Activity and habituation in the brain of the polyclad flatworm Freemania litoricola

1975 ◽  
Vol 62 (2) ◽  
pp. 455-467
Author(s):  
H. Koopowitz
Keyword(s):  
Evoked Potentials ◽  
Spike Activity ◽  
Posterior Part ◽  
Repetitive Stimulation ◽  
Evoked Responses ◽  
Inhibitory System ◽  
Posterior Portion ◽  
Tactile Stimuli ◽  
Vibration Responses ◽  
The Brain

1. A variety of spontaneously active units was measured in the brain of the polyclad flatworm Freemania litoricola. Following application of MgCl2 there was both a decrease in number of active units and a decrease in frequency of firing of those cells which persisted in their activity. 2. Receptors which respond to vibration stimuli evoke potentials in the posterior part of the brain. Repetitive stimulation leads to habituation, the extent of which is dependent on both the number of times stimulated and the strength of the stimulus. Weaker stimuli habituate more rapidly than strong stimuli. Habituated responses can be dishabituated by tactile stimuli and also by stronger intensity stimuli of the same modality. The vibration-evoked potentials appear to occur in at least second-order cells, since vibration responses are abolished by the application of MgCl2. 3. Tactile responses can also be elicited from the posterior portion of the brain when the stimulus is applied to the periphery of the animal. These responses are insensitive to MgCl2. 4. Both vibration and tactile evoked responses are able to evoke further barrages of spike activity. 5. The presence of a dual sensitizing and inhibitory system during habituation is discussed.

Electrophysiology of the peripheral nerve net in the polyclad flatworm Freemania litoricola

1975 ◽  
Vol 62 (2) ◽  
pp. 469-479
Author(s):  
H. Koopowitz
Keyword(s):  
Action Potentials ◽  
Body Wall ◽  
Contralateral Side ◽  
The Body ◽  
Conducting System ◽  
Response Decrement ◽  
Posterior Portion ◽  
Nerve Net ◽  
Tactile Stimuli ◽  
The Brain

1. A diffuse-conducting system close to the dorsal epithelium of the polyclad flatworm Freemania litoricola is described. Tactile stimuli elicit small action potentials which can be conducted around lesions through the body wall. The potentials can occur in bursts or barrages. 2. This conducting system appears to be insensitive to Mg2+ ions. 3. Conduction velocities (0–26--71 m/sec) vary over the animal. Conduction spread in the anterior half of the animal appears to be greater than that in the posterior portion. 4. Response decrement to repeated stimulation can be recorded in the peripheral system but it is not clear if this is due to habituation or fatigue. 5. Conduction from the peripheral net to the brain occurs. Some central units appear to pick up information only, or mainly, through the anterior nerves, while other units can respond to information conducted through the network to nerves of the contralateral side. 6. Different possibilities to account for this system are discussed, and it is suggested that the animals either possess a unique Mg2+ insensitive synaptic nerve-net or else the network is electrically coupled.

ASSESSMENT OF PHYSIOLOGICAL PARAMETERS OF THE TRIGEMINAL AND COCHLEOVESTIBULAR SYSTEMS IN TEMPOROMANDIBULAR JOINT PAIN DYSFUNCTION

2020 ◽  
Vol 17 (2) ◽  
pp. 110-120
Author(s):  
N.D. Sorokina ◽  
◽  
L.R. Shahalieva ◽  
S.S. Pertsov ◽  
L.V. Polma ◽  
...  
Keyword(s):  
Nervous System ◽  
Evoked Potentials ◽  
Temporomandibular Joint ◽  
Differential Diagnostics ◽  
Autonomous Nervous System ◽  
Dental Diseases ◽  
Grade Ii ◽  
The Right ◽  
Distal Occlusion ◽  
The Brain

One of the most common causes of chronic pain in the facial region, including in the trigeminal nerve link, which is not associated with dental diseases, is pain dysfunction of the temporomandibular joint. At the same time, there is evidence in the literature that there are relationships between pain dysfunction of the temporomandibular joint, abnormal occlusion, cervical-muscular tonic phenomena, postural disorders, dysfunction of the Autonomous nervous system and cochleovestibular manifestations. At the same time, neurophysiological indicators of functional disorders in the maxillofacial region and intersystem interactions in pain dysfunction of the temporomandibular joint are insufficiently studied.Goal. The aim of the work is to evaluate the neurophysiological features of trigeminal afferentation in terms of trigeminal somatosensory evoked potentials (TSWP) and the auditory conducting system of the brain in terms of acoustic stem evoked potentials (ASVP) in distal occlusion of the dentition with pain dysfunction of the temporomandibular joint (TMJ) in comparison with physiological occlusion in students 18-21 years old. Material and methods. The main study included 41 students with distal occlusion (21 girls and 20 boys), (grade II Engl, symmetrically right and left in 14 people, and grade II Engl on the left and grade I on the right in 12 people, grade I on the left and grade II on the right in 15 people). All respondents with distal occlusion and who were practically healthy signed an informed consent to participate in the study. We used complex orthodontic methods of examination, subjective degree of severity and intensity of pain in the TMJ, assessment of the Autonomous nervous system (samples and tests), and neurophysiological methods for assessing TSVP and ASVP. Results. Significant differences in ASEP parameters were found in the group of respondents with distal occlusion in the form of a decrease in the latency period of peak I, III, and V compared to physiological occlusion, that correlated with the subjective assessment (in points) of cochleovestibular disorders. According to the TSVP study, a decrease in the duration of latent periods was found, which indicates an increased excitability of non-specific brain stem structures at the medullo-ponto-mesencephalic level compared to the control group. Conclusions. The results obtained are supposed to be used for differential diagnostics, including such dental diseases as TMJ pain dysfunction, occlusion abnormalities accompanied by pain syndrome. Additional functional diagnostics of multi-modal VP of the brain (acoustic evoked potentials, trigeminal evoked potentials) can be performed in conjunction with indicators of autonomic nervous system dysfunction, with parameters of severity of clinical symptoms of cochleovestibular disorders, musculoskeletal dysfunction the maxillofacial area, with indicators of pain, which will determine the tactics and effectiveness of subsequent treatment.

scholarly journals Clinical Validation of the Champagne Algorithm for Evoked Response Source Localization in Magnetoencephalography

2021 ◽  
Author(s):  
Abhishek S. Bhutada ◽  
Chang Cai ◽  
Danielle Mizuiri ◽  
Anne Findlay ◽  
Jessie Chen ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Source Localization ◽  
Clinical Population ◽  
Evoked Responses ◽  
Localization Algorithm ◽  
Equivalent Current Dipole ◽  
Current Dipole ◽  
Tumor Patients ◽  
Equivalent Current ◽  
Sensory Evoked

AbstractMagnetoencephalography (MEG) is a robust method for non-invasive functional brain mapping of sensory cortices due to its exceptional spatial and temporal resolution. The clinical standard for MEG source localization of functional landmarks from sensory evoked responses is the equivalent current dipole (ECD) localization algorithm, known to be sensitive to initialization, noise, and manual choice of the number of dipoles. Recently many automated and robust algorithms have been developed, including the Champagne algorithm, an empirical Bayesian algorithm, with powerful abilities for MEG source reconstruction and time course estimation (Wipf et al. 2010; Owen et al. 2012). Here, we evaluate automated Champagne performance in a clinical population of tumor patients where there was minimal failure in localizing sensory evoked responses using the clinical standard, ECD localization algorithm. MEG data of auditory evoked potentials and somatosensory evoked potentials from 21 brain tumor patients were analyzed using Champagne, and these results were compared with equivalent current dipole (ECD) fit. Across both somatosensory and auditory evoked field localization, we found there was a strong agreement between Champagne and ECD localizations in all cases. Given resolution of 8mm voxel size, peak source localizations from Champagne were below 10mm of ECD peak source localization. The Champagne algorithm provides a robust and automated alternative to manual ECD fits for clinical localization of sensory evoked potentials and can contribute to improved clinical MEG data processing workflows.

Sensory gating of auditory evoked potentials in rats: effects of repetitive stimulation and the interstimulus interval

2001 ◽  
Vol 55 (3) ◽  
pp. 195-213 ◽  
Author(s):  
N.M.W.J de Bruin ◽  
B.A Ellenbroek ◽  
W.J van Schaijk ◽  
A.R Cools ◽  
A.M.L Coenen ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Interstimulus Interval ◽  
Auditory Evoked Potentials ◽  
Sensory Gating ◽  
Repetitive Stimulation

Glossopharyngeal Nerve Evoked Potentials after Stimulation of the Posterior Part of the Tongue in Dogs

Neurosurgery ◽  
2002 ◽  
Vol 51 (4) ◽  
pp. 1026-1033
Author(s):  
Jun Sakuma ◽  
Masato Matsumoto ◽  
Mamoru Ohta ◽  
Tatsuya Sasaki ◽  
Namio Kodama
Keyword(s):  
Evoked Potentials ◽  
Posterior Part ◽  
Glossopharyngeal Nerve ◽  
Stimulation Of

Evoked Potentials by Letters in Printed and Script Forms

1984 ◽  
Vol 59 (1) ◽  
pp. 227-232 ◽  
Author(s):  
Luciano Mecacci ◽  
Dario Salmaso
Keyword(s):  
Information Processing ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Adult Male ◽  
Visual Information ◽  
The Other ◽  
Behavioral Data ◽  
Evoked Responses ◽  
Amplitude Component ◽  
Male Subjects

Visual evoked potentials were recorded for 6 adult male subjects in response to single vowels and consonants in printed and script forms. Analysis showed the vowels in the printed form to have evoked responses with shorter latency (component P1 at about 133 msec.) and larger amplitude (component P1-N1) than the other letter-typeface combinations. No hemispheric asymmetries were found. The results partially agree with the behavioral data on the visual information-processing of letters.

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