Search results for "evoked potential"
showing 10 items of 604 documents
Effects of low-gamma tACS on primary motor cortex in implicit motor learning
2019
Abstract In the primary motor cortex (M1), rhythmic activity in the gamma frequency band has been found during movement planning, onset and execution. Although the role of high-gamma oscillatory activity in M1 is well established, the contribution of low-gamma activity is still unexplored. In this study, transcranial alternating current stimulation (tACS) was used with the aim to specifically modulate low-gamma frequency band in M1, during an implicit motor learning task. A 40 Hz-tACS was applied over the left M1 while participants performed a serial reaction time task (SRTT) using their right hand. The task required the repetitive execution of sequential movements in response to sequences …
Functional Role of Cerebellar Gamma Frequency in Motor Sequences Learning: a tACS Study
2021
Although the role of the cerebellum in motor sequences learning is widely established, the specific function of its gamma oscillatory activity still remains unclear. In the present study, gamma (50 Hz)—or delta (1 Hz)—transcranial alternating current stimulation (tACS) was applied to the right cerebellar cortex while participants performed an implicit serial reaction time task (SRTT) with their right hand. The task required the execution of motor sequences simultaneously with the presentation of a series of visual stimuli. The same sequence was repeated across multiple task blocks (from blocks 2 to 5 and from blocks 7 to 8), whereas in other blocks, new/pseudorandom sequences were reproduce…
Minireview: Nicotinic Acetylcholine Receptors on Hippocampal Neurons: Distribution on the Neuronal Surface and Modulation of Receptor Activity
1997
The recent development of a technique that uses infrared microscopy for the visualization of well-defined areas on the surface of neurons, and a computerized system of micromanipulators led to the discovery that functional nicotinic acetylcholine receptors (nAChRs) are expressed at higher density on the dendrites than on the soma of rat hippocampal neurons. The finding that the expression of alpha-bungarotoxin-sensitive, alpha 7-bearing, nAChRs and dihydro-beta-erythroidine-sensitive, alpha 4 beta 2 nAChRs tends to increase along the dendritic length suggests that these receptors may be highly involved in the integration of synaptic functions in hippocampal neurons. The present report also …
AUDITORY EVOKED POTENTIALS AND VISUAL EVOKED POTENTIALS: A HELPFUL TEST IN THE DIAGNOSIS AND FOLLOW UP OF KAWASAKI DISEASE
2018
Introduction: Kawasaki disease is a systemic vasculitis affecting mainly children; the most serious complications are coronary artery lesions (CAL). Nonetheless, the spectrum of complications involves all the vascular districts, such as the eyes, skin, kidneys, gallbladder, liver, central nervous system. Sensorineural hearing loss is a low diagnosed complication of KD, however, it may be permanent. Objectives: Auditory evoked potentials (ABR) and visual evoked potentials (VEPs) are useful in evaluating children without auditory and/or visual symptoms but with diseases that could sub clinically involve these functions. Methods: We enrolled 52 children (31 M, 21 F; age: 3 months-10 years) wit…
Auditory brain stem responses in patients with human immunotropic virus infection of different stages.
1992
Thirty patients (26 men, 4 women) with human immunotropic virus infection of different stages were examined. Eleven patients had a history of i.v. drug abuse, nine patients had a history of treated lues infection, and one patient suffered from Kaposi's sarcoma. At the time of the examination, opportunistic infections or acute encephalitis were not apparent in any patient. All patients underwent otoneurological examinations, including pure-tone audiometry, caloric vestibular testing, and recording of the auditory brain stem responses (ABR). Six patients reported onset of hearing impairment during the last 3 yr. Two of them had flat sensorineural hearing loss; in the other cases, pure-tone au…
Passive sound exposure induces rapid perceptual learning in musicians: event-related potential evidence.
2013
Musicians show enhanced auditory processing compared to nonmusicians. However, the neural basis underlying the effects of musical training on rapid plasticity in auditory processing has not been systematically studied. Here, the rapid (one session) learning-related plastic changes in event-related potential (ERP) responses for pitch and duration deviants between passive blocks were compared between musicians and nonmusicians. Passive blocks were interleaved with an active discrimination task. In addition to musicians having faster and stronger overall source activation for deviating sounds, source analysis revealed rapid plastic changes in the left and right temporal and left frontal source…
Source localization of event-related potentials to pitch change mapped onto age-appropriate MRIs at 6 months-of-age
2010
Auditory event-related potentials (ERPs) have been used to understand how the brain processes auditory input, and to track developmental change in sensory systems. Localizing ERP generators can provide invaluable insights into how and where auditory information is processed. However, age-appropriate infant brain templates have not been available to aid such developmental mapping. In this study, auditory change detection responses of brain ERPs were examined in 6-month-old infants using discrete and distributed source localization methods mapped onto age-appropriate magnetic resonance images. Infants received a passive oddball paradigm using fast-rate non-linguistic auditory stimuli (tone do…
Musical sound processing in the human brain. Evidence from electric and magnetic recordings.
2001
Recently, our knowledge regarding the brain's ability to represent invariant features of musical information even during the performance of a simultaneous task (unrelated to the sounds) has accumulated rapidly. Recordings of the change-specific mismatch negativity component of event-related brain potentials have shown that temporally and spectrally complex sounds as well as their relations are automatically processed by human auditory cortex. Furthermore, recent magnetoencephalographic and positron emission topographic investigations indicate that this processing differs between phonetic and musical sounds within and between the cerebral hemispheres. These data thus suggest that despite the…
Clinical usefulness of laser-evoked potentials
2003
In contrast to the function of the visual or auditory pathways which are electrophysiologically accessible by visual or auditory evoked potentials, the somatosensory pathway cannot be investigated as a whole by conventional somatosensory evoked potentials (SEP), because these only reflect function of large fibers, dorsal columns, medial lemniscus and their thalamo-cortical projections mediating sensations like touch and vibration. The other half of the somatosensory system, signaling temperature and pain perception, uses a different set of afferents and different central pathways, the function of which is accessible by laser-evoked potentials (LEPs). LEP can document lesions of the spinotha…
Neurophysiological studies of pain pathways in peripheral and central nervous system disorders.
2003
Standard clinical neurophysiological assessment of somatosensory pathways by sensory evoked potentials (SEPs) is limited to the tactile and proprioceptive systems consisting of large fibers in the peripheral nerve, the dorsal columns of the spinal cord and the medial lemniscus in the brainstem. This limitation means that about half of the lesions in the somatosensory system will not be detectable. In recent years, many clinical studies have confirmed that laser evoked potentials (LEPs) allow the assessment of the other half of the somatosensory system. Rapid heating of the skin by infrared laser pulses specifically activates the nociceptive and thermoreceptive pathways consisting of small f…