Transient reduction in theta power caused by interictal spikes in human temporal lobe epilepsy.

The inhibitory impacts of spikes on LFP theta rhythms(4-8Hz) are investigated around sporadic spikes(SSs) based on intracerebral EEG of 4 REM sleep patients with temporal lobe epilepsy(TLE) under the pre-surgical monitoring. Sequential interictal spikes in both genesis area and extended propagation pathway are collected, that, SSs genesis only in anterior hippocampus(aH)(possible propagation pathway in Entorhinal cortex(EC)), only in EC(possible propagation pathway in aH), and in both aH and EC synchronously. Instantaneous theta power was estimated by using Gabor wavelet transform, and theta power level was estimated by averaged over time and frequency before SSs(350ms pre-spike) and after SSs(350ms post-spike). The inhibitory effect around spikes was evaluated by the ratio of theta power level difference between pre-spike and post-spike to pre-spike theta power level. The findings were that theta power level was reduced across SSs, and the effects were more sever in the case of SSs in both aH and EC synchronously than either SSs only in EC or SSs only in aH. It is concluded that interictal spikes impair LFP theta rhythms transiently and directly. The work suggests that the reduction of theta power after the interictal spike might be an evaluation indicator of damage of epilepsy to human cognitive rhythms.

Chemical constituents of organic acid part from Camptosorus sibiricus / 中草药

Objective To study the chemical constituents of the organic acid part from Camptosorus sibiricus.Methods The compounds were isolated by chromatography on silica gel column and identified on the basis of physicochemical constants and spectral analysis.Results Ten compounds were isolated and their structures were identified as 11,12,15-trihydroxy-13-en-octadecenoic acid(Ⅰ),caffeic acid(Ⅱ),courmaric acid(Ⅲ),protocatechuic acid(Ⅳ),4-hydroxybenzoic acid(Ⅴ),isovanillic acid(Ⅵ),2,4-dihydroxybenzoic acid(Ⅶ),cinnamic acid(Ⅷ),succinic acid(Ⅸ),palmitic acid(Ⅹ).Conclusion Compound Ⅰ is a new compound named as camptosoric acid and compounds Ⅲ-Ⅹ are obtained from the plants of Camptosorus Link for the first time.