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Correlation between cat's auditory cortical activities and behavioral discrimination to the sweep direction of frequency-modulated tones
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Abstracts / Neuroscience Research 71S (2011) e108–e415
localization of such specialized neuronal networks has not been investigated. Furthermore, most of these neurons have been classified from the signatures they leave in multiunit activity (MUA), but the relationships that neuronal spiking holds with the underlying sub/supra-threshold postsynaptic activities have not been clarified yet. We used extracellular potentials recorded simultaneously from 64 sites inside the A1 of adult Wistar rats to evaluate neuronal codifiers for fundamental attributes, which were selected from their particular MUA dose-response curves. We demonstrated that the underlying neuronal populations were sparsely and heterogeneously distributed along the A1, even though they complied with the tonotopic organization. Codifying neurons were majorly PCs which showed laminar profiles. MUA was correlated to Beta (12–25 Hz) postsynaptic oscillations in the infragranular layers, while the supragranular layers revealed a better correlation between MUA and Gamma range postsynaptic oscillations (70–170 Hz). We concluded that, for rats, sounds are codified in A1 by a sparsely segregated network involving specialized PCs and that their postsynaptic activity may create the proper conditions for the emergence of sparse and dense spiking patterns. doi:10.1016/j.neures.2011.07.645
response perch during the S+ presentation was rewarded by food while that during the S− presentation resulted in a blackout. Before ABAB and AABB discrimination training was conducted, the ability to discriminate physical properties of the pulse (i.e., frequencies and durations) was confirmed by training the monkey to identify one of four pulse trains that consisted of a combination of either 0.5 or 2 kHz frequencies and 50 or 200 ms durations. However, this monkey showed no improvement of ABAB vs. AABB discrimination after 80 sessions of training. Thus, although the monkey was able to discern A and B pulses, this animal failed o discriminate ABAB and AABB patterns. The current results suggest that the marmoset has limited competence required to abstract segment from the auditory sequences, such as working memory or response inhibition. doi:10.1016/j.neures.2011.07.647
P2-j04 Auditory and vestibular impairment of Slitrk6Deficient mice Yoshifumi Matsumoto 1 , Kei-ichi Katayama 1 , Takehito 2 3 Okamoto , Kazuyuki Yamada , Soichi Nagao 2 , Masaharu Kudoh 4 1
Lab. for Behavioral and Developmental Disorders, BSI, RIKEN, Wako, Japan Laboratory for Motor Learning Control, RIKEN Brain Science Institute (BSI), Wako-shi, Japan 3 Support Unit for Animal Experiments, RIKEN Brain Science Institute (BSI), Wako-shi, Japan 4 Department of Physiology, Teikyo University School of Medicine, Tokyo, Japan 2
P2-j02 Acoustic attributes for identifying target natural sounds by guinea pigs Hisayuki Ojima 1 , Ken-ichi Tabei 2 , Narumi Katsuyama 1 , Masato Taira 1 1 Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan 2 Division of Applied System Neuroscience, Nihon University School of Medicine, Tokyo, Japan
Discrimination of an important natural sound from others is crucial to the survival of animals in the nitche. To examine how animals brain becomes interacted with acoustic signals in a natural situation, we first trained guinea pigs to associate a target sound (TS) with food, and then applied pseudotarget sounds (PSTs) that had been modified from the TS to test what acoustic parameters animals relied on. Through a systematic association of the TS with food, all animals came to initiate a set of report actions soon after the TS onset but before a noise associated with the feeding. The report actions included distinctive behaviors such as circling around a food container and/or swinging head above it. This behavioral response was retained even after a new stimulus set including additional non-target sounds was applied. Thereafter, to elucidate what acoustic attributes the animals had been relying on, a set of PSTs was applied. The modifications included low- and high-pass filtered, time-reversed, intervals expanded between component segments comprising the TS, randomizing order of the component segments, and replacement of the minor segments with major ones or vice versa. Some PSTs evoked false-positive report actions, suggesting the impossibility for animals to discriminate them from the TS. The manipulations of inter-segment intervals, segment magnitude, and segment order most frequently evoked the actions while the time-reverse version elicited virtually no actions. Low- and highpassed sounds were intermittent with the high-pass version more frequently evoking the actions. It can be concluded that animals do not depend on one acoustic attribute but depend on multiple acoustic attributes in responding to biologically important natural sounds. However, it also suggests that these factors are not equally appreciated by animals but may be processed with different weights for the sounds recognition. Research fund: KAKENHI (C) no.22500368 to H.O. doi:10.1016/j.neures.2011.07.646
P2-j03 Discrimination training of auditory patterns in a common marmoset Masumi Wakita Dept. of Behav. Brain Sci., Primate Res. Inst., Kyoto Univ., Inuyama, Japan Common marmoset is a monkey that has a variety of vocal repertoires. Thus, this monkey species can be a suitable animal for the comparative study of the voco-auditory ability of human. Especially, if they can perceive segments embedded in a sound sequence, primate brain region that is homologous to human inferior frontal cortex will be expected to be involved in languagelike analysis. Here, I studied whether the marmoset can discriminate auditory patterns (ABAB vs. AABB). Physical properties of pulses A and B were 0.5 kHz and 50 ms, and 2 kHz and 200 ms, respectively. A marmoset was trained to respond to the auditory stimuli by moving from one perch (a stimulus perch) to the other perch (a response perch). A daily session consisted of 60 trials. When the monkey stayed on the stimulus perch for about 3 s, either S+ or S− stimulus was presented for 6 s in a pseudo-random order. Moving to the
Slitrk6, a transmembrane protein containing a leucine-rich repeat domain, is expressed in inner ear and dorsal thalamus including medial geniculate nucleus. Although Slitrk6 plays a critical role in the inner ear neural circuit formation, its functional significance in auditory and vestibular information processing is unclear. To address this point, Slitrk6 knockout (KO) mice were subjected to auditory and vestibular function tests. Compared to wild-type mice, the auditory brainstem response (ABR) of Slitrk6 KO mice indicated a mid-frequency range (8–16 kHz) hearing loss and reduction of the first ABR wave. We further carried out the functional imaging of Slitrk6 KO auditory cortex by measuring endogenous fluorescence of mitochondrial flavoproteins. As to the vestibular function of Slitrk6 KO mice, vestibulo-ocular reflex (VOR) test showed decreased vertical (head movement-induced) VOR gains and normal horizontal VOR in accordance with the innervation defect to the posterior cristae. These results indicate that the Slitrk6 KO mouse can serve as a model of hereditary sensorineural deafness. We will discuss the role of Slitrk6 in the entire auditory neural circuit together with upcoming results. doi:10.1016/j.neures.2011.07.648
P2-j05 Correlation between cat’s auditory cortical activities and behavioral discrimination to the sweep direction of frequency-modulated tones Chao Dong , Ling Qin, Xinan Zhang, Yu Sato Department of Physiology, University of Yamanashi, Chuo, Yamanashi, Japan Cortical representation of complex sounds is well investigated with the use of electrophysiological recording methods. However, rare psychophysical experiments were conducted to investigate behavioral discrimination of complex sounds in the same species used in physiological experiments. Therefore, the relationship between the activities of auditory cortical neurons and behavior in perceptual decision-making tasks remains unclear. Here, we explored this issue in cats by testing the behavioral discrimination of upward and downward frequency modulated (FM) tones and recording the neural responses of the primary auditory cortex (A1) under non-anesthetized conditions. We found that cats showed high performance (% correct >75%) to detect the change of sweep direction from upward to downward, when the FM tones linearly swept between 0.1 and 16 kHz in 40–160 ms duration; however, behavioral performance dropped below 75% when sweep duration was shortened to 10–20 ms. Aligning individual neural activities by the response latency of upward sweep could construct a population pattern, which showed a spatiotemporal reversal between upward and downward sweeps. The rank-order of response latencies could provide a reliable discrimination of the FM direction, and the discrimination performance paralleled with the cat’s behavioral performance. Our result suggests that the neural representations of A1 were spatiotemporally integrated by subsequent processing stages to mediate behavioral discrimination of FMdirection in this task. Research fund: Strategic Research Program for Brain Sciences 08038015 from the Japan Ministry of Education, Culture, Sports, Science and Technology. doi:10.1016/j.neures.2011.07.649
Abstracts / Neuroscience Research 71S (2011) e108–e415
localization of such specialized neuronal networks has not been investigated. Furthermore, most of these neurons have been classified from the signatures they leave in multiunit activity (MUA), but the relationships that neuronal spiking holds with the underlying sub/supra-threshold postsynaptic activities have not been clarified yet. We used extracellular potentials recorded simultaneously from 64 sites inside the A1 of adult Wistar rats to evaluate neuronal codifiers for fundamental attributes, which were selected from their particular MUA dose-response curves. We demonstrated that the underlying neuronal populations were sparsely and heterogeneously distributed along the A1, even though they complied with the tonotopic organization. Codifying neurons were majorly PCs which showed laminar profiles. MUA was correlated to Beta (12–25 Hz) postsynaptic oscillations in the infragranular layers, while the supragranular layers revealed a better correlation between MUA and Gamma range postsynaptic oscillations (70–170 Hz). We concluded that, for rats, sounds are codified in A1 by a sparsely segregated network involving specialized PCs and that their postsynaptic activity may create the proper conditions for the emergence of sparse and dense spiking patterns. doi:10.1016/j.neures.2011.07.645
response perch during the S+ presentation was rewarded by food while that during the S− presentation resulted in a blackout. Before ABAB and AABB discrimination training was conducted, the ability to discriminate physical properties of the pulse (i.e., frequencies and durations) was confirmed by training the monkey to identify one of four pulse trains that consisted of a combination of either 0.5 or 2 kHz frequencies and 50 or 200 ms durations. However, this monkey showed no improvement of ABAB vs. AABB discrimination after 80 sessions of training. Thus, although the monkey was able to discern A and B pulses, this animal failed o discriminate ABAB and AABB patterns. The current results suggest that the marmoset has limited competence required to abstract segment from the auditory sequences, such as working memory or response inhibition. doi:10.1016/j.neures.2011.07.647
P2-j04 Auditory and vestibular impairment of Slitrk6Deficient mice Yoshifumi Matsumoto 1 , Kei-ichi Katayama 1 , Takehito 2 3 Okamoto , Kazuyuki Yamada , Soichi Nagao 2 , Masaharu Kudoh 4 1
Lab. for Behavioral and Developmental Disorders, BSI, RIKEN, Wako, Japan Laboratory for Motor Learning Control, RIKEN Brain Science Institute (BSI), Wako-shi, Japan 3 Support Unit for Animal Experiments, RIKEN Brain Science Institute (BSI), Wako-shi, Japan 4 Department of Physiology, Teikyo University School of Medicine, Tokyo, Japan 2
P2-j02 Acoustic attributes for identifying target natural sounds by guinea pigs Hisayuki Ojima 1 , Ken-ichi Tabei 2 , Narumi Katsuyama 1 , Masato Taira 1 1 Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan 2 Division of Applied System Neuroscience, Nihon University School of Medicine, Tokyo, Japan
Discrimination of an important natural sound from others is crucial to the survival of animals in the nitche. To examine how animals brain becomes interacted with acoustic signals in a natural situation, we first trained guinea pigs to associate a target sound (TS) with food, and then applied pseudotarget sounds (PSTs) that had been modified from the TS to test what acoustic parameters animals relied on. Through a systematic association of the TS with food, all animals came to initiate a set of report actions soon after the TS onset but before a noise associated with the feeding. The report actions included distinctive behaviors such as circling around a food container and/or swinging head above it. This behavioral response was retained even after a new stimulus set including additional non-target sounds was applied. Thereafter, to elucidate what acoustic attributes the animals had been relying on, a set of PSTs was applied. The modifications included low- and high-pass filtered, time-reversed, intervals expanded between component segments comprising the TS, randomizing order of the component segments, and replacement of the minor segments with major ones or vice versa. Some PSTs evoked false-positive report actions, suggesting the impossibility for animals to discriminate them from the TS. The manipulations of inter-segment intervals, segment magnitude, and segment order most frequently evoked the actions while the time-reverse version elicited virtually no actions. Low- and highpassed sounds were intermittent with the high-pass version more frequently evoking the actions. It can be concluded that animals do not depend on one acoustic attribute but depend on multiple acoustic attributes in responding to biologically important natural sounds. However, it also suggests that these factors are not equally appreciated by animals but may be processed with different weights for the sounds recognition. Research fund: KAKENHI (C) no.22500368 to H.O. doi:10.1016/j.neures.2011.07.646
P2-j03 Discrimination training of auditory patterns in a common marmoset Masumi Wakita Dept. of Behav. Brain Sci., Primate Res. Inst., Kyoto Univ., Inuyama, Japan Common marmoset is a monkey that has a variety of vocal repertoires. Thus, this monkey species can be a suitable animal for the comparative study of the voco-auditory ability of human. Especially, if they can perceive segments embedded in a sound sequence, primate brain region that is homologous to human inferior frontal cortex will be expected to be involved in languagelike analysis. Here, I studied whether the marmoset can discriminate auditory patterns (ABAB vs. AABB). Physical properties of pulses A and B were 0.5 kHz and 50 ms, and 2 kHz and 200 ms, respectively. A marmoset was trained to respond to the auditory stimuli by moving from one perch (a stimulus perch) to the other perch (a response perch). A daily session consisted of 60 trials. When the monkey stayed on the stimulus perch for about 3 s, either S+ or S− stimulus was presented for 6 s in a pseudo-random order. Moving to the
Slitrk6, a transmembrane protein containing a leucine-rich repeat domain, is expressed in inner ear and dorsal thalamus including medial geniculate nucleus. Although Slitrk6 plays a critical role in the inner ear neural circuit formation, its functional significance in auditory and vestibular information processing is unclear. To address this point, Slitrk6 knockout (KO) mice were subjected to auditory and vestibular function tests. Compared to wild-type mice, the auditory brainstem response (ABR) of Slitrk6 KO mice indicated a mid-frequency range (8–16 kHz) hearing loss and reduction of the first ABR wave. We further carried out the functional imaging of Slitrk6 KO auditory cortex by measuring endogenous fluorescence of mitochondrial flavoproteins. As to the vestibular function of Slitrk6 KO mice, vestibulo-ocular reflex (VOR) test showed decreased vertical (head movement-induced) VOR gains and normal horizontal VOR in accordance with the innervation defect to the posterior cristae. These results indicate that the Slitrk6 KO mouse can serve as a model of hereditary sensorineural deafness. We will discuss the role of Slitrk6 in the entire auditory neural circuit together with upcoming results. doi:10.1016/j.neures.2011.07.648
P2-j05 Correlation between cat’s auditory cortical activities and behavioral discrimination to the sweep direction of frequency-modulated tones Chao Dong , Ling Qin, Xinan Zhang, Yu Sato Department of Physiology, University of Yamanashi, Chuo, Yamanashi, Japan Cortical representation of complex sounds is well investigated with the use of electrophysiological recording methods. However, rare psychophysical experiments were conducted to investigate behavioral discrimination of complex sounds in the same species used in physiological experiments. Therefore, the relationship between the activities of auditory cortical neurons and behavior in perceptual decision-making tasks remains unclear. Here, we explored this issue in cats by testing the behavioral discrimination of upward and downward frequency modulated (FM) tones and recording the neural responses of the primary auditory cortex (A1) under non-anesthetized conditions. We found that cats showed high performance (% correct >75%) to detect the change of sweep direction from upward to downward, when the FM tones linearly swept between 0.1 and 16 kHz in 40–160 ms duration; however, behavioral performance dropped below 75% when sweep duration was shortened to 10–20 ms. Aligning individual neural activities by the response latency of upward sweep could construct a population pattern, which showed a spatiotemporal reversal between upward and downward sweeps. The rank-order of response latencies could provide a reliable discrimination of the FM direction, and the discrimination performance paralleled with the cat’s behavioral performance. Our result suggests that the neural representations of A1 were spatiotemporally integrated by subsequent processing stages to mediate behavioral discrimination of FMdirection in this task. Research fund: Strategic Research Program for Brain Sciences 08038015 from the Japan Ministry of Education, Culture, Sports, Science and Technology. doi:10.1016/j.neures.2011.07.649