Historically, there have been two main streams to detect the abnormality of the central nervous system and brain mapping, i.e., function such as EEG since 1929 vs. morphology such as CT/MRI mainly since the late 70s. Both are essential and complement each other, and the neurosurgical approach has helped develop these clinical methods. Since the old era of 19th century, lesion study and seizure semiology study have provided us with the most important, fundamental knowledge of functional mapping of the cerebral cortices. Lesion study provides the information of chronic state of the brain pathology where compensatory mechanisms are already developed, whereas seizure semiology study only provides transient change of brain function without compensatory mechanisms, and thus the two methods may ultimately produce different results. Similarly, recently well established methods, namely 1) direct cortical stimulation and 2) activation studies by means of EEG/MEG (evoked potentials, event-related potentials and the equivalent magnetic field), cerebral blood flow (functional MRI) or receptor imaging (PET, SPECT), also provide similar features with regard to the compensatory mechanism. As for human brain mapping, delineation of the pre-supplementary motor area (SMA) and SMA proper, mapping of the higher cortical function such as language, praxis and will, out-of body-experience, and ictal apraxia will be discussed. In summary, clinically, brain mapping method with the information of the degree of compensatory mechanism will be expected and cortical mapping should always be interpreted with its own sensitivity and specificity.

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  In order to better interpret spatial and temporal changes on electrocorticograms (ECoG) taken during semantic tasks, we developed software to visualize semantic-ECoG dynamics on individual brains. Twenty patients with intractable epilepsy underwent implantation of subdural electrodes (more than 80 channels) bilaterally. Semantic-ECoGs were then recorded during word, figure and face recognition tasks. The ECoG raw data was processed by averaging and time-frequency analysis and the functional profiles were projected on individual brain surfaces. Acquired ECoG was classified by Support Vector Machine and Sparse Logistic Regression to classify brain signals evoked by different stimuli. Because of electrode location variations, we normalized the ECoG elecrtrodes using SPM8. The basal temporal-occipital cortex was activated within 250msec after visual object presentations. Face stimulation evoked significantly higher ECoG amplitudes than other stimuli. The prediction rate of ECoG-classification reached 90%, which is sufficient for clinical use. Semantic-ECoG is a powerful technique to detect and decode human brain functions.

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  We have been studying the underlying mechanisms of face perception in humans using magneto- (MEG) and electro-encephalography (EEG) and near infrared spectroscopy (NIRS).
  With the presentation of both upright and inverted unfamiliar faces, the fusiform gyrus and the superior temporal sulcus were activated simultaneously, but independently, predominantly in the right hemisphere. Latencies with inverted faces relative to those with upright faces were longer in the right hemisphere and shorter in the left hemisphere. We consider that differences in processing upright versus inverted faces are attributable to temporal processing. When viewing the motion of the mouth and eyes, a large clear MEG component, 1M (mean peak latency of approximately 160ms), was elicited to both mouth and eye movement, and was generated mainly in the occipito-temporal border, at human MT/V5. The 1M to mouth movement and the 1M to eye movement showed no significant difference in amplitude or generator location. Therefore, our results indicate that human MT/V5 is active in the perception of both mouth and eye motion, and that the perception of movement of facial parts is probably processed similarly.
  We investigated the effects of subliminal stimulation on visible stimulation to demonstrate the priority of facial discrimination processing, using a unique, indiscernible, color-opponent subliminal (COS) stimulation. We recorded MEG after the presentation of a face or flower stimulus with COS conditioning using a face, flower, random pattern, and blank. The COS stimulation enhanced the response to visible stimulation when the figure in the COS stimulation was identical to the target visible stimulus, but more so for the face than for the flower stimulus. We speculated that the enhancement was caused by an interaction of the responses after subthreshold stimulation by the COS stimulation and the suprathreshold stimulation after target stimulation, such as in the processing for categorization or discrimination.
  We recently measured NIRS in 5-8-month-olds' left and right lateral areas while they were looking at faces. The results of our first study are summarized as follows : (1) the concentration of oxyhemoglobin and total hemoglobin increased significantly in the right lateral area during the upright face condition, and (2) the concentration of total hemoglobin in the right lateral area differed significantly between the upright and inverted conditions. This is the first evidence showing that there is an inter-hemispheric difference on the effect of face inversion in the infant brain using a hemodynamic method. After this report, we have reported face perception and recognition in infants using NIRS concerning profile face perception, scramble face perception, facial expression perception, adaption effect of face, face perception using point-lights, mothers' face perception, and Arcimboldo's funny face perception.

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  The brain-machine interface (BMI) enables us to control machines and to communicate with others, not with the use of input devices, but through the direct use of brain signals.
  BMIs are classified into two types : the invasive type, which uses intracranial electrodes, and the noninvasive type, which uses skin electrodes or near infrared spectroscopy. The invasive type is further subdivided into two subtypes : a less invasive type, which uses brain surface electrodes and a highly invasive type, which uses needle microelectrodes.
  Noninvasive BMIs are promising for neurorehabilitation, while invasive BMIs are promising for use as neural prostheses for severely disabled people.
  The highly invasive type is characterized by high performance utilizing its detailed neural information, while the less invasive type is characterized by high feasibility for clinical application based on long-term stability.
  A fully-implantable wireless system is indispensable for the clinical application of invasive BMIs as it not only reduces the risk of infection but it also contributes to improving convenience.

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  Deep brain stimulation (DBS) has already been recognized as an effective therapy for involuntary movements. As DBS has become more widely used, psychiatric symptoms and personality changes induced by DBS have sometimes been observed. Such phenomena are associated with the close relationship of motor, associative and limbic circuits in the cortico-basal ganglia-thalamic-cortical (CBTC) circuit, which is often selected as a target for DBS. On the other hand, clinical research on DBS by stimulating the CBTC circuit for depression and obsessive compulsive disorder is being carried out in Western countries. The reversibility of DBS allowed it to be used as a new therapeutic method for psychiatric disorders, epilepsy, aggressiveness, obesity, and cluster headache, among others. However, apprehension on the history of abuse of psychosurgery backs up the development of this field. Prospects and ethical and social issues of DBS should be noted.

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  The recent remarkable development of robotic technology has made the myoelectric prosthesis available for use in the rehabilitation field. Accordingly, use of myoelectric prostheses for upper-limb amputee rehabilitation has become wide spread in the clinical field. The main advantage of myoelectric prostheses is the enhanced bimanual ability they deliver to the user. To achieve this performance, sufficient rehabilitation is critical in order for the amputee to use their prosthesis efficiently. Although prosthetic rehabilitation programs have been established for amputees with trans-radial and more distal amputation, a rehabilitation strategy for those amputees with a higher level of amputation remains to be established. In this literature, we propose a “Hybrid Myoelectric Prosthesis”, which consists of a myoelectric hand as a terminal device and a body-powered active elbow joint, for higher level amputees as a realistic solution. The future production of far superior prostheses which meet amputees' demands is expected. For this purpose, it is absolutely imperative to secure the cooperation of both clinicians and engineers.

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  We report a case of acute epidural hematoma associated with a progressive subgaleal hematoma. A 16-year-old adolescent boy was admitted to another hospital after a motorcycle accident. Initial radiography and CT scan showed diastasis of the right lambdoid suture and subgaleal hematoma. CT scan and MRI on the next day revealed enlargement of the subgaleal hematoma communicating with the small epidural hematoma through the diastasis of the lambdoid suture. Cerebral angiography demonstrated continuous extravasation from the middle meningeal artery near the diastasis of the lambdoid suture. The acute epidural hematoma was speculated to have been formed by continuous bleeding from the injured middle meningeal artery into subgaleal space through the diastasis of the lambdoid suture which thereby caused enlargement of the subgaleal hematoma. After embolization of the middle meningeal artery by the endovascular technique, we punctured and completely aspirated the subgaleal hematoma. Percutaneous aspiration of the subgaleal hematoma after embolization of the middle meningeal artery was effective in this case of acute epidural hematoma associated with a subgaleal hematoma.

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  We report a case of reversible posterior leukoencephalopathy syndrome (RPLS) in a patient with eclampsia without hypertension. Fluid-attenuated inversion recovery (FLAIR) and T2-weghted magnetic resonance images showed multiple hyperintense lesions not only in the posterior white matter and cortex but also in the basal ganglia. In cerebral angiography and magnetic resonance angiography, the images showed diffuse vasospasm of the anterior and middle cerebral arteries. We distinguished RPLS from venous sinus thrombosis by the magnetic resonance venography and the cerebral angiogram. The patient discharged without complications.

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