Spatial cognition following early-life seizures in rats: Performance deficits are dependent on task demands

Abstract

Cognitive impairment is a common co-morbidity in childhood epilepsy. Studies in rodents have demonstrated that frequent seizures during the first weeks of life results in impaired spatial cognition when the rats are tested as juvenile or adults. To determine if spatial cognitive deficits following early-life seizures are task-specific or similar across spatial tasks we compared the effects of early-life seizures in two spatial assays: 1) The Morris water maze, a hippocampal-dependent task of spatial cognition; and 2) The active avoidance task, a task that associates an aversive shock stimulus with a static spatial location that requires intact hippocampal-amygdala networks. Rats with early-life seizures tested as adults did not differ from control rats in the water maze. However, while animals with early-life seizures showed some evidence of learning the active avoidance task, they received significantly more shocks in later training trials, particularly during the second training day, than controls. One possibility for the performance differences between the tasks is that the active avoidance task requires multiple brain regions and that inter-regional communication could be affected by alterations in white matter integrity. However, there were no measurable group differences with regard to levels of myelination. The study suggests that elucidation of mild cognitive deficits seen following early-life seizures may be dependent on task features of active avoidance.

Environmental Enrichment Improves Spatial Learning and Memory in Vascular Dementia Rats with Activation of Wnt/β-Catenin Signal Pathway

“…If unable to find the platform within 60 s, the rats would be guided to the platform by the researcher and were left on the platform for 30 s. All rats were subjected to 4 trials per day for 5 consecutive days (n=10/group). On day 6, the platform was removed, and animals underwent the probe test for 60 s. The MWM performance was recorded by a video camera [18]. …”

Effects of early life seizures on coordination of hippocampal–prefrontal networks: Influence of sex and dynamic brain states

“…There are considerable data indicating the disruptive effects of seizures on developing hippocampal oscillations, 7 and studies have examined the effects of seizure on the balance of signal coordination on the hippocampus–mPFC circuit with regard to working memory 25 and sociability 26 deficits. However, the effects of early life seizures (ELSs) on the hippocampus–mPFC circuit in relation to spatial memory deficits 27 remain poorly understood. Moreover, ELS cognitive outcome variables such as dynamic coordination efficacy in the hippocampus–mPFC circuit and sex 28–30 have not been studied.…”

Optogenetic modulation of hippocampal oscillations ameliorates spatial cognition and hippocampal dysrhythmia following early-life seizures

“…Animals underwent testing in the active place avoidance task (Biosignal; Brooklyn, New York) at P50-P60. In this task, animals must attend to their ever-changing position in the room frame lest they be rotated into a pre-determined non-marked zone where they receive a mild electrical shock ( Barry et al, 2015 ; Kloc et al, 2020 ; Niedecker et al, 2021 ; Barry et al, 2020 ; Barry et al, 2016a ; Barry et al, 2016b ).…”