Representation of moving tactile stimuli in the somatic sensory cortex of awake monkeys

Oros-Ruíz, Socorro; Crespo, Patricia; Romo, Ranulfo

doi:10.1152/jn.1995.73.2.525

Cited by 64 publications

(41 citation statements)

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“…Neurons in V1 tend to be subject to the aperture problem, whereas MT neurons integrate information across populations of V1 neurons to compute the veridical direction of motion. Neurons that detect local motion have been identified in the primary somatosensory cortex (SI) (11)(12)(13)(14), but these neurons have yet to be systematically probed with stimuli whose local motion cues are ambiguous.…”

Section: Resultsmentioning

confidence: 99%

“…This ambiguity is resolved at higher processing levels as evidenced by the fact that the veridical direction of motion of objects comprising multiple contours can be readily perceived. The objective of the present study is to determine whether local motion signals, conveyed by local motion detectors, which lie at the early stages of somatosensory processing (11)(12)(13)(14), are integrated to form a global motion percept. To that end, we present the tactile equivalent of stimuli whose perceptual properties are well established in vision, including superimposed gratings (plaids), barber poles, and moving bar fields.…”

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confidence: 99%

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The tactile integration of local motion cues is analogous to its visual counterpart

Pei

Hsiao

Bensmaı̈a

2008

Proc. Natl. Acad. Sci. U.S.A.

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The visual and somatosensory systems have been shown to process spatial information similarly. Here we investigate tactile motion processing using stimuli whose perceptual properties have been well established in vision research, namely superimposed gratings (plaids), barber poles, and bar fields. In both modalities, information about stimulus motion (speed and direction) conveyed by neurons at low levels of sensory processing is ambiguous, a conundrum known as the aperture problem. Our results suggest that the tactile perception of motion, analogous to its visual counterpart, operates in multiple stages: first, the perceived direction of motion is determined by a majority vote from local motion detectors, which are subject to the aperture problem. As in vision, the conflict between the cues from terminators and other local motion cues is gradually resolved over time so that the perceived direction approaches the veridical direction of motion.aperture problem ͉ psychophysics ͉ plaid ͉ barber pole ͉ somatosensory B oth vision and touch share the common problem of inferring stimulus form, texture, and motion from a spatiotemporal pattern of activation across a two-dimensional sensory sheet (i.e., the retina and skin). The two systems have been found to process information about two-dimensional spatial form in a similar fashion (1-3). In both systems, information about motion can be acquired by analyzing how stimulus contours change over time. Both the visual and somatosensory systems may therefore have evolved analogous mechanisms to process motion information as well. Then again, the analogy between the two systems is not absolute: for instance, depth ordering and transparency are problems that have no obvious analogue in the cutaneous sense (although palpation through gloves may involve a tactile equivalent of transparency). Furthermore, shear forces, which have no direct visual analogue, may contribute to the tactile perception of motion (4, 5). These differences between vision and touch may lead to differences in the way the two systems process motion.The study of motion processing provides an opportunity to address an important question in sensory neuroscience, namely: how is the environment represented at each stage of perceptual processing? Indeed, the speed and direction of motion of individual (one-dimensional) edges is ambiguous because information about the motion component parallel to their orientation is not available, a predicament known as the aperture problem (6) (Fig. 1). To acquire a veridical percept of an object's direction of motion, then, it is often necessary to integrate motion information across multiple stimulus contours that differ in orientation (7,8) or to rely on so-called terminators-such as end points, corners, and intersections-whose direction of motion is unambiguous (9, 10).The aperture problem is inherent to individual neurons at low levels of processing because these neurons have spatially restricted receptive fields and only ''see'' local contours of the stimulus. From the sta...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

The tactile integration of local motion cues is analogous to its visual counterpart

Pei

Hsiao

Bensmaı̈a

2008

Proc. Natl. Acad. Sci. U.S.A.

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“…One possibility is that SII region neurons are responsible for coding local stimulus features and that neurons with untuned pads (types UE, UI, and UEI) serve to code tactile functions that are not orientation sensitive, such as texture (Sinclair and Burton, 1993;Jiang et al, 1997;Pruett et al, 2000Pruett et al, , 2001, vibration (Poranen and Hyvarinen, 1982;Burton and Sinclair, 1991;Burton et al, 1997;Romo et al, 2002), or motion processing (Whitsel et al, 1972;Costanzo and Gardner, 1980;Warren et al, 1986;Ruiz et al,1995), and that neurons with tuned pads (type T) are coding local oriented features such as Braille dots.…”

Section: Discussionmentioning

confidence: 99%

Receptive Field (RF) Properties of the Macaque Second Somatosensory Cortex: RF Size, Shape, and Somatotopic Organization

Fitzgerald

Lane

Thakur

et al. 2006

Journal of Neuroscience

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The detailed structure of multidigit receptive fields (RFs) in somatosensory cortical areas such as the SII region has not been investigated previously using systematically controlled stimuli. Recently (Fitzgerald et al., 2004), we showed that the SII region comprises three adjoining fields: posterior, central, and anterior. Here we characterize the RF structures of the 928 neurons that were reported in that study using a motorized oriented bar that was indented into the 12 finger pads of digits 2-5. Most (81%) of the neurons were responsive to the oriented bar stimuli, and 81% of those neurons had RFs that spanned multiple digits. Furthermore, the RFs varied greatly in size, shape, and complexity. Some RFs contained only excitatory finger pads, some contained only inhibitory pads, and some contained both types of pads. A subset of the neurons (23%) showed orientation tuning within one or more pads. The RFs spread across different digits more than within individual digits, and the responsive finger pads for a given neuron tended to cluster together within the hand. Distal and lateral finger pads were better represented than proximal and medial finger pads. Furthermore, neurons in the posterior, central, and anterior SII region fields contained different proportions of RF types. These results collectively indicate that most SII region neurons are selective for different stimulus forms either within single finger pads or across multiple pads. We hypothesize that these RFs represent the kernels underlying the representation of tactile shape.

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“…The PVA has enabled investigation of cortical control of arm movement (e.g., Moran and Schwartz 1999) including phenomena such as illusion perception (Schwartz et al 2004) and has also been used in quite different contexts, such as the representation of moving tactile stimuli in sensory cortex (Ruiz et al 1995). The method originated from the observation that motor cortex neurons are directionally tuned, with broad tuning curves that may be characterized reasonably well by 2 parameters, average firing rate and preferred direction.…”

Section: The Population Vector Algorithm Is Simple and Often Effectivementioning

confidence: 99%

Statistical Issues in the Analysis of Neuronal Data

Kass¹,

Ventura²,

Brown³

2005

Journal of Neurophysiology

252

239

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Kass, Robert E., Valérie Ventura, and Emery N. Brown. Statistical issues in the analysis of neuronal data. J Neurophysiol 94: 8 -25, 2005; doi:10.1152/jn.00648.2004. Analysis of data from neurophysiological investigations can be challenging. Particularly when experiments involve dynamics of neuronal response, scientific inference can become subtle and some statistical methods may make much more efficient use of the data than others. This article reviews wellestablished statistical principles, which provide useful guidance, and argues that good statistical practice can substantially enhance results. Recent work on estimation of firing rate, population coding, and time-varying correlation provides improvements in experimental sensitivity equivalent to large increases in the number of neurons examined. Modern nonparametric methods are applicable to data from repeated trials. Many within-trial analyses based on a Poisson assumption can be extended to non-Poisson data. New methods have made it possible to track changes in receptive fields, and to study trial-to-trial variation, with modest amounts of data. I N T R O D U C T I O NTechnical advances have made available new methods for collecting, storing, and manipulating electrophysiological data. Investigations may now not only characterize neuronal activity in anatomically well defined regions, but they can also examine dynamics of neuronal response and their relationship to behavior. Although elementary methods of data analysis [such as t-tests or visual examination of the peristimulus time histogram (PSTH)] remain useful for many purposes, the growing complexity of neuroscientific experiments, often examining subtle changes on a comparatively fine timescale, requires careful attention to statistical methods for data analysis. In this overview we discuss some of the fundamental data analytical issues that face researchers in neurophysiology, illustrating the general points with the problems of describing the evolution of a neuron's firing rate across time, finding accurate population codes, and assessing time-varying correlation between 2 neurons. In each case recent work has provided a statistical technique that outperforms previous methodology, boosting the scientific information as effectively as if the number of experimental trials, or the number of neurons, had been increased by a substantial factor. We also indicate some of the ways modern statistical procedures can accommodate important complexities, such as dynamic changes in temporal and spatial aspects of hippocampal place cell firing and trial-to-trial variability in cortical neurons recorded from behaving animals. Our review supplements the brief and general guidance offered by Curran-Everett and Benos (2004), and may be regarded as an update to the early work of Perkel et al. (1967a,b).The new field of computational neuroscience uses detailed biophysical models and artificial neural networks to study emergent behavior of neural systems and the way neural systems represent and transmit information (e.g...

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Representation of moving tactile stimuli in the somatic sensory cortex of awake monkeys

Cited by 64 publications

References 0 publications

The tactile integration of local motion cues is analogous to its visual counterpart

The tactile integration of local motion cues is analogous to its visual counterpart

Receptive Field (RF) Properties of the Macaque Second Somatosensory Cortex: RF Size, Shape, and Somatotopic Organization

Statistical Issues in the Analysis of Neuronal Data

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