BACKGROUND: Although serum carotene may contribute to dementia prevention, there is a lack of longitudinal evidence for early cognitive decline before dementia symptoms. The aim of this study was to examine whether serum carotene levels were associated with annually evaluated cognitive trajectories among the Japanese general population. METHODS: Among 581 baseline participants, 199 individuals (83 males; mean age [min, max], 62.7 [39, 90] years) who underwent cognitive assessments more than twice after baseline were analyzed. "Attention" levels were assessed using one- and three-target Digit Cancellation Tests (D-CAT1 and D-CAT3). "General cognitive ability" was assessed by the short version of Mini-Mental State Examination (SMMSE). Serum carotenes (α-carotene, β-carotene and lycopene) were measured by high-performance liquid chromatography. After the measurements, we calculated total carotene levels by summing up the levels of all measured carotene. Carotene levels were categorized into three groups for analysis (low: 0%-25%, middle: 25%-75%, and high: 75%-100%). A linear mixed model was used to estimate the slope of the D-CAT score trajectory and to compare it between three categories. RESULTS: Compared with the middle carotene group, decline of attention was faster in the D-CAT1 for low β-carotene (β = -3.48, p = 0.035), lycopene (β = -3.10, p = 0.062), and total carotene (β = -4.75, p = 0.003), but not for α-carotene (β = -2.60, p = 0.111). For the D-CAT3, decline of attention was faster in the group of low lycopene (β = -3.17, p = 0.002) and total carotene (β = -2.17, p = 0.037) compared with the middle carotene group, while no clear association for α-carotene (β = -0.67, p = 0.521) and β-carotene (β = -0.64, p = 0.639). There were no clear associations between serum carotene and the SMMSE score. CONCLUSIONS These findings suggest low levels of serum lycopene are associated with a decline of attention in the setting of the general population.
Humans ; Male ; Carotenoids/blood* ; Female ; Longitudinal Studies ; Middle Aged ; Japan ; Aged ; Adult ; Aged, 80 and over ; Attention ; Lycopene ; East Asian People

We studied whether exercise fatigue affects somatosensorv input using somatosensory evoked potential (SEP) . Sixteen subjects performed intermittent grip strength exercises with muscle fatigue while ignoring electrical stimulation given to an elbow. We induced SEP in the exercise task (during contraction) in every stage (first stage, middle stage and final stage) . In addition, we induced SEP in the exercise task during relaxation in the first stage and final stage. As a result, the early component amplitude of SEP decreased with the progress of exercise (manifestation of muscle fatigue) during contraction and relaxation. Our findings suggested that somatosensory input decreased with the manifestation of muscle fatigue. Somatosensory input is necessary for control of voluntary movement. Therefore, we speculate that these factors play a role in decreased performance of athletes competing in long-duration events.

The mechanism of the latent reaction time in task completion in elderly men was investigated by comparing the reaction time (RT), EMG-RT and motor time (MT) in young and elderly men. The motor performance was recorded as task completion through as a WS-RS, simple reaction or a choice reaction for each movement using a handgrip and switch.
In this study, we found that the RT and EMG-RT of elderly men in all movements of WS-RS and choice reaction tasks were significantly longer than those of young men, especially in the choice reaction tasks were striking. Moreover, the MT of elderly men in all tasks was significantly longer than those of young men.
These findings suggest that the latent RT and EMG-RT in a choice reaction task may be due to relayed information processing through as the discrimination and cognition functions in the brain, and that it may be also influenced by the mechanism of the latent reaction time of task completion in elderly men.

We examined here, changes in event-related potentials (ERPs) in eighteen children from 7 to 12 years and twelve adults. In addition to ERPs, we examined changes of EMG-RT. Subjects performed an auditory target discrimination task, in which 1000 Hz tones (target) and 2000 Hz tones (standard) were randomly presented with probabilities of 0.2 and 0.8.
We found P300 as most consistent component of ERPs since childhood. P300 latency and EMG-RT in children was significantly prolonged than in adults (p<0.01) . P300 amplitude in children was significantly larger than in adults (p<0.05) . We concluded that both stimulus evaluation time and response selection time in children are more prolonged than that in adults, although ERPs is confirmed in children.

Electrophysiologic effects of physical exercise were investigated by comparing a training group and non-training group. ERPs were recorded by oddball paradigm using auditory stimuli as well as count and reaction tasks. EMG-RT was recorded during the reaction task. No reliable exercise effects on N100 amplitudes or latencies were observed. Concerning P300 amplitudes, no significant difference between the training group and non-training group was seen although P300 latencies of the training group were significantly shorter than those of the non-training group in the count task. Moreover, EMG-RT of the training group was significantly shorter than that of the non-training group.
These findings suggest that the long-term physical exercise improved the efficiency of informa-tion processing and superior cognitive function in the brain.

The purpose of this study was to investigate the effect of the sleep deprivation for central information processing. Therefore we examined the changes in the amplitude and the latency of P300 event-related potentials (ERPs) before and after sleep deprivation in eight subjects. In addition to P300, we examined the power spectral changes of the EEG and the R-R intervals at rest before ERP measurements. The subjects performed an auditory target discrimination task and were instructed to keep mental count of each target stimulus. Then 2000 Hz tones (target) and 1000 Hz tones (nontarget) were randomly presented with probabilities of 0.2 and 0.8.
P300 latency at Fz, Cz, C3 and C4 was significantly prolonged after sleep deprivation (p<0.05) . P300 amplitude at Cz after sleep deprivation was significantly smaller than before sleep deprivation (p<0.05) . Alpha 1 power (8-10 Hz) at Cz on EEG was significantly decreased after sleep deprivation, but no other bands changed on EEG. The R-R interval was also significantly extended after sleep deprivation. We concluded that both central information processing and the autonomic nervous system may be influenced by sleep deprivation.