Using functional near-infrared spectroscopy, we investigated cortical activation while participants observed their own gait and the gait of others. Further, we compared the vividness of motor imagery induced by observing one's own and the gait of others. Participants were instructed to perform a gait observation task. The task had two conditions: observing video clips of one's own walking and observing video clips of other individuals walking. After observing the videos, the participants were asked to evaluate the vividness of the mental image of the observed gait on a visual analog scale. When observing one's own gait, the right dorsal premotor cortex and the superior parietal lobule were activated, whereas when observing the gait of others, the left inferior parietal lobule was activated. Observing one's own gait induced imagery that was significantly more vivid than that induced when viewing the gait of others. We suggest that observing one's own gait generates a representation of one's own body in the brain and induces more vivid gait imagery.

We aimed to investigate differences between the influence of observing one’s own actions and those of others in patients with stroke with hemiplegia. Thirty-four patients with stroke who had experienced a right or left hemispheric lesion (RHL: n = 17; LHL: n = 17) participated in this study. Participants viewed video clips (0.5× speed) of their own stepping movements (SO) as well as those of others (OO). After viewing the video clips, participants were asked to evaluate the vividness of the mental image of the observed stepping movement using a five-point scale, in accordance with that utilized in the Kinesthetic and Visual Imagery Questionnaire (KVIQ). We also examined changes in imagery and execution times following action observation. When all patients were considered, there were no significant differences between SO and OO conditions. However, in the RHL subgroup, KVIQ kinesthetic subscore and changes in imagery and execution times were greater in the OO condition than in the SO condition. In the LHL subgroup, changes in imagery times were greater in the SO condition than in the OO condition. These findings indicated that viewing the movements of others led to more vivid imagery and alteration in performance in patients with right-sided stroke, when compared to viewing one’s own movements. Therefore, the present study suggests that clinicians should consider the side of the damaged hemisphere when implementing action observation therapy for patients with stroke.

[Purpose] Oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex are closely associated with dyspnea. Dyspnea is influenced not only by physical activity, but also by visual stimuli, and several studies suggest that oxy-Hb concentrations change in response to certain external stimuli. However, the effects of internal psychological states on dyspnea have not been reported. This study explored the influence of anticipation triggered by previous episodes of dyspnea on brain activity. [Subjects] The subjects were 15 healthy volunteers with a mean age of 25.0 ± 3.0 years. [Methods] The subjects were shown a variety of photographs and instructed to expect breathing resistance matched to the affective nature of the particular photograph. After viewing the images, varying intensities of breathing resistance that were identical to, easier than, or harder than those shown in the images were randomly administered to the subjects; in fact, the image and resistance were identical 33% of the time and discordant 66% of the time. [Results] The concentrations of oxy-Hb in the right medial prefrontal cortex (rMPFC) increased significantly with an inspiratory pressure that was 30% of the maximum intensity in the subjects shown a pleasant image compared to the concentrations in subjects shown an unpleasant image. Moreover, rMPFC activity was significantly correlated with the magnitude of the dyspnea experienced. [Conclusion] These results suggest that a correlation exists between increased oxy-Hb in the rMPFC and the effects of expectations on dyspnea.

Background Transcranial direct current stimulation, a therapeutic modality to modulate the excitability of injured and uninjured brain hemispheres in stroke patients, is expected to be effective in treating upper limb paralysis. We describe the use of transcranial direct current stimulation to improve the function and frequency of use of the paralyzed hand of a patient with lenticulostriate artery occlusion. Case presentation A Japanese man in his fifties developed a left internal hindfoot perforator branch infarction owing to lenticulostriate artery occlusion, and presented with severe right upper and lower limb paralysis. Multiple interventions for the paralyzed hand, primarily robot therapy, did not noticeably change his hand function or frequency of use in daily life. Therefore, transcranial direct current stimulation was used in combination with upper limb functional exercises for 20 minutes a day, five times a week, for 6 weeks. Consequently, scores for the hand items of the Fugl–Meyer Assessment of the upper extremities improved, and pain and subluxation around the shoulder joint were reduced. Furthermore, the frequency of use and the quality of movement of the paralyzed hand were improved. Conclusions Upper limb functional training and transcranial direct current stimulation improved the function and frequency of use of the paralyzed hand in a stroke patient with severe upper limb paralysis, suggesting that this combined intervention could effectively improve hand function in patients with severe upper limb paralysis.