A computational model of stereoscopic prey capture in praying mantises.

We present a simple model which can account for the stereoscopic sensitivity of praying mantis predatory strikes. The model consists of a single "disparity sensor": a binocular neuron sensitive to stereoscopic disparity and thus to distance from the animal. The model is based closely on th...

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Main Authors: James O'Keeffe, Sin Hui Yap, Ichasus Llamas-Cornejo, Vivek Nityananda, Jenny C A Read
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-05-01
Series:PLoS Computational Biology
Online Access:https://doi.org/10.1371/journal.pcbi.1009666
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author James O'Keeffe
Sin Hui Yap
Ichasus Llamas-Cornejo
Vivek Nityananda
Jenny C A Read
author_facet James O'Keeffe
Sin Hui Yap
Ichasus Llamas-Cornejo
Vivek Nityananda
Jenny C A Read
author_sort James O'Keeffe
collection DOAJ
description We present a simple model which can account for the stereoscopic sensitivity of praying mantis predatory strikes. The model consists of a single "disparity sensor": a binocular neuron sensitive to stereoscopic disparity and thus to distance from the animal. The model is based closely on the known behavioural and neurophysiological properties of mantis stereopsis. The monocular inputs to the neuron reflect temporal change and are insensitive to contrast sign, making the sensor insensitive to interocular correlation. The monocular receptive fields have a excitatory centre and inhibitory surround, making them tuned to size. The disparity sensor combines inputs from the two eyes linearly, applies a threshold and then an exponent output nonlinearity. The activity of the sensor represents the model mantis's instantaneous probability of striking. We integrate this over the stimulus duration to obtain the expected number of strikes in response to moving targets with different stereoscopic disparity, size and vertical disparity. We optimised the parameters of the model so as to bring its predictions into agreement with our empirical data on mean strike rate as a function of stimulus size and disparity. The model proves capable of reproducing the relatively broad tuning to size and narrow tuning to stereoscopic disparity seen in mantis striking behaviour. Although the model has only a single centre-surround receptive field in each eye, it displays qualitatively the same interaction between size and disparity as we observed in real mantids: the preferred size increases as simulated prey distance increases beyond the preferred distance. We show that this occurs because of a stereoscopic "false match" between the leading edge of the stimulus in one eye and its trailing edge in the other; further work will be required to find whether such false matches occur in real mantises. Importantly, the model also displays realistic responses to stimuli with vertical disparity and to pairs of identical stimuli offering a "ghost match", despite not being fitted to these data. This is the first image-computable model of insect stereopsis, and reproduces key features of both neurophysiology and striking behaviour.
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spelling doaj.art-ea24b8478b974c3c8661dcfd6313ff7e2022-12-22T03:00:34ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582022-05-01185e100966610.1371/journal.pcbi.1009666A computational model of stereoscopic prey capture in praying mantises.James O'KeeffeSin Hui YapIchasus Llamas-CornejoVivek NityanandaJenny C A ReadWe present a simple model which can account for the stereoscopic sensitivity of praying mantis predatory strikes. The model consists of a single "disparity sensor": a binocular neuron sensitive to stereoscopic disparity and thus to distance from the animal. The model is based closely on the known behavioural and neurophysiological properties of mantis stereopsis. The monocular inputs to the neuron reflect temporal change and are insensitive to contrast sign, making the sensor insensitive to interocular correlation. The monocular receptive fields have a excitatory centre and inhibitory surround, making them tuned to size. The disparity sensor combines inputs from the two eyes linearly, applies a threshold and then an exponent output nonlinearity. The activity of the sensor represents the model mantis's instantaneous probability of striking. We integrate this over the stimulus duration to obtain the expected number of strikes in response to moving targets with different stereoscopic disparity, size and vertical disparity. We optimised the parameters of the model so as to bring its predictions into agreement with our empirical data on mean strike rate as a function of stimulus size and disparity. The model proves capable of reproducing the relatively broad tuning to size and narrow tuning to stereoscopic disparity seen in mantis striking behaviour. Although the model has only a single centre-surround receptive field in each eye, it displays qualitatively the same interaction between size and disparity as we observed in real mantids: the preferred size increases as simulated prey distance increases beyond the preferred distance. We show that this occurs because of a stereoscopic "false match" between the leading edge of the stimulus in one eye and its trailing edge in the other; further work will be required to find whether such false matches occur in real mantises. Importantly, the model also displays realistic responses to stimuli with vertical disparity and to pairs of identical stimuli offering a "ghost match", despite not being fitted to these data. This is the first image-computable model of insect stereopsis, and reproduces key features of both neurophysiology and striking behaviour.https://doi.org/10.1371/journal.pcbi.1009666
spellingShingle James O'Keeffe
Sin Hui Yap
Ichasus Llamas-Cornejo
Vivek Nityananda
Jenny C A Read
A computational model of stereoscopic prey capture in praying mantises.
PLoS Computational Biology
title A computational model of stereoscopic prey capture in praying mantises.
title_full A computational model of stereoscopic prey capture in praying mantises.
title_fullStr A computational model of stereoscopic prey capture in praying mantises.
title_full_unstemmed A computational model of stereoscopic prey capture in praying mantises.
title_short A computational model of stereoscopic prey capture in praying mantises.
title_sort computational model of stereoscopic prey capture in praying mantises
url https://doi.org/10.1371/journal.pcbi.1009666
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