How do astrocytes control absence seizures and their comorbid cognitive deficits

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Cognitive comorbidities of experimental absence seizures are independent of anxiety

Publication . Neuparth-Sottomayor, Mariana; Pina, Carolina; Morais, Tatiana P.; Farinha Ferreira, Jorge Miguel; Abreu, Daniela Sofia; Solano, Filipa; Mouro, Francisco; Good, Mark; Sebastião, Ana M; Di Giovanni, Giuseppe; Crunelli, Vincenzo; Vaz, Sandra H.

Typical absence seizures (ASs) are brief periods of lack of consciousness, associated with 2.5-4 Hz spike-wave discharges (SWDs) in the EEG, which are highly prevalent in children and teenagers. The majority of probands in these young epileptic cohorts show neuropsychological comorbidities, including cognitive, memory and mood impairments, even after the seizures are pharmacologically controlled. Similar cognition and memory deficits have been reported in different, but not all, genetic animal models of ASs. However, since these impairments are subtle and highly task-specific their presence may be confounded by an anxiety-like phenotype and no study has tested anxiety and memory in the same animals. Moreover, the majority of studies used non-epileptic inbred animals as the only control strain and this may have contributed to a misinterpretation of these behavioural results. To overcome these issues, here we used a battery of behavioural tests to compare anxiety and memory in the same animals from the well-established inbred model of Genetic Absence Epilepsy Rats from Strasbourg (GAERS), their inbred strain of Non-Epileptic Control (NEC) strain (that lack ASs) and normal outbred Wistar rats. We found that GAERS do not exhibit increased anxiety-like behavior and neophobia compared to both NEC and Wistar rats. In contrast, GAERS show decreased spontaneous alternation, spatial working memory and cross-modal object recognition compared to both NEC and Wistar rats. Furthermore, GAERS preferentially used egocentric strategies to perform spatial memory tasks. In summary, these results provide solid evidence of memory deficits in GAERS rats that do not depend on an anxiety or neophobic phenotype. Moreover, the presence of differences between NEC and Wistar rats stresses the need of using both outbred and inbred control rats in behavioural studies involving genetic models of ASs.

2023Artigo científico

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Impairment of spatial working memory but preservation of recognition memory in female rats with spontaneous absence seizures

Publication . Neuparth-Sottomayor, Mariana; Morais, Tatiana P.; Good, Mark; Sebastião, Ana M; Di Giovanni, Giuseppe; Crunelli, Vincenzo; Vaz, Sandra H.

Epidemiological studies reveal gender-specific differences in epilepsy. Childhood absence epilepsy (CAE), which is more prevalent in females, is characterized by typical absence seizures (ASs) consisting of brief periods of unconsciousness, associated with 2.5-4 Hz spike-wave discharges (SWDs) in the electroencephalogram (EEG). Children with CAE often present neuropsychological comorbidities, including deficits in attention and executive function. In this study, we investigated anxiety-like behaviour and memory in female Genetic Absence Epilepsy Rat from Strasbourg (GAERS), a validated model of ASs, compared to Non-Epileptic Control (NEC) and Wistar rats. We found that female GAERS generally showed normal anxiety-like behaviour relative to both control strains, although some tests suggested a reduction in anxiety. Importantly, female GAERS showed impaired spatial working memory, while recognition memory was preserved. These findings when compared with previous data in males indicate that while anxiety levels in female GAERS are preserved as those of male GAERS, memory performance differs, with males showing impairments in both spatial working memory and recognition memory. These findings emphasize the importance of considering gender differences in both clinical and preclinical epilepsy research to better understand the neuropsychological comorbidities associates with ASs. This knowledge is crucial for the identification of gender-specific mechanism, as well as the development of gender-sensitive, personalized therapies targeting both seizures and associated cognitive impairments.

2025Artigo científico

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Fundação para a Ciência e a Tecnologia

Número da atribuição

2023.01003.BD