scholarly journals Role of seizure activity within the parafascicular nucleus in cessation of respiratory rhythm and potentially SUDEP

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Andrew Tryba
Keyword(s):  
Seizure Activity ◽  
Respiratory Rhythm ◽  
Parafascicular Nucleus

scholarly journals Sudden altered mental state in the elderly: nonconvulsive status epilepticus and the role of the Emergency Department

2011 ◽  
Vol 5 (1) ◽  
pp. 15-25
Author(s):  
Rocco Galimi
Keyword(s):  
Status Epilepticus ◽  
Seizure Activity ◽  
The Elderly ◽  
Altered Mental Status ◽  
Nonconvulsive Status Epilepticus ◽  
Recurrent Seizure ◽  
Memory Problems ◽  
Altered Mental State ◽  
New Onset

In the elderly, new onset of epilepsy is often associated with vague complaints such as confusion, altered mental status, or memory problems. The absence of clinically apparent convulsions in association with an electroencephalogram showing continuous or recurrent seizure activity has been called nonconvulsive status epilepticus (NCSE). The purpose of this article is to describe the clinical and electroencephalographic features of NCSE in older adults. NCSE is an important, under-recognised and reversible cause of acute prolonged confusion. Although attempts have been made to define and classify this disorder, there is no universally accepted definition or classification yet that encompasses all subtypes or electroclinical scenarios. A urgent electroencephalogram is considered as the method of choice in the diagnostic evaluation of NCSE. Further researches are needed to better define NCSE.

Imaging the induction and spread of seizure activity in the isolated brain of the guinea pig: the roles of GABA and glutamate receptors

1996 ◽  
Vol 76 (5) ◽  
pp. 3471-3492 ◽  
Author(s):  
P. Federico ◽  
B. A. MacVicar
Keyword(s):  
Guinea Pig ◽  
Receptor Antagonist ◽  
Glutamate Receptor ◽  
Entorhinal Cortex ◽  
Seizure Activity ◽  
Olfactory Cortex ◽  
Receptor Subtypes ◽  
Amygdaloid Nucleus ◽  
Field Potentials

1. The induction and spread of seizure activity was studied using imaging and electrophysiological techniques in the isolated whole brain of the guinea pig. We examined the role of GABA and glutamate receptor subtypes in controlling the spread of seizure activity across the olfactory cortex from a focus in the entorhinal cortex. Seizure spread was monitored by video imaging of intrinsic optical signals (reflectance changes) combined with multiple extracellular recordings. Both the unilateral and bilateral spread of seizure activity was monitored in different experiments. 2. Electrical stimulation of the lateral entorhinal cortex (10-15 V, 5 Hz, 5-10 s) evoked seizure activity that originated in the entorhinal cortex/hippocampus and later spread preferentially toward the posteromedial cortical amygdaloid nucleus ipsilaterally and bilaterally. The pattern of seizure spread in a given brain was highly reproducible. 3. The influence of gamma-aminobutyric acid (GABA) receptors on the spread of seizure activity was monitored at higher resolution on one side of the brain. Perfusion of a low concentration of the GABAA antagonist bicuculline methiodide (20 microM) resulted in spontaneous seizures that spread to the posteromedial cortical amygdaloid nucleus more rapidly than electrically evoked seizures [spread times: 5.5 +/- 3.7 s vs. 15.5 +/- 2.7 s, respectively (means +/- SE)]. Seizure spread was also more extensive in the presence of bicuculline involving the posterior perirhinal cortex and larger areas over the medial amygdala. Higher concentrations of bicuculline (100 microM) resulted in even more widespread propagation of spontaneous seizure activity throughout the olfactory cortex as well as to the perirhinal, insular, and occipital cortices. This concentration of bicuculline also further reduced the time required for seizure activity to spread from the entorhinal cortex to the posteromedial cortical amygdaloid nucleus (spread time = 2.3 +/- 1.7 s). The GABAB antagonist, CGP 35348 (200 microM), in contrast, had no significant effect of seizure induction or propagation. 4. The role of glutamate receptor subtypes in seizure propagation was studied by examining the bilateral spread of seizures. Perfusion of the kainate/alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (K/A) receptor antagonist (6-cyano-7-nitroquinoxaline-2,3-dione, CNQX, 20 microM) completely and reversibly suppressed stimulus-evoked seizure activity as detected electrophysiologically and optically. CNQX also reduced the magnitudes of field potentials recorded in the isolated brain in a reversible manner by an average of 70.8 +/- 2.21% of control. The N-methyl-D-aspartate (NMDA) receptor antagonist dibenzocyclohepteneimine (MK-801) did not significantly alter the magnitudes or shapes of field potentials recorded in the isolated brain nor did it significantly alter seizure activity measured optically or electrophysiologically. 5. Perfusion of the metabotropic glutamate receptor agonist [trans-1-amino-(IS,3R)-cyclopentanedicarboxylic acid (trans-ACPD), 150 microM] completely and reversibly suppressed stimulus-evoked seizure activity as detected electrophysiologically and optically. The magnitudes of field potentials recorded in the isolated brain also were reduced by trans-ACPD an average of 75.4 +/- 5.39% of control values. 6. These results demonstrate that GABAA-mediated transmission is functionally present and may play an important role in epileptic tissue in limiting the spread of seizure activity from the entorhinal cortex to the posteromedial cortical amygdaloid nucleus and in creating functional pathways or preferential routes of seizure spread. GABAB-mediated postsynaptic inhibition played no significant role in the induction or spread of seizure activity in this study. K/A receptors but not NMDA receptors are necessary for the induction and subsequent spread of seizure activity originating in the entorhinal cortex/hippocampus.

scholarly journals Inflammasome-derived cytokine IL18 suppresses amyloid-induced seizures in Alzheimer-prone mice

2018 ◽  
Vol 115 (36) ◽  
pp. 9002-9007 ◽  
Author(s):  
Te-Chen Tzeng ◽  
Yuto Hasegawa ◽  
Risa Iguchi ◽  
Amy Cheung ◽  
Daniel R. Caffrey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Seizure Activity ◽  
Synaptic Proteins ◽  
Amyloid Peptide ◽  
Spine Density ◽  
Central Neurons ◽  
Chemically Induced ◽  
Neuronal Transmission ◽  
Selective Increase

Alzheimer’s disease (AD) is characterized by the progressive destruction and dysfunction of central neurons. AD patients commonly have unprovoked seizures compared with age-matched controls. Amyloid peptide-related inflammation is thought to be an important aspect of AD pathogenesis. We previously reported that NLRP3 inflammasome KO mice, when bred into APPswe/PS1ΔE9 (APP/PS1) mice, are completely protected from amyloid-induced AD-like disease, presumably because they cannot produce mature IL1β or IL18. To test the role of IL18, we bred IL18KO mice with APP/PS1 mice. Surprisingly, IL18KO/APP/PS1 mice developed a lethal seizure disorder that was completely reversed by the anticonvulsant levetiracetam. IL18-deficient AD mice showed a lower threshold in chemically induced seizures and a selective increase in gene expression related to increased neuronal activity. IL18-deficient AD mice exhibited increased excitatory synaptic proteins, spine density, and basal excitatory synaptic transmission that contributed to seizure activity. This study identifies a role for IL18 in suppressing aberrant neuronal transmission in AD.

Effects on respiratory pattern of focal cooling in the medulla of the dog

1988 ◽  
Vol 65 (5) ◽  
pp. 2004-2010 ◽  
Author(s):  
M. Adams ◽  
T. Chonan ◽  
N. S. Cherniack ◽  
C. von Euler
Keyword(s):  
Respiratory Rhythm ◽  
Nucleus Ambiguus ◽  
Respiratory Pattern ◽  
Respiratory Drive ◽  
Timing Effect ◽  
Diaphragm Electrical Activity ◽  
Inspiratory Activity ◽  
Ventral Medullary Surface ◽  
Focal Cooling

Studies in cats have shown that, in addition to respiratory neuron groups in the dorsomedial (DRG) and ventrolateral (VRG) medulla, neural structures in the most ventral medullary regions are important for the maintenance of respiratory rhythm. The purpose of this study was to determine whether a similar superficially located ventral region was present in the dog and to assess the role of each of the other regions in the canine medulla important in the control of breathing, in 20 anesthetized, vagotomized, and artificially ventilated dogs, a cryoprobe was used to cool selected regions of the medulla to 15-20 degrees C. Respiratory output was determined from phrenic nerve or diaphragm electrical activity. Cooling in or near the nucleus of the solitary tract altered timing and produced little change in the amplitude or rate of rise of inspiratory activity; lengthening of inspiratory time was the most common timing effect observed. Cooling in ventrolateral regions affected the amplitude and rate of rise of respiratory activity. Depression of neural tidal volume and apnea could be produced by unilateral cooling in two ventrolateral regions: 1) near the nucleus ambiguus and nucleus para-ambiguus and 2) just beneath the ventral medullary surface. These findings indicate that in the dog dorsomedial neural structures influence respiratory timing, whereas more ventral structures are important to respiratory drive.

scholarly journals Breathing with Phox2b

2009 ◽  
Vol 364 (1529) ◽  
pp. 2477-2483 ◽  
Author(s):  
Véronique Dubreuil ◽  
Jacques Barhanin ◽  
Christo Goridis ◽  
Jean-François Brunet
Keyword(s):  
Reverse Genetics ◽  
Human Genetics ◽  
Respiratory Rhythm ◽  
Neuronal Population ◽  
Cellular Level ◽  
Small Population ◽  
Respiratory Neurons ◽  
Retrotrapezoid Nucleus ◽  
Parafacial Respiratory Group

In the last few years, elucidation of the architecture of breathing control centres has reached the cellular level. This has been facilitated by increasing knowledge of the molecular signatures of various classes of hindbrain neurons. Here, we review the advances achieved by studying the homeodomain factor Phox2b , a transcriptional determinant of neuronal identity in the central and peripheral nervous systems. Evidence from human genetics, neurophysiology and mouse reverse genetics converges to implicate a small population of Phox2b -dependent neurons, located in the retrotrapezoid nucleus, in the detection of CO 2 , which is a paramount source of the ‘drive to breathe’. Moreover, the same and other studies suggest that an overlapping or identical neuronal population, the parafacial respiratory group, might contribute to the respiratory rhythm at least in some circumstances, such as for the initiation of breathing following birth. Together with the previously established Phox2b dependency of other respiratory neurons (which we review briefly here), our new data highlight a key role of this transcription factor in setting up the circuits for breathing automaticity.

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