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Abstracts / Neuroscience

3-h16 Cue response of monkey striatal neurons during auration discrimination tasktsushi Chiba, Ken-Ichi Oshio, Masahiko Inase

Department of Physiology, Kinki University School of Medicine,saka-Sayama, Japan

o clarify neural mechanisms for time perception, neuronal activity wasecorded from the monkey striatum during a duration discrimination task.monkey was presented two visual cues (the first cue, C1 and the second

ue, C2), blue and red-colored squares, successively for different duration.ach cue was followed by a delay period. After the second delay period

D2) the subject was required to choose the longer-presented colored cue.ifty-nine neurons responded to C2, and only 5 neurons responded to C1.f the 59 C2 response neurons, 20 neurons responded to C2 with a con-

tant latency after C2 onset in short-long trials. These neurons increasedheir firing rates during D2 with a short latency after C2 offset in long-hort trials. The C2 and D2 activities were associated with trial types, butot necessarily correlated with C2 duration in each trial type. This resultuggests that the striatum neurons are involved in temporal discrimina-ion between two cue durations during the second cue presentation.

esearch fund: KAKENHI 18500314.

3-h17 Organization of multisynaptic inputs from parietal cor-ex to prefrontal cortex in macaque monkeysoshihiro Hirata1, Shigehiro Miyachi2, Ken-ichi Inoue1, Michikomanishi1, Masahiko Takada1

Dept. System Neurosci., Tokyo Met. Inst. Neurosci., Tokyo,apan; 2 Section of Brain Res., Primate Res. Inst., Kyoto Univ.,apan

o investigate the organization of multisynaptic inputs from the parietalortex to the prefrontal cortex, we injected rabies virus into the dorsald) and ventral (v) parts of area 46 in macaque monkeys. Three days afterhe viral injections, second-order neurons were retrogradely labeled inransynaptic fashion. Neuronal labeling occurred in the medial and lateralanks of the intraparietal sulcus (IPS). The neurons labeled from area 46dere distributed mainly in the caudal portion of the IPS, whereas those

abeled from area 46v were in the rostral portion. These results, togetherith our previous data showing the differential disynaptic projections

rom the inferior temporal area to areas 46d vs. 46v, indicate that therere two distinct pathways responsible for information outflow from thearietal and temporal association areas toward area 46.

3-h19 Laterality of human prefrontal cortex function duringotor inhibitionayato Tabu1, Tatsuya Mima2, Toshihiko Aso2, Nobukatsuawamoto2, Ryousuke Takahashi1, Hidenao Fukuyama2

Department of Neurology, Kyoto University, Kyoto, Japan;Human Brain Research Center, Kyoto University, Kyoto, Japan

brupt inhibition of initiated movement is an important piece of humanotor control. Typical experimental paradigm to quantify motor inhi-

ition is Stop-signal task, which may reflect the prefrontal function.lthough the right side dominance of prefrontal cortex for motor inhibi-

ion has been suggested, the exact laterality is not known. We examinedhe brain activity during Stop-signal task by fMRI and analyzed the lateral-ty of activation using SPM5 in ten healthy subjects. In Go trials (75%) oneeacts to Go cue on the screen and presses the button on left or right hand,

hich the cue arrow directs to. In Stop trials (25%), one reacts to Stop

ue following Go cue and inhibits the movement. Event-related analysisf fMRI revealed that the right prefrontal cortex is more activated than

eft in successful inhibition even when the right and left hand Stop trialsere analyzed separately. This indicates the functional relevance of the

ight prefrontal cortex in inhibition of initiated response.

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3-h2Ø Effects of isolation rearing on the development ofocial behavior and central neurotrophin levels in male Mongo-ian gerbils

ichito Shimozuru1, Takefumi Kikusui2, Yukari Takeuchi1, Yujiori1

Laboratory of Veterinary Ethology, University of Tokyo, Tokyo,apan; 2 Companion Animal Research, Azabu University,anagawa, Japan

e investigated influences of rearing conditions on development of socialehaviors and central neurotrophin levels in male Mongolian gerbils.ubjects were divided at weaning into three groups; the isolation-rearedIR), the group-reared (GR), and the screen-divided-reared (SDR) males,hich were housed in a pair but separated individually by a wire mesh

creen. Social interaction tests revealed that IR and SDR males increasedime spent in the investigation into unfamiliar males, but the increasef aggressive behaviors was observed only in IR males, not in SDR andR males. This suggests that distant sensory interactions with another

ndividual reduce isolation rearing-induced aggression. However, no sig-ificant difference among groups was found in NGF and BDNF levels

n four brain areas at different developmental stages, which implies thatther neurochemical factors would be involved in the mechanism under-

ying isolation-induced behavioral alternation.

3-h21 Genetic analysis of inter-male aggression using con-omic mouse strains established from C57BL/6J and MSMki Takahashi1, Kazuya Tomihara2, Toshihiko Shiroishi1, Tsuyoshioide1

National Institute of Genetics, Shizuoka, Japan; 2 Kagoshimaniversity, Kagoshima, Japan

ggression is very important emotion for animals and evolutionarilyonserved behavior. Recent studies with gene-altered mice have success-ully elucidated several genes related to aggressive behavior. However,he attempts to identify naturally occurring genetic variation relatedo aggressive behavior have not been sufficiently done yet. We hereeport the forward genetics approach for inter-male aggression by usingew genetic resource, consomic mouse strains. We found male of oneonsomic strain B6-15MSM, which have MSM chromosome 15, showedncreased aggressive behavior in resident-intruder test. Behavioral analy-is showed that the increased aggression of B6-15MSM was mainly causedy the effect of intruder. Several congenic strains of B6-15MSM werestablished to identify the genetic locus/loci related to the aggressiveehavior, and revealed that there are several genetic loci that increasedr decreased the aggressive behavior on the chromosome 15.

esearch funds: Grant-in-Aid for JSPS Fellows.

3-h22 Soldier-specific neural modification in termitesuki Ishikawa, Toru Miura

Graduate School of Environmental Science, Hokkaido University,apporo, Japan

ocial insects possess highly organized social system that is accomplishedy elaborate division of labor. To increase the colony performance, colonyembers differentiate into various castes that show morphological and

ehavioral differences. For example, in termites, soldier castes showggressive defense behavior with well-developed mandibles. The compar-son of CNS between soldier and worker indicates that soldiers have largeruboesophageal ganglia than workers. Histological observations showedhat the mandibular motor neurons were enlarged in subesophageal gan-lion of soldiers. The enlargement of neurons should cause effectiveefense behavior by increasing nerve conduction velocity and amount ofeurotransmitters. The soldier-specific giant motor neurons was sharedy all examined termite species, suggesting that this characteristic was

ighly linked to soldier defensive behavior and acquired in the commonncestor of termites. We also analyze differential gene expression in theNS to reveal molecular basis underlying the social behavior.

esearch funds: Grant-in-aid for scientific research on priority areas18047002).