Spectral sensitivity of dipteran retinula cells

Snyder, Allan W.; Pask, C.

doi:10.1007/bf00694147

Cited by 71 publications

(27 citation statements)

References 20 publications

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“…The visual learning paradigm provides an example. Anatomical, physiological, and indirect behavioral experiments have shown that Drosophila has two visual receptor systems, with maximum sensitivities at different wavelengths (14). The present experiments suggest that the fly may use the color information it is equipped to detect.…”

Section: Visual Learningmentioning

confidence: 53%

Conditioned Behavior in Drosophila melanogaster

Quinn

Harris

Benzer

1974

Proc. Natl. Acad. Sci. U.S.A.

620

442

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Populations of Drosophila were trained by alternately exposing them to two odorants, one coupled with electric shock. On testing, the flies avoided the shocka~sociated odor. Pseudoconditioning, excitatory states, odor preference, sensitization, habituation, and subjective bias have been eliminated as explanations. The selective avoidance can be extinguished by retraining. All flies in the population have equal probability of expressing this behavior. Memory persists for 24 hr. Another paradigm has been developed in which flies learn to discriminate between light sources of different color.Because the hereditary mechanics of Drosophila melanogaster are understood in detail, the behavioral repertoire of this organism and the neural system that specifies it are amenable to genetic analysis. Many flies of identical genotype are readily produced, so that behavioral measurements can be made on populations rather than individuals, yielding instant statistics.If a mutation is found in a gene affecting behavior, methods using genetic mosaics exist for localizing the site of the gene's action to a specific region ("focus") in the fly (1). Anatomical or biochemical changes at the foci of various mutants mav then be correlated with alterations in behavior.One aspect of behavior that so far has been inaccessible to this form of analysis is learning. Conditioning experiments in Drosophila and other dipterans are fraught with complications, and most such studies have been inconclusive. A major problem is pseudoconditioning, in which the training schedule nonspecifically alters the state of the organism, producing changes in behavior that can be misinterpreted as associative learning. An example is the "central excitatory state" (2) in the blowfly Phormia regina; exposure of a hungry fly to sucrose solution arouses it so that afterward it extends its proboscis in response to a variety of unrelated stimuli. This probably accounts (3) for the results of Frings (4). The proper control for pseudoconditioning is to disassociate the reinforcement in time from the stimulus; if the response results from true learning it should depend on simultaneous or near-simultaneous presentation of stimulus and reinforcement.Another pitfall is the possibility of odor cues laid down by the flies. Our early experiments indicated that a stimulus, presumably an odor, was left in the apparatus by flies when shocked and later used by them as a cue for avoidance. The presence of odor trails may have affected the results of Murphey (5) on T-maze learning by Drosophila; these have recently been contradicted by Yeatman and Hirsch (6).Habituation is the decrease in a response on repeated presentation of the same stimulus. Although it can be considered a rudimentary form of learning, in some cases it occurs at the sensory receptors (7), so it is not necessarily related to higher learning in the central nervous system. Exposure of Drosophila larvae to odor altered their behavior as adults (8). This was interpreted as associative learning (9), but has si...

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Section: Visual Learningmentioning

confidence: 53%

Conditioned Behavior in Drosophila melanogaster

Quinn

Harris

Benzer

1974

Proc. Natl. Acad. Sci. U.S.A.

620

442

View full text Add to dashboard Cite

show abstract

“…We will mention here a third possible artifact that may have been able to influence our measurements on effective birefringence. For small values of V, the excitation of the first mode depends sensitively upon V (SNYDER and PASK, 1973). Since we have a birefringent structure, V varies with the ~-vector orientation, so that the excitation should vary also.…”

Section: The Characteristic Waveguide Parameter V Of the Fly Rhabdomeresmentioning

confidence: 96%

“…7. The excitation of a mode depends also on V (SNYDER and PASK, 1973): the larger V, the stronger the mode will be excited assuming V < 2. This phenomenon, however, tends to reduce the modulation of the transmitted light as a function of the orientation of the ~-vector if measured as shown in Fig.…”

Section: Dichroic Absorption In Rhabdomeresmentioning

confidence: 99%

“…This number has to be considered as a lower estimate since no waveguide effects have been taken into account. It has been argued (SNYDER, 1973) that the low polarization sensitivity as measured in fly photoreceptors no. 1 to 6 (SCHOLES, 1969) might be due to a high total light absorption within these photoreceptors ("selfscreening") even if the dichroic ratio of the visual pigment itself is rather high.…”

Section: Dichroic Absorption In Rhabdomeresmentioning

confidence: 99%

“…The visual system of the fly is unique in so far as the postulated difference in spectral sensitivities between receptors nos. 1 to 6 and 7/8 may not be due to a difference in their visual pigments but rather to their waveguide properties which could modify the spectral properties of the same photopigment in a different way in the two types of receptors (KIRSCHFELD, 1969;SNYDER and MILLER, 1972;SNYDER and PASK, 1973). Quantitative estimates have shown that the thinner receptors 7 and 8 in the Musca ommatidia are expected to have absorption maxima which are shifted towards shorter wavelengths and, in the UVspectral range, increased in relative size compared with those of the receptors 1 to 6.…”

Section: Introductionmentioning

confidence: 98%

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