Developmental changes in shortening of pro-saccade reaction time while maintaining neck flexion position.

Background: We investigated developmental changes in shortening of pro-saccade reaction time while maintaining neck flexion.

Methods: Subjects comprised 135 children (3-14 years) and 29 young adults (19-23 years). Children were divided into six groups in 2-year age strata.

Timings of attentional switching to perturbation and postural preparation during transient forward or backward floor translation.

Background: Relationships between the timings of attentional switching and postural preparation were investigated using a choice-reaction paradigm with transient floor translation (S2), with the direction indicated by a warning auditory signal (S1).

Methods: Thirteen healthy young adults participated in this study. S2 started 2 s after S1 onset while standing on the platform.

Activation timing of postural muscles of lower legs and prediction of postural disturbance during bilateral arm flexion in older adults.

Background: Activation timings of postural muscles of lower legs and prediction of postural disturbance were investigated in young and older adults during bilateral arm flexion in a self-timing task and an oddball task with different probabilities of target presentation. Arm flexion was started from a standing posture with hands suspended 10 cm below the horizontal level in front of the body, in which postural control focused on the ankles is important.

Methods: Fourteen young and 14 older adults raised the arms in response to the target sound signal.

Postural control and contingent negative variation during transient floor translation while standing with the ankle fixed.

Background: Adaptation changes in postural muscle activity and anticipatory attention were investigated with the ankle joint fixed to change postural control strategies during transient floor translation.

Methods: For 15 healthy young adults, 40 transient floor translations (S2) in the anterior direction were applied 2 s after an auditory warning signal (S1), under conditions with or without fixation of the ankle. Activity of the frontal postural muscles (tibialis anterior (TA), rectus femoris (RF), rectus abdominis) and contingent negative variation (CNV, brain potential) were analyzed for 20 trials each of the early and latter halves under each fixation condition.

Event-related brain potential and postural muscle activity during standing on an oscillating table while the knee, hip, and trunk are fixed.

Background: In this study, a cast brace was used to immobilize the knee, hip, and trunk, and relations between the event-related brain potential (ERP) and postural muscle activity were investigated while standing on an oscillating table.

Methods: Twelve healthy young adults maintained a standing posture for 1 min per trial while oscillating in the anteroposterior direction at 0.5 Hz with a 2.

Postural responses to various frequencies of vibration of the triceps surae and forefoot sole during quiet standing.

The purpose of this study was to determine the role of somatosensory input to the sensory reference system in quiet standing. We applied vibration (0.5 mm amplitude, 1-60 Hz) to the triceps surae and the forefoot sole to stimulate the muscle spindles and the mechanoreceptors, respectively, and evaluated postural responses.

Postural control during transient floor translation while standing with the leg and trunk fixed.

Postural movement was restricted above the ankle, and contingent negative variation (CNV) and postural muscle activity were investigated during a transient floor translation (S2) 2s after an auditory warning signal (S1). For 13 healthy young adults, the joints of the knee, hip, and trunk were fixed using a cast brace. Under no-fixation and fixation, a set of 10 translations was repeated at least 4 times, and center of pressure in the anteroposterior direction (CoPap), posterior postural muscle activity of the body (elector spinae (ES), biceps femoris (BF), gastrocnemius (GcM) and soleus (Sol)), and late CNV at Cz were analyzed in the initial two sets (initial set) and last two sets (late set).

Effect of time pressure on attentional shift and anticipatory postural control during unilateral shoulder abduction reactions in an oddball-like paradigm.

Background: The effect of time pressure on attentional shift and anticipatory postural control was investigated during unilateral shoulder abduction reactions in an oddball-like paradigm.

Methods: A cue signal (S1) - imperative signal (S2) sequence was repeated with various S2-S1 intervals (1.0, 1.

Adaptation changes in dynamic postural control and contingent negative variation during repeated transient forward translation in the elderly.

Background: Adaptation changes in postural control and contingent negative variation (CNV) for the elderly were investigated during repeated forward floor translation.

Methods: Fifteen healthy elderly persons, living in the suburban area of Kanazawa City, Japan, underwent backward postural disturbance by a forward-floor translation (S2) 2 s after an auditory warning signal (S1). A set with 20 trials was repeated until a negative peak of late CNV was recognized in the 600-ms period before S2, and the last set was defined as the final set.

Postural responses accompanying Achilles tendon vibration stimulation during various phases of sit-to-stand movement.

The aim of this study was to determine the postural response accompanying Achilles tendon vibration stimulation during various phases of the sit-to-stand movement. Twelve healthy young adults performed the sit-to-stand movement in response to an auditory signal 2 s after a first one. Vibration stimulation with a 100 Hz frequency was applied to both Achilles tendons during the following phases: (1) 10 s of sitting before standing up; (2) 10 s plus a period until the standing position was achieved; and (3) 5 s after standing.

The effects of neck flexion on cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in related sensory cortices.

Background: A flexed neck posture leads to non-specific activation of the brain. Sensory evoked cerebral potentials and focal brain blood flow have been used to evaluate the activation of the sensory cortex. We investigated the effects of a flexed neck posture on the cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in the related sensory cortices.

Adaptation changes in dynamic postural control and contingent negative variation during backward disturbance by transient floor translation in the elderly.

Background: We investigated adaptation changes in dynamic postural control and contingent negative variation (CNV) in 13 young and 12 elderly adults. Subjects repeatedly underwent backward postural disturbance by a forward floor translation (S2) 2 s after an auditory warning signal (S1). Initial and second sets were conducted, each set with 20 trials.

Contingent negative variation and activation of postural preparation before postural perturbation by backward floor translation at different initial standing positions.

We investigated the effects of balance difficulty on contingent negative variation (CNV) and postural preparation against perturbation. Thirteen subjects were perturbed by a backward floor translation (S2) after an auditory warning stimulus. To alter balance difficulty, subjects maintained standing posture from four initial positions before perturbation.

Relationship between quiet standing position and perceptibility of standing position in the anteroposterior direction.

We investigated the relationship between an individual's center of pressure in the anteroposterior direction in quiet standing (QS) and perceptibility of different standing positions. The position of the center of pressure in the anteroposterior direction (CoPy position) while standing was represented as the percentage distance (%FL) from the hindmost point of the heel in relation to foot length. CoPy position in QS was located from 31 to 58%FL.

Effects of anti-saccade training with neck flexion on eye movement performance, presaccadic potentials and prefrontal hemodynamics in the elderly.

Anti-saccade performance, with strong contributions from frontal brain regions, reportedly deteriorates with age and maintenance of neck flexion and is known to cause brain activation. We investigated the effects of anti-saccade training on eye movement performance and frontal activity, and synergistic effects of training with neck flexion in the elderly. Thirty elderly individuals were divided into three equal groups: training group at neck resting position (NRT); training group at 20° neck flexion position (NFT); and untrained group.

Eye movement performance and prefrontal hemodynamics during saccadic eye movements in the elderly.

No previous study has investigated age-related changes in prefrontal hemodynamics during saccade tasks in a large number of elderly adults. The purpose of this study was to evaluate prefrontal activity related to the performance of anti-saccade in the elderly using near-infrared spectroscopy (NIRS). Ninety-six elderly adults and 22 young adults performed pro- and anti-saccade tasks.

Changes in muscle thickness of gastrocnemius and soleus associated with age and sex.

Background And Aims: Gastrocnemius and soleus in the triceps surae have functional and histological differences.We therefore investigated age-related changes in muscle thickness of these two muscles, as well as the difference in these changes between men and women.

Methods: Participants comprised 847 healthy adults aged 20 to 79 years.