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ABSTRACT: Infantile spasms constitute a severe epileptic encephalopathy of infancy with poor long-term developmental outcome. Many diverse etiologies have been associated with infantile spasms, but the pathophysiological process is still not fully understood. We describe 2 cases of previously healthy 1- and 3-month-old infants who suffered a nonaccidental head injury with extensive cerebral lesions. Both presented with acute focal seizures rapidly controlled with phenobarbital. Nevertheless, they developed infantile spasms after a latency period of 3-4 months. Spasms were rapidly controlled with vigabatrin. Both children manifested with developmental delay, either exacerbated (case 1) or elicited (case 2) by infantile spasms. Our report highlights nonaccidental head injury as a risk factor for developing infantile spasms following a seizure-free latency period. A better understanding of the pathophysiology linking accidental brain trauma with infantile spasms could lead to more effective neuroprotective strategies. In the meantime, increased awareness and follow-up are warranted.
Journal of child neurology 04/2013; · 1.59 Impact Factor
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Martin H Berryer,
Fadi F Hamdan,
Laura L Klitten,
Rikke S Møller, Lionel Carmant,
Jeremy Schwartzentruber,
Lysanne Patry,
Sylvia Dobrzeniecka,
Daniel Rochefort,
Mathilde Neugnot, [......],
Niels Tommerup,
Ladonna Immken,
Miriam H Beauchamp,
Gayle Simpson Patel,
Jacek Majewski,
Mark A Tarnopolsky,
Klaus Scheffzek,
Helle Hjalgrim,
Jacques L Michaud,
Graziella Di Cristo
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ABSTRACT: De novo mutations in SYNGAP1, which codes for a RAS/RAP GTP-activating protein, cause non-syndromic intellectual disability (NSID). All disease-causing point mutations identified until now in SYNGAP1 are truncating, raising the possibility of an association between this type of mutations and NSID. Here, we report the identification of the first pathogenic missense mutations (c.1084T>C [p.W362R]; c.1685C>T [p.P562L]) and three novel truncating mutations (c.283dupC [p.H95PfsX5]; c.2212_2213del [p.S738X]; (c.2184del [p.N729TfsX31]) in SYNGAP1 in patients with NSID. A subset of these patients also showed ataxia, autism, and a specific form of generalized epilepsy that can be refractory to treatment. All of these mutations occurred de novo, except c.283dupC, which was inherited from a father who is a mosaic. Biolistic transfection of wild-type SYNGAP1 in pyramidal cells from cortical organotypic cultures significantly reduced activity-dependent pERK levels. In contrast, constructs expressing p.W362R, p.P562L or the previously described p.R579X had no significant effect on pERK levels. These experiments suggest that the de novo missense mutations, p.R579X, and possibly all the other truncating mutations in SYNGAP1 result in a loss of its function. Moreover, our study confirms the involvement of SYNGAP1 in autism while providing novel insight into the epileptic manifestations associated with its disruption.
Human Mutation 11/2012; · 5.69 Impact Factor
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ABSTRACT: Purpose: To investigate spatial and metabolic changes associated with frontal lobe seizures. Methods: Functional near-infrared spectroscopy combined with electroencephalography (EEG-fNIRS) recordings of patients with confirmed nonlesional refractory frontal lobe epilepsy (FLE). Key Findings: Eighteen seizures from nine patients (seven male, mean age 27 years, range 13-46 years) with drug-refractory FLE were captured during EEG-fNIRS recordings. All seizures were coupled with significant hemodynamic variations that were greater with electroclinical than with electrical seizures. fNIRS helped in the identification of seizures in three patients with more subtle ictal EEG abnormalities. Hemodynamic changes consisted of local increases in oxygenated (HbO) and total hemoglobin (HbT) but heterogeneous deoxygenated hemoglobin (HbR) behavior. Furthermore, rapid hemodynamic alterations were observed in the homologous contralateral region, even in the absence of obvious propagated epileptic activity. The extent of HbO activation adequately lateralized the epileptogenic side in the majority of patients. Significance: EEG-fNIRS reveals complex spatial and metabolic changes during focal frontal lobe seizures. Further characterization of these changes could improve seizure detection, localization, and understanding of the impact of focal seizures.
Epilepsia 11/2012; · 3.96 Impact Factor
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ABSTRACT: Lennox-Gastaut syndrome (LGS) is a severe epileptic encephalopathy. Few current treatment options are effective in improving seizure control. This paper reviews the available treatments of LGS and discusses a new option in Canada, rufinamide. It is a wide spectrum anticonvulsant, approved in a number of countries for the treatment of LGS. In a randomized controlled trial in the LGS population, adjunctive rufinamide therapy has been shown to offer significantly greater reduction in total seizure frequency and tonic-atonic seizure frequency in comparison to placebo. Efficacy has been assessed over three years and appears to be sustained. Most adverse events were cognitive (e.g. somnolence) or gastrointestinal in nature and in many cases transient or mild. based on the efficacy and safety data on rufinamide obtained to date, this medication will provide additional benefits to patients with LGS in Canada and is an important consideration for our patients in the adjunctive treatment setting.
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 11/2012; 39(6):702-11. · 0.97 Impact Factor
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Jonathan Y Bitton,
Hannelore C Sauerwein,
Shelly K Weiss,
Elizabeth J Donner,
Sharon Whiting,
Joseph M Dooley,
Carter Snead,
Kevin Farrell,
Elaine C Wirrell,
Ismail S Mohamed,
Gabriel M Ronen,
Milagros Salas-Prato,
Devendra Amre,
Maryse Lassonde, Lionel Carmant
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ABSTRACT: Purpose: Cognitive impairment is observed commonly in children with a history of infantile spasms (IS). The goal of this study was to prospectively examine the effect on cognitive outcome of a neuroprotective agent used as adjunctive therapy during treatment of the spasms. Methods: In a randomized controlled trial, patients received a standardized therapy plus flunarizine or placebo. The standardized treatment consisted of vigabatrin as first-line therapy. Nonresponders were switched to intramuscular synthetic adrenocorticotropic hormone (sACTH depot) after 2 weeks and, if necessary, to topiramate after two additional weeks. The Vineland Adaptive Behavior Scale (VABS) and Bayley Scales of Infant Development (BSID) were used as outcome measures 24 months after the intervention. Key Findings: Sixty-eight of 101 children diagnosed over 3 years in seven centers in Canada received either adjunctive flunarizine or placebo. Sixty-five of the 68 children (96%) became spasm-free within 8 weeks and no late relapse occurred. Bayley and Vineland results were available at baseline and at 24 months in 45 children. There was no significant difference in the BSID developmental quotient between the flunarizine- and placebo-treated children at baseline (44.3 ± 35.5 vs. 30.9 ± 29.8; p = 0.18) or 24 months later (56.9 ± 33.3 vs. 46 ± 34.2; p = 0.29). However, the 10 flunarizine-treated children with no identified etiology had a better outcome than the eight controls at 24 months on both the Vineland Scale (84.1 ± 11.3 vs. 72.3 ± 9.8; p = 0.03) and the Bayley Scale (87.6 ± 14.7 vs. 69.9 ± 25.3; p = 0.07). Significance: Our study failed to demonstrate a protective effect of flunarizine on cognitive outcome in a cohort of children with IS. An analysis of subgroups suggested that flunarizine may further improve cognitive outcome in children with no identified etiology.
Epilepsia 08/2012; 53(9):1570-1576. · 3.96 Impact Factor
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ABSTRACT: During development, the risk of developing mesial temporal lobe epilepsy (MTLE) increases when the developing brain is exposed to more than one insult in early life. Early life insults include abnormalities of cortical development, hypoxic-ischemic injury and prolonged febrile seizures. To study epileptogenesis, we have developed a two-hit model of MTLE characterized by two early-life insults: a freeze lesion-induced cortical malformation at post-natal day 1 (P1), and a prolonged hyperthermic seizure (HS) at P10. As early life stressors lead to sexual dimorphism in both acute response and long-term outcome, we hypothesized that our model could lead to gender-based differences in acute stress response and long-term risk of developing MTLE. Male and female pups underwent a freeze-lesion induced cortical microgyrus at P1 and were exposed to HS at P10. Animals were monitored by video-EEG from P90 to P120. Pre and post-procedure plasma corticosterone levels were used to measure stress response at P1 and P10. To confirm the role of sex steroids, androgenized female pups received daily testosterone injections to the mother pre-natally and post-natally for nine days while undergoing both insults. We demonstrated that after both insults females did not develop MTLE while all males did. This correlated with a rise in corticosterone levels at P1 following the lesion in males only. Interestingly, all androgenized females showed a similar rise in corticosterone at P1, and also developed MTLE. Moreover, we found that the cortical lesion significantly decreased the latency to generalized convulsion during hyperthermia at P10 in both genders. The cortical dysplasia volumes at adulthood were also similar between male and female individuals. Our data demonstrate sexual dimorphism in long-term vulnerability to develop epilepsy in the lesion + hyperthermia animal model of MTLE and suggest that the response to early-life stress at P1 contributes significantly to epileptogenesis in a gender-specific manner.
PLoS ONE 01/2012; 7(8):e42622. · 4.09 Impact Factor
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ABSTRACT: Febrile seizures occurring in the neonatal period, especially when prolonged, are thought to be involved in the later development of mesial temporal lobe epilepsy (mTLE) in children. The presence of an often undetected, underlying cortical malformation has also been reported to be implicated in the epileptogenesis process following febrile seizures. This paper highlights some of the various animal models of febrile seizures and of cortical malformation and portrays a two-hit model that efficiently mimics these two insults and leads to spontaneous recurrent seizures in adult rats. Potential mechanisms are further proposed to explain how these two insults may each, or together, contribute to network hyperexcitability and epileptogenesis. Finally the clinical relevance of the two-hit model is briefly discussed in light of a therapeutic and preventive approach to mTLE.
Epilepsy research and treatment. 01/2012; 2012:342928.
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ABSTRACT: The combination of two precipitating factors appears to be more and more recognized in patients with temporal lobe epilepsy. Using a two-hit rat model, with a neonatal freeze lesion mimicking a focal cortical malformation combined with hyperthermia-induced seizures mimicking febrile seizures, we have previously reported an increase of inhibition in CA1 pyramidal cells at P20. Here, we investigated the changes affecting excitatory and inhibitory drive onto CA1 interneurons to better define the changes in CA1 inhibitory networks and their paradoxical role in epileptogenesis, using electrophysiological recordings in CA1 hippocampus from rat pups (16-20 d old). We investigated interneurons in CA1 hippocampal area located in stratum oriens (Or) and at the border of strata lacunosum and moleculare (L-M). Our results revealed an increase of the excitatory drive to both types of interneurons with no change in the inhibitory drive. The mechanisms underlying the increase of excitatory synaptic currents (EPSCs) in both types of interneurons are different. In Or interneurons, the amplitude of spontaneous and miniature EPSCs increased, while their frequency was not affected suggesting changes at the post-synaptic level. In L-M interneurons, the frequency of spontaneous EPSCs increases, but the amplitude is not affected. Analyses of miniature EPSCs showed no changes in both their frequency and amplitude. We concluded that L-M interneurons increase in excitatory drive is due to a change in Shaffer collateral axon excitability. The changes described here in CA1 inhibitory network may actually contribute to the epileptogenicity observed in this dual pathology model by increasing pyramidal cell synchronization.
Channels (Austin, Tex.) 01/2012; 6(1). · 1.91 Impact Factor
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Mach. Vis. Appl. 01/2012; 23:299-311.
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ABSTRACT: Functional near-infrared spectroscopy (fNIRS) is a technique that allows continuous non-invasive monitoring of tissue oxygenation and haemodynamics in the brain. By using combined EEG-fNIRS recordings, we sought to better understand the pathophysiology of temporal lobe seizures.
Nine patients (5 males; mean age 35 years; range 11-56 years) with refractory mesial temporal lobe epilepsy underwent combined EEG-fNIRS recordings. Eight complex partial seizures from 3 patients were successfully recorded. All seizures were associated with significant local and remote haemodynamic changes which outlasted the duration of seizures. Over the epileptogenic temporal lobe, increased oxygenation [increase in cerebral blood volume (CBV) and oxyhaemoglobin (HbO), decrease in deoxyhaemoglobin (HbR)] was followed by a deoxygenated state [increase in HbR]. A similar haemodynamic profile was seen over the contralateral temporal lobe (even without evidence of epileptic propagation) though variations generally had lower amplitudes. Heterogeneous haemodynamic changes in remote frontal and/or parietal areas were also noted early on when epileptic activity was limited to the temporal lobe.
EEG-fNIRS reveals complex local and remote oxygenation changes during temporal lobe seizures.
Epilepsy research 11/2011; 99(1-2):112-26. · 2.48 Impact Factor
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ABSTRACT: Retrospective study assessing the efficacy and tolerability of vagus nerve stimulation (VNS) for the treatment of refractory epilepsy at Notre-Dame Hospital.
Chart review of all adult epileptic patients treated by VNS with ≥ 1 year follow-up. Responders were defined as patients with ≥ 50% reduction of baseline seizure frequency.
Thirty-four patients (14M; mean age = 29.9 yrs) received a VNS. Sub-pectoralis implantation (n = 25) was more frequent than subcutaneous (n = 9). Most patients suffered from intractable partial epilepsy. After 6 months, 12 months, 24 months, and 36 months, 14/34 patients (41%), 16/34 patients (47%), 17/30 patients (57%) and 12/20 patients (60%) respectively were responders. Two patients (6%) became seizure-free. Complications related to implantation were minor: eight cases of limited cervical hypoesthesia, two minor scar infections and one Horner syndrome. Adverse events (voice hoarseness, throat paresthesia, coughing) related to stimulation were generally mild and tended to wane over time. However, a reduction in seizure frequency did not translate into a reduction in medication, as only 9% of responders had less antiepileptic medication at last follow-up compared to baseline.
VNS as practiced at Notre-Dame hospital is an efficacious and safe treatment for refractory epilepsy. Quotas allotted to epilepsy centers in the province of Quebec should be lifted or increased to allow more patients to benefit from this therapeutic device.
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 11/2011; 38(6):902-8. · 0.97 Impact Factor
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Pamela Lachance-Touchette,
Patricia Brown,
Caroline Meloche,
Peter Kinirons,
Line Lapointe,
Hélène Lacasse,
Anne Lortie, Lionel Carmant,
Fiona Bedford,
Derek Bowie,
Patrick Cossette
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ABSTRACT: Epilepsy is a heterogeneous neurological disease affecting approximately 50 million people worldwide. Genetic factors play an important role in both the onset and severity of the condition, with mutations in several ion-channel genes being implicated, including those encoding the GABA(A) receptor. Here, we evaluated the frequency of additional mutations in the GABA(A) receptor by direct sequencing of the complete open reading frame of the GABRA1 and GABRG2 genes from a cohort of French Canadian families with idiopathic generalized epilepsy (IGE). Using this approach, we have identified three novel mutations that were absent in over 400 control chromosomes. In GABRA1, two mutations were found, with the first being a 25-bp insertion that was associated with intron retention (i.e. K353delins18X) and the second corresponding to a single point mutation that replaced the aspartate 219 residue with an asparagine (i.e. D219N). Electrophysiological analysis revealed that K353delins18X and D219N altered GABA(A) receptor function by reducing the total surface expression of mature protein and/or by curtailing neurotransmitter effectiveness. Both defects would be expected to have a detrimental effect on inhibitory control of neuronal circuits. In contrast, the single point mutation identified in the GABRG2 gene, namely P83S, was indistinguishable from the wildtype subunit in terms of surface expression and functionality. This finding was all the more intriguing as the mutation exhibited a high degree of penetrance in three generations of one French Canadian family. Further experimentation will be required to understand how this mutation contributes to the occurrence of IGE in these individuals.
European Journal of Neuroscience 06/2011; 34(2):237-49. · 3.63 Impact Factor
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Steve Gibbs,
Bidisha Chattopadhyaya,
Sébastien Desgent,
Patricia N Awad,
Olivier Clerk-Lamalice,
Maxime Levesque,
Rose-Mari Vianna,
Rose-Marie Rébillard,
Andrée-Anne Delsemme,
David Hébert,
Luc Tremblay,
Martin Lepage,
Laurent Descarries,
Graziella Di Cristo, Lionel Carmant
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ABSTRACT: Clinical evidence suggests that febrile status epilepticus (SE) in children can lead to acute hippocampal injury and subsequent temporal lobe epilepsy. The contribution of febrile SE to the mechanisms underlying temporal lobe epilepsy are however poorly understood. A rat model of temporal lobe epilepsy following hyperthermic SE was previously established in our laboratory, wherein a focal cortical lesion induced at postnatal day 1 (P1), followed by a hyperthermic SE (more than 30 min) at P10, leads to hippocampal atrophy at P22 (dual pathology model) and spontaneous recurrent seizures (SRS) with mild visuospatial memory deficits in adult rats. The goal of this study was to identify the long term electrophysiological, anatomical and molecular changes in this model. Following hyperthermic SE, all cortically lesioned pups developed progressive SRS as adults, characterized by the onset of highly rhythmic activity in the hippocampus. A reduction of hippocampal volume on the side of the lesion preceded the SRS and was associated with a loss of hippocampal neurons, a marked decrease in pyramidal cell spine density, an increase in the hippocampal levels of NMDA receptor NR2A subunit, but no significant change in GABA receptors. These findings suggest that febrile SE in the abnormal brain leads to hippocampal injury that is followed by progressive network reorganization and molecular changes that contribute to the epileptogenesis as well as the observed memory deficits.
Neurobiology of Disease 03/2011; 43(2):312-21. · 5.40 Impact Factor
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ABSTRACT: The phenotypic and etiologic spectrum in adults with nodular heterotopias (NHs) has been well characterized. However, there are no large pediatric case series. We, therefore, wanted to review the clinical features of NHs in our population.
Hospital records of 31 patients with pathology or imaging-confirmed NHs were reviewed. Two-sided Fisher's exact t-test was used to assess associations between distribution of NHs and specific clinical features.
NHs were distributed as follows: 8 (26%) unilateral focal subependymal, 3 (10%) unilateral diffuse subependymal, 5 (16%) bilateral focal subependymal, 12 (39%) bilateral diffuse subependymal, and 3 (10%) isolated subcortical. The phenotypic spectrum in our population differs from that described in adults. Significant morbidity and mortality are associated with presentation in childhood. Twenty-two of 31 patients (71%) died in the neonatal period or in childhood. Additional cerebral malformations were found in 80% and systemic malformations in 74%. The majority of patients had developmental delay, intellectual deficit, and intractable epilepsy. Patients with unilateral focal NHs were more likely to have ventriculomegaly (p = 0.027), and those with bilateral diffuse NHs more likely to have cerebellar abnormalities (p = 0.007). Isolated subcortical NHs were associated with multiple malformations (p = 0.049) and cardiac abnormalities (p = 0.027). Underlying etiology was heterogeneous and determined in only six cases (19%): del chr 1p36, del chr 15q11, pyruvate dehydrogenase deficiency, sialic acidosis type 1, Aicardi syndrome, and FLNA mutation.
NHs are present in childhood as part of multiple cerebral and systemic malformations; developmental delay and refractory seizures are the rule rather than the exception. Milder forms go unrecognized until seizure onset in adulthood.
Epilepsia 02/2011; 52(4):728-37. · 3.96 Impact Factor
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The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 01/2011; 38(1):141-2. · 0.97 Impact Factor
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ABSTRACT: We present two methods of implantation for the investigation of suspected insular and perisylvian epilepsy that combine depth and subdural electrodes to capitalize on the advantages of each technique.
Retrospective study of all intracranial EEG studies that included insular electrodes from 2004-2010. Patients were divided according to the implantation scheme. The first method (type 1) consisted of a craniotomy, insertion of insular electrodes after microdissection of the sylvian fissure, orthogonal implantation of mesiotemporal structures with neuronavigation, and coverage of the adjacent lobes with subdural electrodes. The second method (type 2) consisted of magnetic resonance imaging (MRI)-stereotactic frame-guided depth electrode implantation into insula and hippocampus using sagittal axes, and insertion of subdural electrodes through burr holes to cover the adjacent lobes. The combined implantations were developed and performed by one neurosurgeon (AB).
Nineteen patients had an intracranial study that sampled the insula, among other regions. Sixteen patients were implanted using the first method, which allowed a mean of 4, 5, 20, 15, and 42 contacts per patient to be positioned into/over the insular, mesial temporal, neocortical temporal, parietal, and frontal areas, respectively. The second method (three patients) allowed a mean of 8, 7, 16, 6, and 9 contacts per patient to sample the same areas, respectively. The four patients in whom transient neurologic deficits occurred were investigated with use of type 1 implantation.
Combined depth and subdural electrodes can be used safely to investigate complex insular/perisylvian refractory epilepsy. Choice of implantation scheme should be individualized according to presurgical data and the need for functional localization.
Epilepsia 01/2011; 52(3):458-66. · 3.96 Impact Factor
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Fadi F Hamdan,
Hussein Daoud,
Amélie Piton,
Julie Gauthier,
Sylvia Dobrzeniecka,
Marie-Odile Krebs,
Ridha Joober,
Jean-Claude Lacaille,
Amélie Nadeau,
Jeff M Milunsky,
Zhenyuan Wang, Lionel Carmant,
Laurent Mottron,
Miriam H Beauchamp,
Guy A Rouleau,
Jacques L Michaud
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ABSTRACT: Little is known about the genetics of nonsyndromic intellectual disability (NSID). Recently, we reported de novo truncating mutations in the SYNGAP1 gene of 3 of 94 NSID cases, suggesting that its disruption represents a common cause of autosomal dominant NSID.
To further explore the involvement of SYNGAP1 in NSID, we sequenced its exons and intronic boundaries in 60 additional sporadic cases of NSID, including 30 patients with autism spectrum disorders (ASD) and 9 with epilepsy, and in 380 control individuals.
We identified de novo out-of-frame deletions in two patients with NSID and mild generalized epilepsy (c.2677delC/p.Q893RfsX184 and c.321_324delGAAG/p. K108VfsX25) and a de novo splicing mutation (c.2294 + 1G>A), which results in the creation of a premature stop codon, in a patient with NSID and autism. No splicing or truncating mutations were found in control subjects.
We provide evidence that truncating mutations in SYNGAP1 are common in NSID and can be also associated with autism.
Biological psychiatry 01/2011; 69(9):898-901. · 8.93 Impact Factor
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Ala Birca, Lionel Carmant,
Anne Lortie,
Phetsamone Vannasing,
Hannelore Sauerwein,
Manon Robert,
Louise Lemay,
Xiao-Ping Wang,
Dominique Piper,
Valentina Donici,
Maryse Lassonde
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ABSTRACT: We investigated the development of the magnitude and phase alignment of steady-state visual evoked potentials induced by 5 Hz intermittent photic stimulation in 46 children (3 to 16 years) and 8 adults, as a function of age. We found that, over the occipital region, magnitude values were the highest in 8-11-year old children, but decreased with age over all other cerebral regions. Phase alignment values increased with age over the occipital, parietal and frontal cerebral regions. We interpret these findings in terms of the development of functional interactions between different cortical areas involved in the processing of visual stimuli.
International journal of psychophysiology: official journal of the International Organization of Psychophysiology 12/2010; 78(3):295-8. · 3.05 Impact Factor
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ABSTRACT: Febrile seizures occurring during childhood have been shown to interfere with the development of cognitive functions. However, an alteration of the developing sensory systems might also result from febrile seizures. In order to test this hypothesis, seizures were induced by hyperthermia in Long Evans rats on postnatal day 10. Extracellular single neuron recordings were carried out from postnatal days 15 to 30 and at adulthood. The response of neurons in the primary visual cortex to drifting sinusoidal gratings was recorded in anaesthetized rats. As soon as postnatal day 15, the neurons of rats having experienced a hyperthermic seizure showed significantly lower optimal spatial frequencies (SF), broader directional and temporal bandwidths, as well as higher contrast thresholds than did neurons recorded in normal rats. At adulthood, significantly broader spatial bandwidths and lower optimal temporal frequencies (TF) were obtained from neurons of rats subjected to hyperthermia. These results suggest that febrile seizures during infancy could affect the development of spatio-temporal receptive field properties of neurons in primary visual cortex. Such alterations of a sensory system might contribute to the cognitive deficits associated with early-onset febrile seizures.
Neuroscience 10/2010; 171(4):1120-30. · 3.38 Impact Factor
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ABSTRACT: Mutations in the GABRB3 have been recently associated with childhood absence epilepsy (CAE) in families from Honduras and Mexico. In this study, we aimed to determine the frequency of mutation in this gene in our cohort of families with CAE and other related idiopathic generalized epilepsy (IGE) syndromes. We screened the open reading frame of GABRB3 in 183 French-Canadian individuals with IGE, including 88 with CAE. A total of nine single nucleotide polymorphisms (SNPs) have been identified,five of which are novel. The previously described P11S missense mutation was found in three affected and one unaffected individuals from a French-Canadian family. However, the P11S variant was also found in one of our 190 control individuals of French-Canadian origin, suggesting that this variant is rather a rare polymorphism in this population. Further screening of other IGE cohorts from various ethnic origins would help to confirm the association between this rare functional variant and epilepsy.
Epilepsia 09/2010; 51(9):1894-7. · 3.96 Impact Factor
