Reading neuromodulation online: fast-scan cyclic voltammetry in brains of social insects

The vast repertoire of collective behaviours seen in social insects lacks the quantification of the underlying neuromodulation that leads to interindividual variability. The project Reading neuromodulation online: fast-scan cyclic voltammetry in brains of social insects therefore aims to collect information about the internal state of an animal in real-time during the performance of the behaviour.

Neuromodulators can alter and adjust information processing in the brain. This can massively change neural circuit dynamics and sensory processing. How and where such modulators act in the brain remains largely unknown in any species. “We are particularly interested in how social information is processed for decision-making,” says project leader Christoph Kleineidam. For measuring neuromodulation in real-time in the brains of vertebrates and insects, the team, including the physicist Moritz Schlötter, is developing a fast-scan cyclic voltammetry (FSCV) method.

So far, the team has studied context-dependent neuromodulation for individual decisions in insects, resulting in a division of labour and social organization. “We have established our FSCV measuring system for liquid samples and the resolution to quantify and to calibrate the electrode is already very good,” says neurobiologist Christoph Kleineidam. “Observing real-time changes of neuromodulation in a behaviourally responding insect and being able to connect it to collective behaviour while also partly solving the ‘hen-egg’ paradox of post-mortem analyses is highly exciting,” emphasizes Divya Ramesh, the team’s mass spectrometry specialist.

Kleineidam is convinced that FSCV is “a very powerful tool” for studying the dynamics of neuromodulation. “We can now tackle the challenge of taking measurements in tiny brains of behaving insects, for example, ants, running on the treadmill.” Furthermore, the plan is to extend their FSCV research and to study the rewarding nature of social signals and other reinforcers, such as the underlying mechanisms of neural plasticity in juvenile zebrafish, together with Armin Bahl.