AEPおよび脳波に対するcaffeineの効果

We studied the effects of caffeine on the central nervous system by auditory evoked potentials (AEP) with 25 healthy male subjects (T-group: 24-44 y.o., mean caffeine consumption: 251.4 mg/day). According to the DSM-IV criteria for caffeine intoxication, T-group were devided into the light (L-group: 11 subjects, ≦250 mg/ day) and heavy consumer group (H-group: 14 subjects, >250 mg/ day), and into caffeine (CAF-group) and placebo administration group (PLA-group) according to a double-blind cross-over design. EEG containing AEP was recorded through the two deviations (monopolar : Cz→A1+2, bipolar : Cz→T5); before and 30, 60 and 90 min after the oral administration of caffeine or placebo (3 mg/kg of B.W.). Consecutive changes of the latencies and amplitudes in group mean AEP were studied. Those of individual AEP were subjected to the component analysis, and to the statistical assessment with reference to the EEG power % changes. 1. After the administration of caffeine, CAF-group had a significant decrease in N 4 (= N 1, latency : 95-125 msec) and P 5 (=P 2, latency : 160-200 msec) latencies of long latency components, followed by a decrease in N 4-P 5 amplitudes of AEP, which indicated that there was a post-exciting inhibitory effect in CAF(H)-group. In EEG, α power % significantly increased, whereas δ, θ and β power % significantly decreased. These findings indicated that caffeine might have a sedative effect as well as the exciting effects on the primary and secondary auditory cortex. 2. CAF(H)-group had significant changes in latencies of AEP and EEG only 30 min after the administration of caffeine, whereas CAF(L)-group had these changes over 60 min after that, suggesting the hypersensitivity to caffeine by the interruption of caffeine consumption. 3. These changes seemed to be assciated with the effects of caffeine as an adenosine A1 receptor antagonist in the cerebral cortex, although further investigation on the neurotransmitters related to caffeine should be expected

健常成人の対側，同側および両側耳への音刺激によるAEPの差異

Differences among AEPs evoked by left or right monaural, and binaural acoustic stimuli were studied with 40 healthy male subjects (21-33 y.o.). AEPs were evoked by click stimuli and derived from the five derivations and recorded averaging 100 responses, with 1024 msec of analysis time. The following results were obtained. 1) In all of five derivations, the contours of the group mean AEPs were roughly similar in both ipsilateral left and contralateral right monaural stimuli. These findings demonstrated that response characteristics in the cortex which contains receptive field of the two ears were well coincided with each other. 2) The latency of the N1 component was significantly shorter and the peak to peak amplitudes were significantly larger in both contralateral right monaural and binaural AEPs than in ipsilateral left monaural AEPs. These findings reconfirmed reports on both the hemispheric dominance of the contralateral ear and the stronger response of binaural stimuli than monaural stimuli. 3) The latency of the P2 component in contralateral right monaural AEPs was significantly longer than that in ipsilateral left monocular AEPs, and N 1-P 2, P 2-N 2 amplitudes were significantly larger. These findings supported the report that the sourse of P2 is the primary auditory area, and confirmed the hemispheric dominance of the contralateral ear. 4) The latencies of the long latency components in contralateral right monaural and binaural AEPs were significantly longer than those in ipsilateral left monaural AEPs, and their amplitudes were significantly larger. These findings suggested the existence of the complicated auditory imformation processing in the association cortex and long-recovery cycle system in the cortex

HLPおよびDZPのVEPおよび脳波への急性効果

The acute effects of haloperidol (HLP) and diazepam (DZP) on the Visual Evoked Potential (VEP) and EEG were studied with 16 healthy male subjects (26~43 y.o.). In the two experimental session for each subject, HLP (0.02 mg/kg) were intra-venously and DZP (0.1 mg/kg) were per-orally administered. EEGs and VEPs were recorded through the two derivations (2 ch : O1→A1+2, 5 ch : O1→Cz), with 1024 msec of analysis time, averaging 100 responses. In the experimental session, EEGs and VEPs were recorded before and 15, 30, and 45 min after administration of HLP, before and 30,60, and 90 min after DZP. Consecutive change of group mean VEP were studied. Individual VEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following results were obtained. 1. After the administration of HLP, the latencies of short, middle and long latency component significantly increased, and the peak-to-peak amplitude N 1-P 2, P 5-N 5 and N 5-P 6 significantly decreased. The largest peak-to-peak amplitude P 4-N 7 significantly increased. In EEG, δ and θ-power% increased, and α2-power% decreased significantly. Significant positive correlation was found between δ, θ-power% of EEG and VEP latencies, and significant negative correlations was found between α2-power% and VEP latencies. These findings indicate the inhibitory effect of HLP all over the visual system through dopaminergic neuron system. The largest peak-to-peak amplitude (P 4-N 7) increased significantly synchronizing with increased θ waves. 2. After the administration of DZP, the latencies of short and middle latency component, P 3 and P 5, increased, P 2 latency decreased significantly. The peak-to-peak amplitude P 3-N 3, N 3-P 4, P 5-N 5, and N 5-P 6 decreased, N 2-P 3 amplitude increased significantly. In EEG, β1-power% increased, and α2-power% decreased significantly. Significant negative correlation was found between δ, θ-power% of EEG and VEP amplitudes, and positive correlations between α2-power% and VEP amplitudes. These findings indicate the inhibitory effect of DZP mainly on lateral geniculate body, optic radiation, and up to the visual cortex making BZD-receptor and GABA-receptor complex. Some exciting effect of DZP before the lateral geniculate body was suggested

健常成人の対側,同側および両側眼への閃光刺激によるVEPの差異

Differences among VEPs evoked by left and right monocular, and binocular flash stimuli were studied with 40 healthy male subjects (21-33 y.o.). VEPs were evoked by LED flash stimuli and derived from the six derivations and recorded with 1024 msec of analysis time. The following results were obtained. 1) In all of six derivations, the contours of the group mean VEPs were roughly similar in both ipsilateral left monocular and contralateral right monocular stimuli. These findings demonstrate that response characteristics and receptive field properties of the two eyes are well coincided with each other. 2) In details, the latencies of the short and middle latency components of the third (O 1→T 5) and the forth derivation (O 1→Cz) in contralateral right monocular VEPs were significantly shorter than those in ipsilateral left monocular VEPs. In all derivations, the peak to peak amplitudes in contralateral right monocular VEPs were significantly larger than those in ipsilateral left monocular VEPs. These findings verified the hemispheric dominant laterality of the contralateral eye, even with latencies, besides with amplitudes. 3) As compared with left monocular VEPs, the latencies of the short and middle latency components in binocular VEPs were significantly short and the peak to peak amplitudes in binocular VEPs were significantly large. These findings might suggest the existence of "binocular depth cells" of the monkey, which respond when the two eyes stimulated simultaneously, even in man. 4) In details, the latencies of the long latency components in binocular and contralateral right monocular VEPs were significantly longer than those in ipsilateral left monocular VEPs. This finding suggests the delay of the alpha regeneration as a photic after discharge following VEPs, because binocular and contralateral right monocular stimuli are stronger than ipsilateral left monocular stimuli

The effects of insulin-induced hypoglycemia on the human VEP (Visual Evoked Potential) and EEG

The effects of insulin-induced hypoglycemia on central nervous system were studied by visual flash evoked potential (VEP), with 8 schizophrenic patients (31~47 y.o.), during the 'Kleine Insulinbehandlung'. In the three experimental sessions on different days, human regular insulin were injected subcutaneously to each patient, whose consciousness level were lowered to the stage of somnolence and recovered after intake of a solution of glucose (100 g). EEG containing VEPs evoked by flash stimuli once every 5 seconds were derived from the two derivations (2 nd ch : O1→A1+2, 5 th ch : O1→Cz). In the experimental session, EEG containing VEPs were recorded before and 20, 40, 60, 80, 100 and 120 min after the injection of insulin, and 20 min after intake of glucose. Consecutive changes of group mean VEP were studied. Individual VEPs were subjected to the component analysis, and to the statistical assessment together with EEG power%. The following results were obtained. 1. The long latency components of VEP significantly increased in latency and significantly deceased in peak-to-peak amplitude in the early stage after the injection of insulin. These findings indicate the inhibitory effects of insulin-induced hypoglycemia on the cerebral cortex in the early stage. 2. The short latency components of VEP significantly increased in the latency of N2 and significantly decreased in the peak-to-peak amplitude of P2-N2 in the latter stage. In EEG, the power% of δ and θ frequency bands significantly increased and that of α 1~β 2 significantly decreased in the latter stage. These findings indicate the inhibitory effects on the lateral geniculate body due to the decline of the brainstem activity, in the latter stage of insulin-induced hypoglycemia

The effects of caffeine on the human Somatosensory evoked potential (SEP), visual evoked potential (VEP) and EEG

The effects of caffeine on central nervous system were investigated with SEP and VEP (EPs). The subjects were 25 healthy male volunteers aged 24-44 with a mean caffeine consumption of 251.4 mg/day, and were divided into the light and heavy consumer groups according to DSM-IV criteria for caffeine intoxication. They were given 3 mg/kg of body weight of caffeine or placebo in a double-blind cross-over design. EEGs containing SEPs evoked by electric stimuli to the right median nerve and VEPs by flash stimuli were recorded before, 30, 60, 90 minutes after dosing. The consecutive changes in EPs and EEG power% were studied and the following results were obtained. 1. Overall subjects had few components with significant changes in latencies and amplitudes of SEP and VEP after administration of caffeine. 2. EEGs recorded together with EPs showed a significant increase in α1 power% and a significant decrease in δ, θ and β２ power%. 3. There were also no significant differences in EPs measures and EEGs between the light and heavy consumer groups, except for EEG power% of VEP with the heavy costumer group showing an earlier appearance of changes. In conclusion, 3 mg/kg of body weight of caffeine administered in the present study did not effect on SEP and VEP as well as EEGs

Additional file 1 of Effect of age and sex on prescriptions for outpatients with bipolar disorder in the MUSUBI study: a cross‑sectional study

Additional file 1: Table S1 Adjusted standardized residuals of mood stabilizers, antipsychotics, antidepressants and benzodiazepine receptor agonists divided by age