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L42. THE EYE OF THE FLY

C. D. Hopkins

Neuroethology BIONB 4240

Nov 9, 2011

In superposition eyes, light from many focusing lenses converge on a small number of photoreceptors.

No pigment shielding between ommatidiaNight flying insects

In apposition eyes the light from a single photoreceptor is focused on a single rhabdomEric Warrant and Marie Dacke (2011) Ann.

Rev. Entomol.

Cajal’s Anatomical study of the Insect Eye

Cajal wrote, “ the complexity of the insect retina is stupendous, indeed disconcerting, and with no precedent in other animals”

lamina

medulla

lobula

Cajal’s figure reprinted in Llinas (2003) Nature reviews neuroscience

The eye of the fly is divided into ommatidia

Simmons and Young, 2010

Transduction takes place in the rhabdom

locust eye blow fly

rhabdomeres remainseparate

Rhabdom fuses into single light collecting rod

Simmons and Young, 2010

Like vertebrates, insect eyes often have a fovea capable of acute vision

Here, for a praying mantis, the fovea is a small are, forward looking, where the mantis fixates on a prey.

The facet diameter is larger in the fovea. The inter-ommotidial angle is reduced.(more overlap).

Simmons and Young, 2010

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The fovea varies according to the visual behavior of the insect

For four species, contour plots of numbers of ommatidia per unit solid angle.

b)  Caliphora (blowfly)

c) Apis male (honeybee)

d) Annax junius (dragonfly)

e) Gerris (waterstrider)  

Land, M. (1997) Visual accuity in insects. Annu. Rev. Entomol. 1997. 42:147–77

The speed of the eye varies with the flight patterns of two flies

Tipula: crane fly, is nocturnal, slow flying.

Fleshflies are diurnal, fast moving

0.5 s

Simmons and Young, 2010

the photoreceptor responds with depolarizing potential (overshoot, then relax to plateau)

axon responds

The lamina and a lamina monopolar cell

Simmons and Young, 2010

axon responds with depolarizing potentail.

The LMC neuron is inhibited by the photoreceptor. and is more “phasic”.

DC response is eliminated, edges enhanced. (hi-pass).

S. Laughlin

The lamina neurons enhance the transient (flicker) responses by removing background light levels

From Laughlin, S. (in Shepherd and Grilner: handbook of brain microcircuits, 2010)

The fly lamina enhances the high frequency component of the amplitude modulated light

From Laughlin, S. (in Shepherd and Grilner: handbook of brain microcircuits, 2010)

Werner BernhardReichardt Hassenstein

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Early Experiments

Y-Maze

Glossary

• Luminance

• Contrast

• Temporal frequency=velocity/wavelength(variation that a single ( greceptor sees)

The Reichardt (Correlation) Motion Detector

Photoreceptors

Low-pass filters create delay 1F

1 2

2F

Multiplier

Subtractor

t)-(T(T)FA-t)-(T(T)FA R(t) 2112=

1A2A

Lobula Plate Tangential Cells (LPTC) in the lobula plate of the blow fly, Calliphora, respond to motion in the horizontal plane (HS neurons) (a) or vertical plane (VS neurons) anywhere in the visual field of the eye.

HS VSdownward

ccw

Franceschini et al, 1989 (from Simons and Young, 2010)

H1 neurons allow left right comparisons (distinguish rotation from forward visual flow)

Delay line coincidence detector produces motion response in H1 neurons (elementary motion detector)

Nicholas FranceschiniCNRS, Marseille France

sequential activation of just two photoreceptors within a single ommatidium evoke responses from H1 only in the preferred direction. (From Franceschini et al, 1989)

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Motion sensing neurons in Lobula Plate

Borst & Euler Neuron 71, September 22, 2011

Reichardt Motion Detector Model

Possible connectivity

Egelhaaf and Borst (1993)

ReferencesHassenstein, B. & Reichardt, W. Z. Naturforsch.11b, 513–524 (1956).

Reichardt, W. in Sensory Communication (ed. Rosenblith, W. A.) 303–317 (MIT Press, Cambridge, Massachusetts, 1961).

Borst, A. & Egelhaaf, M. Trends Neurosci. 12, 297–306 (1989).

van Santen, J. P. H. & Sperling, G. J. Opt. Soc. Am. A 2, 300–320 (1985).

Adelson, E. H. & Bergen, J. R. J. Opt. Soc. Am. A 2, 284–299 (1985).

Barlow, H. B. & Levick, W. R. J. Physiol. (Lond.)178, 477–504 (1965).

Koch C Poggio T & Torre V Proc Natl Acad Sci USA 80, 2799–2802 (1983).Koch, C., Poggio, T. & Torre, V. Proc. Natl. Acad. Sci.USA 80, 2799 2802 (1983).

Borst, A. (2000) Models of motion detection.  Nature neuroscience supplement 3:1168.

Borst, A. and Euler, T. (2011) Seeing things in motion: models, circuits, and mechanisms. Neuron 71, 974‐94.

Egelhaaf, M. and Borst, A. (1993). Motion computation and visual orientation in flies. Comp Biochem Physiol Comp Physiol 104, 659‐73.

Franceschini, N. Riehle, A. and Le Nestour, A. (19889) Directionally selective motion detection by insect neurons. In Facets of Vision (ed. D. G. Stavenga and R. C. Hardie) pp 360‐390. Berlin. Springer. 

Warrant, E. and Dacke, M. Vision and visual navigation in nocturnal insects. Annu Rev Entomol 56, 239‐54.