Biomedical subjects

Soichi Ando

Publications and source records attributed to Soichi Ando.

5 recordsLinked to original sources

PubMed2026

Network oscillatory dynamics accompany cerebral bioenergetic defence in hypoxia.

A network physiology framework investigated how coordinated interactions among multiple organ systems collectively support the preservation of cerebral bioenergetic function and better distinguish adaptive from maladaptive responses to hypoxia. Twelve healthy males were passively exposed to 6 h of normoxia (21% O2) and hypoxia (12% O2) in a randomised, single-blind, crossover design. Venous blood was assayed for oxidative-nitrosative stress (OXNOS, spectroscopy/chemiluminescence) and neurovascular unit (hs-ELISA) biomarkers. Global cerebral delivery of O2 and glucose were determined by duplex ultrasound. Clinical acute mountain sickness (AMS+) was diagnosed in five participants. Cerebral substrate delivery was well maintained in both hypoxia and AMS+ (p < 0.05 vs normoxia and AMS-) despite marked arterial hypoxemia. Bioenergetic defence coincided with pronounced elevations in the spectral amplitude and phase synchronisation of very low-frequency oscillations (VLFOs, 0.03-0.06 Hz), which were evident across multiple organ systems and most prominent within the cerebral network. Systemic VLFOs were further exaggerated and more functionally connected in AMS+ in the absence of exaggerated systemic OXNOS or structural damage/destabilisation of the neurovascular unit (both p < 0.05 vs normoxia and AMS-). Collectively, these findings suggest that AMS, while characterised by debilitating symptomatology, may reflect a neuroprotective adaptive as opposed to pathologically maladaptive phenotype.

Humans↗

PubMed2005

Increase in reaction time for the peripheral visual field during exercise above the ventilatory threshold.

The purpose of the present study was to determine whether reaction time (RT) for the peripheral visual field increases at exercise intensity above the ventilatory threshold (VT) during incremental exercise and to examine the relationship between aerobic capacity and the extent of increase in the RT. Nine healthy subjects performed a simple manual RT task for the peripheral visual field at rest, during exercise on a cycle ergometer, and immediately after exercise. After warm-up exercise, the subjects cycled at 40 W for 3 min, increasing by 40 W every 3 min until 240 W in a step-wise manner. During incremental exercise, RT measurements were performed 1 min and 30 s after the start of every increase in workload. The RT for the peripheral visual field significantly increased at exercise intensity above VT, as compared with at rest. The increase in the RT, which was calculated by subtracting the RT at rest from the RT at 240 W, negatively correlated with maximal oxygen uptake VO(2max) for each subject (r = -0.73, P < 0.05). It is likely that high aerobic capacity attenuates the increase in the RT for the peripheral visual field during exhaustive exercise.

Adult↗

PubMed2004

Retention of practice effects on simple reaction time for peripheral and central visual fields.

Previous researchers reported that EMG Reaction Time (RT) for a key press in peripheral and central visual fields decreases with practice. The practice effects on the RT for peripheral visual field transferred to the RT for the central visual field, and vice versa. The present study investigated whether practice effects on the RT for peripheral and central visual fields and the corresponding transfer effects lasted 3 wk. or not. 16 male subjects were divided into two groups, one practicing using peripheral vision, the other practicing using central vision. Each group practiced RT tasks for 3 wk. 3 wk. after practice terminated, the practice effects and the transfer effects were maintained as a significant decrease in RT was found over the 3-wk. retention interval, suggesting that once the neural correlates of responding quickly are improved, the improved performances are remarkably stable for at least 3 wk.

Adult↗

PubMed2002

Practice effects on reaction time for peripheral and central visual fields.

The present study examined whether EMG-RT (RT) for a key press to stimulus in peripheral and central visual fields decreases with practice. 16 male students were divided into two groups, one practicing using peripheral vision, the other practicing using central vision. Before and after practice, RT was measured for peripheral and central visual fields. Each group practiced three blocks of 25 trials five days a week for three weeks. RT for peripheral and central visual fields decreased with practice. Practice effects on RT for the peripheral visual field extended to RT for the central visual field, and vice versa. It is suggested that the transfer may reflect the decrease in the central nervous system's processing time in common between two RT tasks.

Adult↗

PubMed2002

Attention can be oriented to intermediate locations within the large area of the visual field.

The present study examined whether attention can be evenly distributed within the large area of the visual field. The stimulus was presented at one of four locations on the horizontal meridian (0 degrees, 10 degrees, 20 degrees, and 30 degrees to the right). In the Fixed Location condition, the stimulus appeared repeatedly at the same location. In the Random Location condition, the stimulus appeared at one of four locations as determined randomly with equal probability. Reaction times (RTs) in the Random Location condition were significantly longer than those in the Fixed Location condition at the 0 degrees and 30 degrees locations, while there were no significant differences at the 10 degrees and 20 degrees locations. The differences in the RT between conditions were significantly larger at the 0 degrees and 30 degrees locations than those at the 10 degrees and 20 degrees locations. These results suggest that attention was oriented to intermediate locations within the large area of the visual field.

Adult↗