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Tidsskrift For Den Norske Laegeforening... Jan 2023The temporal lobes are the part of the brain most likely to give rise to epileptic seizures. Seizures originating in the temporal lobes vary greatly in character; some...
The temporal lobes are the part of the brain most likely to give rise to epileptic seizures. Seizures originating in the temporal lobes vary greatly in character; some may be so unusual that they are not even recognised as epileptic. For patients who have been diagnosed with hippocampal sclerosis and whose seizures cannot be controlled with drugs, epilepsy surgery may be a good treatment option. In this brief clinical review, we summarise the key features of epilepsy and highlight the importance of accurate and early diagnosis for achieving good clinical outcomes.
Topics: Humans; Epilepsy, Temporal Lobe; Seizures; Epilepsy; Temporal Lobe; Brain; Hippocampus; Electroencephalography
PubMed: 36718887
DOI: 10.4045/tidsskr.22.0369 -
Epilepsia Feb 2020Mesial temporal lobe epilepsy (mTLE) is a neurological disorder in which patients suffer from frequent consciousness-impairing seizures, broad neurocognitive deficits,... (Review)
Review
Mesial temporal lobe epilepsy (mTLE) is a neurological disorder in which patients suffer from frequent consciousness-impairing seizures, broad neurocognitive deficits, and diminished quality of life. Although seizures in mTLE originate focally in the hippocampus or amygdala, mTLE patients demonstrate cognitive deficits that extend beyond temporal lobe function-such as decline in executive function, cognitive processing speed, and attention-as well as diffuse decreases in neocortical metabolism and functional connectivity. Given prior observations that mTLE patients exhibit impairments in vigilance, and that seizures may disrupt the activity and long-range connectivity of subcortical brain structures involved in vigilance regulation, we propose that subcortical activating networks underlying vigilance play a critical role in mediating the widespread neural and cognitive effects of focal mTLE. Here, we review evidence for impaired vigilance in mTLE, examine clinical implications and potential network underpinnings, and suggest neuroimaging strategies for determining the relationship between vigilance, brain connectivity, and neurocognition in patients and healthy controls.
Topics: Arousal; Brain Mapping; Epilepsy, Temporal Lobe; Humans; Nerve Net; Neuroimaging
PubMed: 31901182
DOI: 10.1111/epi.16423 -
Nature Communications Oct 2020Epilepsy is one of the most common neurological disorders, yet its pathophysiology is poorly understood due to the high complexity of affected neuronal circuits. To...
Epilepsy is one of the most common neurological disorders, yet its pathophysiology is poorly understood due to the high complexity of affected neuronal circuits. To identify dysfunctional neuronal subtypes underlying seizure activity in the human brain, we have performed single-nucleus transcriptomics analysis of >110,000 neuronal transcriptomes derived from temporal cortex samples of multiple temporal lobe epilepsy and non-epileptic subjects. We found that the largest transcriptomic changes occur in distinct neuronal subtypes from several families of principal neurons (L5-6_Fezf2 and L2-3_Cux2) and GABAergic interneurons (Sst and Pvalb), whereas other subtypes in the same families were less affected. Furthermore, the subtypes with the largest epilepsy-related transcriptomic changes may belong to the same circuit, since we observed coordinated transcriptomic shifts across these subtypes. Glutamate signaling exhibited one of the strongest dysregulations in epilepsy, highlighted by layer-wise transcriptional changes in multiple glutamate receptor genes and strong upregulation of genes coding for AMPA receptor auxiliary subunits. Overall, our data reveal a neuronal subtype-specific molecular phenotype of epilepsy.
Topics: Adolescent; Adult; Biopsy; Case-Control Studies; Cell Nucleus; Datasets as Topic; Drug Resistant Epilepsy; Epilepsy, Temporal Lobe; Female; Glutamic Acid; Humans; Magnetic Resonance Imaging; Male; Microdissection; Middle Aged; Models, Genetic; Nerve Net; Neurons; RNA-Seq; Receptors, AMPA; Receptors, Glutamate; Signal Transduction; Single-Cell Analysis; Temporal Lobe; Transcription, Genetic; Transcriptome; Up-Regulation; Young Adult
PubMed: 33028830
DOI: 10.1038/s41467-020-18752-7 -
Neurosciences (Riyadh, Saudi Arabia) Jul 2015The relationship of the occipital lobe of the brain with schizophrenia is not commonly studied; however, this topic is considered an essential subject matter among... (Review)
Review
The relationship of the occipital lobe of the brain with schizophrenia is not commonly studied; however, this topic is considered an essential subject matter among clinicians and scientists. We conducted this systematic review to elaborate the relationship in depth. We found that most schizophrenic patients show normal occipital anatomy and physiology, a minority showed dwindled values, and some demonstrated augmented function and structure. The findings are laborious to incorporate within single disease models that present the involvement of the occipital lobe in schizophrenia. Schizophrenia progresses clinically in the mid-twenties and thirties and its prognosis is inadequate. Changes in the volume, the gray matter, and the white matter in the occipital lobe are quite evident; however, the mechanism behind this involvement is not yet fully understood. Therefore, we recommend further research to explore the occipital lobe functions and volumes across the different stages of schizophrenia.
Topics: Humans; Magnetic Resonance Imaging; Occipital Lobe; Schizophrenia
PubMed: 26166588
DOI: 10.17712/nsj.2015.3.20140757 -
International Journal of Molecular... Dec 2020Neurosteroids are a family of compounds that are synthesized in principal excitatory neurons and glial cells, and derive from the transformation of cholesterol into... (Review)
Review
Neurosteroids are a family of compounds that are synthesized in principal excitatory neurons and glial cells, and derive from the transformation of cholesterol into pregnenolone. The most studied neurosteroids-allopregnanolone and allotetrahydrodeoxycorticosterone (THDOC)-are known to modulate GABA receptor-mediated transmission, thus playing a role in controlling neuronal network excitability. Given the role of GABA signaling in epileptic disorders, neurosteroids have profound effects on seizure generation and play a role in the development of chronic epileptic conditions (i.e., epileptogenesis). We review here studies showing the effects induced by neurosteroids on epileptiform synchronization in in vitro brain slices, on epileptic activity in in vivo models, i.e., in animals that were made epileptic with chemoconvulsant treatment, and in epileptic patients. These studies reveal that neurosteroids can modulate ictogenesis and the occurrence of pathological network activity such as interictal spikes and high-frequency oscillations (80-500 Hz). Moreover, they can delay the onset of spontaneous seizures in animal models of mesial temporal lobe epilepsy. Overall, this evidence suggests that neurosteroids represent a new target for the treatment of focal epileptic disorders.
Topics: Animals; Anticonvulsants; Brain Waves; Epilepsy, Temporal Lobe; Humans; Neurosteroids; Synaptic Transmission
PubMed: 33321734
DOI: 10.3390/ijms21249391 -
Insights Into Imaging Apr 2016The temporal lobes have unique architecture, and functionality that makes them vulnerable to certain disease processes. Patients presenting with bilateral temporal lobe... (Review)
Review
UNLABELLED
The temporal lobes have unique architecture, and functionality that makes them vulnerable to certain disease processes. Patients presenting with bilateral temporal lobe disease are often confused and have altered consciousness, and are therefore unable to provide cogent histories. For these reasons, imaging plays an important role in their workup and management. Disease entities causing bilateral temporal lobe involvement can be infectious, metabolic, neoplastic, and degenerative aetiologies, as well as trauma and cerebrovascular events. We will first describe the structural and functional anatomy of the temporal lobes and explain the mechanisms that underlie bilateral temporal lobe disease, and then show and discuss the different disease entities and differential diagnosis.
TEACHING POINTS
• Bilateral temporal lobe disease is a unique pattern with specific differential diagnosis. • Patients presenting with bilateral temporal lobe disease are often confused. • Radiologists should be familar with the variety of disease processes that cause bitemporal disease.
PubMed: 26911968
DOI: 10.1007/s13244-016-0481-x -
Epilepsy & Behavior : E&B Dec 2019Careful study of the clinical outcomes of temporal lobe epilepsy (TLE) surgery has greatly advanced our knowledge of the neuroanatomy of human memory. After early cases... (Review)
Review
Careful study of the clinical outcomes of temporal lobe epilepsy (TLE) surgery has greatly advanced our knowledge of the neuroanatomy of human memory. After early cases resulted in profound amnesia, the critical role of the hippocampus and associated medial temporal lobe (MTL) structures to declarative memory became evident. Surgical approaches quickly changed to become unilateral and later, to be more precise, potentially reducing cognitive morbidity. Neuropsychological studies following unilateral temporal lobe resection (TLR) have challenged early models, which simplified the lateralization of verbal and visual memory function. Diagnostic tests, including intracarotid sodium amobarbital procedure (WADA), structural magnetic resonance imaging (MRI), and functional neuroimaging (functional MRI (fMRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT)), can more accurately lateralize and localize epileptogenic cortex and predict memory outcomes from surgery. Longitudinal studies have shown that memory may even improve in seizure-free patients. From 70 years of experience with epilepsy surgery, we now have a richer understanding of the clinical, neuroimaging, and surgical predictors of memory decline-and improvement-after TLR. "Special Issue: Epilepsy & Behavior's 20th Anniversary".
Topics: Cerebral Cortex; Cognition; Epilepsy, Temporal Lobe; Hippocampus; Humans; Longitudinal Studies; Magnetic Resonance Imaging; Memory; Memory Disorders; Seizures; Temporal Lobe; Tomography, Emission-Computed, Single-Photon
PubMed: 31711868
DOI: 10.1016/j.yebeh.2019.106596