Dopaminergic neurons linking threat processing to cardiac modulation and locomotor responses
Heartbeat and behavior are tightly coordinated during defensive states, yet the neuronal mechanisms linking threat processing to cardiac modulation—and the potential contribution of cardiac dynamics to behavioral output—remain poorly understood. Here, using simultaneous recordings of heartbeat and behavior in tethered Drosophila , we show that mechanical threat triggers locomotion together with…
A recent study has shed light on the intricate connection between the brain's threat processing mechanism and the body's cardiac and locomotor responses in Drosophila (fruit flies). By simultaneously recording the heartbeat and behavior of tethered fruit flies, researchers discovered that mechanical threats trigger both rapid cardiac deceleration and increased locomotion.
The study identified two pairs of dopaminergic neurons, designated as DA-WED neurons, which are responsible for mediating this cardiac response. When these neurons were silenced, threat-induced cardiac deceleration was significantly reduced. Conversely, when these neurons were optogenetically activated, cardiac deceleration occurred even in the absence of a threat stimulus.
To further investigate the role of these dopaminergic neurons, the researchers used two-photon calcium imaging to observe the activation of DA-WED neurons by mechanical threat. They also manipulated the activity of these neurons bidirectionally, demonstrating that their modulation could influence threat-induced locomotion.
The findings highlight the link between cardiac dynamics and behavior, suggesting that direct optogenetic manipulation of cardiomyocytes can replicate threat-evoked cardiac deceleration and increase locomotion. Overall, these results provide valuable insights into a dopaminergic descending pathway that connects threat processing to cardiac modulation, suggesting that cardiac dynamics may play a role in shaping defensive behavior in fruit flies.
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