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Neural mechanisms of spatial stimulus-response compatibility: the effect of crossed-hand position

EXPERIMENTAL BRAIN RESEARCH 2004年第1期158卷 9-17页

作者： Matsumoto, E Misaki, M Miyauchi, S Kansai Adv Res Ctr Commun Res Lab Brain Informat Grp Nishi Ku Kobe Hyogo 6512429 Japan

Previous psychological experiments have indicated the existence of a visual-proprioceptive interaction in spatial stimulus-response compatibility (SSRC) tasks, but there is little specific information on the neural basis of such interaction in humans. Using functional magnetic resonance imaging (fMRI), we compared the neural activity associated with two different aspects of spatial coding: the coding of the "internal" spatial position of motor-response effectors (i.e., the position of body parts) as obtained through proprioception, and the coding of "external" positions, i.e., the positions of visual stimuli. A 2x2 factorial design was used to investigate the spatial compatibility (incompatible versus compatible) between a visual stimulus and hand position (crossed versus uncrossed). The subjects were instructed to respond to stimuli presented to the right or left visual field with either the ipsilateral (compatible condition) or the contralateral hand (incompatible condition). The incompatible condition produced stronger activation in the bilateral superior parietal lobule, inferior parietal lobule, and bilateral superior frontal gyrus than the compatible condition. The crossed-hand condition produced stronger activation in the bilateral precentral gyrus, superior frontal gyrus, superior parietal lobule, and superior temporal gyrus than the uncrossed-hand condition. These results suggest that activity in the frontal-parietal regions is related to two functions: (1) representation of the visual stimulus-motor response spatial configuration in an SSRC task, and (2) integration between external visual and internal proprioceptive sensory information. The activation in the superior temporal gyrus was not affected by the visual stimulus-motor response spatial configuration in an SSRC task;rather, it was affected by the crossed-hand posture. Thus, it seems to be related to representing internal proprioceptive sensory information necessary to carry out motor actions.

关键词： stimulus-response compatibility reference frame spatial coding crossed-hand

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Data reduction for the AMBER instrument

Data reduction for the AMBER instrument

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Conference on New Frontiers in Stellar Interferometry

作者： Millour, F Tatulli, E Chelli, A Duvert, G Zins, G Acke, B Malbet, F Observ Grenoble LAOG F-38041 Grenoble 9 France

ISBN: (纸本)0819454230

We present here the general formalism and data processing steps used in the data reduction pipeline of the AMBER instrument. AMBER is a three-telescope interferometric beam combiner in J, H and K bands installed at ESO's Very Large Telescope Interferometer. The fringes obtained on the 3 pairs of telescopes are spatially coded and spectrally dispersed. These are monitored on a 512x512 infrared camera at frame rates up to 100 frames per second, and this paper presents the algorithm used to retrieve the complex coherent visibility of the science target and the subsequent squared visibility, differential phase and phase closure on the 3 bases and in the 3 spectral bands available in AMBER.

关键词： AMBER VLTI long baseline infrared interferometry complex visibility P2VM algorithm data reduction software spectroscopy spatial coding phase closure interspectrum

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Dose-response characteristics of glomerular activity in the moth antennal lobe

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CHEMICAL SENSES 2003年第4期28卷 269-278页

作者： Carlsson, MA Hansson, BS Swedish Univ Agr Sci Dept Crop Sci SE-23053 Alnarp Sweden

Odours are represented as unique combinations of activated glomeruli in the antennal lobes of insects. Receptor neurons arborizing in the glomeruli are not only qualitatively selective, but in addition respond to variations in stimulus concentration. As each glomerulus likely represents a single receptor neuron type, optical recordings of calcium changes in insect antennal lobes show how concentration variations affect a large population of afferents. We measured the glomerular responses in the moth Spodoptera littoralis to different concentrations of plant-related odorants. Localized calcium responses were shown to correspond to individual glomeruli. We found that the dynamic range of glomerular responses spanned 3-4 log units of concentration and the most strongly responding glomeruli often reached a plateau at high stimulus doses. Further, we showed that the single most active glomerulus was often not the same across concentrations. However, if the principal glomerulus moved, it was generally to an adjacent or proximal glomerulus. As concentration increased, a higher number of glomeruli became activated. Correlations of glomerular representations of the same compound at different doses decreased as the difference in concentration increased. Moreover, representations evoked by different odorants were more correlated at high than at low doses, which means that the uniqueness of activity patterns decreased with increasing concentration. Thus, if odours are coded as spatial patterns of glomerular activity, as has been suggested, these olfactory codes are not persistent across concentrations.

关键词： olfaction Spodoptera littoralis optical imaging plant volatile spatial coding

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spatially coded moire matching technique for genome information visualization

Spatially coded moire matching technique for genome informat...

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Conference on Optical Information Processing Technology

作者： Tanida, J Nitta, K Yahata, A Osaka Univ Grad Sch Informat Sci & Technol Suita Osaka 5650871 Japan

ISBN: (纸本)0819447188

A simple and informative method for exploring genome information is presented. The method is based on a spatially coded moire matching technique to visualize a relation between two genome sequences. The basic idea and its extensions to amino acid sequence analysis and multiple sequences comparison are explained with some experimental results.

关键词： photonic bioinformatics moire matching spatial coding genome DNA amino acid visualization

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Comparison between different encoding schemes for synthetic aperture Imaging

Comparison between different encoding schemes for synthetic ...

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Medical Imaging 2002 Conference

作者： Nikolov, SI Jensen, JA Tech Univ Denmark Ctr Fast Ultrasound Imaging DK-2800 Lyngby Denmark

ISBN: (纸本)0819444324

Synthetic transmit aperture ultrasound (STAU) imaging can create images with as low as 2 emissions, making it attractive for 3D real-time imaging. Two are the major problems to be solved: (1) complexity of the hardware involved, and (2) poor image quality due to low signal to noise ratio (SNR). We have solved the first problem by building a scanner capable of acquiring data using STAU in real-time. The SNR is increased by using encoded signals, which make it possible to send more energy in the body, while preserving the spatial and contrast resolution. The performance of temporal, spatial and spatio-temporal encoding was investigated. Experiments on wire phantom in water were carried out to quantify the gain from the different encodings. The gain in SNR using an FM modulated pulse is 12 dB. The penetration depth of the images was studied using tissue mimicking phantom with frequency dependent attenuation of 0.5 dB/(cm MHz). The combination of spatial and temporal encoding have highest penetration depth. Images to a depth of 110 mm, can successfully be made with contrast resolution comparable to that of a linear array image. The in-vivo scans show that the motion artifacts do not significantly influence the performance of the STAU.

关键词： synthetic aperture ultrasound focusing imaging temporal coding spatial coding coding

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spatial coding of eye movements relative to perceived earth and head orientations during static roll tilt

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EXPERIMENTAL BRAIN RESEARCH 1998年第1期121卷 51-58页

作者： Wood, SJ Paloski, WH Reschke, MF KRUG Life Sci Neurosci Lab Houston TX USA

This purpose of this study was to examine the spatial coding of eye movements during static roll tilt (up to +/-45 degrees) relative to perceived earth and head orientations. Binocular videographic recordings obtained in darkness from eight subjects allowed us to quantify the mean deviations in gaze trajectories along both horizontal and vertical coordinates relative to the true earth and head orientations. We found that both variability and curvature of gaze trajectories increased with roll tilt. The trajectories of eye movements made along the perceived earth-horizontal (PEH) were more accurate than movements along the perceived head-horizontal (PHH). The trajectories of both PEH and PHH saccades tended to deviate in the same direction as the head tilt. The deviations in gaze trajectories along the perceived earth-vertical (PEV) and perceived head-vertical (PHV) were both similar to the PHH orientation, except that saccades along the PEV deviated in the opposite direction relative to the head tilt. The magnitude of deviations along the PEV, PHH, and Pi-IV corresponded to perceptual overestimations of roll tilt obtained from verbal reports. Both PEV gaze trajectories and perceptual estimates of tilt orientation were different following clockwise rather than counterclockwise tilt rotation;however, the PEH gaze trajectories were less affected by the direction of tilt rotation. Our results suggest that errors in gaze trajectories along PEV and perceived head orientations increase during roll tilt in a similar way to perceptual errors of tilt orientation. Although PEH and PEV gaze trajectories became nonorthogonal during roll tilt, we conclude that the spatial coding of eye movements during roll tilt is overall more accurate for the perceived earth reference frame than for the perceived head reference frame.

关键词： spatial coding saccades tilt perception adaption human

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Seeing or not seeing where your hands are

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EXPERIMENTAL BRAIN RESEARCH 2000年第4期131卷 458-467页

作者： Làdavas, E Farnè, A Zeloni, G di Pellegrino, G Univ Bologna Dept Psychol I-40127 Bologna Italy Osped INRCA Fraticini I-50100 Florence Italy Inst Psychol I-61029 Urbino Italy

Previous findings have demonstrated the existence of a visual peripersonal space centered on the hand in humans and its modulatory effects on tactile perception. A strong modulatory effect of vision on touch perception was found when a visual stimulus was presented near the hand. In contrast, when the visual stimulus was presented far from the hand, only a weak modulatory effect was found. The aim of the present study was to verify whether such cross-modal links between touch and vision in the peripersonal space centered on the hand could be mediated by proprioceptive signals specifying the current hand positions or if they directly reflect an interaction between two sensory modalities, i.e., vision and touch. To this aim, cross-modal effects were studied in two different experiments: one in which patients could see their hands and one in which vision of their hands was prevented. The results showed strong modulatory effects of vision on touch perception when the visual stimulus was presented near the seen hand and only mild effects when the vision of the hand was prevented. These findings are explained by referring to the activity of bimodal neurons in premotor and parietal cortex of macaque, which have tactile receptive fields on the hand, and corresponding visual receptive fields in the space immediately adjacent to the tactile fields. One important feature of these bimodal neurons is that their responsiveness to visual stimuli delivered near the body part is reduced or even extinguished when the view of the body part is prevented. This implies that, at least for the hand, the vision of the hand is crucial for determining the spatial mapping between vision and touch that takes place in the peripersonal space. In contrast, the proprioceptive signals specifying the current hand position in space do not seem to be relevant in determining the cross-modal interaction between vision and touch.

关键词： peripersonal space tactile extinction cross-modal interaction spatial coding proprioceptive information

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Calcium responses to pheromones and plant odours in the antennal lobe of the male and female moth Heliothis virescens

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JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY 2000年第11期186卷 1049-1063页

作者： Galizia, CG Sachse, S Mustaparta, H Free Univ Berlin Inst Biol Neurobiol D-14195 Berlin Germany Norwegian Univ Sci & Technol NTNU Dept Zool N-7194 Trondheim Norway

In male moths, the primary olfactory integration centre, the antennal lobe, consists of two systems. The macroglomerular complex processes pheromone information, while the ordinary glomeruli process plant odour information. Females lack a macroglomerular complex. We measured the spatial representation of odours using in-vivo optical recording. We found that: (1) pheromone substances elicited activity exclusively in the MGC. No response was found in female antennal lobes. (2) Plant odours elicited combinatorial activity patterns in the ordinary glomeruli in both males and females. No response was found in the MGC of male moths. (3) A clean air puff often led to activity, in both males and females, suggesting that mechano-sensory information is also processed in the antennal lobe. (4) With an interstimulus interval of 5 or 10 s, strongly activated glomeruli were able to follow the temporal structure of the stimulus, while others lost their phase-locking. Some glomeruli showed "off" responses. These properties were odour dependent. This confirms and extends previous studies, showing the functional significance of the two subsystems for processing olfactory information. Pheromones are coded in a combinatorial manner within the macroglomerular complex, with each glomerulus corresponding to one information channel. Plant odours are coded in an across-glomeruli code in the ordinary glomeruli.

关键词： optical imaging calcium green spatial coding olfactory representation repetitive stimulation

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String data matching based on a moire technique using 1-D spatial coded patterns

String data matching based on a moire technique using 1-D sp...

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Conference on Optics in Computing 2000

作者： Tanida, J Nitta, K Osaka Univ Grad Sch Engn Dept Mat & Life Sci Suita Osaka 5650871 Japan

ISBN: (纸本)0819437328

An optical computing method for string data matching applicable to genome information processing is presented. With:encoding one-dimensional data into spatial code patterns, moire fringes between two different coded patterns provide information on the correspondence of the original data, which is useful for string alignment in genome analysis. A new code set for the spatial coding is capable of processing complementary base-pairing DNA sequences. Results of the preliminary experiments are shown to verify effectiveness of the method. Processing performance is evaluated with a simplified model. Finally, two optoelectronic implementations are presented for future directions.

关键词： string matching moire spatial coding parallel processing genome analysis DNA amino acid optoelectronic system

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Orientation masks 3-Gabor alignment performance

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VISION RESEARCH 1998年第6期38卷 827-840页

作者： Keeble, DRT Hess, RF McGill Univ Dept Ophthalmol Montreal PQ H3A 1A1 Canada

Several workers have concluded that Gabor alignment tasks are performed by using central tendencies of the micropatterns as a cue, One reason for this conclusion was that the 3-Gabor alignment task is performed equally well whether the orientations of the patches are collinear or orthogonal to the group orientation, We wished to find out if the orientation of the micropatterns has any effect on performance, We tested subjects in 3-micropattern alignment tasks using a variety of orientational conditions, If three vertically-aligned Gabor patches were vertical, horizontal or both, or if bullseye or Gaussian blobs were used, no difference in performance was found, If, however, the orientation of the patches was randomized, performance became much worse, Similarly, if the three patches were at 45 deg, thresholds were raised, The effect of orientation was maintained across different spatial frequencies, Control conditions involving randomization of the phase of the sinusoidal carrier, or jitter on the size of Gaussian blobs, confirmed that a central tendency of the micropatterns was indeed being used by subjects, indicating that the role of orientation in this task is that of a mask, rather than of a cue. (C) 1998 Elsevier Science Ltd. All rights reserved.

关键词： spatial alignment spatial coding contour orientation

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