Line drawings reveal the structure of internal visual models conveyed by cortical feedback.

Morgan, Andrew; Petro, Lucy S.; Muckli, Lars

doi:10.1101/041186

Cited by 10 publications

(11 citation statements)

References 56 publications

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“…This suggests that feedback may contain 416 coarse information about the scene, but nevertheless retain some fine-grained properties. This is in line with 417 previous work (Morgan et al, 2016) that showed that feedback contains information about both the 418 category of a scene (such as a forest, corresponding to coarse structure) as well as about individual scenes 419 within a category (fine-grained structure of a particular example of a forest scene). However, we should 420 clarify that we do not infer a double dissociation about LSF and HSF in relation to category and exemplar.…”

supporting

confidence: 83%

“…To test feedback signals in the absence of feedforward stimulation, we used an occlusion paradigm 96 previously employed by Smith and Muckli (2010), Muckli et al (2015) and Morgan et al (2016). For the 97 feedback conditions, we occluded the lower right image quadrant with a white rectangle.…”

Section: Feedback Vs Feedforward Condition 95mentioning

confidence: 99%

“…In addition, global scene structure may also be coded in HSFs (Oliva 74 and Torralba, 2006; Walther et al, 2011). Feedback contains information about individual scenes as well as 75 category, suggesting some fine-grained information may remain in feedback (Morgan et al, 2016). 76…”

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confidence: 99%

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Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

2018

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Primary visual cortex (V1) has small receptive fields and processes feedforward information at a fine-18 grained spatial scale, whereas higher visual areas have larger, spatially invariant receptive fields. Therefore, 19 feedback could provide coarse information about the global scene structure or alternatively recover fine-20 grained structure by targeting small receptive fields in V1. We tested if feedback signals generalise across 21 different spatial frequencies of feedforward inputs, or if they are tuned to the spatial scale of the visual 22 scene. Using a partial occlusion paradigm, functional magnetic resonance imaging (fMRI) and multivoxel 23 pattern analysis (MVPA) we investigated whether feedback to V1 contains coarse or fine-grained 24 information by manipulating the spatial frequency of the scene surround outside an occluded image portion. 25We show that feedback transmits both coarse and fine-grained information as it carries information about 26 both low (LSF) and high spatial frequencies (HSF

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supporting

confidence: 83%

Section: Feedback Vs Feedforward Condition 95mentioning

confidence: 99%

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Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

2018

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“…Because of its latency and its polarity reversal for top versus bottom stimulation, this component is believed to reflect feedbacks from higher-level visual areas to the early visual cortex (Miller et al 2015). It was previously suggested that these feedbacks might provide information about low and high-level scene features, such as the category or the depth of the stimuli (Morgan et al 2016;Revina et al 2018). That top-bottom feedback signals are thought to modulate sensory input, providing information about the global scene structure.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of the straight-ahead preference in human visual cortex

et al. 2019

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The objects located straight-ahead of the body are preferentially processed by the visual system. They are more rapidly detected and evoke stronger BOLD responses in early visual areas than elements that are retinotopically identical but located at eccentric spatial positions. To characterize the dynamics of the underlying neural mechanisms, we recorded in 29 subjects the EEG responses to peripheral targets differing solely by their locations with respect to the body. Straight-ahead stimuli led to stronger responses than eccentric stimuli for several components whose latencies ranged between 70 and 350 ms after stimulus onset. The earliest effects were found at 70 ms for a component that originates from occipital areas, the contralateral P1. To determine whether the straight-ahead direction affects primary visual cortex responses, we performed an additional experiment (n = 29) specifically designed to generate two robust components, the C1 and C2, whose cortical origins are constrained within areas V1, V2 and V3. Our analyses confirmed all the results of the first experiment and also revealed that the C2 amplitude between 130 and 160 ms after stimulus onset was significantly stronger for straight-ahead stimuli. A frequency analysis of the pre-stimulus baseline revealed that gaze-driven alterations in the visual hemi-field containing the straight-ahead direction were associated with a decrease in alpha power in the contralateral hemisphere, suggesting the implication of specific neural modulations before stimulus onset. Altogether, our EEG data demonstrate that preferential responses to the straight-ahead direction can be detected in the visual cortex as early as about 70 ms after stimulus onset.

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“…For example, to what extent does the "visuospatial sketchpad" model of working memory actually involve a kind of internal sketching, potentially even involving the internalization of actual experiences with drawing (Tversky, 2019)? Some supporting evidence for lowdimensional inner-sketching can be found in recent work in which the top-down generation of internal visual models is well-described by line drawings (Morgan et al, 2019). The authors note that such images can be traced back to Paleolithic hunters 40,000 years ago (with possibly earlier origins), suggesting that line drawings may represent both effective means of conveying meanings, and may also reveal functional principles of the visual system.…”

Section: Richness Of Consciousness and Grand Illusionsmentioning

confidence: 69%

Integrated World Modeling Theory (IWMT) Revisited

Safron¹

2019

Preprint

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Here, I provide clarifications and discuss further issues relating to Safron (2020), “An Integrated World Modeling Theory (IWMT) of consciousness: Combining Integrated Information and Global Workspace Theories with the Free Energy Principle and Active Inference Framework; towards solving the Hard problem and characterizing agentic causation.” As a synthesis of major theories of complex systems and consciousness, with IWMT we may be able to address some of the most difficult problems in the sciences. This is a claim deserving of close scrutiny and much skepticism. What would it take to solve the Hard problem? One could answer the question of how it is possible that something like subjectivity could emerge from objective brain functioning (i.e., moving from a third person to a first person ontology), but a truly satisfying account might still require solving all the “easy” and “real” problems of consciousness. In this way, IWMT does not claim to definitively solve the Hard problem, as explaining all the particular ways that things feel across all relevant aspects of experience is likely an impossible task. Nonetheless, IWMT does claim to have made major inroads into our understanding of consciousness, and here I will attempt to justify this position by discussing challenging problems and outstanding questions with respect to philosophy, (neuro)phenomenology, computational principles, practical applications, and implications for existing theories of mind and life.

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Line drawings reveal the structure of internal visual models conveyed by cortical feedback.

Cited by 10 publications

References 56 publications

Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

Dynamics of the straight-ahead preference in human visual cortex

Integrated World Modeling Theory (IWMT) Revisited

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