Theoretical understanding of the early visual processes by data compression and data selection

Li, Zhaoping

doi:10.1080/09548980600931995

Cited by 134 publications

(133 citation statements)

References 84 publications

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“…However, recent studies showing large amounts of redundancy during natural stimulation (Puchalla et al, 2005;Schneidman et al, 2006;Doi et al, 2012) cast doubt on this hypothesis. It has been argued that some redundancy is necessary to overcome the deleterious effects of noise and improve information transmission (Barlow, 2001;Zhaoping, 2006;Borghuis et al, 2008;Tkacik et al, 2010). We instead propose that the observed heterogeneity of afferents discussed above (i.e., differences in the response dynamics of irregular vs regular afferents) effectively achieves an efficient representation of the natural sensory environment by allowing appropriate extended temporal summation for low frequencies and simultaneously improving the detection of high-frequency components.…”

Section: Discussionmentioning

confidence: 99%

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

Carriot

Jamali

Chacron

et al. 2014

Journal of Neuroscience

108

161

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It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/f ␣ ), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life.

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Section: Discussionmentioning

confidence: 99%

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

Carriot

Jamali

Chacron

et al. 2014

Journal of Neuroscience

108

161

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“…Theoretical studies suggest that the early visual system allows an efficient representation of natural stimuli (Barlow, 1961;Atick, 1992;Simoncelli and Olshausen, 2001;Simoncelli, 2003;Zhaoping, 2006). Natural scenes exhibit significant correlations in space and time, with amplitude spectrum proportional to the inverse of frequency (Field, 1987;Dong and Atick, 1995).…”

Section: Introductionmentioning

confidence: 99%

The Spatiotemporal Frequency Tuning of LGN Receptive Field Facilitates Neural Discrimination of Natural Stimuli

Tan

Yao²

2009

J. Neurosci.

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The efficient coding hypothesis suggests that the early visual system is optimized to represent stimuli in the natural environment. While it is believed that LGN processing removes the redundant information of natural scenes, it is not clear whether the early visual processing can selectively amplify important signals in natural stimuli to facilitate discrimination. In this study, we examined the functional role of LGN spatiotemporal frequency tuning in the processing of natural scenes. First, we characterized the relationship between spatial and temporal frequency tuning for LGN receptive fields. We found that LGN neurons exhibit inseparable spatiotemporal frequency tuning in a manner consistent with the feature of optimal filters that can maximize information transmission of natural scenes. Second, we analyzed the spatiotemporal power spectrum of natural scenes and found that some frequencies exhibit larger variation in power across different scenes. Interestingly, the preferred frequency of ensemble LGN neurons matches the range of frequencies in which natural power spectrum varies most. Comparison of neural discrimination for natural stimuli and for artificial stimuli with similar mean power spectra but different variation structure showed that the match between LGN tuning and natural spectra variation enhances neural discrimination for natural stimuli. Our results indicate that, in addition to removing redundancy, the spatiotemporal frequency characteristics of LGN neurons can facilitate neural discrimination of natural stimuli.

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“…Neurally, there are complex changes to receptive fields of neurons coding for the adapting stimulus and its fellow travelers. Adaptation's centrality has made it the target of substantial modeling, with mechanistic approaches attempting to integrate the neural and psychological findings (Bednar and Miikkulainen, 2000;Clifford et al, 2000;Teich and Qian, 2003;Jin et al, 2005;Schwartz et al, 2007) and functional approaches suggesting informational or probabilistic underlying principles (Barlow and Foldiak, 1989;Barlow, 1990;Atick, 1992;Wainwright, 1999;Clifford et al, 2000;Stocker and Simoncelli, 2006;Zhaoping, 2006;Schwartz et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Adaptation across the Cortical Hierarchy: Low-Level Curve Adaptation Affects High-Level Facial-Expression Judgments

Xu¹,

Dayan²,

Lipkin³

et al. 2008

J. Neurosci.

101

122

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Adaptation is ubiquitous in sensory processing. Although sensory processing is hierarchical, with neurons at higher levels exhibiting greater degrees of tuning complexity and invariance than those at lower levels, few experimental or theoretical studies address how adaptation at one hierarchical level affects processing at others. Nevertheless, this issue is critical for understanding cortical coding and computation. Therefore, we examined whether perception of high-level facial expressions can be affected by adaptation to low-level curves (i.e., the shape of a mouth). After adapting to a concave curve, subjects more frequently perceived faces as happy, and after adapting to a convex curve, subjects more frequently perceived faces as sad. We observed this multilevel aftereffect with both cartoon and real test faces when the adapting curve and the mouths of the test faces had the same location. However, when we placed the adapting curve 0.2°below the test faces, the effect disappeared. Surprisingly, this positional specificity held even when real faces, instead of curves, were the adapting stimuli, suggesting that it is a general property for facial-expression aftereffects. We also studied the converse question of whether face adaptation affects curvature judgments, and found such effects after adapting to a cartoon face, but not a real face. Our results suggest that there is a local component in facial-expression representation, in addition to holistic representations emphasized in previous studies. By showing that adaptation can propagate up the cortical hierarchy, our findings also challenge existing functional accounts of adaptation.

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Theoretical understanding of the early visual processes by data compression and data selection

Cited by 134 publications

References 84 publications

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

The Spatiotemporal Frequency Tuning of LGN Receptive Field Facilitates Neural Discrimination of Natural Stimuli

Adaptation across the Cortical Hierarchy: Low-Level Curve Adaptation Affects High-Level Facial-Expression Judgments

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