Lateral Interactions in Primary Visual Cortex: A Model Bridging Physiology and Psychophysics

Stemmler, Martin B.; Usher, Marius; Niebur, Ernst

doi:10.1126/science.7569930

Cited by 213 publications

(136 citation statements)

References 27 publications

(6 reference statements)

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“…The mean RTs for each condition (pop-out, size and conjunction); target (target present [TP], target absent [TA]); display size (16,36,81) and for groups (Alzheimer's disease [AD], control) are displayed in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

“…There is evidence that the binding of features may be mediated by areas such as the temporal and parietal cortex [36,41], areas known to be affected by AD-related pathology [2,3,16]. In AD, such problems with aspects of basic visual processing, for example the ability to successfully conjoin features, may also be associated with or underlie the problems in object recognition and other higher level visual problems often encountered in the disease [10,23,35].…”

Section: Discussionmentioning

confidence: 99%

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Visual search in Alzheimer’s disease: a deficiency in processing conjunctions of features

et al. 2002

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Human vision often needs to encode multiple characteristics of many elements of the visual field, for example their lightness and orientation. The paradigm of visual search allows a quantitative assessment of the function of the underlying mechanisms. It measures the ability to detect a target element among a set of distractor elements. We asked whether Alzheimer's disease (AD) patients are particularly affected in one type of search, where the target is defined by a conjunction of features (orientation and lightness) and where performance depends on some shifting of attention. Two non-conjunction control conditions were employed. The first was a pre-attentive, single-feature, "pop-out" task, detecting a vertical target among horizontal distractors. The second was a single-feature, partly attentive task in which the target element was slightly larger than the distractors-a "size" task. This was chosen to have a similar level of attentional load as the conjunction task (for the control group), but lacked the conjunction of two features. In an experiment, 15 AD patients were compared to age-matched controls. The results suggested that AD patients have a particular impairment in the conjunction task but not in the single-feature size or pre-attentive tasks. This may imply that AD particularly affects those mechanisms which compare across more than one feature type, and spares the other systems and is not therefore simply an 'attention-related' impairment. Additionally, these findings show a double dissociation with previous data on visual search in Parkinson's disease (PD), suggesting a different effect of these diseases on the visual pathway.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Visual search in Alzheimer’s disease: a deficiency in processing conjunctions of features

et al. 2002

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“…The present finding is consistent with modeling work in which the activity level of the classical receptive field (i.e., center) determines the nature of center-surround interactions. Specifically, surround suppression is hypothesized to occur at high levels of center activity, whereas surround facilitation should be more pronounced at low levels of center activity (Stemmler et al, 1995;Somers at al., 1998). It should be noted, however, that models based on increased spatial summation at low contrast (cf.…”

Section: Discussionmentioning

confidence: 99%

Fine Temporal Properties of Center–Surround Interactions in Motion Revealed by Reverse Correlation

2006

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Center-surround interactions are a key property of visual motion mechanisms. Using a temporal reverse correlation method with human observers, we investigated perceptual interactions between a brief center motion (ϳ20 ms) and a surround that moved up-down with a new direction chosen randomly every 5 ms. The aim was to reveal interactions between center and surround motions and their dependency on relative direction, contrast, and timing. Hypothesizing that surround computation involves different neural circuitry than the center response, we manipulated surround contrast to affect the relative timing of center and surround signals. The reverse correlation analysis yielded temporal profiles of surround influence indicating, in 5 ms steps, the time course of the effect of the surround on the discriminability of center motion. The resulting temporal profiles varied systematically with contrast: as surround contrast decreased, both the latency and duration of its influence increased. This finding, consistent with longer and variable neural response latencies at low contrast, psychophysically reveals fine-scale temporal interactions between center and surround signals. Additionally, the strength of surround influence was correlated with psychophysical thresholds for discriminating center motion. The directionality of this relationship, however, depended only on center contrast. When center motion was high contrast, poor direction discrimination was associated with an increased probability of same-direction surround motions. Low-contrast center motion, however, was more discriminable when surrounded by motion in the same direction, regardless of surround contrast. This suggests that the previously reported adaptive nature of center-surround interactions in motion is driven primarily by the visibility of the center motion signals.

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“…This interpretation is strengthened by their description of the physiological and psychophysical data to be explained as showing contextual modulation (Stemmler et al 1995). The mechanism they propose is based upon the phenomenon of "stochastic resonance," in which noise enhances detection of weak signals by increasing the gain at weak signal strengths (Stemmler et al 1995). Bezrukov & Vodyanov (1997) have now proved that stochastic resonance can occur in voltage-dependent ion channels, however, so the mechanism that Niebur & Usher propose may be more compatible than they thought with the one we emphasized.…”

Section: R17 How Are Cfs Related To Long-range Interactions In Visumentioning

confidence: 99%

Progress toward an understanding of cortical computation

Phillips¹,

Singer²

1997

Behav Brain Sci

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The additional data, perspectives, questions, and criticisms contributed by the commentaries strengthen our view that local cortical processors coordinate their activity with the context in which it occurs using contextual fields and synchronized population codes. We therefore predict that whereas the specialization of function has been the keynote of this century the coordination of function will be the keynote of the next

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Lateral Interactions in Primary Visual Cortex: A Model Bridging Physiology and Psychophysics

Cited by 213 publications

References 27 publications

Visual search in Alzheimer’s disease: a deficiency in processing conjunctions of features

Visual search in Alzheimer’s disease: a deficiency in processing conjunctions of features

Fine Temporal Properties of Center–Surround Interactions in Motion Revealed by Reverse Correlation

Progress toward an understanding of cortical computation

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