Evoked cortical activity and learning ability are altered by spike-wave-discharges in absence epileptic rats

Abstract

Absence epilepsy which is characterized by spike-wave discharges (SWDs) is often accompanied by a brief loss of consciousness and behavior impairment This behavioral impairment during the occurrence of an SWD is influenced by the complexity or difficulty of a cognitive task Animal models of absence epilepsy display abnormal immobile behavior accompanied by SWDs The performance of learned conditioning paradigms in response to SWDs has great differences in previous studies There is largely unknown about the learning progress during SWDs The present study used the side of face stimulation as a conditioning stimulus to pair the location of a food pellet in a T maze in rats with spontaneous SWDs The performance of learning progress and recognition session during the situations of normal brain wave (noSWD) and SWDs was assessed First four intensities (i e motor threshold 1 2?motor threshold 0 6 mA 1 mA) were used to stimulate face muscles Two kinds of low-intensity stimulations had little effect on SWDs but the other two kinds of stimulations significantly stopped SWD progression Amplitudes and latencies of the cortical somatosensory evoked potentials (SEPs) elicited by two kinds of low-intensity stimulations were significant difference during SWDs compared to those of noSWD However SEPs in response to the other two kinds of high-intensity stimulations were no difference between the noSWD and SWD conditions Second the side of face stimulated by the current of a 1 2?motor threshold was a conditioning stimulus to pair with the location of a food pellet in the multiple phases of a reversal learning task The accuracy showed significantly progressive increase during noSWD but no change during SWDs Reaction time showed significantly progressive reduction in both conditions In the relearned phase of the reversal learning task accuracy showed significantly progressive increase during noSWD However the performance progressively became a random selection during SWDs In the recognition session well-trained rats under the noSWD condition showed ~100% of accuracy in either noSWD or SWD situations In those trained under SWDs the recognition accuracy was ~50% in both conditions Third memory acquired in the reversal leaning task was extinct during SWDs Results of the present study indicate that SWDs and SEPs are affected by different stimulation intensities SWDs modulate learning ability and memory but have no effect on the retrieval of a memory

Date of Award	2014 Feb 12
Original language	English
Supervisor	Fu-Zen Shaw (Supervisor)