The development of active binocular vision under normal and alternate rearing conditions (original) (raw)
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Lecture Notes in Computer Science, 2018
The development of binocular vision encompasses the formation of binocular receptive fields tuned to different disparities and the calibration of accurate vergence eye movements. Experiments have shown that this development is impaired when the animal is exposed to certain abnormal rearing conditions such as growing up in an environment that is deprived of horizontal or vertical edges. Here we test the effect of abnormal rearing conditions on a recently proposed computational model of binocular development. The model is formulated in the Active Efficient Coding framework, a generalization of classic efficient coding ideas to active perception. We show that abnormal rearing conditions lead to differences in the model's development that qualitatively match those seen in animal experiments. Furthermore, the model predicts systematic changes in vergence accuracy due to abnormal rearing. We discuss implications of the model for the treatment of developmental disorders of binocular vision such as amblyopia and strabismus.
Computational and Biological Mechanisms of Visual Coding
2007
This article examines an energy model of binocular interactionwith monocular and binocular response normalization. Disparity selectivityof the model neurons arises from a combination of position-shifts andphase-shifts between the monocular subfields of binocular receptive fields. Position-and phase-shifts have different quantitative properties, and it isargued that both likely contribute to the disparity selectivity of cells in V1. Modelling Binocular Neurons in the Primary Visual Cortex 25Binocular Stimulus Phase-Difference (degrees)
Neural development in the visual cortex depends on the visual experience during the so-called critical period. Recent experiments have shown that under normal conditions rodents develop binocular receptive fields which have similar orientation preferences for the left and right eyes. In contrast, under conditions of monocular deprivation during the critical period, this orientation alignment does not happen. Here we propose a computational model to explain the process of orientation alignment, its underlying mechanisms, and its failure in case of monocular deprivation or uncorrelated binocular inputs. Our model is based on the recently proposed Active Efficient Coding framework that jointly develops eye movement control and sensory representations. Our model suggests that the active maintenance of a binocular visual field, which leads to correlated visual inputs from the two eyes, is essential for the process of orientation alignment. This behavior is analogous to vergence control in primates. However, due to the fact that rodents have large receptive fields with low spatial frequency tuning, the coordination of the eyes need not be very precise. The model also suggests that it is not necessary that coordinated binocular vision be maintained continuously in order for orientation alignment to develop.
Joint Learning of Binocularly Driven Saccades and Vergence by Active Efficient Coding
Frontiers in Neurorobotics, 2017
This paper investigates two types of eye movements: vergence and saccades. Vergence eye movements are responsible for bringing the images of the two eyes into correspondence, whereas saccades drive gaze to interesting regions in the scene. Control of both vergence and saccades develops during early infancy. To date, these two types of eye movements have been studied separately. Here, we propose a computational model of an active vision system that integrates these two types of eye movements. We hypothesize that incorporating a saccade strategy driven by bottom-up attention will benefit the development of vergence control. The integrated system is based on the active efficient coding framework, which describes the joint development of sensory-processing and eye movement control to jointly optimize the coding efficiency of the sensory system. In the integrated system, we propose a binocular saliency model to drive saccades based on learned binocular feature extractors, which simultaneously encode both depth and texture information. Saliency in our model also depends on the current fixation point. This extends prior work, which focused on monocular images and saliency measures that are independent of the current fixation. Our results show that the proposed saliencydriven saccades lead to better vergence performance and faster learning in the overall system than random saccades. Faster learning is significant because it indicates that the system actively selects inputs for the most effective learning. This work suggests that saliency-driven saccades provide a scaffold for the development of vergence control during infancy.
Robust active binocular vision through intrinsically motivated learning
Frontiers in neurorobotics, 2013
The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a bi...
Encoding of binocular disparity by simple cells in the cat's visual cortex
Journal of neurophysiology, 1996
1. Spatiotemporal receptive fields (RFs) for left and right eyes were studied for simple cells in the cat's striate cortex to examine the idea that stereoscopic depth information is encoded via structural differences of RFs between the two eyes. Traditional models are based on neurons that possess matched RF profiles for the two eyes. We propose a model that requires a subset of simple cells with mismatched RF profiles for the two eyes in addition to those with similar RF structure. 2. A reverse correlation technique, which allows a rapid measurement of detailed RF profiles in the joint space-time domains, was used to map RFs for isolated single neurons recorded extracellularly in the anesthetized paralyzed cat. 3. Approximately 30% of our sample of cells shows substantial differences between spatial RF structure for the two eyes. Nearly all of these neurons prefer orientations between oblique and vertical, and are therefore presumed to be involved in processing horizontal dispa...
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 2016
The key problem of stereoscopic vision is traditionally defined as accurately finding the positional shifts of corresponding object features between left and right images. Here, we demonstrate that the problem must be considered in a four-dimensional parameter space; with respect not only to shifts in space (X, Y), but also spatial frequency (SF) and orientation (OR). The proposed model sums outputs of binocular energy units linearly over the multi-dimensional V1 parameter space (X, Y, SF, OR). Theoretical analyses and physiological experiments show that many binocular neurons achieve sharp binocular tuning properties by pooling the output of multiple neurons with relatively broad tuning. Pooling in the space domain sharpens disparity-selective responses in the SF domain so that the responses to combinations of unmatched left-right SFs are attenuated. Conversely, pooling in the SF domain sharpens disparity selectivity in the space domain, reducing the possibility of false matches. A...
Neural mechanisms for processing binocular information I. Simple cells
Journal of neurophysiology, 1999
The visual system integrates information from the left and right eyes and constructs a visual world that is perceived as single and three dimensional. To understand neural mechanisms underlying this process, it is important to learn about how signals from the two eyes interact at the level of single neurons. Using a sophisticated receptive field (RF) mapping technique that employs binary m-sequences, we have determined the rules of binocular interactions exhibited by simple cells in the cat's striate cortex in relation to the structure of their monocular RFs. We find that binocular interaction RFs of most simple cells are well described as the product of left and right eye RFs. Therefore the binocular interactions depend not only on binocular disparity but also on monocular stimulus position or phase. The binocular interaction RF is consistent with that predicted by a model of a linear binocular filter followed by a static nonlinearity. The static nonlinearity is shown to have a...
Procedia Computer Science, 2012
Designing an active visual system, able to autonomously learn its behavior, implies to make the learning controller independent of an external signal (e.g. the error between the actual and the desired vergence angle) or of perceptual decisions about disparity (e.g. from the response of a previously trained network). The proposed approach is based on a direct use of a computational substrate of modeled V1 complex cells that provide a distributed representation of binocular disparity information. The design strategies of the cortical-like architecture, including uniform coverage in feature space and divisive normalization mechanisms, allow the global energy of the population to effectively mediate the learning process towards the proper motor control. Since the learning controller is based on an intrinsic representation of the visual signal, it comes to overlap and coincide with the system that is learning the behaviour, thus closing at an inner cycle the perception-action loop necessary for learning. Experimental tests proved that the control architecture is both able to learn an effective vergence behavior, and to exploit it to fixate static and moving visual targets.
Perception, 1995
Binocular neurons in the visual cortex are thought to form the neural substrate for stereoscopic depth perception. How are the receptive fields of these binocular neurons organized to encode the retinal position disparities that arise from binocular parallax? The conventional notion is that the two receptive fields of a binocular neuron have identical shapes, but are spatially offset from the point of retinal correspondence (zero disparity). We consider an alternative disparity-encoding scheme, in which the two receptive fields may differ in shape (or phase), but are centered at corresponding retinal locations. Using a reverse-correlation technique to obtain detailed spatiotemporal receptive-field maps, we provide support for the latter scheme. Specifically, we show that receptive-field profiles for the left and right eyes are matched for cells that are tuned to horizontal orientations of image contours. However, for neurons tuned to vertical orientations, the left and right recepti...