Source: Harvard University
Summary: Researchers have shown how sensory neurons innervating the face detect environmental temperature, and how this information is passed on to the hindbrain of the fish, where it is processed to produce behavior.
Do you pause what you’re doing to put on a sweater because you feel chilly? Do you click the thermostat up a few degrees on a winter day? What about keeping a fan on your desk, or ducking into an air-conditioned room to beat the heat? If so, then you’ve used sensory information about your environment – the temperature – to alter your behavior. But exactly how the brain processes that information has largely remained a mystery. To shed light on that, a team of researchers from the Harvard University has shown how sensory neurons innervating the face detect environmental temperature, and how this information is passed on to the hindbrain of the fish, where it is processed to produce behavior. The study findings were published in the journal Neuron.
The temperature-sensing process in zebrafish begins in much the same way as it does for humans, with somatosensory neurons in the face. The neurons that detect temperature changes are cells in a structure called the trigeminal ganglion. In humans and zebrafish, this structure is located somewhere between the eyes and the ears. How the trigeminal ganglion encodes the temperature and what those cells do when the temperature changes can be seen. The temperature information is encoded in the firing rates of the neurons, on its own that’s not enough to alter the behavior of the fish. While more work is needed to understand fully how the neurons make that calculation
Research Assoc. Martin Haesemeyer said, “What we have from this study is a model that is pretty good at taking stimuli and predicting activity in the brain and behavior” and further added, “but it’s not a full-circuit implementation, so one place I want to go is to better understand how connectivity and cellular properties shape this computation, because calculating the direction of change allows the fish, or any other animal, to do a simple form of prediction.”
More Information: Martin Haesemeyer et al, “A Brain-wide Circuit Model of Heat-Evoked Swimming Behavior in Larval Zebrafish”, Neuron (2018). DOI: 10.1016/j.neuron.2018.04.013