Studies on Auditory Perception of Patients and Japanese Monkeys with Lesions of Auditory Cortices Revealed by P300
| Project/Area Number |
60480384
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Teikyo University Schol of Medicine |
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Principal Investigator |
KIMITAKA Kaga Teikyo University School of Medicine, Associate Professor, 医学部, 講師 (80082238)
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| Co-Investigator(Kenkyū-buntansha) |
TOSHIHIRO Tsuzuku Teikyo University School of Medicine, Assistant, 医学部, 助手 (60188597)
MITSUKO Shindo Teikyo University School of Medicine, Assistant Professor, 薬学部, 講師 (40082177)
TAIJI Nagai Teikyo University School of Medicine, Assistant, 医学部, 助手 (60130027)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 1986: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1985: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Auditory Cortex / P300 / Pure Tone / Word / CNV / Rare / Frequent / Hippocampus / 中隔 |
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| Research Abstract |
The experiments were designed to study auditory perception with event related potentials P300. <I> . Human Experiments: Acoustic stimuli included pure tones (1 KHz vs. 2 KHz) or speech sounds (Aka vs. Kuro) which were rare (20%) or frequent (80%) for P300 recordings. Meantime, CNV of which the first signal was click and the second signal was flash was recorded for comparison. The subjects with the left hemisphere's auditory cortex lesion showed normal P300 for pure tones but abnormal P300 for speech sounds and the subjects with bilateral lesions of auditory cortices showed absent P300 for pure tones and speech sounds. In conclusion, human auditory cortex is important for generation of acoustically stimulated P300.
<II> . Animal Experiment: Acoustic stimuli included loud clicks which were rare (15%) or frequent (80%), soft clicks which were reciprocally frequent or rare, and tone pulses (5%) followed by eyelid shock which focussed the cat's attention. EEG recorded from a steel screw at t
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he vertex was averaged separately for each of the 3 stimuli in 500-trial blocks. A "P300" was scored as present if the rare loud click response was significantly more positive in the 200-500 msec range than the frequent response. Paired t-tests of data points across the 40-1000 msec latency period showed that a "P300" was present in every cat before the lesion.
A. Cortical Studies. To test the hypothesis that P300 generation requires primary sensory cortex, the auditory cortex was aspirated bilaterally in four cats. No significant change in the P300 was observed postoperatively. Thus, we conclude that primary sensory cortex is not essential for P300 generation.
B. Basal Forebrain-Hippocampal Projection System Studies. To test the hypothesis that the cat "P300" response is significantly dependent upon the cholinergic components of the basal forebrain system, the following studies were carried out.
1. Septal lesions. In the cat, as in the human, choline acetyltransferase (ChAT)-immunoreactive cells in the medial septal nucleus and vertical and horizontal limbs of the diagonal band project strongly to the hippocampus. The septal area containing these cells was lesioned bilaterally in 5 cats and postmortem histochemistry showed almost complete depletion of acetyl-cholinesterase (AChE) in the hippocampus bilaterally. The P300 was enhanced during postoperative days 1-5, then decreased and disappeared between days 6-12.
2. Hippocampal recordings. The antero-posterior structure of 8 hippocampi was mapped for P300 field potentials. Loci at which the P300 attainrd maximum amplitude, and either disappeared or inverted in adjacent regions, were predominantly clustered in the posterior half of the hippocampus. These data show that the cat P300 can be recorded as a depth field potential, with inversion loci, in the posterior hippocampus. Less
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