Human cortico-hippocampal activity related to auditory discrimination revealed by neuromagmetic field

Kikuchi, Yoshihiro; Endô, Hiroshi; Yoshizawa, Shuji; Kait, Michiko; Nishimura, Chiaki; Tanaka, Masayuki; Kumagai, Toru; Takeda, Tsunehiro

doi:10.1097/00001756-199705060-00020

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…Identifying neuromagnetic sources in the deep regions of the brain such as the hippocampus has been considered difficult. However, several studies have succeeded in observing neuronal activities in the hippocampal area, using MEG (Tesche, 1996;Kikuchi et al, 1997;Nishitani et al, 1998). In particular, Nishitani et al (1998) and Tesche et al (1996) measured evoked magnetic fields emanating from hippocampal areas using a planar first-order gradiometer, which is better suited for measuring neuronal activity at the cortical surface.…”

Section: Discussionmentioning

confidence: 99%

“…For example, Kikuchi et al (1997) reported that hippocampal activity emerged at 280 -400 ms after auditory stimuli. Tesche et al (1996) reported latencies ranging from 200 -500 ms. Nishitani et al (1998) measured M400 components, which correspond to the P300 component of the electroencephalogram (EEG), and described a latency range of 345-462 ms following stimulus onset.…”

Section: Latencies Of the Hippocampal Activitiesmentioning

confidence: 99%

“…More recently, studies using magnetoencephalography (MEG), which has an improved spatial resolution over conventional electrical scalp recordings, have identified neuromagnetic components corresponding to P300 within the hippocampal region when elicited by auditory oddball stimuli (Tesche, 1996;Kikuchi et al, 1997;Nishitani et al, 1998). These studies reported that the latencies of the hippocampal activity were 200 -500, 345-462, and 280 -400 ms, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic fields in the human hippocampal area evoked by a somatosensory oddball task

et al. 2004

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We recorded neuromagnetic fields evoked by a somatosensory oddball task requiring subjects to discriminate target stimuli from nontarget stimuli, which are different in stimulation intensity, with a mental count of the target stimuli. A whole head type 80-channel magnetoencephalography (MEG) system with a 50-mm baseline gradiometer array was used. Targets and nontargets were somatosensory stimuli with an electrical current intensity of twice and three times the sensory threshold, respectively. The source current locations of the evoked magnetic fields in three dimensions and the equivalent current dipole (ECD) moments were calculated by using a single dipole model, assuming the brain as a sphere. In 28 of 63 recording sessions for 7 subjects, the loci of neuronal activities were observed in the left and/or right hippocampal areas. The latency of left hippocampal activity (293 +/- 49 ms) was significantly shorter than that of the right (333 +/- 45 ms) (P = 0.027, non-paired t-test). In view of previous studies that have shown the time window of sensory integration as approximately 200-300 ms, sensory information may be transferred to hippocampal areas following sensory integration.

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Section: Discussionmentioning

confidence: 99%

Section: Latencies Of the Hippocampal Activitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic fields in the human hippocampal area evoked by a somatosensory oddball task

et al. 2004

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“…Human studies showed that lateral superior temporal regions were activated in the processing of speech sounds (Rauschecker et al, , 1998 and environmental noises (Engelien et al, 1995;O'Leary et al, 1996). Parahippocampal gyrus has been recognized as a central component of a neural network engaged during auditory discrimination (Kikuchi et al, 1997). The activation of the left frontal operculum could be related to verbalization and semantic processing of complex sounds.…”

Section: Regions Selectively Activated By Sound Recognitionmentioning

confidence: 99%

Distinct pathways involved in sound recognition and localization: A human fMRI study

Maeder¹,

Meuli²,

Adriani³

et al. 2000

NeuroImage

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Evidence from psychophysical studies in normal and brain-damaged subjects suggests that auditory information relevant to recognition and localization are processed by distinct neuronal populations. We report here on anatomical segregation of these populations. Brain activation associated with performance in sound identification and localization was investigated in 18 normal subjects using fMRI. Three conditions were used: (i) comparison of spatial stimuli simulated with interaural time differences; (ii) identification of environmental sounds; and (iii) rest. Conditions (i) and (ii) required acknowledgment of predefined targets by pressing a button. After coregistering, images were normalized and smoothed. Activation patterns were analyzed using SPM99 for individual subjects and for the whole group. Sound recognition and localization activated, as compared to rest, inferior colliculus, medial geniculate body, Heschl gyrus, and parts of the temporal, parietal, and frontal convexity bilaterally. The activation pattern on the fronto-temporo-parietal convexity differed in the two conditions. Middle temporal gyrus and precuneus bilaterally and the posterior part of left inferior frontal gyrus were more activated by recognition than by localization. Lower part of inferior parietal lobule and posterior parts of middle and inferior frontal gyri were more activated, bilaterally, by localization than by recognition. Regions selectively activated by sound recognition, but not those selectively activated by localization, were significantly larger in women. Passive listening paradigm revealed segregated pathways on superior temporal gyrus and inferior parietal lobule. Thus, anatomically distinct networks are involved in sound recognition and sound localization.

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“…On the other hand, temporal resolution of magnetoencephalography (MEG) is sensitive enough to measure neural process in the millisecond range. In fact, a whole-cortex neuromagnetic measurement shows the possibility of imaging the human cortico-hippocampal neural networks on the millisecond time scale during cognitive processes (Kikuchi et al, 1997). In near future, asymmetries of the neural activities in each area may be clarified in the millisecond range during some cognitive processes, in normal male and female brains, using MEG.…”

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confidence: 99%

Male brain and female brain.

Kikuchi

1998

Appl Human Sci

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Men and women, so different in their adult behavior, are expected to have different brain organizations. Research with nonhuman animals has recently begun to uncover the brain mechanisms in the hypothalamus that underlie male-female differences in such basic functions as mating behaviors. Furthermore, even in the higher structures, sex differences have been observed.Sex differences in brain asymmetry have been reported for a species of albino rat. Diamond et al. (1981) reported that male rats showed significant thicker right hemispheres at all ages except very old. On the other hand, female rats somewhat showed thicker left hemispheres, although the differences for females were not significant statistically. Furthermore, measurements of the hippocampus show laterality effects as well. The male rat has large, significant differences favoring the right hippocampus early in life: these differences decrease considerably with age. The female rat shows the reverse asymmetry; the left hippocampus is thicker than the right, with the differences reaching statistical significance only at 21 and 90 days of age. In addition, the size of the corpus callosum is larger in the male rat than in the female rat. If testosterone is administered to newly born female rats, the corpus callosum becomes larger. On the other hand, male fetuses exposed to an antiandrogen have a smaller corpus callosum.Such facts emerging from the animal literature provide indirect support for the notion that the human brain is sexually differentiated. A quantitative analysis of the volume of 4 cell groups in the interstitial nuclei of the anterior hypothalamus (INAH) of 22 age-matched male and female individuals showed gender-related differences in the 2 cell gropus. One nucleus (INAH 3) is 2.8 times larger in the male brain than in the female brain irrespective of age. The other cell group (INAH 2) is twice as large in the male brain, but also appeared to be related in women to circulating steroid hormone levels. These results suggest that functional sex differences in the hypothalamus may be related to sex differences in neural structure (Allen et al., 1989). The volumes of four cell groups in the INAH 1, 2, 3 and 4 were measured in postmortem tissure from two subject groups: men who were presumed to be heterosexual, and homosexual. No differences were found between the groups in the volumes of INAH 1, 2 or 4. INAH 3 was more than twice as large in the heterosexual men as in the homosexual men (LeVay, 1991). This finding indicates that INAH is dimorphic with sexual orientation, at least in men, and suggests that sexual orientation has a biological substrate.Sexual differentiation is not limited to hypothalamic structures. Sylvian fissures of 67 brain specimens were measured postmortem from people who had been tested before death for detailed hand preference. Men having consistent-right-hand preference had longer the horizontal segments of sylvian fissure in both hemispheres compared to men not having consistentright-hand preference. Contrary to this, no...

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Human cortico-hippocampal activity related to auditory discrimination revealed by neuromagmetic field

Cited by 15 publications

References 8 publications

Magnetic fields in the human hippocampal area evoked by a somatosensory oddball task

Magnetic fields in the human hippocampal area evoked by a somatosensory oddball task

Distinct pathways involved in sound recognition and localization: A human fMRI study

Male brain and female brain.

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