A model of feedforward, global, and lateral inhibition in the locust visual system predicts responses to looming stimuli
| Autor: | Erik G. N. Olson, Travis Wiens, John R. Gray |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Physics General Computer Science Feed forward Stimulus (physiology) Inhibitory postsynaptic potential 03 medical and health sciences 030104 developmental biology 0302 clinical medicine medicine.anatomical_structure Looming Lateral inhibition Excitatory postsynaptic potential medicine Tonic (music) Neuron Neuroscience 030217 neurology & neurosurgery Biotechnology |
| Zdroj: | Biological Cybernetics. 115:245-265 |
| ISSN: | 1432-0770 0340-1200 |
| Popis: | Detection of looming obstacles is a vital task for both natural and artificial systems. Locusts possess a visual nervous system with an extensively studied obstacle detection pathway, culminating in the lobula giant movement detector (LGMD) neuron. While numerous models of this system exist, none to date have incorporated recent data on the anatomy and function of feedforward and global inhibitory systems in the input network of the LGMD. Moreover, the possibility that global and lateral inhibition shape the feedforward inhibitory signals to the LGMD has not been investigated. To address these points, a novel model of feedforward inhibitory neurons in the locust optic lobe was developed based on the recent literature. This model also incorporated global and lateral inhibition into the afferent network of these neurons, based on their observed behaviour in existing data and the posited role of these mechanisms in the inputs to the LGMD. Tests with the model showed that it accurately replicates the behaviour of feedforward inhibitory neurons in locusts; the model accurately coded for stimulus angular size in an overall linear fashion, with decreasing response saturation and increasing linearity as stimulus size increased or approach velocity decreased. The model also exhibited only phasic responses to the appearance of a grating, along with sustained movement by it at constant speed. By observing the effects of altering inhibition schemes on these responses, it was determined that global inhibition serves primarily to normalize growing excitation as collision approaches, and keeps coding for subtense angle linear. Lateral inhibition was determined to suppress tonic responses to wide-field stimuli translating at constant speed. Based on these features being shared with characterizations of the LGMD input network, it was hypothesized that the feedforward inhibitory neurons and the LGMD share the same excitatory afferents; this necessitates further investigation. |
| Databáze: | OpenAIRE |
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