Effects of a single bout of walking on psychophysiologic responses and executive function in elderly adults: a pilot study

Background: The purpose of this study was to examine the effects of a single bout of walking on mood, psychophysiologic responses, and executive function in elderly adults.Methods: Twenty healthy, elderly adults (10 women and 10 men; mean age 70.50 ± 3.4 years) participated in this study. Mood, as assessed by the Profile of Mood States, and salivary α-amylase activity were examined before and after walking. Executive functions were also evaluated by the Wisconsin Card Sorting Test.Results: Negative feeling scores such as tension-anxiety, anger-hostility, and confusion significantly improved after walking. No significant differences were found for either salivary α-amylase activities or Wisconsin Card Sorting Test scores before and after walking. However, the changes in salivary α-amylase activity before and after walking correlated positively with the number of total errors and perseverative errors of Nelson in the Wisconsin Card Sorting Test.Conclusion: These results suggest that moderate exercise, such as self-paced one-time walking, induces beneficial psychologic effects in elderly adults. Meanwhile, the significant increase in salivary α-amylase activity after walking might temporarily cause deterioration of executive function

ERP evidence of attentional somatosensory processing and stimulus-response coupling under different hand and arm postures

We investigated (1) the effects of divided and focused attention on event-related brain potentials (ERPs) elicited by somatosensory stimulation under different response modes, (2) the effects of hand position (closely-placed vs. separated hands) and arm posture (crossed vs. uncrossed forearms) on the attentional modulation of somatosensory ERPs, and (3) changes in the coupling of stimulus- and response-related processes by somatosensory attention using a single-trial analysis of P300 latency and reaction times. Electrocutaneous stimulation was presented randomly to the thumb or middle finger of the left or right hand at random interstimulus intervals (700–900 ms). Subjects attended unilaterally or bilaterally to stimuli in order to detect target stimuli by a motor response or counting. The effects of unilaterally-focused attention were also tested under different hand and arm positions. The amplitude of N140 in the divided attention condition was intermediate between unilaterally attended and unattended stimuli in the unilaterally-focused attention condition in both the mental counting and motor response tasks. Attended infrequent (target) stimuli elicited greater P300 in the unilaterally attention condition than in the divided attention condition. P300 latency was longer in the divided attention condition than in the unilaterally-focused attention condition in the motor response task, but remained unchanged in the counting task. Closely locating the hands had no impact, whereas crossing the forearms decreased the attentional enhancement in N140 amplitude. In contrast, these two manipulations uniformly decreased P300 amplitude and increased P300 latency. The correlation between single-trial P300 latency and RT was decreased by crossed forearms, but not by divided attention or closely-placed hands. Therefore, the present results indicate that focused and divided attention differently affected middle latency and late processing, and that hand position and arm posture also differently affected attentional processes and stimulus–response coupling

Effect of Motor Preparation, Motor Response and Stimulus Discrimination on Contingent Negative Variation (CNV) Resolution Processes

We investigated effect of various tasks on contingent negative variation (CNV) resolution processes. Above all, it is investigated how the existence of motor preparation, of motor response and of stimulus discrimination on imperative stimulus affects CNV resolution. The subjects were 16 normal students. Five tasks were performed by the subjects. As a result, CNV resolution time was prolonged in the simple motor task compared to other tasks. The appearance of component like P300 on S_2 was unclear. But in other conditions, component like P300 on S_2 was found. Moreover it is found that the appearance of component like P300 affected CNV resolution. A significant difference in the CNV resolution was found between discrimination motor task and discrimination mental task. Based on these results, it is concluded that CNV resolution was depended on the discrimination of S_2 stimulus, but did not on the existence of motor preparation or motor response

自発的な足，足趾，手指動作に先行する運動前脳電位

本論文において著者達は，随意的な手動作に先行して動作肢と反対側大脳半球上で優位を示す大脳準備電位（RP）が下肢や足指動作の場合も同じ分布を示すかということを，加算平均されたEEG，EMGを用いて調べた。その結果，下肢や足指動作に先行して出現する大脳準備電位は動作肢と同側大脳半球上で優位を示す傾向にあったが，統計的には有意ではなかった。一般的に，下肢や足指の投射領域は大脳縦裂にそった深部にあり，手の領域は中心回の内部に埋もれていると考えられている。MEG（magnetoencephalgraphic）記録も下肢や足指動作に先行する大脳準備電位は動作肢と同側半球上で優位を示すことを確認している。それゆえ，本実験結果や今までの一連の研究から，手と下肢，足指動作間の大脳準備電位の頭皮上分布差は，大脳半球上での支配領域の差ではなく，大脳準備電位発生に関与していると推測されている二つの発生源の時間的な差によるものであると推察される。Whether the Readiness Potential (RP) prior to foot and toe movements shows a larger amplitude over the hemisphere ipsilateral to the movement was examined by the averaged EEG and EMG. Analysis showed that prior to foot and toe movements, the RP amplitudes were slightly larger over the ipsilateral hemisphere than over the contralateral hemisphere to the movement, but not consistently significant. The RP for finger movement, however, was clearly larger over the contralateral hemisphere to the movement. It is considered that the project area of the lower limb is situated in the depth along the fissure longitudinalis and that of the hand area lies mainly buried within the central sulcus. The MEG (magnetoencephalographic ) recordings of other studies did not show the paradoxical EEG side preponderance with respect to the RP prior to the foot movement. Therefore, from the recent studies and the present results, it is concluded that the distribution difference between the RP for foot and finger movement was not due to a control difference of the cerebral hemisphere between foot and finger responses, but to the difference of temporal ordering of the principal generators which might contribute to the RP constitution

H波発達曲線勾配による運動ニューロンプール興奮性の評価

ヒト脊髄運動ニューロンプール興奮性を示す新たな指標としての，M波閾値の刺激強度以下でのH反射の発達勾配の妥当性を，従来用いられてきたH／M比率法との比較から検討した．H／M比率法ではのM波誘発に伴うα運動線維の逆行性伝導によるH反射の閉塞現象が避けられず，H反射の最大値はH反射とM波の閾値差に依存することから，求められたH反射の最大値が必ずしも運動ニューロンプール全体に対する反射性に興奮しうる運動ニューロンの割合を示さないことが判明した．一方，H反射の発達勾配はH反射とM波の閾値差に依存しなかった．従って，H反射の発達勾配は従来用いられてきたH／M比率法より，安静時における脊髄運動ニューロンプール興奮性の指標としてはより妥当なものであることが示唆された．また，その個人内変動に有意差は認められず，個人に固有なH反射の発達勾配，すなわち運動ニューロンプール興奮性の個人の特性を示す可能性が示唆された．The individual intrinsic excitability of the motoneuron pool was investigated by the H-reflex method. A linear regression line was calculated to be fitted to the recruitment curve of the H-reflex evoked at a range of electric stimulation lower than the threshold of the M-response. The slope of this regression line was found to be significantly invariant among repeated measurements within an individual. This invariant slope of the regression line was suggested to be more effective as a parameter to evaluate the individual intrinsic excitability of the motoneuron pool than the ratio of maximal amplitube of the H-reflex to that of the M-response

Information-Processing Mediating the Location-Distance Interference in Motor Short-Term Memory

We reviewed the literature on basic psychological correlates of the well-known phenomenon of the location-distance interference in motor short-term memory (Kerr, 1978 ; Walsh, Russell, Imanaka, & James, 1979). The location-distance interference in motor short-term memory has frequently been demonstrated as an unavoidable interference phenomenon observed in the reproduction of movement location and distance in arm positioning. The most important aspect of this phenomenon is that even when a subject concentrates on a specific cue (i.e., either end-location or distance) the other cue is also coded unintentionally and, as a result, the reproduction movement guided on the basis of the specific cue is unavoidably influenced by the other nonspecific cue. In thls review article, we first reviewed the literature on the basic theories and nature of shortterm memory, particularly on the limited processing capacity. We then referred to the unlimited, automatic processing in visual-verbal domains, referring to the Stroop phenomenon. Finally, in conjunction with the notion of automatic processing, we examined the possible aspects of information processing which may be responsible for mediating the location-distance interference in motor short-term memor