Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “neuronal activity”

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.

At least 19 recordsLinked to original sources
PubMed1978

Activation of hypothalamic neuronal activity by the electrolytic deposition of iron into the preoptic area.

Changes in brain activity after electrochemical stimulation of the preoptic area of pro-oestrous rats were studied by the measurement of the electro-encephalogram (EEG) of the frontal cortex and the recording of single neurones in the anterior hypothalamus. All rats were anaesthetized with urethane between 10.00 and 12.00 h to allow prolonged electrophysiological recording and to block the spontaneous surge of LH during the afternoon. Electrochemical stimulation was applied, between 12.00 and 14.00 h, as an anodal current through an implanted steel electrode; this caused the electrolytic deposition of iron and evoked the release of LH and ovulation. Electrochemical stimulation of the preoptic area changed the cortical EEG, either immediately or after a delay of a few minutes, from a labile pattern with alternate periods of arousal and slow-wave sleep, to a stage of continuous arousal which persisted for the remainder of the recording period (2--3 h). Conversely, the EEG pattern of the cortex was not disturbed by electrolytic lesions placed in the preoptic area through a platinum electrode. Electrochemical stimulation of the arcuate region of the hypothalamus, the lateral septal area, the medial amygdaloid complex and the anterior parts of the thalamus caused no obvious change in the EEG patterns. Ipsilateral anterior hypothalamic neurones, about 1 mm caudal to the focus of electrochemical stimulation, displayed an immediate decrease in electrical activity after application of the current. After 10--20 min however, the rates of discharge of action potentials in 9 out of the 16 neurones under consideration increased progressively from 0.5 to 15--25 action potentials/s and these rates were maintained until the recordings were lost after 90--230 min. No such acceleration in electrical activity was observed in neurones on the contralateral side. Iron deposited during electrochemical stimulation was precipitated as sulphide and stained by Timm's method. There was a central damaged area of radius 0.6 mm surrounded by an 'undamaged' area with considerable infiltration of iron, up to a distance of 1.7 mm from the electrode tip. Cells within the area of infiltration did not stain for iron 10 min after electrochemical stimulation, but after 30 min, neural elements in this peripheral zone were stained in a manner similar to the Golgi method. The concentrations of LH in the plasma remained unchanged in all rats for 10--15 min after electrochemical stimulation. Thereafter, the concentrations increased progressively and approximately in parallel to the changes in action potential activity until, after 2 h, the individual concentrations of 300--600 ng LH/ml were more than six times the values obtained before stimulation. Bilateral electrochemical stimulation resulted in appreciably higher concentrations of LH and produced values close to those observed during the pro-oestrous surge of the hormone...

Action Potentials↗
PubMedDate not supplied

Effects of cervical vagus nerve stimulation on hypothalamic neuronal activity.

The effects of cervical vagus nerve stimulation on the activity of 56 neurons recorded in various parts of the rat brain were determined. Recordings were made from neurons in both the ipsilateral and contralateral hemispheres during vagus nerve stimulation. Both frequency, 10 to 100 Hz, and voltage, 1 to 20 V, of 0.5 msec pulses were applied to the nerve in a random manner over a 4 sec period while monitoring ongoing single neuronal activity. Frequency response relationships were established for 64% of the lateral preoptic-lateral hypothalamic-medial forebrain bundle (LPA-LH-MFB) neurons which were tested. Four types of LPA-LH-MFB neuronal responses were observed. Twenty percent of the neurons increased in discharge frequency as stimulation frequency was increased, 9% increased in discharge frequency as stimulation frequency was decreased, 23% decreased in discharge frequency as stimulation frequency was increased, and 14% decreased in discharge frequency as stimulation frequency was decreased. Increasing the stimulation voltage always enhanced the magnitude of the effects observed due to changing the stimulation frequency. Neurons observed in some other parts of the brain were not affected by the same stimulation. In addition, cells tested in the LPA-LH-MFB area which were previously tested and affected by gastric distension were also affected similarly by vagus nerve stimulation. Results are discussed in terms of peripheral afferent control over LPA-LH-MFB neuronal activity related to ingestive behavior.

Afferent Pathways↗
PubMed1977

Determination of transmitter function by neuronal activity.

The role of neuronal activity in the determination of transmitter function was studied in cultures of dissociated sympathetic neurons from newborn rat superior cervical ganglia. Cholinergic and adrenergic differentiation were assayed by incubating the cultures with radioactive choline and tyrosine and determining the rate of synthesis and accumulation of labelled acetylcholine and catecholamines. As in previous studies, pure neuronal cultures grown in control medium displayed much lower ratios of acetylcholine synthesis to catecholamine synthesis than did sister cultures grown in medium previously conditioned by incubation on appropriate nonneuronal cells (conditioned medium). However, here we report that neurons treated with the depolarizing agents elevated K(+) or veratridine, or stimulated directly with electrical current, either before or during application of conditioned medium, displayed up to 300-fold lower acetylcholine/catecholamine ratios than they would have without depolarization, and thus remained primarily adrenergic. Elevated K(+) and veratridine produced this effect on cholinergic differentiation without significantly altering neuronal survival. Because depolarization causes Ca(2+) entry in a number of cell types, the effects of several Ca(2+) agonists and antagonists were investigated. In the presence of the Ca(2+) antagonists D600 or Mg(2+), K(+) did not prevent the induction of cholinergic properties by conditioned medium. Thus depolarization, either steady or accompanying activity, is one of the factors determining whether cultured sympathetic neurons become adrenergic or cholinergic, and this effect may be mediated by Ca(2+).

Acetylcholine↗
PubMed2025

A Massively Parallel CRISPR-Based Screening Platform for Modifiers of Neuronal Activity.

Understanding the complex interplay between gene expression and neuronal activity is crucial for unraveling the molecular mechanisms underlying cognitive function and neurological disorders. Here, we developed pooled screens for neuronal activity, using CRISPR interference (CRISPRi) and the fluorescent calcium integrator CaMPARI2. Using this screening method, we evaluated 1343 genes for their effect on excitability in human iPSC-derived neurons, revealing potential links to neurodegenerative and neurodevelopmental disorders. These genes include known regulators of neuronal excitability, such as TARPs and ion channels, as well as genes associated with autism spectrum disorder and Alzheimer's disease not previously described to affect neuronal excitability. This CRISPRi-based screening platform offers a versatile tool to uncover molecular mechanisms controlling neuronal activity in health and disease.

Journal Article↗
PubMed1977

Effect of H+ on spontaneous neuronal activity in the surface layer of the rat medulla oblongata in vitro.

The effect of changing extracellular pH (pHe) on the spontaneous activity of neurons in brain slices taken from the ventral layer of the rat medulla oblongata was compared to the response of neurons in dorsal slices. In the ventral medulla, more than 50% of the neurons were excited by H+. These neurons were found just lateral to the pyramidal tract between the root of the hypoglossal nerve and the trapezoid body. In the dorsal medulla, low pHe caused an inhibition of activity in most neurons, although a few were excited. The fact that H+ elicted excitation predominantly in the ventral medullary substrate to respond to pHe changes. Depression of synaptic transmission within the neuronal network in the slice by reducing the [Ca2+]e and increasing the [Mg2+]e altered the nature of responses of neurons to H+: In the ventral medulla, the majority of neurons were inhibited by H+, whereas in the dorsal medulla more than 50% of neurons were excited. Therefore, "specificity" of the ventral medullary neurons seemed to be dependent upon intact synaptic connections. A possible role of acetylcholine-acetylcholinesterase system in the response of ventral medullary neurons to H+ is discussed.

Action Potentials↗
PubMedDate not supplied

[Prolonged effect of 5-hydroxytryptophan on trace processes of neuronal activity].

In experiments on rabbits a study was made of the influence of serotonin's precursor, 5-oxytriptophane (5-OTP), on trace processes in spike activity of neurones in the visual and sensorimotor cortical areas. Rhythmic light was used as a stimulus with a frequency of 2 or 5 per second. Administration of 5-OTP produced prolonged action of the trace processes, significant for 2 per second frequency and less pronounced for 5 per second frequency of the flashes. This property was possessed both by the neurones which increased their activity frequency and those which reduced it. It is assumed that the prolonging effect of 5-OTP is the consequence of its modulating influence on the brain activity, which is manifested in a selective potentiation of the functioning of a neuronal system with a relatively lower frequency of spontaneous firing.

5-Hydroxytryptophan↗
PubMed1977

Vestibular-related neuronal activity in the thalamus of the alert monkey during sinusoidal rotation in the dark.

1. In the alert monkey neuronal activity was recorded in the ventro-posterior nucleus (VP) of the thalamus in the dark during sinusoidal rotation over a frequency range from 0.01-1 Hz. 2. From 57 neurons 38 (67%) were activated with rotation to the ipsilateral side (type I) and 19 (33%) to the contralateral side (type II). The spontaneous activity was low (average 10.1 imp/sec) and irregular. No activity changes were found with eye movements. 3. At 0.2-0.1 Hz neuronal activity showed a phase lead of 10-20 degrees relative to chair velocity. At the lowest frequency (0.01 Hz) the phase lead was only slightly higher (about 30 degrees). Accordingly the decrease in gain was only moderate. 4. At lower frequencies the simultaneously recorded eye movements (nystagmus) showed an increase in phase lead comparable to the values for the neuronal activity in the thalamus. For both neuronal activity in the thalamus and nystagmus a time constant between 25-35 sec was calculated. 5. The data are compared with vestibular nerve and nuclei recordings. It is argued that the time constants of vestibular neurons in the thalamus are very similar to the time constants of neurons in the vestibular nuclei in alert animals.

Animals↗
PubMed1978

Effect of ethanol on neuronal activity in the parietal association cortex of alert monkeys.

The effect of alcohol was studied in alert monkeys on the cellular mechanisms of the posterior parietal association cortex, a region that normally participates in visuo-spatial co-ordination of hand movements. In thirty-two experiments, the effects of intracardiac administration of ethanol were monitored by the intracortical multiple-unit recording technique. Alcohol produced rhythmic groupings of the spontaneous impulse activity; the rhythm was accentuated by closing the eyes. The dominant frequency of this rhythm (3.5 to 1 Hz) correlated inversely with the blood alcohol level. Three groups of response types were studied in Brodmann's area 7. At 8 of 12 recording sites, a close correlation was observed between the monkey's reaching accuracy and the magnitude of integrate multineuronal responses to reaching with the contralateral arm under visual guidance, or to grasping an object. Half of the 10 recording sites which were activated by complex visual stimulation also showed a close correlation with the behavioural action of alcohol. Least sensitive to alcohol were somatosensory responses; only 3 of 10 of such recording sites were influenced by moderate doses of alcohol. Larger doses producing coma increased the proportion of responses blocked by alcohol, whereas no effects were observed in the adjacent primary somatosensory cortex. Our results show that the posterior parietal association cortex is very sensitive to the action of alcohol. Moreover, these findings support the theory that the action of alcohol in various parts of the central nervous system depends on the complexity of synaptic contacts to the location under study.

Action Potentials↗
PubMed1979

Comparison of effects of pentobarbital and ethanol on the neuronal activity in the posterior parietal association cortex.

The problem of this study was whether the effects produced by alcohol in the posterior parietal association cortex are specific to this drug or shared by other centrally acting depressant drugs such as barbiturates. The effect of graded doses of pentobarbital on multineuronal impulse activity was recorded with transdural microelectrode technique in 30 expts. in Brodmann's area 7 of five stump-tailed monkeys (Macaca speciosa). The results were compared with those from 32 expts. performed with alcohol and published separately. The dosage of the two drugs was determined on the basis of the monkeys' sensori-motor coordination which was assessed with a rating scale of reaching accuracy for food rewards. There were several recording sites where the actions of the two drugs were similar at similar behavioural levels of intoxication. However, in the distribution of effects among various functional types of recording sites a significant difference was found between pentobarbital and alcohol. Alcohol commonly diminished cellular activity related to motor behaviour (reaching, grasping) and only rarely responses to somesthetic stimuli, whereas the effects of pentobarbital were the opposite being most common on somatosensory responses and least common on activity related to motor behaviour. Also responses to visual stimuli were more sensitive to pentobarbital than to alcohol. The actions of pentobarbital and alcohol on responses evoked by sensory stimulation differed significantly (P less than 0.01). We conclude that significant differences exist in the mechanisms of action of alcohol and barbiturate on the associative systems of the brain.

Animals↗
PubMed1978

[Neuronal activity in an epileptic focus formed as a result of the effect of tetanus toxin on the motor area of the cat cerebral cortex].

Activity of single neurons was recorded intracellularly in the cortical epileptic focus produced by tetanus toxin. The activity of all studied neurons correlated positively with ECoG during the interictal period. A group of neurons was found with continuous background activity. The membrane potential of these neurons gradually decreased and the frequency of discharges increased during the interictal intervals. The neurons with continuous background activity during the interictal intervals revealed paroxismal depolarization without the following hyperpolarization. In some neurons with random background spikes hyperpolarizing shifts after paroxismal depolarization were observed. The mechanisms of the organization of the neuronal "epileptic aggregates" as well as of inhibition of these functional structures are considered.

Animals↗
PubMed1979

Coupling between neuronal activity and focal blood flow in experimental seizures.

Local blood flow, ECoG and single cortical neurone activity were recorded simultaneously from single microelectrodes in 17 cats. Seizures were induced by repeated intravenous injections of pentylenetetrazol (PTZ, 10-20 mg/kg) or by local application of 1 M Na-penicillin. Seven to 20 sec after appearance of burst activity in cortical neurones and ECoG, focal flow increased up to 300% of control. The extent of this flow increase was significantly correlated with the change in firing rate of the neurones. With cessation of seizure activity the flow returned to or below control values. Forty to 70 mg/kg PTZ caused status epilepticus with high voltage rhythmic discharges lasting 30 min-2 h. In 3 cats with status, the flow decreased below control despite persisting seizures, indicative of uncoupling between activity and flow. The delayed coupling between activity and flow during drug-induced seizures indicates a metabolic mediator. Uncoupling observed in cases with long lasting seizures may be due to brain oedema following increased permeability of the blood-brain barrier.

Animals↗
PubMed1978

Alterations of spontaneous neuronal activity in the caudate-putamen, nucleus accumbens and amygdaloid complex of rats produced by D-amphetamine.

Changes in spontaneous neuronal activity in the caudate-putamen, accumbens nucleus and amygdaloid complex of immunobilized, locally anesthetized rats were recorded following intraperitoneal injection of 2.5 mg/kg d-amphetamine sulfate. In each site, d-amphetamine typically produced a prolonged depression of firing rate which, in most cases, occurred after an inital, brief potentiation of activity. However, the onset of the amphetamine-induced depression occurred signficantly later in the amygdala. Subsequent IP administration of either 5.0 mg/kg chlorpromazine or 2.0 mg/kg haloperidol reversed, to varying degrees, the amphetamine-induced depression of neuronal activity in each area. These results are discussed in terms of the known biochemical effects of amphetamine on catecholaminergic transmission and the alleged role of the nigro-neostriatal mesolimbic dopamine systems in the amphetamine behavioral response.

Amygdala↗
PubMedDate not supplied

[Characteristics of the neuronal activity of structures of the hippocampal formation (presubiculum)].

Analysis of neuronal activity of presubiculum was performed in unanaesthetized rabbits. The level of spontaneous activity was high, in 33% of neurones it consisted in high frequency bursts which periodically followed regularly with alternating frequencies from 0.5 cps up to 15.0 cps. Presubicular neurones responded to sensory stimuli of various modalities, but visual stimuli were the most effective. Responses of specific, patterned type dominated over simple phasic and tonic effects. Various types of incremental dynamics were observed with repeated stimulation, habituation was present only in a limited number of neurones (15%). Comparison of presubicular neuronal characteristics with those of other sub-divisions of the hippocampal formation revealed a significant resemblance between presubiculum and the entorhinal cortex and a strong difference from subiculum.

Animals↗
PubMed1978

Background neuronal activity in cat somatosensory cortex before and after VPL damage. Histogram and taxonomic analysis.

Two groups of cats under barbiturate anaesthesia are used to study the effect of electrolytic coagulation in the VPL of the thalamus on the extracellular unit activity in the somatosensory cortex (the focus of maximum activity (FMA) of this part of the nucleus affected by the lesion). In the first group of animals a comparison is made between the unit activity before and immediately after coagulation, while in the second group of animals the activity of the neurones, recorded in FMA of the intact VPL is compared with that of the neurones in the homologous symmetrical point in the hemisphere, ipsilateral to the VPL coagulate 10-14 days before the acute experiment. The activity of 246 neurones is studied. Histogram, statistical and taxonomic analyses are performed. It is found that lesion in VPL modifies to a certain extent the pattern of neuronal discharges, although even after the damage rhythmic groups of action potentials simultaneous with the spindle-like EEG waves are recorded in the primary somatosensory cortex (FMA). Evidently, the relay VPL nucleus is not the only pacemaker of spindle activity in its projection cortical area, which is in contradiction with some views expressed in the literature.

Animals↗