The Brain Topography Associated with High versus Low Contextual Constraint in Dominant Temporal Lobe Resected Patients: Potential Reorganization of Lexical Access

Cats, similar to humans, are known to be affected by hippocampal sclerosis (HS), potentially causing antiepileptic drug (AED) resistance. HS can occur as a consequence of chronic seizure activity, trauma, inflammation, or even as a primary disease. In humans, temporal lobe resection is the standardized therapy in patients with refractory temporal lobe epilepsy (TLE). The majority of TLE patients are seizure free after surgery. Therefore, the purpose of this prospective cadaveric study is to establish a surgical technique for hippocampal resection in cats as a treatment for AED resistant seizures. Ten cats of different head morphology were examined. Pre-surgical magnetic resonance imaging (MRI) and computed tomography (CT) studies of the animals’ head were carried out to complete 3D reconstruction of the head, brain, and hippocampus. The resected hippocampal specimens and the brains were histologically examined for tissue injury adjacent to the hippocampus. The feasibility of the procedure, as well as the usability of the removed specimen for histopathological examination, was assessed. Moreover, a micro-CT (mCT) examination of the brain of two additional cats was performed in order to assess temporal vasculature as a reason for possible intraoperative complications. In all cats but one, the resection of the temporal cortex and the hippocampus were successful without any evidence of traumatic or vascular lesions in the surrounding neurovascular structures. In one cat, the presence of mechanical damage (a fissure) of the thalamic surface was evident in the histopathologic examination of the brain post-resection. All hippocampal fields and the dentate gyrus were identified in the majority of the cats via histological examination. The study describes a new surgical approach (partial temporal cortico-hippocampectomy) offering a potential treatment for cats with clinical and diagnostic evidence of temporal epilepsy which do not respond adequately to the medical therapy.

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Induction of the Nrf2 Pathway by Sulforaphane Is Neuroprotective in a Rat Temporal Lobe Epilepsy Model

Antioxidants ◽

10.3390/antiox10111702 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1702

Author(s):

Sereen Sandouka ◽

Tawfeeq Shekh-Ahmad

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Status Epilepticus ◽

Temporal Lobe Epilepsy ◽

Antioxidant Capacity ◽

Temporal Lobe ◽

Epileptiform Activity ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

The Brain

Epilepsy is a chronic disease of the brain that affects over 65 million people worldwide. Acquired epilepsy is initiated by neurological insults, such as status epilepticus, which can result in the generation of ROS and induction of oxidative stress. Suppressing oxidative stress by upregulation of the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown to be an effective strategy to increase endogenous antioxidant defences, including in brain diseases, and can ameliorate neuronal damage and seizure occurrence in epilepsy. Here, we aim to test the neuroprotective potential of a naturally occurring Nrf2 activator sulforaphane, in in vitro epileptiform activity model and a temporal lobe epilepsy rat model. Sulforaphane significantly decreased ROS generation during epileptiform activity, restored glutathione levels, and prevented seizure-like activity-induced neuronal cell death. When given to rats after 2 h of kainic acid-induced status epilepticus, sulforaphane significantly increased the expression of Nrf2 and related antioxidant genes, improved oxidative stress markers, and increased the total antioxidant capacity in both the plasma and hippocampus. In addition, sulforaphane significantly decreased status epilepticus-induced neuronal cell death. Our results demonstrate that Nrf2 activation following an insult to the brain exerts a neuroprotective effect by reducing neuronal death, increasing the antioxidant capacity, and thus may also modify epilepsy development.

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Magnetic resonance spectroscopy of the brain in the diagnosis of temporal lobe epilepsy

Neurology neuropsychiatry Psychosomatics ◽

10.14412/2074-2711-2018-1s-51-55 ◽

2018 ◽

Vol 10 (1S) ◽

pp. 51-55

Author(s):

E. S. Solomatova ◽

N. A. Shnaider ◽

A. A. Molgachev ◽

D. V. Dmitrenko ◽

I. G. Strotskaya

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

English Language ◽

Russian Language ◽

Resonance Spectroscopy ◽

Epileptogenic Focus ◽

Patients With Epilepsy ◽

The Brain

The temporal lobe is the most epileptogenic region of the brain. 90% of patients with temporal ictal epileptomorphic EEG activity have a variable long history of seizures. Magnetic resonance spectroscopy (MRS) may be useful in identifying an epileptogenic focus in patients with epilepsy without apparent structural pathology at neuroimaging.Objective: to systematize the results of early studies on this issue.Materials and methods. An electronic search was carried out in two English-language (Medline, PubMed) and one Russian-language (eLIBRARY.RU) databases. The search queries found 18,019 citations, by which 12 full-text articles were selected.Results and discussion. The main criteria for the diagnosis of temporal lobe epilepsy by MRS is to lower the level of N-acetylaspartate (NAA), the ratio of NAA to creatinine + choline (NAA/(Cr + Cho) in the brain region where there is neuronal death or damage, as well as a change in the level of myo-inositol, the elevated level of which indicates the presence of an epileptogenic focus, while the decreased one shows the spread of pathological activity to the adjacent tissues.Conclusion. This review will contribute to a better diagnosis of temporal lobe epilepsy, as well as to the intravital noninvasive detection of metabolic changes in the brain long before the development of structural pathology.

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Characterization of postsurgical functional connectivity changes in temporal lobe epilepsy

Journal of Neurosurgery ◽

10.3171/2019.3.jns19350 ◽

2020 ◽

Vol 133 (2) ◽

pp. 392-402 ◽

Cited By ~ 3

Author(s):

Victoria L. Morgan ◽

Baxter P. Rogers ◽

Hernán F. J. González ◽

Sarah E. Goodale ◽

Dario J. Englot

Keyword(s):

Functional Connectivity ◽

Temporal Lobe ◽

Network Connectivity ◽

Temporal Lobectomy ◽

Seizure Outcome ◽

Seizure Recurrence ◽

Female Age ◽

Selective Amygdalohippocampectomy ◽

The Brain

OBJECTIVESeizure outcome after mesial temporal lobe epilepsy (mTLE) surgery is complex and diverse, even across patients with homogeneous presurgical clinical profiles. The authors hypothesized that this is due in part to variations in network connectivity across the brain before and after surgery. Although presurgical network connectivity has been previously characterized in these patients, the objective of this study was to characterize presurgical to postsurgical functional network connectivity changes across the brain after mTLE surgery.METHODSTwenty patients with drug-refractory unilateral mTLE (5 left side, 10 female, age 39.3 ± 13.5 years) who underwent either selective amygdalohippocampectomy (n = 13) or temporal lobectomy (n = 7) were included in the study. Presurgical and postsurgical (36.6 ± 14.3 months after surgery) functional connectivity (FC) was measured with 3-T MRI and compared with findings in age-matched healthy controls (n = 44, 21 female, age 39.3 ± 14.3 years). Postsurgical connectivity changes were then related to seizure outcome, type of surgery, and presurgical disease parameters.RESULTSThe results demonstrated significant decreases of FC from control group values across the brain after surgery that were not present before surgery, including many contralateral hippocampal connections distal to the surgical site. Postsurgical impairment of contralateral precuneus to ipsilateral occipital connectivity was associated with seizure recurrence. Presurgical impairment of the contralateral precuneus to contralateral temporal lobe connectivity was associated with those who underwent selective amygdalohippocampectomy compared to those who had temporal lobectomy. Finally, changes in thalamic connectivity after surgery were linearly related to duration of epilepsy and frequency of consciousness-impairing seizures prior to surgery.CONCLUSIONSThe widespread contralateral hippocampal FC changes after surgery may be a reflection of an ongoing epileptogenic progression that has been altered by the surgery, rather than a direct result of the surgery itself. This network evolution may contribute to long-term seizure outcome. Therefore, the combination of presurgical network mapping with the understanding of the dynamic effects of surgery on the networks may ultimately be used to create predictors of the likelihood of long-term seizure recurrence in individual patients after mTLE surgery.

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Recent developments in cognitive fMRI for temporal lobe epilepsy

Zeitschrift für Epileptologie ◽

10.1007/s10309-019-00303-w ◽

2019 ◽

Vol 33 (1) ◽

pp. 30-36 ◽

Cited By ~ 1

Author(s):

Victor Schmidbauer ◽

Silvia Bonelli

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Visual Memory ◽

Imaging Modality ◽

Memory Function ◽

Brain Regions ◽

Epileptogenic Zone ◽

Brain Areas ◽

Recent Developments ◽

The Brain

AbstractEpilepsy is frequently accompanied by severe cognitive side effects. Temporal lobe epilepsy (TLE), and even successful surgical treatment, may affect cognitive function, in particular language as well as verbal and visual memory function. Epilepsy arising from the temporal lobe can be controlled surgically in up to 70% of patients. The goals of epilepsy surgery are to remove the brain areas generating the seizures without causing or aggravating neuropsychological deficits. This requires accurate localization of the brain areas generating the seizures (“epileptogenic zone”) and the areas responsible for motor and cognitive functions, such as language and memory (“essential brain regions”) during presurgical evaluation. In the past decades, functional magnetic resonance imaging (fMRI) has been increasingly used to noninvasively lateralize and localize not only primary motor and somatosensory areas, but also brain areas that are involved in everyday language and memory processes. The imaging modality also shows potential for predicting the effects of temporal lobe resection on language and memory function. Together with other MRI modalities, cognitive fMRI is a promising tool to improve surgical strategies tailored to individual patients with regard to functional outcome, by virtue of definition of epileptic cerebral areas that need to be resected and eloquent areas that need to be spared.The aim of this review is to provide an overview of recent developments and practical recommendations for the clinical use of cognitive fMRI in TLE.

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Neuropsychological correlates of syndromes in schizophrenia

The British Journal of Psychiatry ◽

10.1192/bjp.170.2.134 ◽

1997 ◽

Vol 170 (2) ◽

pp. 134-139 ◽

Cited By ~ 65

Author(s):

Ross M. G. Norman ◽

A. K. Malla ◽

S. L. Morrison-Stewart ◽

E. Helmes ◽

P. C. Williamson ◽

...

Keyword(s):

Prefrontal Cortex ◽

Temporal Lobe ◽

Neuropsychological Tests ◽

Dorsolateral Prefrontal Cortex ◽

Neuropsychological Performance ◽

Left Temporal Lobe ◽

Impaired Performance ◽

Dorsolateral Prefrontal ◽

Reality Distortion ◽

The Brain

BackgroundOn the basis of Liddle's three-syndrome model of schizophrenia, it was predicted that: (1) symptoms of psychomotor poverty would be particularly correlated with impaired performance on neuropsychological tests likely to reflect functioning of the dorsolateral prefrontal cortex; (2) disorganisation would be particularly correlated with impaired performance on tests sensitive to medio-basal prefrontal functioning; and (3) reality distortion would be particularly correlated with measures sensitive to temporal lobe functioning.MethodThe above hypotheses were tested on 87 subjects with a confirmed diagnosis of schizophrenia. Patients' symptoms were scored for each of the three syndromes. Patients completed six neuropsychological tests designed to measure impairment in specific areas of the brain.ResultsThere was no support for the first two hypotheses. There was, however, evidence of a specific relationship between reality distortion and neuropsychological performance usually considered to be related to left temporal lobe functioning.ConclusionsAlthough not directly supporting the first two hypotheses; the results are, in general, consistent with there being different cortical-subcortical circuits associated with each of psychomotor poverty and disorganisation. Temporal lobe functioning appears to have particular significance for the reality distortion syndrome.

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Shadows in the Brain

Journal of Cognitive Neuroscience ◽

10.1162/089892903322370780 ◽

2003 ◽

Vol 15 (6) ◽

pp. 862-872 ◽

Cited By ~ 9

Author(s):

Umberto Castiello ◽

Dean Lusher ◽

Carol Burton ◽

Peter Disler

Keyword(s):

Human Brain ◽

Temporal Lobe ◽

Shape Perception ◽

Conscious Awareness ◽

Visual Neglect ◽

Object Shape ◽

Brain Injured ◽

The Right ◽

Injured Patients ◽

The Brain

The aims of the present study were to investigate whether the processing of an object shadow occurs implicitly, that is without conscious awareness, and where physically within the human brain shadows are processed. Here we present neurological evidence, obtained from studies of brain-injured patients with visual neglect, that shadows are implicitly processed and that this processing may take place within the temporal lobe. Neglect patients with lesions that do not involve the right temporal lobe were still able to process shadows to optimize object shape perception. In contrast, shadow processing was not found to be as efficient in neglect patients with lesions that involve the right temporal lobe.

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