MIT researchers have mapped the neural processes that allow C. elegans to navigate toward attractive odors or away from aversive ones. By tracking the electrical activity of over 100 neurons, the study revealed a specific sequence of neural activation, moving through stages of sensing, planning turns, reversing, and executing movement, that shows these organisms act with more intentionality than previously understood. The coordination of this entire sensorimotor arc is driven by the neuromodulator tyramine.
- specific neurons responsible for odor detection, turn planning, and motor execution.
- precise sequence of forward, reverse, and turning motions to navigate gradients.
- Role of the neuron RIM and the chemical tyramine in organizing sequential brain activity patterns.
- specific neurons responsible for odor detection, turn planning, and motor execution.
- precise sequence of forward, reverse, and turning motions to navigate gradients.
- Role of the neuron RIM and the chemical tyramine in organizing sequential brain activity patterns.
Thigmotaxis is a behavioral response to tactile stimuli, referring to an organism's movement in reaction to physical contact with surfaces or objects. It manifests as wall‑following or centrophobic behavior, where animals tend to stay near perimeters in enclosed spaces. The response is genetically grounded and observed across species, including rodents, insects, and fish. Positive thigmotaxis involves moving toward or staying in contact with a surface, often for shelter or safety, while negative thigmotaxis involves moving away from contact. Mechanisms involve mechanoreceptors such as tactile receptors in vertebrates or setae and antennae in invertebrates, which relay sensory input to the nervous system to trigger motor responses. Researchers use thigmotaxis as an assay for anxiety, stress, and navigation in animal models.
A study found that wild mice, and other animals like frogs, rats, and shrews, will voluntarily use a running wheel placed in their environment, suggesting play is an innate behavior, not just a result of captivity.
