Naoko Tokimoto

Tool-use training in a species of rodent: the emergence of an optimal motor strategy and functional understanding.

Background Tool use is defined as the manipulation of an inanimate object to change the position or form of a separate object. The expansion of cognitive niches and tool-use capabilities probably stimulated each other in hominid evolution. To understand the causes of cognitive expansion in humans, we need to know the behavioral and neural basis of tool use. Although a wide range of animals exhibit tool use in nature, most studies have focused on primates and birds on behavioral or psychological levels and did not directly address questions of which neural modifications contributed to the emergence of tool use. To investigate such questions, an animal model suitable for cellular and molecular manipulations is needed. Methodology/Principal Findings We demonstrated for the first time that rodents can be trained to use tools. Through a step-by-step training procedure, we trained degus (Octodon degus) to use a rake-like tool with their forelimbs to retrieve otherwise out-of-reach rewards. Eventually, they mastered effective use of the tool, moving it in an elegant trajectory. After the degus were well trained, probe tests that examined whether they showed functional understanding of the tool were performed. Degus did not hesitate to use tools of different size, colors, and shapes, but were reluctant to use the tool with a raised nonfunctional blade. Thus, degus understood the functional and physical properties of the tool after extensive training. Conclusions/Significance Our findings suggest that tool use is not a specific faculty resulting from higher intelligence, but is a specific combination of more general cognitive faculties. Studying the brains and behaviors of trained rodents can provide insights into how higher cognitive functions might be broken down into more general faculties, and also what cellular and molecular mechanisms are involved in the emergence of such cognitive functions.

Alarm call discrimination in a social rodent: adult but not juvenile degu calls induce high vigilance

Many social animals develop vocal communications to send and receive information efficiently in a group. In alarm communication, call recipients in a social group evaluate alarm calls, enhancing their probability of survival in the face of predatory threats. Calls from naïve and younger group members might be less evocative, in terms of rendering group members vigilant, than calls from more experienced adults because adults are generally more reliable. It remains uncertain, however, what acoustic characteristics render an alarm call reliable. Here, we report that adult degus, Octodon degus (Rodentia, Octodontidae), produced an alarm with a frequency-modulated (FM) syllable, accompanied by low bandwidth and entropy, to evoke a high-vigilance response amongst receivers. Unlike adults, subadult degus did not emit the FM syllable in the warning context, and their call without the FM syllable evoked less vigilance than the adult alarm. We suggest that the FM structure of the adult-produced syllable serves as the primary feature characterizing a reliable alarm call. Our results are consistent with those found in other social rodents, e.g., ground squirrels and gerbils, also produce FM alarm calls in high-urgency situations supports the importance of the FM syllable in alarm communication.

Complex vocal behavior and cortical-medullar projection

We argue that the intentional control of vocal organ is the most basic predisposition for vocal learning and thus for language acquisition. Anatomical substrates for intentional vocal control are the direct cortical-medullar projections that connect face motor cortecies and the nucleus retro-ambiguus. We ask how such projections may be reinforced in non-vocal learners including macaque monkeys and rodents by behavioral manipulations. We hypothesize how such connections may be prepared in humans.

Perspective-Taking in Sentence Comprehension: Time and Empathy

This study examines the neural substrate of perspective-taking by analyzing the electroencephalographic (EEG) activity elicited by the auditory comprehension of sentences for which the comprehender had to adopt the perspective of the person described in them. Recent studies suggest that the ability of perspective-taking can be an integrative function of temporal and spatial information processing. We thus examined the independence and possible interaction of human perspective shifts and temporal perspective-taking by utilizing Japanese subsidiary verbs for giving, namely -ageru and -kureru. We manipulated human perspective shifts and temporal perspective-taking independently in experimental sentences by syntactically changing the subject and the object between the speaker and a third person, while we manipulated the tense to be past or non-past tense via sentence-final particles ru/ta (non-past/past). The EEG analyses via electrodes indicated the suppression of the β band for human perspective shifts in sentences in non-past tense and the absence of such suppression in sentences in past tense. The analyses for the clusters of independent components indicated β suppression for past tense against non-past tense in sentences without a human perspective shift. This response pattern suggests a close relationship between human perspective shifting and temporal perspective-taking. The β suppression for the human perspective shift in our experiment can be understood as a replication of the previous EEG findings observed for perspective-taking in the presentation of visual images. The preceding findings and our result suggest that the ability or the function of perspective-taking is not specific to the modality. Furthermore, the generator of the β suppression for past tense against non-past tense without human perspective shifting was localized in the precuneus, which is consistent with recent findings indicating that the precuneus is deeply involved in time perception.

EEG coherence in comprehension of communicative intention: Deduction and abduction

s / Neuroscience Research 71S (2011) e108–e415 e285 P3-p18 Correlates of high foreign-language proficiency in adults’ mother-tongue processing: An event-related potential (ERP) study Shiro Ojima 1 , Atsushi Nagai 2, Fumihiko Taya 1, Yukio Otsu 3, Shigeru Watanabe 4 1 CARLS, Keio Uni, Tokyo 2 Grad School Hum Relations, Keio Uni, Tokyo 3 ICL, Keio Uni, Tokyo 4 Dept Psychol, Keio Uni, Tokyo A foreign language is a language not spoken in one’s country (e.g. English for Japanese people). It is currently unknown how one’s proficiency in a foreign language is correlated with his/her proficiency in the mother tongue. Here two possibilities exist. One is that higher foreign-language proficiency is correlated with lower mother-tongue proficiency. Thousands of hours of learning are necessary to attain a high level of foreign-language proficiency, and those hours inevitably reduce exposure to the mother tongue. This reduced exposure might lower one’s proficiency in the mother tongue. Alternatively, higher foreign-language proficiency may be correlated with higher mother-tongue proficiency, due to the presence of common neural systems underlying the abilities in both languages. In the presentation, we provide behavioral and event-related potential (ERP) evidence in favor of the second possibility. Two groups of Japanese adults with either low or high English proficiency were compared in Japanese. In all three behavioral tasks which required meta-linguistic judgments on Japanese sentences, the participants with higher English proficiency were significantly more accurate than those with lower proficiency. The ERP data also supported the superiority of the higher-proficiency participants. The ERP responses to Japanese words embedded in sentence contexts were larger, and more critically, faster, in the participants with higher English proficiency. The two groups differed in both semantic and grammatical conditions tested. These data are consistent with the possibility that higher foreign-language proficiency is correlated with higher, rather than lower, mother-tongue proficiency. Due to the presence of common underlying neural systems for both languages, the learning of a foreign language may have positive influences on one’s mother tongue. Whether such effects appear in young children learning a foreign language is an important future issue. Research fund: Global COE program (No. D09) for CARLS, Keio Univ. doi:10.1016/j.neures.2011.07.1243 P3-p19 Cerebral bases of linguistic and non-linguistic cue decoding in neonates Yasuyo Minagawa-Kawai 1 , Takeshi Arimitsu 2, Mariko UchidaOta 1, Tatsuhiko Yagihashi 2, Isamu Hokuto 2, Kazushige Ikeda 2, Takao Takahashi 2 1 Grad Sch of Hum Relations, Keio Univ, Tokyo, Japan 2 Dept Pediatr, Keio Univ, Tokyo, Japan This study investigated the early cerebral base of speech perception by comparing functional lateralization in neonates for processing linguistic and non-linguistic sound contrasts. For this purpose, two experiments (Exp) measured auditory evoked responses of full-term neonates to phonemic and prosodic contrasts (Exp. 1) and their non-speech analogues (Exp. 2). We used near-infrared spectroscopy (NIRS) to examine the activations in the temporal and frontal areas and part of the parietal areas. Linguistic stimuli used here were phonemic contrast/itta/and/itte/and prosodic contrast of declarative and interrogative forms/itta/and/itta?/. Non-linguistic stimuli consisted of three pure tones which simulated the vowel formants of each three word/itta/,/itta?/and/itte/. The results of Exp. 1 showed clear hemodynamic responses to both phonemic and prosodic changes in the temporal areas and part of the parietal and frontal regions. In particular, significantly higher hemoglobin (Hb) changes were observed for the prosodic change in the right temporal area than for that in the left one, whereas Hb responses to the vowel change were similarly elicited in bilateral temporal areas. However, Hb responses to the vowel contrast were asymmetrical in the parietal area, with stronger activation in the left. These results suggest a specialized function of the right hemisphere in prosody processing, which is already present in neonates. Innate cerebral basis for the domain-driven system will be discussed by comparing the cerebral responses to speech and non-speech stimuli. Research fund: Grant-in-Aid for Scientific Research (A) (Project no. 21682002), Academic Frontier Project supported by MEXT. doi:10.1016/j.neures.2011.07.1244 P3-p20 An MEG study on language comprehension dependent on emotional context Aya Ihara 1 , Qiang Wei 1, Ayumu Matani 1,2, Norio Fujimaki 1,3, Haruko Yagura 1, Takeshi Nogai 1, Tsutomu Murata 1 1 NICT, Kobe, Japan 2 The University of Tokyo, Kashiwa, Japan 3 Kyushu Institute of Technology, Kitakyushu, Japan Language can be interpreted differently depending upon the context, as determined by different types of linguistic and paralinguistic information. For example, the same sentence may be interpreted differently depending on the emotional context, which is often derived from prosody, i.e., whether words are spoken in a happy, sad, or angry tone. Language comprehension that is dependent on the emotional context plays an important role in the establishment of smooth communication and good personal relationships. To clarify the effect of emotional context on language processing, we performed experiments using a cross-modal priming paradigm with an auditorily presented prime and a visually presented target. The primes we used were the names of people, e.g., “Mr. Aoki,” which were spoken with happy, neutral, or sad intonation. The targets were interrogative one-word sentences, which consisted of a verb, e.g., “walk?,” having emotionally neutral content. Using magnetoencephalography (MEG), we measured the neural activities during silent reading of the targets presented in an emotional context. We identified two conditional differences dependent upon the emotional context: (1) The happy and sad conditions produced less activity than the neutral condition in the right posterior inferior and middle frontal cortices in the latency window from 300 to 400 ms, and (2) the happy and neutral conditions produced greater activity than the sad condition in the left posterior inferior frontal cortex in the latency window from 400 to 500 ms. These results suggest that the use of emotional context stored in the right frontal cortex starts at ∼300 ms, that integration of linguistic information with emotional context starts at ∼400 ms in the left frontal cortex, and that language comprehension dependent on emotional context is achieved by ∼500 ms. Our study provides evidence that the bilateral frontal cortices play important roles in language comprehension dependent on emotional context. doi:10.1016/j.neures.2011.07.1245 P3-p21 EEG coherence in comprehension of communicative intention: Deduction and abduction Shingo Tokimoto 1 , Yayoi Miyaoka 2, Naoko Tokimoto 3, Sachiko Takahama 4 1 Mejiro University, Tokyo, Japan 2 Hiroshima University of Economics, Hiroshima, Japan 3 Shobi University, Saitama, Japan 4 Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan This study discusses the possible neural manifestation of the kinds of inference in the coherence of electroencephalogram (EEG). Human inferences are generally classified into deduction, induction and abduction. Abduction, which is peculiar to human beings, is an evolutionarily important mental process to understand causal relationships by developing hypotheses. The experimental studies on induction and abduction are quite few, however, while many studies are known for deduction. This is because few empirical methods are available for higher-processing like inference, and it is difficult to manipulate the kind of inference experimentally. We here manipulate the kinds of inference in the comprehension of communicative intention by the pragmatic manipulation of discourse, and try to detect the EEG coherences specific to different kinds of inference and derive suggestions on temporal characteristics of inference. In discourse (1) with three speakers (A, B and C), B can derive (2) deductively at the utterance of C, with the utterance of A as the context. (1) A: I hear the new professor, Mr. Yamada is a philosopher.B: Have you talked with Mr. Yamada?C: I never talk with a philosopher. (2) C has never talked with Mr. Yamada.We can still derive (2) even when the utterance of A in (1) is changed as in (3). (3) A: I hear the new professor, Mr. Yamada comes from Kansai area. We can here assume that B abductively develops a hypothesis ‘Mr. Yamada is a philosopher’ as the context and derives (2). We can thus manipulate the kind of inference in the comprehension of the communicative intention of C by changing part of the utterance of A, as deduction in (1) and abduction in (3). We visually presented the discourses sentence-by-sentence and recorded the EEG coherence and its temporal change. We will touch on the possible sug-

Learnability of courtship song in Octodon degu

s S241 P3-k04 Correlation between brain activity during delayed matching task and verbal IQ in healthy children Kohei Asano, Yasuyuki Taki, Hiroshi Hashizume, Yuko Sassa, Michiko Asano, Mijin Lee, Hikaru Takeuchi, Ryuta Kawashima IDAC Tohoku University, Japan Difference in cognitive ability may affect cognitive process even in a simple task. This fMRI study examined the correlation between brain activation during delayed matching task (DMT) and verbal and performance IQ (VIQ and PIQ, respectively) in healthy children. We hypothesized that the VIQ is correlated with brain activation during the DMT because both VIQ and DMT are involved in short-term or working memory. 95 healthy right-handed children (6–18 years) participated. The VIQ and PIQ were acquired from WAIS-III/WISC-III score from each subject. Multiple linear regression analysis was performed for the brain activation using VIQ score, PIQ score, age, gender, reaction time, and accuracy as covariates. The VIQ showed statistically significant positive correlation with parameter estimate at the left orbitofrontal cortex and the right thalamus during the DMT whereas the PIQ did not. These results suggest that the VIQ more affects cognitive process in the DMT relative to the PIQ. doi:10.1016/j.neures.2009.09.1360 P3-k05 Effect of color information on face processing in adults and infants: An ERP study Tetsuto Minami1, Kimiko Goto1, Shoji Itakura2, Michiteru Kitazaki1, Shigeki Nakauchi1 1 Toyohashi University of Technology, Toyohashi, Japan; 2 Kyoto University,