The purpose of this paper is to assess time varying changes of electroencephalogram (EEG) under the emotional stress stimuli. Twenty-two healthy subjects were evaluated their psychosomatic states using Cornell Medical Index (CMI) and were categorized into normal group (I in CMI) and high CMI value group (II, III, and IV in CMI) based on the results of CMI. EEG under the emotional stimuli (relaxed, pleasant, and unpleasant sessions) was measured and was analyzed using wavelet analysis. The mean scalogram (wavelet spectrum) in alpha band in each session was calculated, and the mean scalogram values between stimuli and between groups in each electrode site were compared. The relative mean scalogram value in every 4 second-epoch was calculated based on the baseline from non-stimuli epoch at the beginning of the experiment and was assessed using regression analysis. The results showed that EEG reactions to the emotional stimuli in normal group were larger and steeper than the reactions in high CMI value group. The scalogram values in the relaxed and pleasant sessions in normal group were restored to the baseline with time, and the scalogram value in the unpleasant session in normal group increased with time. The results indicated that time varying changes of EEG under the emotional stress stimuli were different according to the psychosomatic states.

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To understand the development of visual tracking ability during childhood, upper limb motor functions of 405 children aged 3–12 years and 52 adults aged 20 years (control) were evaluated. We calculated 12 parameters, namely, the mean values and standard deviations of radial deviation, angle deviation, movement distance per each sampling time, pen pressure, and pen pressure variability, residual sum squares of the power spectrum of acceleration in X axis and residual sum squares of the power spectrum of acceleration in Y axis. Then, factor analysis was applied against these parameters, and 3 factors were identified to be important; these 3 factors were the skillfulness of drawing, stability of tremor, and stability of pen pressure. Our results show that the curve for development of skillfulness of drawing and stability of tremor against increasing age was hyperbolic. The stability of pen pressure showed linear development until an age of 6 or 7 years and little development after that age. Therefore, we think that a three-dimensional model can be used to describe the development of visual tracking ability.

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This paper describes our investigation on functional imaging of human nerve electrical activity in the lumbar spine area using its evoked neuromagnetic field. The neuromagnetic measurements were conducted for five healthy male over the surface of lower back after stimulation of the tibial nerves at the ankle. The nerve electrical activity was reconstructed over a curved surface which was determined using the subject’s lateral X-ray image. We applied the recursive null steering (RENS) spatial filter to reconstruct the nerve activity. The results of our experiments, showed that the dynamics of nerve electrical activities in the lumbar spine could clearly be visualized for all five subjects.

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To determine the relationship between skull surface brainstem auditory evoked potentials (BAEPs) and near-field potentials, short latency auditory-evoked potentials were directly recorded from the brainstem surface in humans and cats using monopolar and bipolar recording techniques. However, monopolar recordings did not sufficiently define BAEP generator sources. Detection results of phase-reversal bipolar recordings in cats demonstrated the importance of two-electrode positions, fiber directions, and impulse directions. In contrast, responses recorded from bipolar electrodes on the contralateral caudal pons demonstrated that only the component associated with time at P3 revealed a phase reversal. These results suggested that waves I, II, and III in humans corresponded to the same components in cats. In addition, wave III generated the structures in the contralateral pons, which was likely the contralateral superior olive to the stimulated ear. Further studies combining other experimental techniques are needed to determine the exact BAEP generators.

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The present study determined the generation sites of brainstem auditory evoked potentials (BAEPs) and the effects of space-occupying lesions. The subjects were assigned to six groups: midbrain tumor, pontine intramedullary tumor, IVth ventricle tumor, C-P angle tumor, clival tumor, and cervico-medullary space-occupying lesions according to location and effect of brainstem compression. In the midbrain tumor group, most pineal tumors did not have an effect on BAEPs, because they stayed in the rostral half of the midbrain. In the midbrain tumor, which primarily involved the midbrain tegmentum, including the quadrigeminal plate, only wave V on BAEPs was severely attenuated from left and right stimulation. An additional tumor in the unilateral side of the ponto-midbrain junction exhibited attenuation of wave IV to ipsilateral stimulation, and of wave V to contralateral stimulation, from the lesion side. Results of midbrain tumors suggested that the generator(s) of wave V were located in the lower midbrain, and generators and/or pathways of waves IV and V were present on the opposite side of the brainstem to the stimulated ear.
Effects on BAEPs in cases with pontine intramedullary tumors and IVth ventricle tumors the long tracts were similar, i.e., wave III was easily affected even if symptoms remained mild. In contrast, in the C-P angle tumor group, when the T/BS ratio reached 80%, the wave V or wave IV/V complex on the BAEP contralateral stimulation to the lesion side was lost. These suggested that auditory tracts generating waves IV and V were located more laterally in the lower pons than wave III.
Four kinds of tumors—IVth ventricle tumor, cerebellar tumor, C-P angle tumor, and cervico-medullary tumor—exhibited similar unilateral BAEP abnormalities, i.e., wave II was absent or severely attenuated, and the succeeding components were delayed. According to MRI and neurological findings, tumor lesions in the former two cases of the above-mentioned four cases did not affect the VIIIth nerve, but rather compressed the cochlear nucleus. Those results strongly suggested that wave II was generated by cochlear nucleus.
In summary, results from the present study showed the following: 1) wave V was generated in the caudal region of the midbrain tegmentum; 2) generators and/or pathways of waves IV and V were on opposite sides at the rostral pons level; 3) generators and/or pathways of waves IV and V were more lateral in the caudal half of the pons than wave III; and 4) wave II was generated in and around the cochlear nucleus.

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