Space reconstruction by primary visual cortex activity: a parallel, non-computational mechanism of object representation

Gur, Moshe

doi:10.1016/j.tins.2015.02.005

Cited by 17 publications

(18 citation statements)

References 71 publications

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“…Indeed, it is our perception of details that enables us to discriminate between facesin spite of their inherent similarity. Elsewhere, I show (Gur 2015) that because V1 is the only visual area that represents space at a resolution and topographical exactitude that is compatible with our perceptual abilities, its preintegration response patterns ("V1 map") must be the neural substance of image representation. From these preintegration response patterns, information converges in successive hierarchical stages, from V1 orientation-selective cells through downstream cortical areas V2, V4, and the inferotemporal cortex (IT).…”

Section: Introductionmentioning

confidence: 94%

“…1 in Gur & Snodderly 2008), where the spatial extent of its synaptic connectivity is rather spread out (Rockland 1994). Such connectivity rules out any direct, spatially circumscribed influence over V1 upper layers' cells representing the objects' details (Gur 2015;Gur et al 2005). Even more important, the route into the visual cortex goes through the large RF cells of the IT cortex.…”

Section: Introductionmentioning

confidence: 99%

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Cognition does not affect perception: Evaluating the evidence for “top-down” effects

Firestone¹,

Scholl²

2015

Behav Brain Sci

780

764

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Abstract:What determines what we see? In contrast to the traditional "modular" understanding of perception, according to which visual processing is encapsulated from higher-level cognition, a tidal wave of recent research alleges that states such as beliefs, desires, emotions, motivations, intentions, and linguistic representations exert direct, top-down influences on what we see. There is a growing consensus that such effects are ubiquitous, and that the distinction between perception and cognition may itself be unsustainable. We argue otherwise: None of these hundreds of studies -either individually or collectively -provides compelling evidence for true top-down effects on perception, or "cognitive penetrability." In particular, and despite their variety, we suggest that these studies all fall prey to only a handful of pitfalls. And whereas abstract theoretical challenges have failed to resolve this debate in the past, our presentation of these pitfalls is empirically anchored: In each case, we show not only how certain studies could be susceptible to the pitfall (in principle), but also how several alleged top-down effects actually are explained by the pitfall (in practice). Moreover, these pitfalls are perfectly general, with each applying to dozens of other top-down effects. We conclude by extracting the lessons provided by these pitfalls into a checklist that future work could use to convincingly demonstrate top-down effects on visual perception. The discovery of substantive top-down effects of cognition on perception would revolutionize our understanding of how the mind is organized; but without addressing these pitfalls, no such empirical report will license such exciting conclusions.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Cognition does not affect perception: Evaluating the evidence for “top-down” effects

Firestone¹,

Scholl²

2015

Behav Brain Sci

780

764

View full text Add to dashboard Cite

show abstract

“…All those elaborate spatial details are perceived, simultaneously and in parallel. As I show elsewhere (Gur 2015), it is the neural activity in the primary visual cortex (V1) with its veridical depiction of the spatial elements comprising the visual image (a V1 "map") that is the basis of object representation, perception, and recognition. A second process evident in our conscious perception is the integration of the neural activity occurring in disparate V1 loci into holistic objects.…”

Section: Moshe Gurmentioning

confidence: 99%

“…A second process evident in our conscious perception is the integration of the neural activity occurring in disparate V1 loci into holistic objects. The ability of the brain to generate perceived objects is quite remarkable; a small number of dots that individually carry no information of orientation, size, or length can be easily recognized as meaningful shapes (Gur 2015). Even when flashed for a mere 50 microseconds or less (Greene & Ogden 2012;Greene & Visani 2015), during which time visual cells fire just one or two spikes (Gur & Snodderly 1997), it is possible to successfully detect the shapes represented by the dots.…”

Section: Moshe Gurmentioning

confidence: 99%

Homing in on consciousness in the nervous system: An action-based synthesis

Morsella

Godwin²,

Jantz³

et al. 2015

Behav Brain Sci

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Abstract:What is the primary function of consciousness in the nervous system? The answer to this question remains enigmatic, not so much because of a lack of relevant data, but because of the lack of a conceptual framework with which to interpret the data. To this end, we have developed Passive Frame Theory, an internally coherent framework that, from an action-based perspective, synthesizes empirically supported hypotheses from diverse fields of investigation. The theory proposes that the primary function of consciousness is well-circumscribed, serving the somatic nervous system. For this system, consciousness serves as a frame that constrains and directs skeletal muscle output, thereby yielding adaptive behavior. The mechanism by which consciousness achieves this is more counterintuitive, passive, and "low level" than the kinds of functions that theorists have previously attributed to consciousness. Passive frame theory begins to illuminate (a) what consciousness contributes to nervous function, (b) how consciousness achieves this function, and (c) the neuroanatomical substrates of conscious processes. Our untraditional, action-based perspective focuses on olfaction instead of on vision and is descriptive (describing the products of nature as they evolved to be) rather than normative (construing processes in terms of how they should function). Passive frame theory begins to isolate the neuroanatomical, cognitivemechanistic, and representational (e.g., conscious contents) processes associated with consciousness.

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“…One might reasonably attribute the persistence of orientation information seen in those studies to this cortical location. Gur (2015) makes the case that conscious perception is mediated by activity in primary visual cortex, this being for dot patterns as well as for lines and edges. Given that, it would be tempting to attribute the iconic memory effects observed in Experiment 4 to primary visual cortex.…”

Section: Further Evaluation Of Locusmentioning

confidence: 99%

Recognition of letters displayed as briefly flashed dot patterns

Greene

Visani

2015

Atten Percept Psychophys

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Complex shapes can be identified (named) when only the outer boundary of the shape is represented by discrete dots and with the dots being displayed for a duration lasting only a few microseconds (μs). This line of work is extended here to include recognition of letters with 10 μs flashes as a means to study visible persistence and information persistence. The first two studies were designed to assess visible persistence. Models were derived that quantified how recognition changed as a function of flash intensity. Then each letter was displayed twice, each at a near-threshold level of intensity and varying the interval between flashes. The second flash was able to boost the influence of the first flash for about 100 ms. This corresponds to the duration that a brief flash will remain visible, so these conditions likely were producing visible persistence. Information persistence was studied by manipulating dot density of the letter patterns. Recognition declined as the density of dots in each letter pattern was reduced. When two complimentary low-density samples were flashed, there was summation of their influence that declined to an asymptote in about 200 ms, and then remained above the one-flash control out to the maximum test interval of 1 s. The summation of high-salience, low-density dot patterns over such a long interval likely reflects both iconic memory persistence and access to working memory.

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Space reconstruction by primary visual cortex activity: a parallel, non-computational mechanism of object representation

Cited by 17 publications

References 71 publications

Cognition does not affect perception: Evaluating the evidence for “top-down” effects

Cognition does not affect perception: Evaluating the evidence for “top-down” effects

Homing in on consciousness in the nervous system: An action-based synthesis

Recognition of letters displayed as briefly flashed dot patterns

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