title: Echoic memory: investigation of its temporal resolution by auditory offset cortical responses.
abstract: Previous studies showed that the amplitude and latency of the auditory offset cortical response depended on the history of the sound, which implicated the involvement of echoic memory in shaping a response. When a brief sound was repeated, the latency of the offset response depended precisely on the frequency of the repeat, indicating that the brain recognized the timing of the offset by using information on the repeat frequency stored in memory. In the present study, we investigated the temporal resolution of sensory storage by measuring auditory offset responses with magnetoencephalography (MEG). The offset of a train of clicks for 1 s elicited a clear magnetic response at approximately 60 ms (Off-P50m). The latency of Off-P50m depended on the inter-stimulus interval (ISI) of the click train, which was the longest at 40 ms (25 Hz) and became shorter with shorter ISIs (2.5∼20 ms). The correlation coefficient r2 for the peak latency and ISI was as high as 0.99, which suggested that sensory storage for the stimulation frequency accurately determined the Off-P50m latency. Statistical analysis revealed that the latency of all pairs, except for that between 200 and 400 Hz, was significantly different, indicating the very high temporal resolution of sensory storage at approximately 5 ms.
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan; Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Aichi, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Nishihara
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Inui
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Morita
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Minori
authors.initials: M
authors.lastname: Kodaira
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Mochizuki
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Otsuru
authors.affiliation: Department of Psychiatry, Division of Neuroscience, Mie University Graduate School of Medicine, Tsu, Mie, Japan.
authors.forename: Eishi
authors.initials: E
authors.lastname: Motomura
authors.affiliation: Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Aichi, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ushida
authors.affiliation: Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kakigi
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged