We examined neurocognitive process of response control during the Stop-signal task by setting up the difference of visual stimulus condition. The aim of this study was to examine how the type of Go and Stop stimuli and combination of them, related to car (the car stimulus condition) and sign (the sign stimulus condition), is reflected in behavioral performances and ERP. Twenty-three adults participated in this experiment. As a result, the reaction time (RT) and the stop signal reaction time (SSRT) was significantly prolonged in the car stimulus condition, and also the commission error rate to Go stimulus was significantly increased, than in the sign stimulus condition. In ERP, significantly higher GFP peak and longer GFP latency from 175 ms to 225 ms after the Go stimulus was onset, in the car stimulus condition. Similarly, significantly higher GFP peak from 175 ms to 225 ms after the Stop stimulus was onset, and significantly lower GFP peak from 230 ms to 400 ms after the Stop stimulus was onset, additionally the amplitude of the SST-P3 decreased in the car stimulus condition, than in the sign stimulus condition. These results suggest that the difference of the stimulus condition, especially the difficulty of the stimuli distinction, affects the attentional resource allocation to the both Go stimuli and Stop ones in the Stop-signal task. And the effects might be reflected in the both behavioral performances and ERPs.
Examination of the training method to successfully synchronize finger movements with rhythmic auditory stimulations is presented with due consideration of the difficulties involved in predicting the next stimulus. Twenty-four healthy subjects were divided into two groups—A and B—and both groups were asked to perform different trainings. Subjects in group A were asked to synchronize finger tappings with rhythmic stimulations at intervals of 2,000 ms. Similarly, those in group B performed the finger-tapping exercise at a frequency of one tapping per two rhythmic stimulations at intervals of 1,000 ms. Prior to the commencement of as well as after the training, both groups were evaluated for their ability to synchronize finger tapping with stimulations that repeat at intervals of 2,000 ms with due consideration of the difficulties involved in predicting the next stimulus. In the post-training evaluation, variations in the intertap interval and synchronization error as well as the rate of occurrence of reactive tapping were found to be significantly smaller in group B than in group A. This illustrates that rhythmic stimulations repeating at 1,000-ms intervals facilitate ease in feeling the tempo while also refining the precision of internal timing mechanisms involved in the control of periodic movement at intervals of 2,000 ms.
Empathy is vital for communication and survival in social environments. Empathy consists of cognitive (cognitive empathy) and affective (affective empathy) components, which complement each other in deploying empathic functions. In this study, we investigated the differences between the neural basis of cognitive and affective empathy using functional magnetic resonance imaging (fMRI). Our cohort of 16 healthy adult women was required to passively observe (Affective Task: AT) and assess (Cognitive Task: CT) images of different faces that evoke positive emotions, whilst undergoing MRI. We found heightened activation of the bilateral inferior parietal lobules during the AT compared to the CT. Conversely, we detected heighted activation of the left inferior frontal gyrus during the CT compared to the AT. In summary, our results suggest that affective empathy is associated with reproducing the mental states of others, and that cognitive empathy integrates the neural activity required to infer the meaning of facial expressions. Both the inferior parietal lobule and the inferior frontal gyrus are part of the mirror neuron system: these brain regions have a proposed involvement in empathy. Here we found that different brain regions in the mirror neuron system are associated with affective and cognitive empathy, respectively.
Magnetoencephalography (MEG) is one of the best ways to analyze neural function. In particular, MEG is valuable for assessing brain activity in children with epilepsy, because it is non-invasive and can be used multiple times for the same patient, thus enabling changes in epileptogenicity to be monitored as a child’s grows. The single-dipole analyses tools can resolve localized epileptic MEG discharges and demonstrate equivalent current dipoles (ECDs) in cerebral cortex. An alternative MEG tool: source distribution analysis is used for widespread or multi-focal epileptogenic areas. In conclusion, the single-dipole method and source distribution analysis could successfully resolve an epileptogenic area in patients with epilepsy. Thus, MEG analysis is potentially useful for presurgical evaluation or the diagnosis of epileptic syndromes for almost every patient with epilepsy.
Epilepsy and autonomic dysregulation are closely related because the centers of the autonomic nervous system are located within the cerebral cortices. Patients with epilepsy can manifest autonomic dysregulation during the ictal and/or interictal periods. Patients with epilepsy may suffer various autonomic symptoms including bradycardia/tachycardia, apnea/tachypnea, abdominal discomfort/nausea/vomiting, and hypersalivation during seizures, caused by propagation of ictal discharges to the central autonomic network. We reported that onset time of heart rate increase occurred significantly earlier during right than left seizures in patients with mesial temporal lobe epilepsy. Heart rate variability (HRV) is an established parameter for the assessment of cardiac autonomic regulation, a balanced parasympathetic-sympathetic autonomic activity. Patients with epilepsy show abnormal HRV during interictal periods, which may correlate with sudden unexpected death in epilepsy (SUDEP). However, the clinical factors associated with abnormal HRV remain unclear, and the relationship between abnormal HRV and seizure lateralization is controversial. We found that patients with right hemispheric focal epilepsy showed significantly lower high-frequency power during non-REM sleep than patients with left hemispheric focal epilepsy and non-epileptic patinets and that patients with left hemispheric focal epilepsy showed significantly higher low-frequency power during non-REM sleep and high-frequency power during wakefulness than patients with right hemispheric focal epilepsy and non-epileptic patients. Timing of ictal heart rate increase and interictal HRV during non-REM sleep as well as wakefulness may be useful lateralizing signs of focal seizures including temporal seizures.