The Detection and Analysis of Optic Flow by Crabs: from Eye Movements to Electrophysiology

Barnes, W. Jon. P.; Horseman, B.G.; Macauley, M W S

doi:10.1007/978-3-662-04843-6_35

Cited by 4 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The importance of this optic flow cannot be underestimated for studies on a number of different animals have shown that it provides information about the three-dimensional structure of the environment as well as different aspects of the animal's own movements, including turns, velocity of motion, and distance travelled (for reviews see Lappe, 2000;Zanker & Zeil, 2001). However, although a clear-cut role for rotational optic flow in course control has been identified in fiddler crabs (Layne et al, 2003), and neurones tuned to translational optic flow have been identified in the crab visual pathway (Barnes et al, 2001(Barnes et al, , 2002, Separation of optic flow-field components by land crabs more work is required to identify the precise ways in which crabs utilize this information.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of light intensity and pattern contrast on the ability of the land crab,Cardisoma guanhumi, to separate optic flow-field components

2004

Self Cite

View full text Add to dashboard Cite

Using a novel suite of computer-generated visual stimuli that mimicked components of optic flow, the visual responses of the tropical land crab, Cardisoma guanhumi, were investigated. We show that crabs are normally successful in distinguishing the rotational and translational components of the optic flow field, showing strong optokinetic responses to the former but not the latter. This ability was not dependent on the orientation of the crab, occurring both in "forwards-walking" and "sideways-walking" configurations. However, under conditions of low overall light intensity and/or low object/background contrast, the separation mechanism shows partial failure causing the crab to generate compensatory eye movements to translation, particularly in response to low-frequency (low-velocity) stimuli. Using this discovery, we then tested the ability of crabs to separate rotational and translational components in a combined rotation/translation flow field under different conditions. We demonstrate that, while crabs can successfully separate such a combined flow field under normal circumstances, showing compensatory eye movements only to the rotational component, they are unable to make this separation under conditions of low overall light intensity and low object/background contrast. Here, the responses to both flow-field components show summation when they are in phase, but, surprisingly, there is little reduction in the amplitude of responses to rotation when the translational component is in antiphase. Our results demonstrate that the crab's visual system finds separation of flow-field components a harder task than detection of movement, since the former shows partial failure at light intensities and/or object/background contrasts at which movement of the world around the crab is still generating high-gain optokinetic responses.

show abstract

Section: Discussionmentioning

confidence: 99%

“…However, simpler animals use eye movements to compensate for the rotational component, leaving optic flow consisting of only the translational component. Neurones tuned to translational optic flow have been found in many animals, including insects (Krapp & Hengstenberg, 1996) and crabs (Barnes et al, 2001(Barnes et al, , 2002.…”

Section: Introductionmentioning

confidence: 99%

Effects of light intensity and pattern contrast on the ability of the land crab,Cardisoma guanhumi, to separate optic flow-field components

2004

Self Cite

View full text Add to dashboard Cite

show abstract

“…8D show extended horizontal areas. A common feature of lobula neurone response maps, illustrated in Fig.8A,B (but not in Fig.7B), is for the response map to be extended horizontally, perhaps providing a template for the horizontal skylines that dominate most seascapes (Barnes et al, 2001;Eckert and Zeil, 2001). …”

Section: Types Of Response Map and Their Propertiesmentioning

confidence: 96%

“…The lobula neurones would be stimulated by the approaching scene, the medulla neurones by the receding scene. Preliminary accounts of these experiments appear in Barnes et al (Barnes et al, 2001;Barnes et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Neuronal processing of translational optic flow in the visual system of the shore crabCarcinus maenas

Horseman

Macauley

Barnes

2011

Journal of Experimental Biology

Self Cite

View full text Add to dashboard Cite

SUMMARYThis paper describes a search for neurones sensitive to optic flow in the visual system of the shore crab Carcinus maenas using a procedure developed from that of Krapp and Hengstenberg. This involved determining local motion sensitivity and its directional selectivity at many points within the neurone's receptive field and plotting the results on a map. Our results showed that local preferred directions of motion are independent of velocity, stimulus shape and type of motion (circular or linear). Global response maps thus clearly represent real properties of the neurones' receptive fields. Using this method, we have discovered two families of interneurones sensitive to translational optic flow. The first family has its terminal arborisations in the lobula of the optic lobe, the second family in the medulla. The response maps of the lobula neurones (which appear to be monostratified lobular giant neurones) show a clear focus of expansion centred on or just above the horizon, but at significantly different azimuth angles. Response maps such as these, consisting of patterns of movement vectors radiating from a pole, would be expected of neurones responding to self-motion in a particular direction. They would be stimulated when the crab moves towards the pole of the neurone's receptive field. The response maps of the medulla neurones show a focus of contraction, approximately centred on the horizon, but at significantly different azimuth angles. Such neurones would be stimulated when the crab walked away from the pole of the neurone's receptive field. We hypothesise that both the lobula and the medulla interneurones are representatives of arrays of cells, each of which would be optimally activated by self-motion in a different direction. The lobula neurones would be stimulated by the approaching scene and the medulla neurones by the receding scene. Neurones tuned to translational optic flow provide information on the three-dimensional layout of the environment and are thought to play a role in the judgment of heading.

show abstract

Polarization vision in crayfish motion detectors

Glantz

2008

J Comp Physiol A

View full text Add to dashboard Cite

Motion detector interneurons were examined to determine their responsiveness to the motion of polarized light images (i.e. images segmented by spatial variations in e-vector angle). Computer generated images were displayed as intensity contrasts or polarization contrasts on a modified LCD projection panel. The stimuli included the motion of a single stripe (45 degrees -55 degrees /s) and the global motion of a square wave grating (3.3 degrees /s). Neurons were impaled in the medulla interna. Of the neurons which exhibited a directional response to the motion of intensity contrast stimuli, about 2/3 were also directional in the response to polarized light images. Transient (nondirectional) stimuli included looming and jittery motions. The responses to the transient motions of the polarized light images were roughly comparable to those elicited by intensity contrast. The results imply that behavioral responses to polarized light images (i.e. optokinetic and defense reflexes) may have a basis in the polarization sensitivity and synaptic organization of the medulla interna.

show abstract

The Detection and Analysis of Optic Flow by Crabs: from Eye Movements to Electrophysiology

Cited by 4 publications

References 47 publications

Effects of light intensity and pattern contrast on the ability of the land crab,Cardisoma guanhumi, to separate optic flow-field components

Effects of light intensity and pattern contrast on the ability of the land crab,Cardisoma guanhumi, to separate optic flow-field components

Neuronal processing of translational optic flow in the visual system of the shore crabCarcinus maenas

Polarization vision in crayfish motion detectors

Contact Info

Product

Resources

About