scholarly journals Intrinsic dynamics enhance temporal stability of stimulus representation along rodent visual cortical hierarchies

2019 ◽  
Author(s):  
Eugenio Piasini ◽  
Liviu Soltuzu ◽  
Paolo Muratore ◽  
Riccardo Caramellino ◽  
Kasper Vinken ◽  
...  
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Neural Coding ◽  
Temporal Stability ◽  
Ventral Stream ◽  
Dynamic Stimuli ◽  
The Stability ◽  
Visual Cortical ◽  
Predictive Processes ◽  
The Impact

SummaryAlong the ventral stream, cortical representations of brief, static stimuli become gradually more invariant to identity-preserving transformations. In the presence of long, temporally structured dynamic stimuli, higher invariance should imply temporally persistent representations at the top of this functional hierarchy. However, such stimuli could engage adaptive and predictive processes, whose impact on neural coding dynamics is unknown. By probing the rat analogue of the ventral stream with movies, we uncovered a hierarchy of temporal scales, with deeper areas encoding visual information more persistently. Furthermore, the impact of intrinsic dynamics on the stability of stimulus representations gradually grew along the hierarchy. Analysis of a large dataset of recordings from the mouse visual hierarchy yielded similar trends, revealing also their dependence on the behavioral state of the animal. Overall, these findings show that visual representations become progressively more stable along rodent visual processing hierarchies, with an important contribution provided by intrinsic processing.

scholarly journals Temporal stability of stimulus representation increases along rodent visual cortical hierarchies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eugenio Piasini ◽  
Liviu Soltuzu ◽  
Paolo Muratore ◽  
Riccardo Caramellino ◽  
Kasper Vinken ◽  
...  
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Neural Coding ◽  
Temporal Stability ◽  
Receptive Fields ◽  
Ventral Stream ◽  
Dynamic Stimuli ◽  
The Stability ◽  
Visual Cortical ◽  
The Impact

AbstractCortical representations of brief, static stimuli become more invariant to identity-preserving transformations along the ventral stream. Likewise, increased invariance along the visual hierarchy should imply greater temporal persistence of temporally structured dynamic stimuli, possibly complemented by temporal broadening of neuronal receptive fields. However, such stimuli could engage adaptive and predictive processes, whose impact on neural coding dynamics is unknown. By probing the rat analog of the ventral stream with movies, we uncovered a hierarchy of temporal scales, with deeper areas encoding visual information more persistently. Furthermore, the impact of intrinsic dynamics on the stability of stimulus representations grew gradually along the hierarchy. A database of recordings from mouse showed similar trends, additionally revealing dependencies on the behavioral state. Overall, these findings show that visual representations become progressively more stable along rodent visual processing hierarchies, with an important contribution provided by intrinsic processing.

scholarly journals Reliability and practical aspects of the disease impact measure on hypertensive patients

2013 ◽  
Vol 21 (6) ◽  
pp. 1258-1265 ◽  
Author(s):  
Renata Bigatti Bellizzotti Pavan ◽  
Kátia Melissa Padilha ◽  
Simey de Lima Lopes Rodrigues ◽  
Roberta Cunha Matheus Rodrigues ◽  
Maria Cecília Jayme Bueno Gallani
Keyword(s):  
Internal Consistency ◽  
Temporal Stability ◽  
Emotional Impact ◽  
Disease Symptoms ◽  
Hypertensive Patients ◽  
Social And Emotional ◽  
Disease Impact ◽  
Physical Impact ◽  
The Stability ◽  
The Impact

OBJECTIVE: to evaluate the feasibility, acceptability, the ceiling and floor effects and the reliability of the Instrument to Measure the Impact of Coronary Disease on Patient's Daily Life (IDCV) when applied to hypertensive patients. METHOD: one hundred and thirty seven hypertensive outpatients were interviewed, using questionnaires to collect sociodemographic and clinical data, followed by the IDCV. Reliability was assessed according to the temporal stability and internal consistency criteria. RESULTS: the IDCV was applied in 8.0 (±3.0) minutes with 100% of the items answered. A ceiling effect of 31.4% was observed in the domain Adjustment to the Disease. The stability measure was observed for the total score and for all domains. There was evidence of internal consistency of the total IDCV (α=0.83) and the domains Physical Impact of the Disease - Symptoms (α=0.78) and Social and Emotional Impact of the Disease (α=0.74). CONCLUSION: the IDCV is an instrument of easy use and its reliability among hypertensive patients is evidenced. The domain Adjustment to the Disease, however, should be reviewed in further studies.

scholarly journals Behavioral response to visual motion impacts population coding in the mouse visual thalamus

2018 ◽  
Author(s):  
Karolina Socha ◽  
Matt Whiteway ◽  
Daniel A. Butts ◽  
Vincent Bonin
Keyword(s):  
Visual Processing ◽  
Behavioral Response ◽  
Neural Coding ◽  
Visual Motion ◽  
Population Coding ◽  
Behavioral State ◽  
Visual Thalamus ◽  
Thalamocortical Axons ◽  
And Function ◽  
The Impact

SummaryVisual motion is a ubiquitous component of animals’ sensory experience and its encoding is critical for navigation and movement. Yet its impact on behavior and neural coding is not well understood. Combining pupillometry with cellular calcium imaging measurements of thalamocortical axons in awake behaving mice, we examined the impact of arousal and behavioral state on encoding of visual motion in the visual thalamus. We discovered that back-to-front visual motions elicits a robust behavioral response that shapes tunings of visual thalamic responses. Consistent with an arousal mechanism, the effects were pronounced during stillness and weak or absent during locomotor activity and under anesthesia. The impact on neuronal tuning was specific, biasing population response patterns in favor of back-to-front motion. The potent influence of visual motion on behavioral state dynamically affect sensory coding at early visual processing stages. Further research is required to reveal the circuitry and function of this novel mechanism.

scholarly journals Continuous Flash Suppression Known and Unknowns

2019 ◽  
Author(s):  
Ali Pournaghdali ◽  
Bennett L Schwartz
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Continuous Flash Suppression ◽  
Low Level ◽  
Experimental Configuration ◽  
High Level ◽  
The Impact ◽  
Nonconscious Perception

Studies utilizing continuous flash suppression (CFS) provide valuable information regarding conscious and nonconscious perception. There are, however, crucial unanswered questions regarding the mechanisms of suppression and the level of visual processing in the absence of consciousness with CFS. Research suggests that the answers to these questions depend on the experimental configuration and how we assess consciousness in these studies. The aim of this review is to evaluate the impact of different experimental configurations and the assessment of consciousness on the results of the previous CFS studies. We review studies that evaluated the influence of different experimental configuration on the depth of suppression with CFS and discuss how different assessments of consciousness may impact the results of CFS studies. Finally, we review behavioral and brain recording studies of CFS. In conclusion, previous studies provide evidence for survival of low-level visual information and complete impairment of high-level visual information under the influence of CFS. That is, studies suggest that nonconscious perception of lower-level visual information happens with CFS but there is no evidence for nonconscious highlevel recognition with CFS.

scholarly journals The impact of joint attention on the sound-induced flash illusions

2021 ◽  
Author(s):  
Lucas Battich ◽  
Isabelle Garzorz ◽  
Basil Wahn ◽  
Ophelia Deroy
Keyword(s):  
Joint Attention ◽  
Cognitive Processing ◽  
Visual Processing ◽  
Visual Information ◽  
Focus Of Attention ◽  
Audiovisual Integration ◽  
Gaze Following ◽  
Information Encoding ◽  
Single Flash ◽  
The Impact

AbstractHumans coordinate their focus of attention with others, either by gaze following or prior agreement. Though the effects of joint attention on perceptual and cognitive processing tend to be examined in purely visual environments, they should also show in multisensory settings. According to a prevalent hypothesis, joint attention enhances visual information encoding and processing, over and above individual attention. If two individuals jointly attend to the visual components of an audiovisual event, this should affect the weighing of visual information during multisensory integration. We tested this prediction in this preregistered study, using the well-documented sound-induced flash illusions, where the integration of an incongruent number of visual flashes and auditory beeps results in a single flash being seen as two (fission illusion) and two flashes as one (fusion illusion). Participants were asked to count flashes either alone or together, and expected to be less prone to both fission and fusion illusions when they jointly attended to the visual targets. However, illusions were as frequent when people attended to the flashes alone or with someone else, even though they responded faster during joint attention. Our results reveal the limitations of the theory that joint attention enhances visual processing as it does not affect temporal audiovisual integration.

scholarly journals Shared ancestry influences community stability by altering competitive interactions: evidence from a laboratory microcosm experiment using freshwater green algae

2013 ◽  
Vol 280 (1768) ◽  
pp. 20131548 ◽  
Author(s):  
Patrick A. Venail ◽  
Markos A. Alexandrou ◽  
Todd H. Oakley ◽  
Bradley J. Cardinale
Keyword(s):  
Related Species ◽  
Temporal Stability ◽  
Biodiversity Loss ◽  
Competitive Interactions ◽  
Ecological Communities ◽  
Freshwater Microalgae ◽  
Community Biomass ◽  
Shared Ancestry ◽  
The Stability ◽  
The Impact

The impact of biodiversity on the stability of ecological communities has been debated among biologists for more than a century. Recently summarized empirical evidence suggests that biodiversity tends to enhance the temporal stability of community-level properties such as biomass; however, the underlying mechanisms driving this relationship remain poorly understood. Here, we report the results of a microcosm study in which we used simplified systems of freshwater microalgae to explore how the phylogenetic relatedness of species influences the temporal stability of community biomass by altering the nature of their competitive interactions. We show that combinations of two species that are more evolutionarily divergent tend to have lower temporal stability of biomass. In part, this is due to negative ‘selection effects’ in which bicultures composed of distantly related species are more likely to contain strong competitors that achieve low biomass. In addition, bicultures of distantly related species had on average weaker competitive interactions, which reduced compensatory dynamics and decreased the stability of community biomass. Our results demonstrate that evolutionary history plays a key role in controlling the mechanisms, which give rise to diversity–stability relationships. As such, patterns of shared ancestry may help us predict the ecosystem-level consequences of biodiversity loss.

scholarly journals The Effect of Spatial Frequency on the Visual Category Representation in the Macaque Inferior Temporal Cortex

2021 ◽  
Author(s):  
Esmaeil Farhang ◽  
Ramin Toosi ◽  
Behnam Karami ◽  
Roxana Koushki ◽  
Ehsan Rezayat ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Visual Processing ◽  
Visual Information ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Category Representation ◽  
Neural Basis ◽  
Shape Information ◽  
Category Information ◽  
The Impact

ABSTRACTTo expand our knowledge about the object recognition, it is critical to understand the role of spatial frequency (SF) in an object representation that occurs in the inferior temporal (IT) cortex at the final stage of processing the visual information across the ventral visual pathway. Object categories are being recognized hierarchically in at least three levels of abstraction: superordinate (e.g., animal), mid-level (e.g., human face), and subordinate (e.g., face identity). Psychophysical studies have shown rapid access to mid-level category information and low SF (LSF) contents. Although the hierarchical representation of categories has been shown to exist inside the IT cortex, the impact of SF on the multi-level category processing is poorly understood. To gain a deeper understanding of the neural basis of the interaction between SF and category representations at multiple levels, we examined the neural responses within the IT cortex of macaque monkeys viewing several SF-filtered objects. Each stimulus could be either intact or bandpass filtered into either the LSF (coarse shape information) or high SF (HSF) (fine shape information) bands. We found that in both High- and Low-SF contents, the advantage of mid-level representation has not been violated. This evidence suggests that mid-level category boundary maps are strongly represented in the IT cortex and remain unaffected with respect to any changes in the frequency content of stimuli. Our observations indicate the necessity of the HSF content for the superordinate category representation inside the IT cortex. In addition, our findings reveal that the representation of global category information is more dependent on the HSF than the LSF content. Furthermore, the lack of subordinate representation in both LSF and HSF filtered stimuli compared to the intact stimuli provide strong evidence that all SF contents are necessary for fine category visual processing.

Are the dorsal/ventral pathways sufficiently distinct to resolve perceptual theory?

2002 ◽  
Vol 25 (1) ◽  
pp. 96-97 ◽  
Author(s):  
George J. Andersen
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Ventral Stream ◽  
Central Issue ◽  
Direct Perception ◽  
Perceptual Theory ◽  
Psychophysical Studies

The author argues that the theory of a dorsal/ventral stream for visual processing can be used to reconcile the constructivist and direct perception theories. My commentary discusses neurophysiological and psychophysical studies that run counter to the view. In addition, the central issue of debate between the constructionist and direct perception approaches regarding what is visual information is discussed.

Image-Computable Ideal Observers for Tasks with Natural Stimuli

2020 ◽  
Vol 6 (1) ◽  
pp. 491-517 ◽  
Author(s):  
Johannes Burge
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Neural Coding ◽  
Ideal Observer ◽  
Perceptual Task ◽  
Vision Science ◽  
Natural Stimuli ◽  
Ideal Observers ◽  
Perceptual Performance ◽  
And Performance

An ideal observer is a theoretical model observer that performs a specific sensory-perceptual task optimally, making the best possible use of the available information given physical and biological constraints. An image-computable ideal observer (pixels in, estimates out) is a particularly powerful type of ideal observer that explicitly models the flow of visual information from the stimulus-encoding process to the eventual decoding of a sensory-perceptual estimate. Image-computable ideal observer analyses underlie some of the most important results in vision science. However, most of what we know from ideal observers about visual processing and performance derives from relatively simple tasks and relatively simple stimuli. This review describes recent efforts to develop image-computable ideal observers for a range of tasks with natural stimuli and shows how these observers can be used to predict and understand perceptual and neurophysiological performance. The reviewed results establish principled links among models of neural coding, computational methods for dimensionality reduction, and sensory-perceptual performance in tasks with natural stimuli.

scholarly journals Laws of concatenated perception: Vision goes for novelty, Decisions for perseverance

2017 ◽  
Author(s):  
D. Pascucci ◽  
G. Mancuso ◽  
E. Santandrea ◽  
C. Della Libera ◽  
G. Plomp ◽  
...  
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Process Model ◽  
Multilevel Modelling ◽  
Sensory Adaptation ◽  
Serial Dependence ◽  
Human Visual Perception ◽  
History Of ◽  
High Level ◽  
The Impact

AbstractEvery instant of perception depends on a cascade of brain processes calibrated to the history of sensory and decisional events. In the present work, we show that human visual perception is constantly shaped by two contrasting forces, exerted by sensory adaptation and past decisions. In a series of experiments, we used multilevel modelling and cross-validation approaches to investigate the impact of previous stimuli and responses on current errors in adjustment tasks. Our results revealed that each perceptual report is permeated by opposite biases from a hierarchy of serially dependent processes: low-level adaptation repels perception away from previous stimuli; high-level, decisional traces attract perceptual reports toward previous responses. Contrary to recent claims, we demonstrated that positive serial dependence does not result from continuity fields operating at the level of early visual processing, but arises from the inertia of decisional templates. This finding is consistent with a Two-process model of serial dependence in which the persistence of read-out weights in a decision unit compensates for sensory adaptation, leading to attractive biases in sequential responses. We propose the first unified account of serial dependence in which functionally distinct mechanisms, operating at different stages, promote the differentiation and integration of visual information over time.

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