Observations on the Myo-Neural Physiology of a Polyclad Flatworm: Inhibitory Systems

1970 ◽  
Vol 53 (1) ◽  
pp. 1-8
Author(s):  
H. KOOPOWITZ ◽  
D. W. EWER
Keyword(s):  
Spontaneous Activity ◽  
Low Frequency ◽  
Relaxation Effect ◽  
Time Interval ◽  
Inhibitory System ◽  
Repetitive Electrical Stimulation ◽  
Pass Through ◽  
The Brain ◽  
High Frequency Stimulus ◽  
Conduction Of Excitation

1. The spontaneous activity displayed by Planocera preparations decreased with repetitive electrical stimulation. It was also found that the amplitude of response was related to the time since previous spontaneous activity. The response decreased as the time interval between spontaneous activity and stimulus decreased. 2. When a preparation was stimulated at a low frequency then there was an increase in the tone of the preparation. If the low-frequency stimulus was then followed by a stimulus at a slightly higher frequency then there was a drop in tone caused by a relaxation of the preparation. 3. The extent of relaxation which occurred depended on parameters or the high-frequency stimulus but could be facilitated by increasing either the frequency or the duration of the initial low-frequency stimulus. 4. Pathways involved with conduction of excitation from one side of the animal to the other pass through the brain. The brain is also required for transmission of the relaxation effect. 5. It is concluded that these relaxation and depressant effects reflect the presence of a true inhibitory system which also shows facilitation.

scholarly journals Single-neuron firing cascades underlie global spontaneous brain events

2021 ◽  
Vol 118 (47) ◽  
pp. e2105395118
Author(s):  
Xiao Liu ◽  
David A. Leopold ◽  
Yifan Yang
Keyword(s):  
Spontaneous Activity ◽  
Large Scale ◽  
Significant Proportion ◽  
Field Potential ◽  
Low Frequency ◽  
Isolated Cells ◽  
Physiological Indicators ◽  
Global Events ◽  
Subcortical Regions ◽  
The Brain

The resting brain consumes enormous energy and shows highly organized spontaneous activity. To investigate how this activity is manifest among single neurons, we analyzed spiking discharges of ∼10,000 isolated cells recorded from multiple cortical and subcortical regions of the mouse brain during immobile rest. We found that firing of a significant proportion (∼70%) of neurons conformed to a ubiquitous, temporally sequenced cascade of spiking that was synchronized with global events and elapsed over timescales of 5 to 10 s. Across the brain, two intermixed populations of neurons supported orthogonal cascades. The relative phases of these cascades determined, at each moment, the response magnitude evoked by an external visual stimulus. Furthermore, the spiking of individual neurons embedded in these cascades was time locked to physiological indicators of arousal, including local field potential power, pupil diameter, and hippocampal ripples. These findings demonstrate that the large-scale coordination of low-frequency spontaneous activity, which is commonly observed in brain imaging and linked to arousal, sensory processing, and memory, is underpinned by sequential, large-scale temporal cascades of neuronal spiking across the brain.

scholarly journals Single neuron firing cascades underlie global spontaneous brain events

2021 ◽  
Author(s):  
Xiao Liu ◽  
David A. Leopold ◽  
Yifan Yang
Keyword(s):  
Spontaneous Activity ◽  
Large Scale ◽  
Significant Proportion ◽  
Field Potential ◽  
Low Frequency ◽  
Isolated Cells ◽  
Physiological Indicators ◽  
Subcortical Regions ◽  
The Brain ◽  
Local Field Potential Lfp

AbstractThe resting brain consumes enormous energy and shows highly organized spontaneous activity. To investigate how this activity is manifest among single neurons, we analyzed spiking discharges of ∼10,000 isolated cells recorded from multiple cortical and subcortical regions of the mouse brain during immobile rest. We found that firing of a significant proportion (∼70%) of neurons conformed to a ubiquitous, temporally sequenced cascade of spiking that was synchronized with global events and elapsed over timescales of 5-10 seconds. Across the brain, two intermixed populations of neurons supported orthogonal cascades. The relative phases of these cascades determined, at each moment, the response magnitude evoked by an external visual stimulus. Furthermore, the spiking of individual neurons embedded in these cascades was time locked to physiological indicators of arousal, including local field potential (LFP) power, pupil diameter, and hippocampal ripples. These findings demonstrate that the large-scale coordination of low-frequency spontaneous activity, which is commonly observed in brain imaging and linked to arousal, sensory processing, and memory, is underpinned by sequential, large-scale temporal cascades of neuronal spiking across the brain.

Changes in the Total Power of Beta and Theta Bands When Using EEG Biofeedback in Primary School-Age Children Having Difficulties with Voluntary Regulation

2020 ◽  
pp. 331-340
Author(s):  
Yuliya S. Dzhos ◽  
◽  
Irina A. Men’shikova ◽  
Keyword(s):  
Left Hemisphere ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
School Age Children ◽  
Total Power ◽  
Eeg Biofeedback ◽  
Beta Band ◽  
Bioelectric Activity ◽  
Voluntary Regulation ◽  
The Brain

This article presents the results of the study on spectral electroencephalogram (EEG) characteristics in 7–10-year-old children (8 girls and 22 boys) having difficulties with voluntary regulation of activity after 10 and 20 neurofeedback sessions using beta-activating training. Brain bioelectric activity was recorded in 16 standard leads using the Neuron-Spectrum-4/VPM complex. The dynamics was assessed by EEG beta and theta bands during neurofeedback. An increase in the total power of beta band oscillations was established both after 10 and after 20 sessions of EEG biofeedback in the frontal (p ≤ 0.001), left parietal (p ≤ 0.036), and temporal (p ≤ 0.003) areas of the brain. A decrease in the spectral characteristics of theta band oscillations was detected: after 10 neurofeedback sessions in the frontal (p ≤ 0.008) and temporal (p ≤ 0.006) areas of both hemispheres, as well as in the parietal area of the left hemisphere (p ≤ 0.005); after 20 sessions, in the central (p ≤ 0.004), frontal (p ≤ 0.001) and temporal (p ≤ 0.001) areas of both hemispheres, as well as in the occipital (p ≤ 0.047) and parietal (p ≤ 0.001) areas of the left hemisphere. The study into the dynamics of bioelectric activity during biofeedback using EEG parameters in 7–10-year-old children with impaired voluntary regulation of higher mental functions allowed us to prove the advisability of 20 sessions, as the increase in high-frequency activity and decrease in low-frequency activity do not stop with the 10th session. Changes in these parameters after 10 EEG biofeedback sessions are expressed mainly in the frontotemporal areas of both hemispheres, while after a course of 20 sessions, in both the frontotemporal and central parietal areas of the brain.

scholarly journals Toward asleep DBS: cortico-basal ganglia spectral and coherence activity during interleaved propofol/ketamine sedation mimics NREM/REM sleep activity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jing Guang ◽  
Halen Baker ◽  
Orilia Ben-Yishay Nizri ◽  
Shimon Firman ◽  
Uri Werner-Reiss ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Rem Sleep ◽  
Standard Procedure ◽  
Low Frequency ◽  
Nrem Sleep ◽  
Sleep Cycle ◽  
Advanced Parkinson’S Disease ◽  
Low Frequency Power ◽  
The Brain ◽  
Frequency Power

AbstractDeep brain stimulation (DBS) is currently a standard procedure for advanced Parkinson’s disease. Many centers employ awake physiological navigation and stimulation assessment to optimize DBS localization and outcome. To enable DBS under sedation, asleep DBS, we characterized the cortico-basal ganglia neuronal network of two nonhuman primates under propofol, ketamine, and interleaved propofol-ketamine (IPK) sedation. Further, we compared these sedation states in the healthy and Parkinsonian condition to those of healthy sleep. Ketamine increases high-frequency power and synchronization while propofol increases low-frequency power and synchronization in polysomnography and neuronal activity recordings. Thus, ketamine does not mask the low-frequency oscillations used for physiological navigation toward the basal ganglia DBS targets. The brain spectral state under ketamine and propofol mimicked rapid eye movement (REM) and Non-REM (NREM) sleep activity, respectively, and the IPK protocol resembles the NREM-REM sleep cycle. These promising results are a meaningful step toward asleep DBS with nondistorted physiological navigation.

scholarly journals Simultaneous Cranioplasty and External Ventricular Drain Implantation in Patients with Hydrocephalus: Case Series and Literature Review

2021 ◽  
Author(s):  
Lívio Pereira de Macêdo ◽  
Arlindo Ugulino Netto ◽  
Kauê Franke ◽  
Pierre Vansant Oliveira Eugenio ◽  
John Anderson da Silva Rocha ◽  
...  
Keyword(s):  
External Ventricular Drain ◽  
Neurological Complication ◽  
Case Series ◽  
Neurological Deficits ◽  
Time Interval ◽  
Automobile Accidents ◽  
Decompressive Hemicraniectomy ◽  
Cerebral Herniation ◽  
Intraoperative Period ◽  
The Brain

Abstract Introduction The increase in intracranial pressure (ICP) is a neurological complication resulting from numerous pathologies that affect the brain and its compartments. Therefore, decompressive craniectomy (DC) is an alternative adopted to reduce ICP in emergencies, especially in cases refractory to clinical therapies, in favor of patient survival. However, DC is associated with several complications, including hydrocephalus (HC). The present study presents the results of an unusual intervention to this complication: the implantation of an external ventricular drain (EVD) in the intraoperative period of cranioplasty (CP). Methods Patients of both genders who presented with HC and externalization of the brain through the cranial vault after decompressive hemicraniectomy and underwent EVD implantation, to allow the CP procedure, in the same surgical procedure, were included. Results Five patients underwent DC due to a refractory increase in ICP, due to automobile accidents, firearm projectiles, falls from stairs, and ischemic strokes. All evolved with HC. There was no uniform time interval between DC and CP. The cerebrospinal fluid (CSF) was drained according to the need for correction of cerebral herniation in each patient, before undergoing cranioplasty. All patients progressed well, without neurological deficits in the immediate postoperative period. Conclusion There are still several uncertainties about the management of HC resulting from DC. In this context, other CP strategies simultaneous to the drainage of CSF, not necessarily related to ventriculoperitoneal shunt (VPS), should be considered and evaluated more deeply, in view of the verification of efficacy in procedures of this scope, such as the EVD addressed in this study.

Utility of CT perfusion scanning in patient selection for acute stroke intervention: experience at University at Buffalo Neurosurgery–Millard Fillmore Gates Circle Hospital

2011 ◽  
Vol 30 (6) ◽  
pp. E4 ◽  
Author(s):  
Peter T. Kan ◽  
Kenneth V. Snyder ◽  
Parham Yashar ◽  
Adnan H. Siddiqui ◽  
L. Nelson Hopkins ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Patient Selection ◽  
Ct Perfusion ◽  
Brain Parenchyma ◽  
National Institutes Of Health ◽  
Time Interval ◽  
Case Examples ◽  
Flow Parameters ◽  
Selection For ◽  
The Brain

Computed tomography perfusion scanning generates physiological flow parameters of the brain parenchyma, allowing differentiation of ischemic penumbra and core infarct. Perfusion maps, along with the National Institutes of Health Stroke Scale score, are used as the bases for endovascular stroke intervention at the authors' institute, regardless of the time interval from stroke onset. With case examples, the authors illustrate their perfusion-based imaging guidelines in patient selection for endovascular treatment in the setting of acute stroke.

scholarly journals Imaging angiogenesis using 68Ga-NOTA-PRGD2 positron emission tomography/computed tomography in patients with severe intracranial atherosclerotic disease

2017 ◽  
Vol 37 (10) ◽  
pp. 3401-3408 ◽  
Author(s):  
Shi Shu ◽  
Li Zhang ◽  
Yi Cheng Zhu ◽  
Fang Li ◽  
Li Ying Cui ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Emission Tomography ◽  
Time Interval ◽  
Arterial Lesion ◽  
Event Time ◽  
Intracranial Atherosclerotic Disease ◽  
Positron Emission ◽  
Recent Group ◽  
The Brain

Angiogenesis is a critical compensation route, which has been demonstrated in the brain following ischemic stroke; however, few studies have investigated angiogenesis in chronic intracranial atherosclerosis disease (ICAD). We used 68Ga-NOTA-PRGD2 positron emission tomography/computed tomography based imaging to detect angiogenesis in chronic ICAD and to explore the factors that may have affected it. A total of 21 participants with unilateral severe chronic ICAD were included in the study. Of the 21 participants, 19 were men; the mean (SD) age was 52 (15) years. In 18 participants, we observed elevated 68Ga-NOTA-PRGD2 uptake in the peri-infarct, subcortical, and periventricular regions of the lesioned side, with a higher 68Ga-NOTA-PRGD2 SUVmax compared to that in the contralateral hemisphere (0.15 vs. 0.06, p=0.001). The 18F-FDG PET SUVmax was significantly lower on the lesioned side (11.28 vs. 13.92, p=0.001). Subgroup analyses revealed that the recent group (<6 months) had a higher lesion-to-contralateral region ratio SUVmax than the remote group (>6 months) (6.73 vs. 2.36, p<0.05). Our results provide molecular imaging evidence of angiogenesis in patients with severe chronic ICAD. Furthermore, the extent of angiogenesis in chronic ICAD may be affected by the post-qualified event time interval, and not by infarction itself or the severity of the arterial lesion.

scholarly journals THE PROBABLE NATURE OF THE INFECTIOUS AGENT OF TRACHOMA

1937 ◽  
Vol 65 (5) ◽  
pp. 735-755 ◽  
Author(s):  
L. A. Julianelle ◽  
R. W. Harrison ◽  
M. C. Morris
Keyword(s):  
Tissue Culture ◽  
Gentian Violet ◽  
Infectious Agent ◽  
Heat Inactivation ◽  
Time Interval ◽  
General Observation ◽  
Specific Reaction ◽  
Rare Occasion ◽  
Probable Nature ◽  
The Brain

1. The infectious agent of trachoma can be freed from extraneous bacteria by passage through rabbit testicle. 2. The infectious agent multiplies little, if at all, during such passage, but in many instances retains its infectivity undiminished. 3. No specific changes occur in the rabbit testicle incidentally to the passage. 4. On rare occasion the trachoma agent may be freed from bacteria by intracerebral passage. The brain tissues show no specific reaction. 5. Filtration experiments with Seitz, Kramer, Berkefeld, and Elford filters confirm the general observation that the infectious agent is filterable with difficulty. 6. Tissue culture experiments, with tissues containing the infectious agent (conjunctiva, rabbit testicle, brain, etc.), conducted under a wide variety of conditions, proved uniformly unsuccessful in the cultivation of the agent. 7. The agent is inactivated by bile, AgNO3, phenol, cocaine, tartar emetic, and gentian violet. Its heat inactivation temperature is between 45° and 50°C., at a time interval of 15 minutes. 8. Attempts to preserve the infectious agent in glycerine were unsuccessful. 9. The accumulated evidence suggests that the infectious agent of trachoma is a virus.

Experimental Third Ventriculostomy Performed Using Endovascular Surgical Techniques and Their Adaptation to Percutaneous Intradural Neuronavigation: Proof of Concept Cadaver Study

Neurosurgery ◽  
2003 ◽  
Vol 53 (2) ◽  
pp. 387-392 ◽  
Author(s):  
Michael B. Horowitz ◽  
Kamal Ramzipoor ◽  
Ajit Nair ◽  
Susan Miller ◽  
George Rappard ◽  
...  
Keyword(s):  
Third Ventricle ◽  
Surgical Techniques ◽  
Cadaver Study ◽  
Brain Parenchyma ◽  
Third Ventriculostomy ◽  
General Anesthetic ◽  
The Third ◽  
Noncommunicating Hydrocephalus ◽  
Pass Through ◽  
The Brain

Abstract OBJECTIVE Endoscopic third ventriculostomy has developed into a therapeutic alternative to shunting for the management of carefully selected patients with primarily noncommunicating hydrocephalus. This procedure, however, requires a general anesthetic and necessitates violation of the brain parenchyma and manipulation near vital neural structures to access the floor of the third ventricle. Using two cadavers and off-the-shelf angiographic catheters, we sought to determine whether it was possible to navigate a catheter, angioplasty balloon, and stent percutaneously through the subarachnoid space from the thecal sac into the third ventricle so as to perform a third ventriculostomy from below. METHODS Using biplane angiography and off-the-shelf angiographic catheters along with angioplasty balloons and stents, we were able to pass a stent coaxially from the thecal sac to and across the floor of the third ventricle so as to achieve a third ventriculostomy from below. RESULTS Coaxial catheter techniques allowed for the percutaneous insertion of a stent across the floor of the third ventricle. Ventriculostomy was confirmed by injecting contrast medium into the lateral ventricle and seeing it pass through the stent and into the chiasmatic cistern. CONCLUSION We describe the performance of third ventriculostomies in two cadavers by use of the new concept of percutaneous intradural neuronavigation. This procedure may obviate the need for general anesthetic and minimize the potential for brain and vascular injury, especially if ultimately combined with magnetic resonance fluoroscopy.

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