Figure 6. Whole-Brain Neuronal Activity Imaging of Taste and Odor Responses.

(A) C. elegans were subjected to three chemosensory stimuli: a repulsive taste (160 mM NaCl) and two attractive odors (10⁻⁴ 2-butanone and 10⁻⁴ 2,3-pentanedione).

(B) Animals were immobilized inside a microfluidic chip. Stimuli were delivered in chemotaxis buffer. Each animal was imaged using a spinning disk confocal microscope with four excitation lasers. The NeuroPAL color map was imaged to identify all neurons. Thereafter, brainwide activity was recorded via the panneuronal calcium sensor GCaMP6s (Videos S3 and S4).

(C) Peak neuronal activity, before and during stimulus presentation, for 109 head neuron classes and subclasses.

(D–F) Neuronal activity traces for selected (D) sensory neurons, (E) interneurons, and (F) pharyngeal neurons that responded to stimuli. The 10-s stimulus delivery period is indicated by the vertical colored bar. Black activity traces represent all neurons combined into one representative group. Colored activity traces divide neurons into groups exhibiting known asymmetric responses: stereotyped asymmetries between the ASEL and ASER neuron pair and stochastic asymmetries between the AWC^ON and AWC^OFF neuron pair. Significant responses (p or q ≤ 0.05) are highlighted by bold borders. “Post,” significant post-stimulus response; ns, no significant response.

(F–I) Average pairwise correlations between 189 neurons in the 30 s following onset of (G) NaCl, (H) 2-butanone, and (I) 2,3-pentanedione. All three correlation maps are presented on the same axes, determined by clustering the full-time-course correlations. The set of correlated and anti-correlated neurons differs for each stimulus presentation.

(J and K) Comparison of functional activity to the connectome. We observe minimal correspondence between synapse counts and pairwise-functional-activity correlations for the (J) head and (K) tail.

See Table S6 for primary data. See also Figures S1 and S2.