The updating of the representation of visual space in parietal cortex by intended eye movements.
03 Jan 1992-Science (American Association for the Advancement of Science)-Vol. 255, Iss: 5040, pp 90-92
TL;DR: Parietal cortex both anticipates theretinal consequences of eye movements and updates the retinal coordinates of remembered stimuli to generate a continuously accurate representation of visual space.
Abstract: Every eye movement produces a shift in the visual image on the retina. The receptive field, or retinal response area, of an individual visual neuron moves with the eyes so that after an eye movement it covers a new portion of visual space. For some parietal neurons, the location of the receptive field is shown to shift transiently before an eye movement. In addition, nearly all parietal neurons respond when an eye movement brings the site of a previously flashed stimulus into the receptive field. Parietal cortex both anticipates the retinal consequences of eye movements and updates the retinal coordinates of remembered stimuli to generate a continuously accurate representation of visual space.
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TL;DR: A new framework for a more adequate theoretical treatment of perception and action planning is proposed, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference, showing that the main assumptions are well supported by the data.
Abstract: Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account for the goal-directedness of even the simplest reaction in an experimental task We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data
2,736 citations
Journal Article•
TL;DR: In this article, the authors propose that the brain produces an internal representation of the world, and the activation of this internal representation is assumed to give rise to the experience of seeing, but it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness.
Abstract: Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual \"filling in,\" visual stability despite eye movements, change blindness, sensory substitution, and color perception.
2,271 citations
TL;DR: In this article, the authors propose that the brain produces an internal representation of the world, and the activation of this internal representation is assumed to give rise to the experience of seeing, but it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness.
Abstract: Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual “filling in,” visual stability despite eye movements, change blindness, sensory substitution, and color perception.
2,264 citations
TL;DR: A mechanism is proposed that is able to encode the desired goal of the action and is applicable to different levels of representational organization, as well as investigating the role of posterior parietal and premotor cortical areas in schema instantiation.
Abstract: This paper concerns how motor actions are neurally represented and coded. Action planning and motor preparation can be studied using a specific type of representational activity, motor imagery. A close functional equivalence between motor imagery and motor preparation is suggested by the positive effects of imagining movements on motor learning, the similarity between the neural structures involved, and the similar physiological correlates observed in both imaging and preparing. The content of motor representations can be inferred from motor images at a macroscopic level, based on global aspects of the action (the duration and amount of effort involved) and the motor rules and constraints which predict the spatial path and kinematics of movements. A more microscopic neural account calls for a representation of object-oriented action. Object attributes are processed in different neural pathways depending on the kind of task the subject is performing. During object-oriented action, a pragmatic representation is activated in which object affordances are transformed into specific motor schemas (independently of other tasks such as object recognition). Animal as well as human clinical data implicate the posterior parietal and premotor cortical areas in schema instantiation. A mechanism is proposed that is able to encode the desired goal of the action and is applicable to different levels of representational organization.
2,154 citations
TL;DR: The ability of psychophysical observers and single cortical neurons to discriminate weak motion signals in a stochastic visual display is compared and psychophysical decisions in this task are likely to be based upon a relatively small number of neural signals.
Abstract: We compared the ability of psychophysical observers and single cortical neurons to discriminate weak motion signals in a stochastic visual display. All data were obtained from rhesus monkeys trained to perform a direction discrimination task near psychophysical threshold. The conditions for such a comparison were ideal in that both psychophysical and physiological data were obtained in the same animals, on the same sets of trials, and using the same visual display. In addition, the psychophysical task was tailored in each experiment to the physiological properties of the neuron under study; the visual display was matched to each neuron's preference for size, speed, and direction of motion. Under these conditions, the sensitivity of most MT neurons was very similar to the psychophysical sensitivity of the animal observers. In fact, the responses of single neurons typically provided a satisfactory account of both absolute psychophysical threshold and the shape of the psychometric function relating performance to the strength of the motion signal. Thus, psychophysical decisions in our task are likely to be based upon a relatively small number of neural signals. These signals could be carried by a small number of neurons if the responses of the pooled neurons are statistically independent. Alternatively, the signals may be carried by a much larger pool of neurons if their responses are partially intercorrelated.
1,939 citations
Cites background from "The updating of the representation ..."
...4762 Britten et al. * MT Neurons and Psychophysical Performance al., 199 1; Duhamel et al., 1992 )....
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...…and Van Essen, 1983a; Ungerleider and Desimone, 1986) and recent physiological data suggest that neurons in this region participate in the planning of intended eye movements (Gnadt and Anderson, 1988; Barash et et al. * MT Neurons and Psychophysical Performance al., 199 1; Duhamel et al., 1992)....
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References
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Book•
01 Dec 1962
TL;DR: A composite thin film resistor is disclosed, including an electrically inert substrate upon which is deposited a nickel-chromium alloy thin film, and an overlying second thin film - which is initially deposited as metallic tantalum - which provides a very high degree of environmental protection with respect to the Ni-Cr film.
Abstract: A composite thin film resistor is disclosed, including an electrically inert substrate upon which is deposited a nickel-chromium alloy thin film, and an overlying second thin film - which is initially deposited as metallic tantalum. In the final product the tantalum is passivated, as by thermal oxidation, so that the said film is substantially tantalum oxide throughout, except where such film underlies a pair of conductive terminal pads. The terminal pads are spaced on the substrate, so that the resistive path therebetween is defined through the nickel-chromium thin film - via the thin metallic tantalum film interfacing between the nickel-chromium film and conductive pads. The overlying tantalum oxide provides a very high degree of environmental protection with respect to the Ni-Cr film, whereby the product not only displays the desirably low TCR characteristics of Ni-Cr, but is also highly resistant to moisture and other environmental factors. The product also exhibits outstanding resistance to the adverse effects of electrolysis supported by the presence of moisture. The various films, including a gold film from which the terminal pads are derived, may be deposited upon the inert substrate by sequential sputtering during a single evacuation of a vacuum chamber. Desired resistive patterns may then be formed by photo-etching, subsequent to which oxidation of accessible portions of the tantalum film can be effected by heating in an appropriate atmosphere.
1,683 citations
TL;DR: Unit recording studies in the lateral bank of the intraparietal cortex (area LIP) have demonstrated a response property not previously reported in posterior cortex, which appears to represent a memory-related motor-planning signal encoding motor error in the Rhesus monkey.
Abstract: Unit recording studies in the lateral bank of the intraparietal cortex (area LIP) have demonstrated a response property not previously reported in posterior cortex. Studies were performed in the Rhesus monkey during tasks which required saccadic eye movements to remembered target locations in the dark. Neurons were found which remained active during the time period for which the monkey had to withhold eye movements while remembering desired target locations. The activity of the cells was tuned for eye movements of specific direction and amplitude, and it was not necessary for a visual stimulus to fall within the response field. The responses appeared to represent a memory-related motor-planning signal encoding motor error. The relation of the activity to the behavior of the animal suggests that the response represents the intent to make eye movements of specific direction and amplitude.
997 citations
TL;DR: It is suggested that the role of area 7 in visual attention may be mediated by the enhancement of visual responses to selected stimuli, which resembles the psychological phenomenon of selective spatial attention.
Abstract: that area 7 of posterior parietal cortex plays a role in visual attention and eye movements. We have operationally defined attention as a stimulus-selection process independent of the specific movement used to respond to the stimulus. We trained monkeys to make various hand or eye movements and recorded from single neurons in area 7 while the monkeys were performing these tasks. 2. As demonstrated previously ( 19, 20, 46, 47, 63), many cells in area 7 respond to visual stimuli independent of any behavior. The discharge to a stimulus may be enhanced when the animal makes an eye movement to the stimulus. 3. We used two paradigms to study the modulation of visual responses when the animal used a stimulus without making an eye movement. The first was a peripheral-attention task in which the animal had to signal the occurrence of a peripheral stimulus without making an eye movement to it. Half of the cells studied gave an enhanced response in this task. In the second task, the animal had to reach out and touch a stimulus without making an eye movement to it. Visually responsive parietal neurons also yielded enhanced responses in this task. 4. The enhancements demonstrable in the saccade, peripheral-attention, and handreach tasks probably represent the same underlying process because their frequency of occurrence in our sample is almost identical, the intensities are quite similar, and cells that give an enhanced response on one task give an enhanced response in the others. 5. These results show that in posterior parietal cortex, the behavioral enhancement of a visual response is independent of the specific movement used to respond to the stimulus. The physiological mechanism of enhancement, which is movement independent and spatially selective, resembles the psychological phenomenon of selective spatial attention. We suggest that the role of area 7 in visual attention may be mediated by the enhancement of visual responses to selected stimuli.
851 citations
818 citations
TL;DR: The present results indicate that this modulating effect of eye position may be a general one, as it is found in 3 types of responses in 2 cortical areas, and it is proposed that these eye position effects play an important role in making coordinate transformations for visually guided movement.
Abstract: We studied the effect of eye position on the light-sensitive, memory, and saccade-related activities of neurons of the lateral intraparietal area and area 7a in the posterior parietal cortex of rhesus monkeys. A majority of the cells showed significant effects of eye position, for each of the 3 types of response. The direction tuning of the light- sensitive, memory and saccade responses did not change with eye position but the magnitude of the response did. Since previous work showed a similar effect for the light-sensitive response of area 7a neurons (Andersen and Mountcastle, 1983; Andersen et al., 1985b), the present results indicate that this modulating effect of eye position may be a general one, as it is found in 3 types of responses in 2 cortical areas. Gain fields were mapped by measuring the effect of eye position on the magnitude of the response at 9 different eye positions for each neuron. The gain fields were usually planar or largely planar for all 3 types of response in both areas, indicating that the magnitude of the response usually varies linearly with both horizontal and vertical eye position. A similar observation was made previously for the gain fields of the light-sensitive response of area 7a neurons (Andersen et al., 1985b). Although gain fields sloped in all directions for the population of cells, the gain field slopes of the light- sensitive, memory and saccade responses for individual cells were usually similar. It is proposed that these eye position effects play an important role in making coordinate transformations for visually guided movement.
681 citations