the ear drum of the affected ear is necessary. Patient acceptance has been high. Long-term success in control of vertigo is over 80%. Although hearing loss is not improved, Meniett device usage does not adversely affect balance, as do most forms of surgical therapy. Use of the device does not preclude later surgical therapy.
Clinical Trials as Topic↗
Generalized paroxysmal discharges induced by visual stimuli and eye movements.
The generalized paroxysmal discharges (GPDs) induced by the visuo-sensory and oculomotor activations in a total of 30 patients were investigated. The patients consisted of 27 epileptics and 3 with sequelae of head trauma; all of them showed photoconvulsive response. The visuo-sensory activation with red-flicker of 15 cycles/sec or with visual stimuli containing patterns, "pattern," was carried out under the constant condition of 20 cd/m-2. In 22 cases (73%), G-type (simultaneous occurrence of GPD over all the areas) was induced by red-flicker, while in 28 cases (93%) P-type (GPD was preceded by posterior spikes) was induced by "pattern." With the oculomotor activation, paroxysmal discharges were induced in 11 cases of photogenic epilepsy; 10 cases (91%) were of A-type (GPD was preceded by anterior spikes), and one case (9%) showed focal spikes over the right frontal area. In 21 cases (70%), the type of GPD changed from G-type to P-type as the red-flicker activation was replaced by the "pattern" activation. Further, in seven (33%) out of the 21 cases it changed from P-type to A-type as the activation with "pattern" was replaced by the oculomotor activation. It was suggested that the non-specific thalamo-cortical system, the visual cortex, and the frontal eye field are chiefly concerned with the occurrences of G-type, P-type, and A-type, respectively, when such stimuli as described above are given independently.
Adolescent↗
Characteristics of milk ejection, associated intramammary pressure changes and oxytocin release in the mare.
The neuroendocrine reflex theory of milk ejection was investigated in the horse under natural suckling conditions. To this end 12 lactating mares were provided with acute jugular catheters and with intramammary pressure (IMP) recording catheters. The foal had free access to the contralateral mammary complex. Intramammary pressure could thus be recorded while blood was drawn simultaneously for oxytocin analysis from the undisturbed animal. Suckling periods associated with a characteristic increase in IMP lasted significantly longer than unsuccessful nursing attempts. Elements of successful sucklings involved physical stimulation of the mammary gland, a quiet phase and a sudden increase in IMP. Successful suckling took place at about 20-min intervals with a wide range from less than 5 min to greater than 100 min. Between 5 and 10 mU oxytocin i.v. were sufficient to evoke an increase in IMP identical in shape and duration to a naturally induced increase in IMP. Mean peak oxytocin levels reached 15.8 pmol/l plasma, with a maximal release of 39 pmol/l. In the majority of cases (greater than 80%) peak oxytocin release did not occur until after the increase in IMP; in some cases an oxytocin surge was not detectable at all, despite a milk ejection-associated increase in IMP. In three cases increase in IMP could be observed while the foals were away from the mother with no signs of any intention to suckle. The data indicate that in the horse some elements of the neuroendocrine reflex, such as tactile stimulation of the teat and a surge of oxytocin before an increase in IMP, are facultative and not essential for normal milk ejection.
Animals↗
Effects of D-tubocurarine on the ampullar receptors of the frog.
Explore the source record for details and available documents.
Action Potentials↗
Pursuit opposite to the vestibulo-ocular reflex (VOR) during sinusoidal stimulation in humans.
Pursuit opposite to a simultaneously activated vestibulo-ocular reflex (VOR) was tested during passive sinusoidal body oscillations (0.1-1.0 Hz, amplitudes 10-80 degrees) about the vertical axis in 4 healthy humans, while subjects were asked to pursue a small target moving in phase with the rotating chair with about half its amplitude relative to the head and 1.5 times its amplitude with respect to space. The decrease in gain of the pursuit opposite to the VOR occurred at lower stimulus frequency, stimulus velocity and stimulus acceleration than pure visual pursuit when gain was calculated in relation to target motion in head coordinates. It resembles that of pure pursuit when calculated in relation to target motion in space (earth coordinates, sum of the displacements of the mirror image and of the chair) thus taking the oppositely directed VOR into account. The data fit the assumption of a linear interaction of the VOR (in counterphase) and pursuit.
Eye Movements↗
Influence of vestibular and visual climbing fiber signals on Purkinje cell discharge in the cerebellar nodulus of the rabbit.
Extracellular recordings of the climbing fiber responses (CFRs) of single Purkinje cells were made in the cerebellar nodulus and ventral uvula of anesthetized pigmented rabbits. Natural vestibular and optokinetic stimuli were used to evoke responses from these Purkinje cells. Using a null response technique we sorted vestibularly-evoked CFRs into two canal-related categories. CFRs were related to either the ipsilateral anterior and contralateral posterior semicircular canal (iAC+cPC) or to the ipsilateral posterior and contralateral anterior semicircular canal (iPC+cAC). Both canal-related CFRs also responded to downward optokinetic stimulation.
Acceleration↗
Unit analysis of inputs to cingulate cortex in awake, sitting squirrel monkeys. I. Exteroceptive systems.
Explore the source record for details and available documents.
Acoustic Stimulation↗
Morphine-induced modification of the functional properties of ventral tegmental area neurons in conscious rat.
To elucidate the functional role of mesolimbocortical dopamine(DA)-containing and other mediator-specific neurons in mediation of different pharmacological effects of opiates, morphine (6 mg/kg, SC)-induced modification of spontaneous discharges of different types VTA-units and their changes during polymodal activating and aversive stimulation and spontaneous movement were studied in conscious, restrained rats. In presumed DA-containing neurons (D-type) prolonged increase of discharge rate, regularization of their pattern and decrease of firing changes during all types of external stimulation and spontaneous or stimulus-induced movement activity were found. This decrease of unit firing changes was connected with significant rising of atypical, compared with control conditions, firing inhibitions. Changes of presumed acetylcholine(ACh)-containing neurons (A-B type) properties were defined as prolonged and pronounced decrease of firing rate, intensification of bursting pattern and decrease of discharge changes during all types of stimulation used and animal movements. This decrease of discharge changes was associated with significant lowering of activations-typical for these units in control conscious animals and rising of firing inhibitions. In presumed ACh- or GABA-containing interneurons of C-type a significant decrease of firing rate, increase of activations and decrease of firing inhibitions, typical for these units in control conscious rats were found. The modifications of different VTA-unit functional properties are discussed in view of main pharmacological effects of opiates (sedation, analgesia, positive reinforcement, movement activation).
Acoustic Stimulation↗
Rehabilitation following brain damage: some neurophysiological mechanisms. The effects of repetitive stimulation in recovery from damage to the central nervous system.
There is a growing body of evidence that the central nervous system (CNS), even in the adult animal, is capable of adaptation and reorganization not only as a result of partial damage to the CNS but also in response to stimulation. Environmental stimulation produces changes including expansion of visual cortex, increases in dendritic branching, glia and cholinesterase. Environmental stimulation also produces behavioural changes. Experimental electrical stimulation produces changes in synapse size, synaptic vesicle change, dendritic branching and changes in synaptic transmission. In man, repetitive electrical stimulation via epidural electrodes increases plasma levels of norepinephrine, epinephrine, and dopamine, and CSF levels of norepinephrine. Repetitive electrical stimulation in man dates back to 1967 and has been used for the control of pain, to improve spasticity, bladder control, motor deficit and the autonomic hyperreflexia of spinal cord injury. In addition, improvement has been reported in epilepsy, cerebral palsy, torticollis and peripheral vascular diseases. The best controlled studies are in multiple sclerosis and peripheral vascular disease, and these results will be presented in more detail.
Animals↗
Synaptic transmission in the ventro-lateral thalamic nucleus during natural sleep and wakefulness: its relation to the cerebellum and sensori-motor cortex.
Explore the source record for details and available documents.
Animals↗
Recent advances in operant conditioning technology: a versatile and affordable computerized touchscreen system.
We report the construction of a new operant chamber that incorporates modern computer, touchscreen, and display technologies. An LCD display was housed in the front wall of a lightweight Plexiglas chamber. An Apple eMac computer was used to present visual stimuli on the monitor and to control other chamber events. Responses to the stimuli were recorded using a transparent resistive-type touchscreen that overlaid the monitor. The resulting system is simple and inexpensive to construct but powerful and flexible enough to explore a broad range of issues in animal learning and behavior.
Animals↗
[Effects of optokinetic stimulation on head movement and body sway of children].
We evaluated the effects of horizontal and vertical optokinetic stimulation on head movement (HM) and body sway (BS) in children and adults, using a Jung type optokinetic stimulator, a strain gauge-platform, and a encephalography. Twenty healthy children aged 7 to 9 years and twenty healthy adults aged 20 to 26 years were instructed to stand with feet close together on the platform with eyes open with and without optokinetic stimulation for 60 seconds. In all subjects, optokinetic stimulation significantly increased the total lengths of HM and BS. In addition, optokinetic stimulation significantly increased the areas of HM and BS in children, but not in adults. Although the ratio of the anteroposterior component to the lateral component in BS was significantly higher in children than in adults, the value of HM was not. Children exhibited a characteristic BS in which the anteroposterior swaying velocity was larger than the lateral swaying velocity. In the anteroposterior component, averaged divisional frequencies of BS were significantly larger in children than in adults. However, averaged divisional frequencies in the lateral component of BS and those in the anteroposterior and lateral components of HM did not differ between the two age groups. The ratio of the total length of HM to that of BS was significantly higher in children than in adults. These results suggest that HM and BS of children are readily affected by optokinetic stimulation, and that in children, the BS velocity in the anteroposterior direction is higher than that in the lateral direction.
Adult↗