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292 Abstracts / Neuroscience R

2-l11 Dynamic causal modeling of effective connectivityuring rule changes in Irritable Bowel Syndromemiko Aizawa 1 , Yasuhiro Sato 2, Takanori Kochiyama 5, Joeorisita 1, Motyori Kanazawa 1, Keisetsu Shima 4, Michio Hongo 4,ajime Mushiake 2,3, Shin Fukudo 1

behavioral medicine, University of Tohoku, Sendai, Japan 2 Departments ofsychosomatic Medicine, University of Hospital, Sendai, Japan 3 Departmentsf Comprehensive Medicine, University of Tohoku Hospital, Sendai, JapanDepartment of Neurophysiology, University of Tohoku, Sendai, JapanAdvanced Telecommunications Research Institute International, Brainctivity Imaging Center, Kyoto, Japan

im: Patients with irritable bowel syndrome (IBS) have exaggerated colonicotility and inappropriate coping behaviours in response to psychosocial

tress. However little is known about how cognitive functions are affected byBS. To clarify this issue we examined task performance and brain activationsing the Wisconsin Card Sorting Test (WCST). We hypothesized that indi-iduals with IBS have latent impairment of cognitive flexibility due to alteredctivity in the dorsolateral prefrontal cortex (DLPFC) and altered connectivitymong brain regions.ethods: Subjects were individuals with IBS (n = 30, aged 21.7 ± 3.0) diag-

osed with Rome III criteria. They were compared with 30 Age-, sex-,nd education-matched controls. Using Siemens Magnetom Symphony 1.5Tcanner, event-related functional magnetic resonance imaging (fMRI) waserformed to determine the specific location and pattern of activation inhe brain during cognitive flexibility task. The task was loaded with WCST.rain image was analyzed with statistical parametric mapping 5 and 8, andynamic causal modeling (DCM).esults: IBS subjects showed no difference in WAIS-R from controls. IBS sub-

ects had significantly more Nelson-type perseverative errors (p < 0.05) andifficulties of maintaining set (p < 0.05) than controls. IBS subjects showedignificantly less activityin the right DLPFC (BA9, p < 0.001) and significantlyore activityin the left insula (p < 0.001) during set shifting than controls.

ask-related modulation of effective connectivity from the anterior cingu-ate cortex (ACC) to right pre-supplementary motor cortex (pre-SMA) wasignificantly less in IBS subjects than those in controls.onclusion: These findings suggest that individuals with IBS have latent

mpairment of cognitive flexibility due to more activity in the insula andess activity in the DLPFC, and impaired connectivity between the ACC andre-SMA.

oi:10.1016/j.neures.2010.07.1296

2-l12 Selectivity of tactile attention: an MEG studyetsuo Kida 1,2 , Ryusuke Kakigi 1

Dept. Integr. Physiol., NIPS, Okazaki, Japan 2 Dept. Neurobiol. Behav.,agasaki University Grad. Sch. Biomed. Sci., Nagasaki, Japan

n this study, we investigated selectivity of modulation of neural activity inactile spatial attention using magnetoencephalography (MEG). Electrocuta-eous stimulation was delivered to either of five fingers of the right hand in aandom order through the ring electrodes. Interstimulus interval varied ran-omly between 750–1250 ms. Subjects were instructed to attend to the indexr ring finger or both, and to count the target stimulus presented there. Neuralesponses to the electrocutaneous stimulus were recorded using a whole-ead MEG system.A response around the central sulcus at 50–70 ms was notignificantly modulated by tactile attention whereas the response aroundhe sylvian fissure at 80 ms∼ was enhanced especially when stimulated fin-er was spatially congruent with the finger attended. These responses werestimated to be generated mainly in the primary and secondary somatosen-ory cortices, respectively. Thus, the present study demonstrates the fingerelectivity of modulation by tactile spatial attention.

oi:10.1016/j.neures.2010.07.1297

2-l13 Lesions of the isthmo-optic nucleus impair targetelection for visually guided reachingiroyuki Uchiyama , Hiroshi Ohno, Ryuki Kodama

Department Info. & Biomed. Eng., Kagoshima University

eurons in the the isthmo-optic nucleus (ION), the isthmo-optic (IO) neu-

ons, send their axons to the contralateral retina, and the IO signal transientlynd focally enhances visual responses of the retinal ganglion cells throughetinal intrinsic neurons. The IO neurons, in turn, receive a predominant inputrom the optic tectum (OT), and the ION is thought to function as a neu-al substrate for globally competitive tuning in the pathway from the OT to

ch 68S (2010) e223–e334

the retina. The IO neurons fire phasically before the onset of head saccadestoward their receptive field, indicating that the IO signal to the retina may beinvolved in initiation of visual orienting behaviors. In the present study, wetrained Japanese quail to peck a target stimulus presented on a touch-sensormonitor. ION lesions decreased the response accuracies of the birds withat least a right ION lesion by 16.3–19.5% in the mild competitive conditionwith two distractor (Student’s t-test, P < 0.001–0.05), and 39.6–52.0% in thehighly competitive condition with 19 distractors (P < 0.001), resulting fromerroneous pecks onto distractors. Response accuracies were not uniformlyimpaired over the two-dimensional stimulus array in the ION lesioned birds.Impairments tended to be more severe when the targets were presented inthe left columns in the birds with right ION lesion. However, the ION lesionedbirds performed almost perfectly in the uncompetitive condition. The impair-ments in the competitive visual search observed in the ION lesioned birdsgradually recovered. Time course and overall degree of the recoveries variedamong the birds. Thus, removal of the IO signal severely impaired targetselection in a competitive visual search, as if the ION lesioned birds suf-fered visual extinction. This study suggests that the avian OT and its relatedstructures play an important role in target selection for visually guided beakreaching.

doi:10.1016/j.neures.2010.07.1298

P2-l14 Trajectories and temporal patterns of cancellationtask in patients with unilateral spatial neglectKatsuhiro Mizuno 1,2,4 , Kenji Kato 3, Keiichiro Shindo 1,4, MeigenLiu 1

1 Department of Rehabilitation Medicine, Keio Universitiy School ofMedicine, Tokyo, Japan 2 National Hospital Organization Murayama Medi-cal Center, Tokyo, Japan 3 Department of Biosciences and Informatics, KeioUniversity 4 Tokyo Metropolitan Rehabirlitation Hospital

Background and purpose: Various cancellation tasks are often used to eval-uate unilateral spatial neglect (USN). However, it is difficult to discriminatebetween stimulus-centered and viewer-centered neglects only with a sim-ple cancellation task. A circle test is a task in which patients select completecircles from complete and left- or right-chipped circles. Patients with leftstimulus-centered neglect select not only complete circles but also left-chipped circles. We developed a program to evaluate USN using a computerand a touch panel device, and estimated trajectories and temporal patternsof cancellation of patients with USN.Method: Seven right brain damaged patients were estimated with two typesof cancellation tasks, the simple star cancellation task and the circle test.Trajectories and temporal patterns of cancellation were assessed with thesimple star cancellation task, and stimulus-centered and viewer-centeredneglect were discriminated with the circle test.Results: With the circle test, one patient was classified as having stimulus-centered neglect and another as having viewer-centered neglect. Thetrajectories and temporal patterns of the stimulus-centered patient wereirregular, while those of the viewer-centered patient were regular. Thepatient having viewer-centered neglect could complete simple star cancel-lation task, but he paused and searched the next star when he transferredfrom the right side to the left side of the screen.Conclusion: Trajectories and temporal patterns of the simple cancellation taskwere different among patients with different subtypes of neglect, which indi-cated that we could discriminate subtypes with trajectories and temporalpatterns of the simple cancellation task.

doi:10.1016/j.neures.2010.07.1299

P2-l15 Cue response properties of monkey striatal neuronsduring duration discrimination taskAtsushi Chiba , Ken-ichi Oshio, Masahiko InaseDepartment of Physiology, Kinki University School of Medicine

Functional imaging and lesion studies in human and animals suggest that thebasal ganglia are involved in temporal information processing. To elucidateneuronal mechanisms of time perception in the basal ganglia, we adopteda duration discrimination task and recorded single-unit activity from thestriatum of two monkeys. In the task, two visual cues (C1 and C2) were pre-sented successively in different duration (0.2–2.0 s). Each cue presentation

was followed by a 1-s delay period (D1 and D2 periods). The monkeys wereinstructed to choose a longer presented cue after the D2 period. In our pre-vious study, we analyzed the delay period activity, and found D1-responseneurons, whose activity changed depending on C1 duration, and D2-responseneurons, whose activity changed according to the sequence of cue dura-