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S Kyuhou

Publications and source records attributed to S Kyuhou.

17 recordsLinked to original sources
PubMed2001

Cerebello-thalamo-cortical projections to the posterior parietal cortex in the macaque monkey.

The cerebello-thalamo-posterior parietal cortical projections were investigated electrophysiologically and morphologically in macaque monkeys. In anesthetized monkeys, electrical stimulation of every cerebellar nucleus evoked marked surface-positive, depth-negative (s-P, d-N) cortical field potentials in the superior parietal lobule and the cortical bank of the intraparietal sulcus, but no responses in the inferior parietal lobule. Tract-tracing experiments combining the anterograde method with the retrograde one indicated that the interposed and lateral cerebellar nuclei projected to the posterior parietal cortex mainly through the nucleus ventral lateralis caudalis of the thalamus. The significance of the projections is discussed in connection with cognitive functions.

Animals↗
PubMed1999

Cortical field potentials associated with audio-initiated vocalization in monkeys.

Five monkeys vocalizing at self-pace (self-paced vocalization) were well trained to vocalize in response to a monkey call (audio-initiated vocalization). Field potentials associated with audio-initiated vocalizations were recorded by using electrodes which were implanted chronically on the surface and at a 2.0-3.0 mm depth in various cortical areas. A surface-negative (s-N), depth-positive (d-P) potential (at about 70 ms latency after stimulus onset) was recorded in the rostral bank of the inferior limb of the arcuate sulcus in the left hemisphere, in which an insignificant potential was associated with self-paced vocalizations. An s-N, d-P slow potential which occurred in the motor and somatosensory cortices with a latency of about 300 ms after stimulus, started about 700 ms before vocalizations. The duration and amplitude of this potential was substantially the same with those of the potential which occurred with self-paced vocalizations. Reaction times from stimulus onset to vocalization start were variable, but were about 0.9s on the average. The findings were discussed in connection with reaction-time hand movements.

Acoustic Stimulation↗
PubMed1999

Injection of orphanin FQ/nociceptin into the periaqueductal gray suppresses the forebrain-elicited vocalization in the guinea pig.

Electrical stimulation of the caudoventral part of the anterior cingulate cortex (AC) evokes a species-specific vocalization in the guinea pig. After injections of glutamate receptor antagonists into the periaqueductal gray (PAG) regions where the AC projected, the forebrain-elicited vocalization (FEV) was suppressed completely. This result indicated that the FEV was induced at least partly by glutamatergic activation of PAG neurons. Injection of orphanin FQ/nociceptin (OFQ/N) into the PAG profoundly suppressed the FEV. This inhibitory effect of OFQ/N was not antagonized by naloxone, an opioid receptor antagonist. Since OFQ/N was reported to modify the glutamatergic transmission, the present results suggest that OFQ/N exerts influences upon the vocalization by regulating the glutamatergic inputs into the PAG.

Animals↗
PubMed1998

Two vocalization-related subregions in the midbrain periaqueductal gray of the guinea pig.

Vocal communications are well-developed in guinea pigs: they emit a separation call when isolated from the conspecifics, and vocalize mating calls during sexual activities. Similar calls were induced by the electrical stimulation of the midbrain periaqueductal gray (PAG) and the locations where the separation and mating calls were induced were segregated in the PAG. The morphological findings demonstrated that the PAG subregion where the separation call was induced receives massive input from the anterior cingulate cortex (which is related to social attachment behavior), while the subregion where the mating call was emitted has inputs mainly from the medial hypothalamus (related to sexual behaviors), suggesting that guinea pigs used multiple neuronal networks for various species-specific calls.

Animals↗
PubMed1997

Pontine neurons which relay projections from the superior colliculus to the posterior vermis of the cerebellum in the cat: distribution and visual properties.

Extracellular unit recording revealed that the dorsolateral pontine nucleus (DLPN) and nucleus reticularis tegmenti pontis (NRTP) of the cat constituted pontine relays for transmission of visual information from the superior colliculus (SC) to the posterior vermis (lobules VI and VII) of the cerebellum. The relay neurons in DLPN/NRTP responded to moving visual stimuli with large receptive fields (23-75 degrees ) which occupied mainly the contralateral hemifield including the fovea. These neurons were usually more responsive to large-sized stimuli than to discrete-spot stimuli, had direction selectivity, and showed preference to visual motion at a relatively high speed. No clear differences in visual properties were observed between DLPN and NRTP. After a local injection of lidocaine into SC, the visual responses in DLPN/NRTP transiently disappeared, indicating that DLPN/NRTP received the visual inputs through SC.

Animals↗
PubMed1997

Cerebello-cerebral projections onto the ventral part of the frontal cortex of the macaque monkey.

The cerebellar projections to the ventral part of the frontal cortex were investigated in the Japanese monkey (Macaca fuscata). In anesthetized monkeys, stimulation of either the lateral or interposed cerebellar nucleus evoked marked surface-negative and depth-positive potentials in the face motor area (Mf) and the upper part of the ventral premotor area (PMv) on the contralateral side; responses were hardly recorded in the lower part of PMv including the areas related to the laryngeal movements. Stimulation of the medial cerebellar nucleus induced no significant responses in these areas. The results of the combined anterograde and retrograde tracing study indicated that the cerebellar nuclei projected to Mf and the upper part of PMv mainly through the nucleus ventralis posterior lateralis pars oralis and area X of the thalamus, respectively.

Animals↗
PubMed1997

Motivation-dependent activity in the dorsolateral part of the prefrontal cortex in the monkey.

Field potentials were recorded on self-paced hand and mouth movements with implanted electrodes on the surface and at 2.0-3.0 mm depth in respective cortical areas in seven monkeys. Surface-negative (s-N), depth-positive (d-P) premovement slow potentials were recorded in the prefrontal cortex only when the movements were performed with an intense motivation for a reward. Such a motivation-dependent activity was mainly obtained in the rostral bank of the arcuate sulcus on both sides (except for the inferior limb of the arcuate sulcus in the left hemisphere). Three of the seven monkeys were also tasked with visuo-initiated hand movements. As motivation for reward decreased, s-N, d-P potentials at a latency of about 80 ms after stimulus onset became gradually smaller in the rostral bank of the arcuate sulcus in the right hemisphere. These facts suggest that motivation-dependent activity is represented in the dorsolateral part of the prefrontal cortex in monkeys, and that the cortical part is involved in motivational functions as well as in cognitive functions.

Animals↗
PubMed1997

Genesis of MEG signals in a mammalian CNS structure.

Neuromagnetic signals of guinea pig hippocampal slices were characterized and compared with the extracellular field potential to elucidate the genesis of magnetoencephalographic signals in a mammalian CNS structure. The spatial distribution of magnetic evoked field (MEF) directed normal to bath surface was similar for transverse CA1, longitudinal CA1 and longitudinal CA3 slices in the presence of 0.1 mM picrotoxin (PTX) which blocks inhibitory synaptic transmission. Their MEFs were produced by currents along the longitudinal axis of the pyramidal cells. Comparisons of the MEF with the laminar potential profile revealed that the MEF was generated by intracellular longitudinal currents. The dipolar component of the intracellular currents was the dominant factor generating the MEF even at a distance of 2 mm from the slice. The MEF from a slice in Ringer's solution without PTX became similar in temporal waveform with time to the MEF in the presence of PTX, indicating the predominance of excitatory connections in generating the MEF and the existence of highly synchronous populations activities across the slice even in PTX-free Ringer's solution. The presence of such highly synchronous population activities underlying the MEFs was verified directly with field potentials recorded across the slice. A systematic variation of the stimulation site revealed a characteristic waveform for each site. The variation of the with stimulation site suggested the contribution of many factors, both synaptic and voltage-sensitive conductances, to the overall waveform of the MEF.

Action Potentials↗
PubMed1996

Studies on integrative functions of the human frontal association cortex with MEG.

Our MEG studies on the human frontal association cortex are briefly reviewed. (1) The no-go potential was first found at go/no-go reaction-time hand movement task with discrimination between different colour light stimuli in the prefrontal cortex of monkeys. The potential was recorded in human subjects with EEG over the scalp, but its current dipoles could be localized only by use of MEG, in the dorsolateral part of the frontal association cortex in both cerebral hemispheres. The function for no-go decision and subsequent suppressor action was thus substantiated in the human frontal cortex. (2) Utterance of a short noun in Japanese was found to be initially preceded by an activity in the lower lateral part of the frontal lobe and then by that around the central sulcus. The area of the former, often in both hemispheres, appears to correspond to Broca's motor speech centre and that of the latter, always in both hemispheres, to correspond to the motor-somatosensory cortices. (3) Intensive and continuous concentration on mental calculation and some 'abstract' thinking for a few minutes were often associated with magnetic theta (5-7 Hz) wave bursts in the frontal part of the scalp. Dipole fitting suggested that the electrical current dipoles occur successively and scattered in wide areas of the frontal lobe on both sides. They are to be called "frontal mental theta wave", revealing dynamic and active participation of the frontal lobe in mental functions.

Adult↗
PubMed1995

Motor speech centres in the frontal cortex.

Activities of the frontal cortices in both cerebral hemispheres preceding utterance of a short word were recorded and analyzed with multichannel SQUID gradiometers. Light stimuli of two different colours of 500 ms duration were delivered in front of a subject at random time intervals and in irregular order of the different colours. The subject should respond to either of the stimuli by uttering a short word, e.g., 'en' [en] ('round' in Japanese) or another by a short simple voice without meaning as a word, e.g., 'e' [e]. The initial sounds of both voices are to be the same, i.e., 'e' [e] in these examples. The 37 gradiometers covering either the left or the right frontal-parietal part of the hemisphere recorded different magnetic fields between the word and the simple voice. Magnetic fields averaged 100 times at the onset of the stimuli revealed that the utterance of a word is preceded by significant magnetic field changes at a peak latency of 120-165 ms from the onset of light stimuli, whereas the utterance of a simple voice is not preceded by such changes. At a peak latency of 160-190 ms, about 20-40 ms before the start of perioral EMGs, both the utterances are commonly preceded by magnetic field changes. Dipole fittings based on these magnetic fields suggest that the earlier magnetic fields reflect electrical activities in the ventral lateral part of the frontal association area, usually in both left and right hemispheres, and that the later fields represent those in the sensorimotor area in both the hemispheres. That part of the frontal association area appears to be the centre for organizing words to speak and to correspond possibly to the Broca's speech area.

Adult↗
PubMed1994

Dynamic activities of the frontal association cortex in calculating and thinking.

We found 5-7 Hz magnetic theta waves in the frontal association cortex of adult human subjects during calculation and musical imagination by using 37-channel SQUID gradiometers. Simultaneous recording from the left and right cerebral hemispheres with two sets of 37-channel gradiometers revealed that the theta activity appeared in a waxing and waning manner in the frontal cortices of both hemispheres during the mental exercises. Electrical current dipoles for the theta waves were estimated to occur repeatedly and scatteringly in various parts of the frontal lobes of both hemispheres during continuous and intense mental exercises for 2 min. The results suggest a dynamic mode of activities in the frontal association cortex during mental effort such as calculating and thinking.

Adult↗
PubMed1993

Detection of magnetic evoked fields associated with synchronous population activities in the transverse CA1 slice of the guinea pig.

1. Magnetic evoked fields (MEFs) associated with synchronous population activities in the transverse CA1 of guinea pig (approximately 1.2 mm3) were characterized with a high-resolution superconducting magnetic field detector. 2. Electrical stimulations of the stratum radiatum with a pair of bipolar electrodes produced synchronous population spikes in the field potential and a strong MEF (as much as 3.5 picoteslas 3 mm above tissue) in the presence of 0.05 mM picrotoxin. The MEF's spatial pattern and direction indicated currents in pyramidal cells as its source. Bath application of kynurenic acid extinguished most of the signals, indicating a strong contribution of post-synaptic currents to the field. The kynurenic acid-insensitive component was abolished by tetrodotoxin, indicating the remaining component was neuronal in origin as well. 3. It may be possible to refine our technique to study the genesis of MEG signals--i.e., the relationship between evoked fields and the underlying neuronal currents--in a mammalian CNS structure, since the electrophysiology of the hippocampus is well understood.

Animals↗
PubMed1992

Cerebro-cerebellar projections from the ventral bank of the anterior ectosylvian sulcus in the cat.

1. Stimulation of the ventral bank of the anterior ectosylvian sulcus (AESv) induced marked mossy fibre (MF) and climbing fibre (CF) responses in the cerebellar posterior vermis (lobules VI-VII) and moderate sized ones in the paraflocculus, paramedian lobules and crus I and II of the cat. The relay stations for these responses to the posterior vermis were investigated morphologically and electrophysiologically. 2. It can be considered that the MF responses were relayed at least in part via the dorsolateral, peduncular and paramedian pontine nuclei, since in these nuclei there were units orthodromically responsive to AESv stimulation and antidromically responsive to stimulation of the posterior vermis. The MF responses are thought to be relayed monosynaptically, since the distribution of axon terminals labelled after injection of wheatgerm agglutinin-conjugated peroxidase (WGA-HRP) into the AESv overlapped in these pontine nuclei with that of neurons labelled after injection of WGA-HRP into the posterior vermis. 3. It is thought that the CF responses are relayed in the caudomedial part of the medial accessory olive (MAOcm), because neurons in the MAOcm were orthodromically responsive to AESv stimulation and antidromically responsive to stimulation of the posterior vermis. 4. It is suggested that the cerebro-olivary projection which transmits the orthodromic responses in the MAOcm is indirect, via the superior colliculus (SC), because injection of WGA-HRP into the AESv labelled axon terminals not in the MAOcm but in the SC, and injection of WGA-HRP into the MAOcm gave rise to retrograde labelling of cells in the SC. Synaptic connections between the axon terminals of the cerebrotectal projection and the tecto-olivary neurons were demonstrated by extracellular unit studies in the SC. 5. The hypothesis that the CF responses were transmitted via the SC was supported by the finding that the CF responses disappeared transiently after muscimol or lidocaine was injected into the SC. 6. These findings provide evidence that the MF responses are transmitted at least in part via the cerebro-ponto-cerebellar projection, while the CF responses are relayed via the cerebro-tecto-olivo-cerebellar projection. These cerebro-cerebellar pathways from the AESv are suggested to participate in conducting visual information to the posterior vermis.

Animals↗
PubMed1991

Topographical organization of the tecto-olivo-cerebellar projection in the cat.

The superior colliculus sends a climbing fiber output to cerebellar vermal lobules VI-VII through the inferior olive. The present study in cats morphologically clarified the existence of a topographical organization in the tecto-olivo-cerebellar projection. A horseradish peroxidase study on the tecto-olivary projection showed that the rostral and caudal superior colliculus projected mostly contralaterally to the caudal and rostral areas of the caudomedial part of the medial accessory olive, respectively. The lateral superior colliculus was found to project more laterally than was the medial superior colliculus. Investigation on the olivocerebellar projection demonstrated that the rostral and caudal areas of the caudomedial part of the medial accessory olive sent climbing fiber terminals contralaterally to the lateral and medial parts of vermal lobules VI-VII, respectively. Thus, it was revealed that the rostral superior colliculus projected mostly to the medial part of ipsilateral vermal lobules VI-VII while the caudal superior colliculus projected mostly to the lateral part of ipsilateral vermal lobules VI-VII.

Afferent Pathways↗
PubMed1987

Cerebellocerebral projection from the fastigial nucleus onto the frontal eye field and anterior ectosylvian visual area in the cat.

The fastigiocerebral projection in the cat was investigated electrophysiologically by recording field potentials and unit activities and also morphologically by anterograde and retrograde HRP methods. Three cortical areas mostly hidden in sulci, two in the frontal cortex and one in the insular cortex, were responsive to fastigial stimulation under pentobarbital anesthesia. The responsive areas in the frontal cortex were the ventral bank of the cruciate sulcus and the area surrounding the fundus of the presylvian sulcus; the latter area corresponds to a subregion of the frontal eye field. The responsive area in the insular cortex was the ventral bank of the anterior ectosylvian sulcus, which overlaps largely with the "anterior ectosylvian visual area." The response in the frontal cortex was a surface-positive, depth-negative wave, whereas the response in the insular cortex was a surface-negative, depth-positive wave. Anterogradely labeled terminals of the fastigiothalamic projection were most dense in the ventromedial (VM) nucleus in which retrogradely labeled neurons were numerous when WGA-HRP was injected into any one of the three cortical areas. In agreement with the results of the HRP studies, units that responded orthodromically to fastigial stimulation and antidromically to cortical stimulation were located in the thalamic VM nucleus. There was a marked difference between the frontal and insular cortices in laminar distribution of terminals of the thalamocortical projection fibers. Anterogradely labeled terminals after injection of WGA-HRP into the VM nucleus were distributed mainly in layers I and III in the frontal cortex, whereas they were distributed mainly in layer I in the insular cortex.

Animals↗
PubMed1985

Cerebellocerebral projection from the fastigial nucleus onto the frontal cortex in the cat.

Two frontal cortical areas hidden in sulci were found to be responsive to stimulation of the cerebellar fastigial nucleus under pentobarbital anesthesia: one is the ventral bank of the cruciate sulcus and the other is the area surrounding the fundus of the presylvian sulcus which corresponds to subregions of the frontal eye field. The fastigial projection onto these areas via the thalamic ventromedial (VM) nucleus was identified electrophysiologically and morphologically.

Animals↗