Reduction of Dopamine Level Enhances the Attractiveness of Male Drosophila to Other Males

Dopamine is an important neuromodulator in animals and its roles in mammalian sexual behavior are extensively studied. Drosophila as a useful model system is widely used in many fields of biological studies. It has been reported that dopamine reduction can affect female receptivity in Drosophila and leave male-female courtship behavior unaffected. Here, we used genetic and pharmacological approaches to decrease the dopamine level in dopaminergic cells in Drosophila, and investigated the consequence of this manipulation on male homosexual courtship behavior. We find that reduction of dopamine level can induce Drosophila male-male courtship behavior, and that this behavior is mainly due to the increased male attractiveness or decreased aversiveness towards other males, but not to their enhanced propensity to court other males. Chemical signal input probably plays a crucial role in the male-male courtship induced by the courtees with reduction of dopamine. Our finding provides insight into the relationship between the dopamine reduction and male-male courtship behavior, and hints dopamine level is important for controlling Drosophila courtship behavior

Distinct acute zones for visual stimuli in different visual tasks in Drosophila.

The fruit fly Drosophila melanogaster has a sophisticated visual system and exhibits complex visual behaviors. Visual responses, vision processing and higher cognitive processes in Drosophila have been studied extensively. However, little is known about whether the retinal location of visual stimuli can affect fruit fly performance in various visual tasks. We tested the response of wild-type Berlin flies to visual stimuli at several vertical locations. Three paradigms were used in our study: visual operant conditioning, visual object fixation and optomotor response. We observed an acute zone for visual feature memorization in the upper visual field when visual patterns were presented with a black background. However, when a white background was used, the acute zone was in the lower visual field. Similar to visual feature memorization, the best locations for visual object fixation and optomotor response to a single moving stripe were in the lower visual field with a white background and the upper visual field with a black background. The preferred location for the optomotor response to moving gratings was around the equator of the visual field. Our results suggest that different visual processing pathways are involved in different visual tasks and that there is a certain degree of overlap between the pathways for visual feature memorization, visual object fixation and optomotor response

Some recent advances in basic neuroscience research in China

Neuroscience as a distinct discipline or research programme has been a rather recent event in most Chinese universities and in the Chinese Academy of Sciences. However, the last few years have witnessed increased funding and an improved research environment for neuroscience, both of which facilitated an influx of Chinese neuroscientists trained abroad. In this review, we have highlighted some recent research advances made by neuroscientists in China. Based on our own expertise, this review is focused mainly on findings that have contributed to our understanding of the mechanisms underlying brain development, neural plasticity and cognitive processes, and neural degeneration

Distinct Acute Zones for Visual Stimuli in Different Visual Tasks in Drosophila

Distinct Acute Zones for Visual Stimuli in Different Visual Tasks in Drosophil

The location effect of a black bar on the fixation performance of WTB flies.

<p>(A) The MED had a significant location dependence (<i>p</i> = 1.4509×10⁻⁹). The best location for black bar fixation was 10° below the flies. (B) The fixation performance at 2 locations (−10°; 30°) was selected to show more details of the dwelling time in the whole panorama. Note the sharp peak in the dwelling time in the central quadrant (−45∼+45° area around the bar in the panorama) at the location θ = −10°; the distribution of dwelling time was quite even at the location θ = 30°. (C) Obvious location dependence in the rDT_abs between the central quadrant and the rest area (<i>p</i> = 1.1145×10⁻⁸). (D) There was no obvious location dependence in the rDFS between the central quadrant and the rest area (<i>p</i> = 0.7273). These differences were quite small. The data in (A&B) are given as the mean±SEM; the data in (C&D) are shown by box plot; the red crosses represent outliers; the <i>p</i> values were calculated by the Kruskal-Wallis test; the y-axes of certain charts are truncated for compactness.</p

A lower location was preferred for COGs memorization against a white background.

<p>(A) A standard 24 min visual operant conditioning experiment to memorize COGs with a white background. Top panel, patterns used in this experiment (ΔCOGs = 20°). Middle panel, PIs of flies when the patterns were 20° above them. The test PIs of the flies were not different from zero (<i>p</i> = 0.5186) in this condition. Bottom panel, PIs of flies when the patterns were 20° below them. Flies showed a tendency to avoid dangerous patterns in the test session for this condition. The test PIs at the location θ = −20° were higher than those at the location θ = +20°, although the difference was not significant (<i>p</i> = 0.0927). These PIs were not significantly different from zero (<i>p</i> = 0.084). (B–D) There was no significant difference in the other 3 indices between the 2 locations. (B) Discrimination value, <i>p</i> = 0.1563. (C) The rDT_abs between safe quadrants and dangerous quadrants, <i>p</i> = 0.7667. (D) The rDFS between safe quadrants and dangerous quadrants, <i>p</i> = 0.8691. The data in (A) are given as the mean±SEM; the data in (B–D) are shown by box plot; the red cross represents outlier; significant differences between PIs and zero were judged by the signed-rank test; significant differences between 2 groups were judged by the rank-sum test.</p

Distinct Acute Zones for Visual Stimuli in Different Visual Tasks in <i>Drosophila</i>

<div><p>The fruit fly <i>Drosophila melanogaster</i> has a sophisticated visual system and exhibits complex visual behaviors. Visual responses, vision processing and higher cognitive processes in <i>Drosophila</i> have been studied extensively. However, little is known about whether the retinal location of visual stimuli can affect fruit fly performance in various visual tasks. We tested the response of wild-type Berlin flies to visual stimuli at several vertical locations. Three paradigms were used in our study: visual operant conditioning, visual object fixation and optomotor response. We observed an acute zone for visual feature memorization in the upper visual field when visual patterns were presented with a black background. However, when a white background was used, the acute zone was in the lower visual field. Similar to visual feature memorization, the best locations for visual object fixation and optomotor response to a single moving stripe were in the lower visual field with a white background and the upper visual field with a black background. The preferred location for the optomotor response to moving gratings was around the equator of the visual field. Our results suggest that different visual processing pathways are involved in different visual tasks and that there is a certain degree of overlap between the pathways for visual feature memorization, visual object fixation and optomotor response.</p></div

Effects of grating location on the optomotor responses of WTB flies.

<p>(A) Schematic of the experimental setup for testing the optomotor response of <i>Drosophila</i>. Θ, elevation angle between the center of the grating and the tethered fly. (B) Periodic yaw torque responses to gratings at different vertical locations. Yaw torques were normalized. The black curve is the mean of the yaw torques (n = 19); the gray shadow is the standard deviation of the yaw torques. From top to bottom, the vertical location Θ of the gratings changed from +40° to −40°; the red curve in the middle panel was the sine curve used as the ideal response model. (C&D) The acute zone for optomotor response is near the equator of the visual field. (C) Box plots of the amplitudes of the yaw torques at all 9 vertical locations. There was no significant location dependence (<i>p</i> = 0.3887). (D) Box plots of the amplitudes of the 0.25 Hz component of the yaw torques, which were calculated by fast-Fourier transform. There was no significant location dependence (<i>p</i> = 0.3418). The <i>p</i> values were calculated by the Kruskal-Wallis test; the red crosses represent outliers; the y-axes of certain charts are truncated for compactness.</p