scholarly journals The influence of surround suppression on adaptation effects in primary visual cortex

2012 ◽  
Vol 107 (12) ◽  
pp. 3370-3384 ◽  
Author(s):  
Stephanie C. Wissig ◽  
Adam Kohn
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Orientation Tuning ◽  
Sensory Stimuli ◽  
Specific Suppression ◽  
Neurophysiological Studies ◽  
And Shifts ◽  
Adaptation Effects

Adaptation, the prolonged presentation of stimuli, has been used to probe mechanisms of visual processing in physiological, imaging, and perceptual studies. Previous neurophysiological studies have measured adaptation effects by using stimuli tailored to evoke robust responses in individual neurons. This approach provides an incomplete view of how an adapter alters the representation of sensory stimuli by a population of neurons with diverse functional properties. We implanted microelectrode arrays in primary visual cortex (V1) of macaque monkeys and measured orientation tuning and contrast sensitivity in populations of neurons before and after prolonged adaptation. Whereas previous studies in V1 have reported that adaptation causes stimulus-specific suppression of responsivity and repulsive shifts in tuning preference, we have found that adaptation can also lead to response facilitation and shifts in tuning toward the adapter. To explain this range of effects, we have proposed and tested a simple model that employs stimulus-specific suppression in both the receptive field and the spatial surround. The predicted effects on tuning depend on the relative drive provided by the adapter to these two receptive field components. Our data reveal that adaptation can have a much richer repertoire of effects on neuronal responsivity and tuning than previously considered and suggest an intimate mechanistic relationship between spatial and temporal contextual effects.

scholarly journals Orientation Tuning, But Not Direction Selectivity, Is Invariant to Temporal Frequency in Primary Visual Cortex

2005 ◽  
Vol 94 (2) ◽  
pp. 1336-1345 ◽  
Author(s):  
Bartlett D. Moore ◽  
Henry J. Alitto ◽  
W. Martin Usrey
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimulus ◽  
Visual Processing ◽  
Cortical Neurons ◽  
Temporal Frequency ◽  
Direction Selectivity ◽  
Orientation Tuning ◽  
Orientation Contrast ◽  
Wide Range

The activity of neurons in primary visual cortex is influenced by the orientation, contrast, and temporal frequency of a visual stimulus. This raises the question of how these stimulus properties interact to shape neuronal responses. While past studies have shown that the bandwidth of orientation tuning is invariant to stimulus contrast, the influence of temporal frequency on orientation-tuning bandwidth is unknown. Here, we investigate the influence of temporal frequency on orientation tuning and direction selectivity in area 17 of ferret visual cortex. For both simple cells and complex cells, measures of orientation-tuning bandwidth (half-width at half-maximum response) are ∼20–25° across a wide range of temporal frequencies. Thus cortical neurons display temporal-frequency invariant orientation tuning. In contrast, direction selectivity is typically reduced, and occasionally reverses, at nonpreferred temporal frequencies. These results show that the mechanisms contributing to the generation of orientation tuning and direction selectivity are differentially affected by the temporal frequency of a visual stimulus and support the notion that stability of orientation tuning is an important aspect of visual processing.

scholarly journals Effects of V1 surround modulation tuning on visual saliency and the tilt illusion

2018 ◽  
Vol 120 (3) ◽  
pp. 942-952
Author(s):  
Sander W. Keemink ◽  
Clemens Boucsein ◽  
Mark C. W. van Rossum
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Neural Coding ◽  
Saliency Detection ◽  
Tilt Illusion ◽  
Wide Range ◽  
Neurophysiological Studies ◽  
Salient Features ◽  
The Impact

Neurons in the primary visual cortex respond to oriented stimuli placed in the center of their receptive field, yet their response is modulated by stimuli outside the receptive field (the surround). Classically, this surround modulation is assumed to be strongest if the orientation of the surround stimulus aligns with the neuron’s preferred orientation, irrespective of the actual center stimulus. This neuron-dependent surround modulation has been used to explain a wide range of psychophysical phenomena, such as biased tilt perception and saliency of stimuli with contrasting orientation. However, several neurophysiological studies have shown that for most neurons surround modulation is instead center dependent: it is strongest if the surround orientation aligns with the center stimulus. As the impact of such center-dependent modulation on the population level is unknown, we examine this using computational models. We find that with neuron-dependent modulation the biases in orientation coding, commonly used to explain the tilt illusion, are larger than psychophysically reported, but disappear with center-dependent modulation. Therefore we suggest that a mixture of the two modulation types is necessary to quantitatively explain the psychophysically observed biases. Next, we find that under center-dependent modulation average population responses are more sensitive to orientation differences between stimuli, which in theory could improve saliency detection. However, this effect depends on the specific saliency model. Overall, our results thus show that center-dependent modulation reduces coding bias, while possibly increasing the sensitivity to salient features. NEW & NOTEWORTHY Neural responses in the primary visual cortex are modulated by stimuli surrounding the receptive field. Most earlier studies assume this modulation depends on the neuron’s tuning properties, but experiments have shown that instead it depends mostly on the stimulus characteristics. We show that this simple change leads to neural coding that is less biased and under some conditions more sensitive to salient features.

scholarly journals Encoding of 3D Head Orienting Movements in Primary Visual Cortex

2020 ◽  
Author(s):  
Grigori Guitchounts ◽  
Javier Masis ◽  
Steffen BE Wolff ◽  
David Cox
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Processing ◽  
Efference Copy ◽  
Three Dimensions ◽  
Movement Direction ◽  
Sensory Stimuli ◽  
Cortical Dynamics ◽  
Specific Manner

AbstractAnimals actively sample from the sensory world by generating complex patterns of movement that evolve in three dimensions. At least some of these movements have been shown to influence neural codes in sensory areas. For example, in primary visual cortex (V1), locomotion-related neural activity influences sensory gain, encodes running speed, and predicts the direction of visual flow. As most experiments exploring movement-related modulation of V1 have been performed in head-fixed animals, it remains unclear whether or how the naturalistic movements used to interact with sensory stimuli– like head orienting–influence visual processing. Here we show that 3D head orienting movements modulate V1 neuronal activity in a direction-specific manner that also depends on the presence or absence of light. We identify two largely independent populations of movement-direction-tuned neurons that support this modulation, one of which is direction-tuned in the dark and the other in the light. Finally, we demonstrate that V1 gains access to a motor efference copy related to orientation from secondary motor cortex, which has been shown to control head orienting movements. These results suggest a mechanism through which sensory signals generated by purposeful movement can be distinguished from those arising in the outside world, and reveal a pervasive role of 3D movement in shaping sensory cortical dynamics.

scholarly journals Describing complex cells in primary visual cortex: a comparison of context and multifilter LN models

2018 ◽  
Vol 120 (2) ◽  
pp. 703-719 ◽  
Author(s):  
Johan Westö ◽  
Patrick J. C. May
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Primary Visual Cortex ◽  
Correlation Coefficients ◽  
The Novel ◽  
Context Model ◽  
Model Framework ◽  
Sensory Stimuli ◽  
Complex Cells ◽  
Context Models

Receptive field (RF) models are an important tool for deciphering neural responses to sensory stimuli. The two currently popular RF models are multifilter linear-nonlinear (LN) models and context models. Models are, however, never correct, and they rely on assumptions to keep them simple enough to be interpretable. As a consequence, different models describe different stimulus-response mappings, which may or may not be good approximations of real neural behavior. In the current study, we take up two tasks: 1) we introduce new ways to estimate context models with realistic nonlinearities, that is, with logistic and exponential functions, and 2) we evaluate context models and multifilter LN models in terms of how well they describe recorded data from complex cells in cat primary visual cortex. Our results, based on single-spike information and correlation coefficients, indicate that context models outperform corresponding multifilter LN models of equal complexity (measured in terms of number of parameters), with the best increase in performance being achieved by the novel context models. Consequently, our results suggest that the multifilter LN-model framework is suboptimal for describing the behavior of complex cells: the context-model framework is clearly superior while still providing interpretable quantizations of neural behavior. NEW & NOTEWORTHY We used data from complex cells in primary visual cortex to estimate a wide variety of receptive field models from two frameworks that have previously not been compared with each other. The models included traditionally used multifilter linear-nonlinear models and novel variants of context models. Using mutual information and correlation coefficients as performance measures, we showed that context models are superior for describing complex cells and that the novel context models performed the best.

scholarly journals Similar adaptation effects in primary visual cortex and area MT of the macaque monkey under matched stimulus conditions

2014 ◽  
Vol 111 (6) ◽  
pp. 1203-1213 ◽  
Author(s):  
Carlyn A. Patterson ◽  
Jacob Duijnhouwer ◽  
Stephanie C. Wissig ◽  
Bart Krekelberg ◽  
Adam Kohn
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Cortical Area ◽  
Neuronal Response ◽  
Macaque Monkey ◽  
Stimulus Size ◽  
Area Mt ◽  
And Shifts ◽  
Adaptation Effects

Recent stimulus history, or adaptation, can alter neuronal response properties. Adaptation effects have been characterized in a number of visually responsive structures, from the retina to higher visual cortex. However, it remains unclear whether adaptation effects across stages of the visual system take a similar form in response to a particular sensory event. This is because studies typically probe a single structure or cortical area, using a stimulus ensemble chosen to provide potent drive to the cells of interest. Here we adopt an alternative approach and compare adaptation effects in primary visual cortex (V1) and area MT using identical stimulus ensembles. Previous work has suggested these areas adjust to recent stimulus drive in distinct ways. We show that this is not the case: adaptation effects in V1 and MT can involve weak or strong loss of responsivity and shifts in neuronal preference toward or away from the adapter, depending on stimulus size and adaptation duration. For a particular stimulus size and adaptation duration, however, effects are similar in nature and magnitude in V1 and MT. We also show that adaptation effects in MT of awake animals depend strongly on stimulus size. Our results suggest that the strategies for adjusting to recent stimulus history depend more strongly on adaptation duration and stimulus size than on the cortical area. Moreover, they indicate that different levels of the visual system adapt similarly to recent sensory experience.

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