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Visual peripersonal space centred on the face in humans

BRAIN 1998年第12期121卷 2317-2326页

作者： Làdavas, E Zeloni, G Farnè, A Univ Bologna Dept Psychol I-40127 Bologna Italy Osped INRCA I Fraticini Florence Italy

A convergent series of studies in monkeys and man suggests that the computation of visual space is performed in several brain regions for different behavioural purposes, Among these multiple spatial areas, the ventral intraparietal cortex, the putamen and the ventral aspect of the premotor cortex (area 6) contain a system for representing visual space near the face (peripersonal space). In these cerebral areas some neurons are bimodal: they have tactile receptive fields on the face, and they can also be driven by visual stimuli located near the tactile field. The spatial correspondence between the visual and tactile receptive fields provides a map of near visual space coded in body-part-centred co-ordinates, In the present study we demonstrate for the first time the existence of a visual peripersonal space centred on the face in humans, In patients with right hemispheric lesions, visual stimuli delivered in the space near the ipsilesional side of the face extinguished tactile stimuli on the contralesional side (cross-modal visuotactile extinction) to the same extent as did an ipsilesional tactile stimulation (unimodal tactile extinction). Furthermore, a visual stimulus presented in the proximity of the contralesional side of the face improved the detection of a left tactile stimulus: i.e. under bilateral tactile presentation patients were more accurate to report the presence of a left tactile stimulus when a simultaneous visual stimulus was presented near the left side of the face. However, when visual stimuli were delivered far from the face, visuotactile extinction and visuotactile facilitation effects were dramatically reduced. These findings are consistent with the hypothesis of a representation of visual peripersonal space coded in body-part-centred co-ordinates, and they provide a striking demonstration of the modularity of human visual space.

关键词： face-centred space tactile extinction spatial coding space reference system cross-modal interaction

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Topographic bulbar projections and dual neural pathways of the primary olfactory neurons in salmonid fishes

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NEUROSCIENCE 1998年第1期82卷 301-313页

作者： Hara, TJ Zhang, C UNIV MANITOBA DEPT ZOOLWINNIPEGMB R3T 2N2CANADA

A growing body of evidence indicates spatial patterning of molecular expression and physiological activities in the olfactory epithelium and primary afferent circuits of the vertebrate olfactory bulb. Because our previous studies indicate that olfactory receptors specific for amino acids and a bile acid, taurocholic acid, project to segregated coding centres in the olfactory bulb, we further examined the afferent projections and pathways of the primary neuronal responses to putative pheromones by recording the electroencephalogram from various regions of the olfactory bulb. First, using the electro-olfactogram, we determined olfactory sensitivities of six salmonid species to these odorants. Prostaglandin F-2 alpha and 15-keto-prostaglandin F-2 alpha were potent olfactory stimulants for ail tested salmonids, except rainbow trout (Oncorhynchus mykiss). None of the salmonids responded to 17 alpha,20 beta-dihydroxy-4-pregnen-3-one. However, they were sensitive to etiocholan-3 alpha-ol-17-one glucuronide. In all salmonids examined, electroencephalograms to amino acids and taurocholic acid, applied singly or in combination, projected to two segregated regions, the lateroposterior and mid-olfactory bulb, respectively. Neither prostaglandin F-2 alpha, 15-keto-prostaglandin F-2 alpha nor etiocholan-3 alpha-ol-17-one glucuronide elicited electroencephalograms. These data indicate that, in salmonids, olfactory neurons responsive to amino acids and taurocholic acid project to spatially segregated regions and thereby generated signals are encoded spatially and temporarily. The results also suggest that olfactory signals due to hormonal pheromones are processed in a manner distinct from those for amino acids and bile acids, and may possibly be mediated by extrabulbar primary olfactory fibres bypassing the bulb. (C) 1997 IBRO. Published by Elsevier Science Ltd.

关键词： spatial coding electro-olfactogram electroencephalogram olfactory epithelium olfactory bulb pheromone

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spatial projections to the olfactory bulb of functionally distinct and randomly distributed primary neurons in salmonid fishes

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NEUROSCIENCE RESEARCH 1996年第1期26卷 65-74页

作者： Hara, TJ Zhang, CB UNIV MANITOBA DEPT ZOOLWINNIPEGMB R3T 2N2CANADA

In fish, olfactory sensory neurons expressing specific odorant receptors are randomly distributed throughout the olfactory epithelium, and, yet, these subsets of olfactory neurons segregate as they enter the olfactory bulb and project to restricted regions. We investigated the functional significance of this projection pattern by recording electroencephalographic responses (EEGs) from the olfactory bulb, while simultaneously monitoring electro-olfactograms (EOGs) in response to two distinct odorant groups, amino acids (AA) and a bile acid, taurocholic acid (TCA), in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). EEGs to AA and TCA distributed in two segregated regions, lateroposterior and mid olfactory bulb. When olfactory rosettes were subjected to partial lamellectomy (removal of the anterior, posterior, medial, or lateral half), both EOGs and EEGs to these odorants were uniformly reduced, and the degree of reduction was not dependent on the rosette region removed. These results indicate that the entire rosette contributes to the generation of EOGs, leading to transmission to the bulb. We conclude that in salmonid fishes olfactory neurons responsive to AA and TCA are randomly distributed throughout the olfactory epithelium, and yet project to spatially segregated regions and thereby generated signals are encoded independently in the bulb.

关键词： amino acid bile acid electroencephalogram electro-olfactogram odorant receptors olfactory epithelium olfactory neuron spatial coding

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SIGNALING SYSTEM FOR MULTIPLE-ACCESS LASER COMMUNICATIONS AND INTERFERENCE PROTECTION

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APPLIED OPTICS 1993年第11期32卷 1965-1972页

作者： RIZA, NA HERSHEY, JE HASSAN, AA The authors are with the General Electric Corporate Research and Development Center P.O. Box 8 KWB617 Schenectady New York 12301.

Signaling by spatial coding is proposed for asynchronous multiple-access free-space optical communications and interference mitigation. The large spatial bandwidth (e.g., 10(6) pixels) of each laser transmitter aperture is utilized for user coding, while the transmitter temporal bandwidth is preserved for information signals. Signal recovery is based on incoherent optical detection, spatial sampling, and electronic or optical matched filtering of the remotely received transmit optical beam Fresnel or Fraunhofer diffraction pattern. The proposed signaling method is appropriate for multiple-access free-space laser links involving multiple transmitters that use a common receiver. With electronic filtering, low-to-medium (e.g., 3 Mbits/s) data-rate users are appropriate. With a lenslet-array-based incoherent optical correlator, higher (e.g., 100 Mbits/s) data rates can be achieved. Improved interference protection is achieved by spatially distributed bit-duration-based processing. Preliminary simulation results are carried out to demonstrate operating principles.

关键词： LASER COMMUNICATIONS MULTIPLE-ACCESS COMMUNICATIONS spatial coding FREE-SPACE SPACE TIME coding

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EFFECTS OF GAZE ON APPARENT VISUAL RESPONSES OF FRONTAL-CORTEX NEURONS

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EXPERIMENTAL BRAIN RESEARCH 1993年第3期93卷 423-434页

作者： BOUSSAOUD, D BARTH, TM WISE, SP NIMH NEUROPHYSIOL LABPOB 289POOLESVILLEMD 20837

Previous reports have argued that single neurons in the ventral premotor cortex of rhesus monkeys (PMv, the ventrolateral part of Brodmann's area 6) typically show spatial response fields that are independent of gaze angle. We reinvestigated this issue for PMv and also explored the adjacent prearcuate cortex (PAv, areas 12 and 45). Two rhesus monkeys were operantly conditioned to press a switch and maintain fixation on a small visual stimulus (0.2-degrees x 0.2-degrees) while a second visual stimulus (1-degrees x 1-degrees or 2-degrees x 2-degrees) appeared at one of several possible locations on a video screen. When the second stimulus dimmed, after an unpredictable period of 0.4-1.2 s, the monkey had to quickly release the switch to receive liquid reinforcement. By presenting stimuli at fixed screen locations and varying the location of the fixation point, we could determine whether single neurons encode stimulus location in ''absolute space'' or any other coordinate system independent of gaze. For the vast majority of neurons in both PMv (90%) and PAv (94%), the apparent response to a stimulus at a given screen location varied significantly and dramatically with gaze angle. Thus, we found little evidence for gaze-independent activity in either PMv or PAv neurons. The present result in frontal cortex resembles that in posterior parietal cortex, where both retinal image location and eye position affect responsiveness to visual stimuli.

关键词： FRONTAL CORTEX GAZE PREMOTOR CORTEX spatial coding MONKEY

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PARIETAL NEURONS ENcoding spatial LOCATIONS IN CRANIOTOPIC COORDINATES

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EXPERIMENTAL BRAIN RESEARCH 1993年第2期96卷 221-229页

作者： GALLETTI, C BATTAGLINI, PP FATTORI, P UNIV TRIESTE FAC FISIOLI-34127 TRIESTEITALY

The receptive fields of visual neurons are known to be retinotopically arranged, and in awake animals they ''move'' with gaze, maintaining the same retinotopic location regardless of eye position. Here, we report the existence in the monkey parietal cortex of cells (called ''real-position'' cells) whose receptive field does not systematically move with gaze. These cells respond to the visual stimulation of the same spatial location regardless of eye position and therefore directly encode visual space in craniotopic instead of retinotopic coordinates.

关键词： PARIETAL CORTEX EYE POSITION spatial coding CRANIOTOPIC COORDINATES MONKEY

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BEAM SCANNING BINARY LOGIC

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JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 1990年第7期29卷 L1268-L1269页

作者： ITOH, H MUKAI, S WATANABE, M MORI, M YAJIMA, H Electrotechnical Laboratory Optical Information Section

A novel optoelectronic logic operation technique using a beam scanning laser diode is proposed. This technique realizes fundamental logic operation gates and a spatial encoder with simple configurations.

关键词： Beam scanning Logic gate Optical computing spatial coding Twin-stripe laser diode

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spatial coding OF OLFACTORY INFORMATION IN THE ANTENNAL LOBE OF DROSOPHILA-MELANOGASTER

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BRAIN RESEARCH 1988年第1-2期453卷 299-307页

作者： RODRIGUES, V MAX PLANCK INST BIOL CYBERNET D-7400 TUBINGEN FED REP GER

[3H]2-deoxyglucose autoradiography has revealed foci in the antennal lobe of Drosophila melanogaster that are active during olfactory stimulation. Labeling in the receptor axons and the lobe interneurons can be observed. Each class of odors stimulates activity in a specific subset of antennal glomeruli. This defines the activity domain, which is recognizably distinct, although overlapping, for different classes of volatile chemicals. Unilateral stimulation with attractants predominantly results in excitation of the ipsilateral glomeruli. Collaterals of the receptor neurons to the contralateral lobe stimulate no visible postsynaptic activity. On the other hand, unilateral stimulation with repellent odors, such as benzaldehyde, results in an equally strong activity in both antennal lobes.

关键词： spatial coding Olfaction Antennal lobe Olfactory stimulation Deoxyglucose Autoradiography

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MORPHOMETRIC MODIFICATIONS ASSOCIATED WITH EARLY SENSORY EXPERIENCE IN THE RAT OLFACTORY-BULB .1. VOLUMETRIC STUDY OF THE BULBAR LAYERS

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JOURNAL OF COMPARATIVE NEUROLOGY 1989年第4期289卷 586-593页

作者： ROYET, JP JOURDAN, F PLOYE, H UNIV LYON 1 ICBMC PHYSIOL NEUROSENSORIELLE LAB CNRS 43 BD 11 NOVEMBRE 1918 F-69622 VILLEURBANNE FRANCE UNIV LYON 1 IASBSE BIOMETALLAB CNRS F-69622 VILLEURBANNE FRANCE

Current models of sensory coding in the olfactory bulb are based on the notion of topographical specificity in the processing of stimuli. Part of this hypothesis comes from studies of patterns of radiolabelled 2-deoxyglucose uptake, and local morphometric variations of the mitral cell size observed following prolonged exposure to an odor. The present study explored the possibility that exposing young rats to a long-term stimulation with an odor would induce spatially distributed volumetric variations of the bulbar layers. Three groups of 5 rats have been studied: (1) stimulated with ethyl acetoacetate from birth to 1 month of age, (2) unilaterally deprived following early cauterization of one nostril, and (3) normal animals of same age. Fourteen frontal histological sections uniformly distributed along the rostrocaudal axis of the olfactory bulb were used for this study. Areas of the bulbar layers were measured with the aid of an image analyser and the volume of the corresponding layers deduced by computation. Following complete sensory deprivation, the volume of all bulbar layers, except the periventricular core, was homogeneously reduced along the rostrocaudal axis of the olfactory bulb. Following long-term stimulation with ethyl acetoacetate, volume reduction was significantly higher in anterior and middle regions than in the posterior part of the olfactory bulb. It is assumed that neuronal pathways activated by ethyl acetoacetate stimulation are mainly located in the posterior part of the olfactory bulb. Functional interpretations of these results are discussed with respect to the spatial dimension in olfactory coding.

关键词： sensory deprivation spatial coding volumetry computer-assisted image analysis

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REGIONAL AUTONOMY IN THE PERIPHERAL PROCESSING OF ODOR SIGNALS IN NEWBORN RABBITS

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BRAIN RESEARCH 1987年第1-2期421卷 85-94页

作者： HUDSON, R DISTEL, H Institut fu¨r Medizinische Psychologie Universita¨t Mu¨nchen Mu¨nchen F.R.G.

In newborn rabbits, small and apparently arbitrary regions of the olfactory bulb and associated epithelium appear capable of a high degree of odor processing. After medial or lateral removal of up to 80% of the olfactory bulbs, including the accessory bulb, newborn pups were still able to respond appropriately to the pheromone-governing suckling behavior (Expt. I), could rapidly learn to associate a novel, artificial odor with suckling (Expt. II), and continued to respond appropriately to artificial odors learned prior to lesioning (Expt. III). These findings suggest that the perception and recognition of such suckling signals does not depend on the integration of information from the entire bulb or epithelium, and question the extent to which patterns of 2-deoxyglucose uptake in the bulb reflect the neural coding for specific odors. However, as the tasks set here only required detection of odor signals and not true odor discrimination, it may still be that the full bulbar pattern of activation is necessary for higher-order processing, such as distinguishing between odors and attributing different meanings to them.

关键词： Odor processing spatial coding 2-Deoxyglucose Olfactory bulb Olfactory epithelium Suckling pheromone Odor learning Newborn rabbit

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