A study in fruit-fly larvae found that two individually identified dopaminergic neurons, or DANs, showed different conditions for retrieving an aversive memory. DAN-d1 showed aversive associative memory when the larvae were tested under blue light, but not when they were tested in darkness. DAN-f1 memory was retrieved only when DAN-f1 was also active during testing. Together, the two results show that the tested neurons did not share the same retrieval condition.
The question behind the test
The experiment addressed a larger question: whether the same individual central-brain dopaminergic neurons in Drosophila larvae can support both memory-related functions and movement. The d1 and f1 tests speak specifically to memory retrieval, while the wider question asks whether individual neurons can also be relevant to movement. That made the comparison broader than a single memory test. It asked whether a neuron examined for one behavioral role could be considered alongside another outcome in the same larval system.
The animals were third-instar, feeding-stage Drosophila melanogaster larvae, aged four to five days after egg laying. This defines the setting for the result: it is evidence from a particular larval stage and species. The findings therefore belong to the tested Drosophila larval system, rather than serving as a direct result about other animals.
A targeted experiment
To test the neurons, the researchers crossed ChR2-XXL or CsChrimson effectors with broad or split-Gal4 drivers for dopaminergic neurons. Those crosses produced transgenic larvae for optogenetic tests. The design supplied different neuron-targeting conditions for the memory experiments, including the blue-light and darkness tests used to examine DAN-d1 and DAN-f1. The result should therefore be read as a finding from these defined optogenetic conditions and the neurons selected for them.
The difference appeared at retrieval
The important distinction came at retrieval. DAN-d1 showed the aversive memory during blue-light testing but not in darkness. DAN-f1, by contrast, showed memory retrieval only when DAN-f1 was also active during the test. The study thus did not report one uniform retrieval pattern across the two cells. It reported one condition for DAN-d1 and another for DAN-f1, making the identity of the tested neuron part of the result.
A result with a narrow scope
Behavioral values were analyzed with two-tailed non-parametric tests. The reported toolkit included Kruskal-Wallis tests for multiple groups, Mann-Whitney U tests for pairwise comparisons, Wilcoxon signed-rank tests for comparisons with zero, and Bonferroni-Holm procedures for multiple comparisons. In plain terms, the study used different formal comparisons for different types of behavioral data. Those analyses help organize the reported differences, but they do not change the fact that the experiment involved selected neurons in a defined larval model.
The broader takeaway is not that every dopaminergic neuron has the same role. It is that the study tested whether individual central-brain neurons could support memory-related functions and movement, then found different retrieval conditions for DAN-d1 and DAN-f1. In the reported conditions, memory retrieval was tied to both which neuron was tested and whether that neuron was active during testing. The evidence connects the question of memory with the question of movement, while leaving the answer specific to the larval experiments described here.
Paper data and sources
Original title: Individual dopaminergic neurons induce unique, yet overlapping combinations of behavioural modulations, including safety learning, memory retrieval, and acute locomotion
Authors: Toshima N, Behrad A, Behnke F et al.
Journal/Repository: eLife
Status: Peer-reviewed
First online: 2026-10-19
DOI: Not available
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