Spatial contextual effects in primary visual cortex limit feature representation under crowding

Henry, Christopher A.; Kohn, Adam

doi:10.1038/s41467-020-15386-7

Cited by 24 publications

(40 citation statements)

References 68 publications

(97 reference statements)

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“…Our results seem to be in-line with prior work showing degradation of information when there are multiple stimuli presented (Day and Delgutte 2013;Day et al 2012;Henry and Kohn 2020). If this reduction in information scales with number of stimuli it could potentially explain the finding that the number of distinctly identifiable sounds saturates at three (Zhong and Yost 2017).…”

Section: Discussionsupporting

confidence: 92%

Multiple sounds degrade the frequency representation in monkey inferior colliculus

Willett

2020

Preprint

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AbstractHow the brain encodes information about simultaneously occurring stimuli is largely unknown, especially if those stimuli recruit largely overlapping populations of neurons. One hypothesis is that tuning curves might sharpen or shift to limit the number of stimuli driving any given neuron. To investigate this possibility, we recorded the activity of neurons in the inferior colliculus while monkeys localized either one or two simultaneous sounds that differed in frequency. Although monkeys were quite capable of performing this task (~90% correct), comparison of frequency tuning in single versus dual sound trials revealed frequency selectivity was degraded in the dual-sound case. Frequency tuning curves broadened, and frequency modulation of firing rate was attenuated in dual sound conditions. These tuning curve changes led to a slightly worse performance on dual sound trials by a maximum-likelihood decoder trained to predict the presented condition only from held-out spike counts. These results do not support that changes in frequency response functions could be used to overcome the overlap problem in the representation of simultaneous sounds, and suggest recent evidence of alternations in firing rate between rates corresponding to each of the two stimuli may be a more promising line of research.

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Section: Discussionsupporting

confidence: 92%

Multiple sounds degrade the frequency representation in monkey inferior colliculus

Willett

2020

Preprint

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“…When the number of objects gets too great, it is unlikely that neurons can fluctuate between all of them, and this is likely to have consequences for perception, perhaps accounting for well-known limits on the number of objects we can perceive, attend to and remember (e.g. Miller, 1956;Whitney and Levi, 2011;Henry and Kohn, 2020).…”

Section: Discussionmentioning

confidence: 99%

Coordinated multiplexing of information about separate objects in visual cortex

Jun

Ruff

Kramer

et al. 2019

Preprint

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How the brain preserves information about more than one stimulus at a time remains poorly understood. We recently showed that when more than one stimulus is present, single neurons may fluctuate between coding one vs. the other(s) across some time period. A critical unanswered question is whether and how any such fluctuations are coordinated across the neural population. Here, we analyzed the spike count ("noise") correlations observed between pairs of primary visual cortex (V1) neurons under a variety of conditions. We report that when two separate grating stimuli are presented simultaneously, distinct distributions of positive and negative correlations emerge, depending on whether the two neurons in the pair both respond more strongly to the same vs. different individual stimuli. Neural pairs that shared the same stimulus preference were more likely to show positively correlated spike count variability whereas those with different preferences were more likely to show negative correlations, suggesting that the population response to one particular stimulus may be enhanced over the other on any given trial. This pattern of results was not present when the two gratings were superimposed and formed a single plaid, supporting the interpretation that the pattern of correlated fluctuations is related to the segregation of individual objects in the visual scene.2

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“…This observation appears to suggest that an increase in objects in a VE may impact the effectiveness of guidance. The reason for this occurrence, may be visual crowding, as objects may become more difficult to differentiate (Whitney and Levi, 2011;Henry and Kohn, 2020). This is often as a result of attention and spatial integration (Henry and Kohn, 2020), in which the distance between objects in an environment are crucial for being able to identify a target object (Bouma, 1970;Whitney and Levi, 2011;Melnik et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…The reason for this occurrence, may be visual crowding, as objects may become more difficult to differentiate (Whitney and Levi, 2011;Henry and Kohn, 2020). This is often as a result of attention and spatial integration (Henry and Kohn, 2020), in which the distance between objects in an environment are crucial for being able to identify a target object (Bouma, 1970;Whitney and Levi, 2011;Melnik et al, 2020). Although this study did not infer the attractors as a target object, participants may have identified this as a target object within the VE, however visual crowding may have occurred when placing more objects into the VE, making it more difficult to identify the attractors as a target object.…”

Section: Discussionmentioning

confidence: 99%

The Use of Embedded Context-Sensitive Attractors for Clinical Walking Test Guidance in Virtual Reality

Croucher¹,

Powell²,

Dicks³

et al. 2021

Front. Virtual Real.

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Virtual reality is increasingly used in rehabilitation and can provide additional motivation when working toward therapeutic goals. However, a particular problem for patients regards their ability to plan routes in unfamiliar environments. Therefore, the aim of this study was to explore how visual cues, namely embedded context-sensitive attractors, can guide attention and walking direction in VR, for clinical walking interventions. This study was designed using a butterfly as the embedded context-sensitive attractor, to guide participant locomotion around the clinical figure of eight walk test, to limit the use of verbal instructions. We investigated the effect of varying the number of attractors for figure of eight path following, and whether there are any negative impacts on perceived autonomy or workload. A total of 24 participants took part in the study and completed six attractor conditions in a counterbalanced order. They also experienced a control VE (no attractors) at the beginning and end of the protocol. Each VE condition lasted a duration of 1 min and manipulated the number of attractors to either singular or multiple alongside, the placement of turning markers (virtual trees) used to represent the cones used in clinical settings for the figure of eight walk test. Results suggested that embedded context-sensitive attractors can be used to guide walking direction, following a figure of eight in VR without impacting perceived autonomy, and workload. However, there appears to be a saturation point, with regards to effectiveness of attractors. Too few objects in a VE may reduce feelings of intrinsic motivation, and too many objects in a VE may reduce the effectiveness of attractors for guiding individuals along a figure of eight path. We conclude by indicating future research directions, for attractors and their use as a guide for walking direction.

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Spatial contextual effects in primary visual cortex limit feature representation under crowding

Cited by 24 publications

References 68 publications

Multiple sounds degrade the frequency representation in monkey inferior colliculus

Multiple sounds degrade the frequency representation in monkey inferior colliculus

Coordinated multiplexing of information about separate objects in visual cortex

The Use of Embedded Context-Sensitive Attractors for Clinical Walking Test Guidance in Virtual Reality

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