title: Noninvasive scalp recording of cortical auditory evoked potentials in the alert macaque monkey.
abstract: Scalp-recorded evoked potentials (EP) provide researchers and clinicians with irreplaceable means for recording stimulus-related neural activities in the human brain, due to its high temporal resolution, handiness, and, perhaps more importantly, non-invasiveness. This work recorded the scalp cortical auditory EP (CAEP) in unanesthetized monkeys by using methods that are essentially identical to those applied to humans. Young adult rhesus monkeys (Macaca mulatta, 5-7 years old) were seated in a monkey chair, and their head movements were partially restricted by polystyrene blocks and tension poles placed around their head. Individual electrodes were fixated on their scalp using collodion according to the 10-20 system. Pure tone stimuli were presented while electroencephalograms were recorded from up to nineteen channels, including an electrooculogram channel. In all monkeys (n = 3), the recorded CAEP comprised a series of positive and negative deflections, labeled here as macaque P1 (mP1), macaque N1 (mN1), macaque P2 (mP2), and macaque N2 (mN2), and these transient responses to sound onset were followed by a sustained potential that continued for the duration of the sound, labeled the macaque sustained potential (mSP). mP1, mN2 and mSP were the prominent responses, and they had maximal amplitudes over frontal/central midline electrode sites, consistent with generators in auditory cortices. The study represents the first noninvasive scalp recording of CAEP in alert rhesus monkeys, to our knowledge.
authors.affiliation: Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Niigata, 951-8585, Japan. Electronic address: itoh@bri.niigata-u.ac.jp.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Itoh
authors.affiliation: Cognitive Neuroscience Section, Primate Research Institute, Kyoto University, 41-2, Kanrin, Inuyama, Aichi 484-8506, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nejime
authors.affiliation: Cognitive Neuroscience Section, Primate Research Institute, Kyoto University, 41-2, Kanrin, Inuyama, Aichi 484-8506, Japan.
authors.forename: Naho
authors.initials: N
authors.lastname: Konoike
authors.affiliation: Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Niigata, 951-8585, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakada
authors.affiliation: Cognitive Neuroscience Section, Primate Research Institute, Kyoto University, 41-2, Kanrin, Inuyama, Aichi 484-8506, Japan.
authors.forename: Katsuki
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001301:Audiometry, Pure-Tone; D001303:Auditory Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D004585:Electrooculography; D005072:Evoked Potentials, Auditory; D005260:Female; D008253:Macaca mulatta; D008297:Male; D023421:Models, Animal; D011237:Predictive Value of Tests; D012535:Scalp; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014851:Wakefulness
keywords: Auditory evoked potential (AEP); Auditory late response (ALR); Electroencephalogram (EEG); Event-related potential (ERP); Nonhuman primates; Old world monkey