scholarly journals A predictive focus of gain modulation encodes target trajectories in insect vision

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Steven D Wiederman ◽  
Joseph M Fabian ◽  
James R Dunbier ◽  
David C O’Carroll
Keyword(s):  
Target Location ◽  
Insect Vision ◽  
Gain Modulation ◽  
Brain Hemispheres ◽  
Contrast Gain ◽  
Enhanced Sensitivity ◽  
Neuronal Mechanisms ◽  
New Locations ◽  
Direction Tuning ◽  
Predictive Processes

When a human catches a ball, they estimate future target location based on the current trajectory. How animals, small and large, encode such predictive processes at the single neuron level is unknown. Here we describe small target-selective neurons in predatory dragonflies that exhibit localized enhanced sensitivity for targets displaced to new locations just ahead of the prior path, with suppression elsewhere in the surround. This focused region of gain modulation is driven by predictive mechanisms, with the direction tuning shifting selectively to match the target’s prior path. It involves a large local increase in contrast gain which spreads forward after a delay (e.g. an occlusion) and can even transfer between brain hemispheres, predicting trajectories moved towards the visual midline from the other eye. The tractable nature of dragonflies for physiological experiments makes this a useful model for studying the neuronal mechanisms underlying the brain’s remarkable ability to anticipate moving stimuli.

EXPRESS: How the size of exogenous attentional cues alters visual performance: from response gain to contrast gain

2021 ◽  
pp. 174702182110248
Author(s):  
Xiaogang Wu ◽  
Aijun Wang ◽  
Ming Zhang
Keyword(s):  
Visual Selective Attention ◽  
Visual Performance ◽  
Target Size ◽  
Field Size ◽  
Gain Modulation ◽  
Absolute Size ◽  
Contrast Gain ◽  
Exogenous Cues ◽  
Exogenous Cue ◽  
Attentional Cues

The normalization model of attention (NMoA) predicts that the attention gain pattern is mediated by changes in the size of the attentional field and stimuli. However, existing studies have not measured gain patterns when the relative sizes of stimuli are changed. To investigate the NMoA, the present study manipulated the attentional field size, namely, the exogenous cue size. Moreover, we assessed whether the relative rather than the absolute size of the attentional field matters, either by holding the target size constant and changing the cue size (experiments 1-3) or by holding the cue size constant and changing the target size (experiment 4), in a spatial cueing paradigm of psychophysical procedures. The results show that the gain modulations changed from response gain to contrast gain when the precue size changed from small to large relative to the target size (experiments 1-3). Moreover, when the target size was once again made larger than the precue size, there was still a change in response gain (experiment 4). These results suggest that the size of exogenous cues plays an important role in adjusting the attentional field and that relative changes rather than absolute changes to exogenous cue size determine gain modulation. These results are consistent with the prediction of the NMoA and provide novel insights into gain modulations of visual selective attention.

scholarly journals Precise visuotopic organization of the blind spot representation in primate V1

2015 ◽  
Vol 113 (10) ◽  
pp. 3588-3599 ◽  
Author(s):  
João C. B. Azzi ◽  
Ricardo Gattass ◽  
Bruss Lima ◽  
Juliana G. M. Soares ◽  
Mario Fiorani
Keyword(s):  
Neuronal Activity ◽  
Receptive Fields ◽  
Blind Spot ◽  
Mapping Method ◽  
Optic Disk ◽  
Topographic Map ◽  
Multiple Electrodes ◽  
Neuronal Mechanisms ◽  
Global Mapping ◽  
Direction Tuning

The optic disk is a region of the retina consisting mainly of ganglion cell axons and blood vessels, which generates a visual scotoma known as the blind spot (BS). Information present in the surroundings of the BS can be used to complete the missing information. However, the neuronal mechanisms underlying these perceptual phenomena are poorly understood. We investigate the topography of the BS representation (BSR) in cortical area V1 of the capuchin monkey, using single and multiple electrodes. Receptive fields (RFs) of neurons inside the BSR were investigated using two distinct automatic bias-free mapping methods. The first method (local mapping) consisted of randomly flashing small white squares. For the second mapping method (global mapping), we used a single long bar that moved in one of eight directions. The latter stimulus was capable of eliciting neuronal activity inside the BSR, possibly attributable to long-range surround activity taking place outside the borders of the BSR. Importantly, we found that the neuronal activity inside the BSR is organized topographically in a manner similar to that found in other portions of V1. On average, the RFs inside the BS were larger than those outside. However, no differences in orientation or direction tuning were found between the two regions. We propose that area V1 exhibits a continuous functional topographic map, which is not interrupted in the BSR, as expected by the distribution of photoreceptors in the retina. Thus V1 topography is better described as “visuotopic” rather than as a discontinuous “retinotopic” map.

scholarly journals The contribution of forward masking to saccadic inhibition of return

2017 ◽  
Author(s):  
David Souto ◽  
Sabine Born ◽  
Dirk Kerzel
Keyword(s):  
Inhibition Of Return ◽  
Target Location ◽  
Reaction Times ◽  
Gain Control ◽  
Forward Masking ◽  
Contrast Gain ◽  
Contrast Gain Control ◽  
Saccadic Reaction Times ◽  
Return Effect

Inhibition of return is the name typically given to the prolonged latency of motor responses directed to a previously cued target location. There is intense debate about the origins of this effect and its function, but most take for granted (despite lack of evidence) that it depends little on forward masking. Therefore, we re-examined the role of forward masking in inhibition of return. Forward masking was indexed by slower saccadic reaction times (SRTs) when the target orientation repeated the cue orientation at the same location. We confirmed effects of orientation repetition in the absence of an attentional bias when cues were presented on both sides of fixation (bilateral presentation). The effect of orientation repetition was reduced with high target contrast, consistent with a low-level origin such as contrast gain control in early visual areas. When presenting cues on only one side of fixation (unilateral presentation), we obtained inhibition of return with longer cue-target intervals and facilitation with targets presented shortly after the cue. The effect of orientation repetition was reduced when facilitation was observed, but was as strong as with bilateral cues when inhibition of return was observed. Therefore, forward masking may contribute to the inhibition of return effect by delaying reaction times to repeated features at the same location, but is not a principal cause of inhibition of return; in agreement with previous views.

scholarly journals Author response: A predictive focus of gain modulation encodes target trajectories in insect vision

2017 ◽  
Author(s):  
Steven D Wiederman ◽  
Joseph M Fabian ◽  
James R Dunbier ◽  
David C O’Carroll
Keyword(s):  
Insect Vision ◽  
Author Response ◽  
Gain Modulation

scholarly journals Enhanced learning and sensory salience in a cerebellar mouse autism model

2021 ◽  
Author(s):  
Marlies Oostland ◽  
Mikhail Kislin ◽  
Yuhang Chen ◽  
Tiffany Chen ◽  
Sarah Jo Venditto ◽  
...  
Keyword(s):  
Autism Spectrum ◽  
Central Coherence ◽  
Auditory Cues ◽  
Optogenetic Stimulation ◽  
Enhanced Sensitivity ◽  
Neuronal Mechanisms ◽  
Electrophysiological Responses ◽  
Sensory Evidence ◽  
Enhanced Learning ◽  
Complex Spikes

Among the impairments manifested by autism spectrum disorder (ASD) are sometimes islands of enhanced function. Although neuronal mechanisms for enhanced functions in ASD are unknown, the cerebellum is a major site of developmental alteration, and early-life perturbation to it leads to ASD with higher likelihood than any other brain region. Here we report that a cerebellum-specific transgenic mouse model of ASD shows faster learning on a sensory evidence-accumulation task. In addition, transgenic mice showed enhanced sensitivity to touch and auditory cues, and prolonged electrophysiological responses in Purkinje-cell complex spikes and associative neocortical regions. These findings were replicated by pairing cues with optogenetic stimulation of Purkinje cells. Computational latent-state analysis of behavior revealed that both groups of mice with cerebellar perturbations exhibited enhanced focus on current rather than past information, consistent with a role for the cerebellum in retaining information in memory. We conclude that cerebellar perturbation can activate neocortex via complex spike activity and reduce reliance on prior experience, consistent with a weak-central-coherence account in which ASD traits arise from enhanced detail-oriented processing. This recasts ASD not so much as a disorder but as a variation that, in particular niches, can be adaptive.

Eyes and ears: Rejection and enhanced sensitivity to auditory and visual social cues

2003 ◽  
Author(s):  
Cynthia L. Pickett ◽  
Wendi L. Gardner ◽  
Megan Knowles
Keyword(s):  
Social Cues ◽  
Enhanced Sensitivity

Comparison between different boost dose delivery techniques to the tumor bed of right sided breast cancer patients.

2017 ◽  
Vol 13 (1) ◽  
pp. 4605-4617
Author(s):  
Aly Mahmoud El-Hdidy
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Target Location ◽  
Breast Cancer Patients ◽  
Photon Beams ◽  
Lung Dose ◽  
Dose Volume Histograms ◽  
Tumor Bed ◽  
Boost Dose ◽  
Treatment Plans

Comparisons between three different techniques by which the boost dose was delivered to the tumor bed were carried out , aiming to present the best technique of treatment for right breast cancer patients.In this study, ten right sided breast cancer computed tomography (CT) scans were selected for ten early right breast cancer patients. We made three different treatment plans for each patient CT using three different irradiation techniques to deliver a prescribed boost dose of 10 Gy in 5 fractions to the boost PTV. In the first technique, two tangential photon beams were used, in the second technique we, two oblique photon beams were used and in the third technique, a single electron beam was used. The comparative analyses between the three techniques were performed by comparing the boost PTV- dose volume histograms (DVHs), the ipsilateral breast (right breast) DVHs, the ipsilateral lung (right lung) DVHs and the heart DVHs of the three techniques for each patient. Furthermore the dose that covering 100% , 95% of the volume (D100% , D95%) and the volume covered by 95% of the dose (V95%)of  the boost PTV of all techniques, were calculated for each patient to investigate the dose coverage of the target.Results showed that there were variations of the dose received by tumor bed, right breast and OARs depending on the technique used and the target location and size. A decrease of D100% than 90% of the prescribed dose was observed with the 3rd technique for patients 8, 9 and 10, and was observed with the 2nd technique for patient 5. A reduction of right breast dose was observed when the 3rd technique was use in comparison with the 1st and the 2nd techniques for patients 1, 2, 3, 4, 6 and 8.  Also reduction of right breast was observed when the 2nd technique used in comparison with 1st technique. An increase of lung dose was observed with the 3rd technique for patients 1, 2, 5 and 6, also was observed with 2nd technique in patient 3, 5 and 7. A decrease of lung dose was observed with the 1st technique for patients 2, 4, 5, 6, 7, 8 and 9An individualized treatment, several plans using different irradiation techniques should be developed for each patient individually to reach the best boost PTV dose coverage with minimal OARs’ dose. 

Spatial suppression due to statistical regularities is driven by distractor suppression not by target activation

2018 ◽  
Author(s):  
Michel Failing ◽  
Benchi Wang ◽  
Jan Theeuwes
Keyword(s):  
High Probability ◽  
Target Location ◽  
Target Selection ◽  
Visual Space ◽  
Alternative Interpretation ◽  
Distractor Location ◽  
Target Presentation ◽  
Statistical Regularities ◽  
Low Probability ◽  
Presentation Experiment

Where and what we attend to is not only determined by what we are currently looking for but also by what we have encountered in the past. Recent studies suggest that biasing the probability by which distractors appear at locations in visual space may lead to attentional suppression of high probability distractor locations which effectively reduces capture by a distractor but also impairs target selection at this location. However, in many of these studies introducing a high probability distractor location was tantamount to increasing the probability of the target appearing in any of the other locations (i.e. the low probability distractor locations). Here, we investigate an alternative interpretation of previous findings according to which attentional selection at high probability distractor locations is not suppressed. Instead, selection at low probability distractor locations is facilitated. In two visual search tasks, we found no evidence for this hypothesis: neither when there was only a bias in target presentation but no bias in distractor presentation (Experiment 1), nor when there was only a bias in distractor presentation but no bias in target presentation (Experiment 2). We conclude that recurrent presentation of a distractor in a specific location leads to attentional suppression of that location through a mechanism that is unaffected by any regularities regarding the target location.

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