Early visual experience and the receptive-field organization 
of optic flow processing interneurons in the fly motion pathway

Karmeier, Katja; Tabor, Rico; Egelhaaf, Martin; Krapp, Holger G.

doi:10.1017/s0952523801181010

Cited by 43 publications

(30 citation statements)

References 29 publications

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“…The diversity of neuron classes and their packing density have together constituted the major challenge faced by those researchers who would seek to identify wiring specificity in this or other regions of the fly's brain but are, we suggest, most easily tackled among the repeated neuronal arrays of a visual neuropil. Furthermore, some aspects of the optic lobe's deeper circuits depend little on the fly's visual experience (22,23), indicating that there, at least, the accuracy of synaptic wiring is inbuilt, making the medulla a clear candidate for neuronal stereotypy and an excellent test bed to examine both the accuracy with which neurons contact each other to form synaptic networks and, correspondingly, the accuracy of EM reconstructions used to catalog those networks.…”

Section: Significancementioning

confidence: 99%

Synaptic circuits and their variations within different columns in the visual system of Drosophila

Takemura

Lǚ

et al. 2015

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

265

379

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We reconstructed the synaptic circuits of seven columns in the second neuropil or medulla behind the fly's compound eye. These neurons embody some of the most stereotyped circuits in one of the most miniaturized of animal brains. The reconstructions allow us, for the first time to our knowledge, to study variations between circuits in the medulla's neighboring columns. This variation in the number of synapses and the types of their synaptic partners has previously been little addressed because methods that visualize multiple circuits have not resolved detailed connections, and existing connectomic studies, which can see such connections, have not so far examined multiple reconstructions of the same circuit. Here, we address the omission by comparing the circuits common to all seven columns to assess variation in their connection strengths and the resultant rates of several different and distinct types of connection error. Error rates reveal that, overall, <1% of contacts are not part of a consensus circuit, and we classify those contacts that supplement (E+) or are missing from it (E−). Autapses, in which the same cell is both presynaptic and postsynaptic at the same synapse, are occasionally seen; two cells in particular, Dm9 and Mi1, form ≥20-fold more autapses than do other neurons. These results delimit the accuracy of developmental events that establish and normally maintain synaptic circuits with such precision, and thereby address the operation of such circuits. They also establish a precedent for error rates that will be required in the new science of connectomics.neural circuits | stereotypy | biological error rates | reconstruction error rates

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Section: Significancementioning

confidence: 99%

Synaptic circuits and their variations within different columns in the visual system of Drosophila

Takemura

Lǚ

et al. 2015

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

265

379

View full text Add to dashboard Cite

show abstract

“…In fact, the dendritic spanning field of VS cells is unaltered in flies with genetically ablated eyes [122], and flies reared in the dark show no abnormalities in the receptive field organization of lobula plate cells [123]. Similarly, in the mammalian retina, where direction selectivity occurs independent of vision [for review, see 124], an intriguing subcellular topography has been reported for directionally tuned inputs on starburst amacrine cells [7].…”

Section: Deconvolution Of the Fluorescence Tracesmentioning

confidence: 99%

Subcellular mapping of dendritic activity in optic flow processing neurons

2014

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i AbstractDendritic integration is a fundamental element of neuronal information processing.So far, few studies have provided a detailed picture of this process, describing the properties of local dendritic activity and its subcellular organization.Here, I used 2--photon calcium imaging in optic flow processing neurons of the blowfly Calliphora vicina to determine the preferred location and direction of local motion cues for small branchlets throughout the entire dendrite. I found a pronounced retinotopic mapping on both the subcellular and the cell population level. In addition, dendritic branchlets residing in different layers of the neuropil were tuned to distinct directions of motion. Within one layer, local preferred directions varied according to the deflections of the ommatidial lattice. Summing the local receptive fields of all dendritic branchlets reproduced the characteristic properties of these neurons' axonal output receptive fields.These results corroborate the notion that the dendritic morphology of vertical system cells allows them to selectively collect local motion inputs with particular directional preferences from a spatially organized input repertoire, thus forming filters that match global patterns of optic flow. These data illustrate a highly structured circuit organization as an efficient way to hard--wire a complex sensory task.

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“…1a) [27, 29,30]. The sophisticated global patterns of preferred directions do not depend on visual experience and thus represent phylogenetic rather than developmental adaptations to optic-flow analysis [31]. The computation of self-motion based on optic flow is facilitated by the geometry of the compound eye lattice (Fig.…”

Section: Exploiting Global Features Of Optic Flow By Spatial Pooling mentioning

confidence: 99%

Neural encoding of behaviourally relevant visual-motion information in the fly

Egelhaaf

Kern

Krapp

et al. 2002

Trends in Neurosciences

149

109

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The goal of neuroethology is to explain behaviour in terms of the activity of nerve cells and their interactions. This can only be achieved if the experimental animal can be analysed at different levels ranging from behaviour to individual neurons. Cellular mechanisms underlying processing of neuronal information are frequently analysed using in vitro preparations where artificial stimulation replaces the natural sensory input. Although such studies provide fascinating insights into the complex computational abilities of neurons [1], the results may not be extrapolated easily to in vivo conditions, where the range of response amplitudes of neurons and their temporal activity patterns may differ considerably from artificially induced activity. In systems such as the retina of the horseshoe crab [5,6], it is now feasible to analyse the neuronal representation of visual input as it is experienced during behaviour (reviewed in Refs [7,8]). Until now, however, in most systems the underlying neuronal mechanisms have been difficult to unravel.In the fly it is possible to employ both quantitative behavioural approaches as well as in vivo electrophysiological and imaging methods to analyse how behaviourally relevant visual input is processed [9][10][11][12][13][14][15][16][17][18][19][20]. Although the latter techniques are mainly employed in the blowfly, which is relatively big, they are complemented by studies of the smaller fruitfly, Drosophila, where a broad range of genetic approaches can be applied to dissect the visual system in an increasingly specific way [21,22].We review recent progress on the encoding of optic-flow information in the blowfly. Optic flow is an important source of information about self-motion and the three-dimensional layout of the environment, not only for flies but for most moving animals including humans (Box 1, [4,[23][24][25]). Flies exploit optic flow to guide their locomotion [13] and to control compensatory head movements [26], and understanding the computational principles underlying optic-flow processing in flies could provide insights into visual-motion analysis in general.Information processing in visual systems is constrained by the spatial and temporal characteristics of the sensory input and by the biophysical properties of the neuronal circuits. Hence, to understand how visual systems encode behaviourally relevant information, we need to know about both the computational capabilities of the nervous system and the natural conditions under which animals normally operate. By combining behavioural, neurophysiological and computational approaches, it is now possible in the fly to assess adaptations that process visual-motion information under the constraints of its natural input. It is concluded that neuronal operating ranges and coding strategies appear to be closely matched to the inputs the animal encounters under behaviourally relevant conditions.

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Early visual experience and the receptive-field organization of optic flow processing interneurons in the fly motion pathway

Cited by 43 publications

References 29 publications

Synaptic circuits and their variations within different columns in the visual system of Drosophila

Synaptic circuits and their variations within different columns in the visual system of Drosophila

Subcellular mapping of dendritic activity in optic flow processing neurons

Neural encoding of behaviourally relevant visual-motion information in the fly

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