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<p><b>BACKGROUND</b>Few characteristic changes of linear electroencephalograph (EEG) have been reported in schizophrenia. The aim of the present study was to investigate the changes in temporal-spatial dimensional properties of EEG under different cognitive tasks in patients with schizophrenia.</p><p><b>METHODS</b>EEG was recorded by using EEG-1518K system and mapping system (Nihon Kohden Tomioka Corporation, Japan) in 45 schizophrenic patients and 47 healthy adults (normal control, NC) under five states: eyes closed, eyes open, mental arithmetic test with eyes closed, memory test with eyes open, and number cancellation test. Correlation dimension (D2) and point-wise correlation dimension (PD2) were calculated for all EEG analyses.</p><p><b>RESULTS</b>(1) There were no significant differences of D2 and PD2 between NC and schizophrenic patients under states of eyes open and closed. (2) Compared with NC, schizophrenic patients showed decreased performance of D2 in mental arithmetic test with eyes closed and number cancellation test (mental arithmetic test with eyes closed: Nc 5.9 ± 0.6, Sch 3.0 ± 0.8; number cancellation test: Nc 6.0 ± 0.6, Sch 4.4 ± 0.7; P < 0.05 or P < 0.01). (3) Schizophrenic patients also showed decrease performance of PD2 in mental arithmetic test with eyes closed, memory test with eyes open, and number cancellation test (mental arithmetic test with eyes closed: Nc 6.9 ± 0.7, Sch 4.0 ± 0.8; memory test with eyes open: Nc 6.6 ± 0.8, Sch 5.0 ± 0.9; number cancellation test: Nc 7.1 ± 0.7, Sch 4.8 ± 0.9; P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>Nonlinear dynamic analysis provided a new approach in clinical investigation of EEG signals. It was helpful to further understand the cerebral mechanism in schizophrenic cognitive process.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Cognition , Physiology , Electroencephalography , Nonlinear Dynamics , SchizophreniaABSTRACT
<p><b>BACKGROUND</b>The neonatal ventral hippocampal lesion (NVHL) rat model has been proposed as an experimental model for schizophrenia. NVHL rats display impaired central nervous system (CNS) inhibition, which may lead to a phenomenon similar to P50 sensory gating deficits observed in schizophrenic patients. In this study, we investigated whether sensory gating deficits occurred in the NVHL rat as a model for schizophrenia.</p><p><b>METHODS</b>We created the NVHL rat model using ibotenate. The P20 and N40 were measured to assess sensory response and gating in NVHL and sham rats. Epidural electrodes recorded evoked potentials (EPs), from which latencies, amplitudes, difference scores (S1-S2), and gating ratios (S2/S1) were assessed.</p><p><b>RESULTS</b>Compared with sham controls, prolonged S1 N40 latency and decreased S2 N40 amplitude were detected in the NVHL group. In neither difference scores nor gating ratios, a significant difference was found between NVHL group and sham controls.</p><p><b>CONCLUSIONS</b>NVHL rats may be a valid animal model for schizophrenia. This strategy will be useful in future neurobiological studies investigating the etiology of schizophrenia.</p>
Subject(s)
Animals , Rats , Animals, Newborn , Central Nervous System , Evoked Potentials, Auditory , Hippocampus , Ibotenic Acid , Toxicity , Schizophrenia , Sensory GatingABSTRACT
<p><b>BACKGROUND</b>Prior research about N400 has been mainly based on English stimuli, while the cognitive processing of Chinese characters is still unclear. The aim of the present study was to further investigate the semantic processing of Chinese idioms.</p><p><b>METHODS</b>Event related potentials (ERP) component N400 was elicited by 38 pairs of matching (congruent) and mismatching (incongruent) ended Chinese idioms: ending words with same phoneme but different shape and meaning (sPdSdM), with similar shape but different phoneme and meaning (sSdPdM), with same meaning but different phoneme and shape (sMdPdS), and words with different phoneme, shape and meaning (dPdSdM) and recorded by Guangzhou Runjie WJ-1 ERP instruments. In 62 right-handed healthy adults (age 19 - 50 years), N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz, Cz and Pz.</p><p><b>RESULTS</b>N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz. The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending words in healthy adults. Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-words idioms in healthy adults (P < 0.05). Compared with matching ending-words idioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones. N400s elicited by different types of stimuli showed different latencies and amplitudes, and longest N400 latency and largest N400 amplitude were elicited by ending-words with dPdSdM. No gender difference was found of N400 latency and amplitude in this study (P > 0.05).</p><p><b>CONCLUSIONS</b>Compared with English stimuli, Chinese ideographic words could provide more flexible stimuli for N400 research in that the words have 3-dimension changes - phoneme, shape and meaning. Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the word. Some issues of N400 elicited by Chinese characters deserve further research.</p>
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Cognition , Evoked Potentials , Physiology , Reaction Time , Reading , Semantics , Sex CharacteristicsABSTRACT
0.05)and significantly delayed reaction time,(305?109)ms vs(212?70)ms(P
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Objective To assess the changes on the whole night polysomnography (PSG) in patients with chronic fatigue syndrome(CFS). Methods The whole night PSGs were recorded from 24 patients with CFS and 33 normal subjects. Results Compared with normal subjects, patients with CFS showed significantly reduced total sleep duration ([488.7?21.7]min vs [515.9?31.7]min, P
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Objective To study P300 of the first episode depression and mismatch negativity(MMN) changes after antidepressant treatment. Methods Sixty-four patients with first episode depression were evaluated by HAMD 17, and P300 and MMN tests were performed at the baseline and week 12. The cognitive potentials were compared with those of control group(N=36). Results Compared with the control group, depressive patients had longer latency of P300 and MMN,lower amplitude of P300 and MMN before treatment (P