Faculty Opinions recommendation of Hippocampal sharp waves and reactivation during awake states depend on repeated sequential experience.

Author(s):  
James Knierim
Keyword(s):  
1999 ◽  
Vol 30 (3) ◽  
pp. 114-117 ◽  
Author(s):  
Marcia Ribeiro ◽  
E. Niedermeyer ◽  
Sharon Hertz
Keyword(s):  

1991 ◽  
Vol 11 (5) ◽  
pp. 779-785 ◽  
Author(s):  
Daisuke Uematsu ◽  
Joel H. Greenberg ◽  
Nobuo Araki ◽  
Martin Reivich

The effects of the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 and the dihydropyridine calcium antagonist nimodipine on NMDA-induced phenomena were investigated using an in vivo fluorometric technique with indo-1. Indo-1, a fluorescent cytosolic free calcium ([Ca2+]i) indicator, was loaded into the cat cortex approximately 500 μm in depth by super-fusion with the membrane-permeant indo-1 acetoxymethyl ester (indo-1-AM). Changes in [Ca2+]i signals (400 and 506 nm) and reduced nicotinamide adenine dinucleotide (NADH) fluorescence (464 nm) were simultaneously measured directly from the cortex during ultraviolet excitation (340 nm). Superfusion of 100 μM NMDA over the exposed cortex induced an elevation of the [Ca2+]i signal ratio (400/506 nm), biphasic changes in NAD/NADH redox state (initial oxidation followed by progressive reduction), and characteristic changes in the EEG (abrupt depression in amplitude followed by an excitatory pattern of 18–22 Hz poly spikes or sharp waves). These changes were completely blocked by treatment with MK-801 and reduced by nimodipine. The mechanism underlying the protective effects of systemically administered MK-801 on the NMDA-induced neuronal injury was verified in vivo.


Vestnik ◽  
2021 ◽  
pp. 46-50
Author(s):  
Д.А. Митрохин ◽  
М.М. Ибрагимов ◽  
А.Н. Симбинова ◽  
Н.Ш. Буйракулова ◽  
В.В. Харченко ◽  
...  

В остром и раннем восстановительном периодах церебрального инсульта взаимосвязь между биоэлектрической активностью головного мозга и клинической картиной заболевания представляют значительный научный и практический интерес. В данной статье, представлены результаты исследования клинико-неврологических и электроэнцефалографических показателей, в остром и раннем восстановительном периодах церебрального инсульта, 67 больных в возрасте от 43 до 78 лет. Показано, что у больных в остром и раннем восстановительном периодах церебрального инсульта на фоне двигательных и речевых расстройств, наблюдались легкие и умеренные когнитивные нарушения, а также тревожно-депрессивные проявления. Головная боль, соответствующая критериям головной боли напряжения отмечалась у 61,1% больных. Биоэлектрическая активность головного мозга характеризовалась выраженной дельта и тета активностью, а также единичными острыми волнами, спайками, преимущественно в пораженном полушарии головного мозга, межполушарной асимметрией, повышением мощности спектров в сторону преобладания медленных волн. Показатели индекса когерентности по всем отведениям были снижены, что свидетельствует о нарушении функциональных межполушарных взаимосвязей. Более значительное повышение индекса когерентности в дельта и тета диапазонах у пациентов, перенесших геморрагический инсульт, может указывать на более грубые межполушарные нарушения, в сравнении с ишемическим инсультом. In the acute and early recovery periods of cerebral stroke, the correlation between bioelectrical activity of the brain and the clinical picture of the disease is of considerable scientific and practical interest. This article presents the results of a study of clinical, neurological and electroencephalographic parameters, in the acute and early recovery periods of cerebral stroke, in 67 patients aged from 43 to 78. Mild and moderate cognitive impairment as well as anxiety and depressive manifestations were shown among patients in the acute and early recovery periods of cerebral stroke amid the motor and speech disorders. Headache meeting the criteria of tension headache was reported among 61,1% of patients. The bioelectrical activity of the brain was characterised by marked delta and theta activity as well as single sharp waves, commissures mainly in the affected cerebral hemisphere, interhemispheric asymmetry and by increase in the spectrum power towards the predominance of slow waves. The coherence index scores were decreased on all directions, indicating impaired functional interhemispheric connectivity. A greater increase in coherence index in the delta and theta bands among haemorrhagic stroke patients may indicate more severe interhemispheric disturbances compared to ischaemic stroke.


2011 ◽  
Vol 69 (4) ◽  
pp. 648-653 ◽  
Author(s):  
Soniza Vieira Alves-Leon ◽  
Renata Gomes Nunes ◽  
Maria Emilia Cosenza Andraus ◽  
José Carlos Biagini Junior ◽  
Marta Hemb ◽  
...  

This study intended to investigate the clinical and electroencephalographic benign occipital epilepsy of childhood (BOEC) characteristics in a population sample of patients from two tertiary Brazilian hospitals. We analyzed retrospectively 4912 electroencephalograms (EEGs) records, and the included patients were submitted to a new clinical and EEG evaluation. Were included 12 (0.92%) patients; 4 (33.3%) with criteria for early BOEC; 6 (50%) for late form and 2 (16.7%) with superimposed early and late onset forms. After new investigation, 2 (16.7%) had normal EEG; 4 (33.3%) had paroxysms over the occipital region; 3 (25%) over the temporal posterior regions and 3 (25%) over the posterior regions. Sharp waves were the predominant change, occurring in 8 (66.6%); spike and slow wave complexes in 1 (8.3%) and sharp and slow wave complexes in 1 (8.3%). Vomiting, headache and visual hallucinations were the most common ictal manifestations, presented in 100% of patients with superimposed forms. Vomiting were absent in the late form and headache was present in all forms of BOEC.


2008 ◽  
Vol 25 (5) ◽  
pp. 250-254 ◽  
Author(s):  
Gerhard Bauer ◽  
Richard Bauer ◽  
Judith Dobesberger ◽  
Iris Unterberger ◽  
Martin Ortler ◽  
...  

2005 ◽  
Vol 385 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Laura Lee Colgin ◽  
Yousheng Jia ◽  
Jean-Marc Sabatier ◽  
Gary Lynch

1997 ◽  
Vol 273 (3) ◽  
pp. R911-R919 ◽  
Author(s):  
J. A. Fernandes ◽  
P. L. Lutz ◽  
A. Tannenbaum ◽  
A. T. Todorov ◽  
L. Liebovitch ◽  
...  

The anoxia-tolerant turtle brain slowly undergoes a complex sequence of changes in electroencephalogram (EEG) activity as the brain systematically downregulates its energy demands. Following N2 respiration, the root mean square voltage rapidly fell, reaching approximately 20% of normoxic levels after approximately 100 min of anoxia. During the first 20- to 40-min transition period, the power of the EEG decreased substantially, particularly in the 12- to 24-Hz band, with low-amplitude slow wave activity predominating (3-12 Hz). Bursts of high voltage rhythmic slow (approximately 3-8 Hz) waves were seen during the 20- to 100-min period of anoxia, accompanied by large sharp waves. During the next 400 min of N2 respiration, two distinct patterns of electrical activity characterized the anoxic turtle brain: 1) a sustained but depressed activity level, with an EEG amplitude approximately 20% of the normoxic control and with total EEG power reduced by one order of magnitude at all frequencies, and 2) short (3-15 s) periodic (0.5-2/min) bursts of mixed-frequency activity that interrupted the depressed activity state. We speculate that the EEG patterns seen during sustained anoxia represent the minimal or basic electrical activities that are compatible with the survival of the anoxic turtle brain as an integrated unit, which allow the brain to return to normal functioning when air respiration resumed.


2021 ◽  
pp. 181-183
Author(s):  
Andrew McKeon

A 21-year-old woman with a long-standing history of migraine sought care at her local provider for a 1-week history of confusion and mixing up her words. She then had a witnessed seizure, with dyscognitive features and secondary generalization. On hospitalization, electroencephalography demonstrated left temporal theta slowing and sharp waves. Magnetic resonance imaging showed patchy T2-signal abnormality, nonenhancing, in the left temporal region (only a report was available). Thyroid peroxidase antibodies were increased at 271 IU/mL. A diagnosis of an autoimmune encephalopathy was made, and the patient was treated with phenytoin, levetiracetam, and high-dose corticosteroids, followed by a slow oral prednisone taper. The patient improved cognitively but had considerable emotional lability and an increase in headache frequency and severity and, thus, sought a second opinion. Blood was drawn for genetic testing. The patient died in her sleep a short time later, most likely in the context of sudden unexplained death in epilepsy. Her genetic testing results became available 1 month later, which showed findings consistent with MELAS syndrome: heteroplasmic sequence variation m.3243A>G (tRNA Leu) and homoplasmic rare variant m.2294A>G (16S rRNA). Encephalopathy or encephalitis of subacute onset with fluctuating course is not unique to autoimmune encephalitis. Common acquired metabolic disorders must be considered and excluded in all cases, such as deficiencies of vitamin B12 and folate, hypothyroidism, sepsis, and central nervous system–active medications.


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