NeuroTABLE 1: Hermaphrodite sensory receptors.

Male has many additional sensors (Sulston et al., 1980; Liu and Sternberg, 1995; Hall et al., 2006). Each entry includes cell name (cell number, position in the body). Some neurons are represented under several categories according to current information, but additional sensory modalities may yet be found for any of these sensors. Sensory neurons in C. elegans perform specific functions. Sixty of these contain modified, nonmotile cilia; 32 of these ciliated neurons are chemosensory and 26 are exposed to the environment through several sensilla (Bargmann and Mori, 1997; Mori, 1999; Melkman and Sengupta, 2004). Six unexposed, ciliated, sensillar neurons sense odorants and two others are involved in thermotaxis. Some of the remaining ciliated neurons as well as a subset of nonciliated neurons possess mechanosensory and proprioceptive functions.
¹ASH neurons mediate avoidance from noxious odors (octanol), hyperosmolarity, mechanical stimuli, heavy metals, bitter substances (quinine), and low pH (Kahn-Kirby and Bargmann, 2006).
²May be sensing food within pharyngeal lumen.
³Contain striated rootlet (only in males for PHC).
⁴Sense surface texture (e.g., roundness of bacteria, sephadex beads); food-mediated slowing response (Sawin et al., 2000).
⁵Dauer formation (entry or exit) (Bargmann and Horvitz, 1991).
⁶Interaction between food detection and egg-laying circuit.
⁷Avoidance (copper, cadmium). ASE has a minor role (Sambongi et al., 1999).
⁸ Avoidance (SDS) by ASH neurons. Phasmid neurons antagonize this avoidance behavior (Hilliard et al., 2002).
⁹Positive chemotaxis to water-soluble attractants (ASE, ASG, ASK, ASI: lysine; ASE, ASG, ADF, ASI: cAMP, biotin, Na+, Cl–). ASJ, ADF, ASI, ASG, ASK have minor roles (Bargmann, 2006; Bergamasco and Bazzicalupo, 2006).
¹⁰Avoidance of volatile repellents (octanol, 2-nonanone). ADL has a minor role.
¹¹Positive chemotaxis to volatile attractants (AWC: benzaldehyde, butanone, thiazole, isoamyl alcohol; AWA: diacetyl, pyrazine).
¹²Touch receptor neurons that function in avoidance response to gentle body touch. Activation of this circuit also resets defecation cycle and suppresses pharyngeal pumping, foraging head movement, and egg-laying. The sensory mechanotransduction channel is formed by MEC-4/MEC-10/MEC-6.
¹³Detect nose touch. IL1 and OLQ; head withdrawal response to dorsal or ventral nose touch. ASH, FLP, and OLQ; reversal of movement in response to head-on collision.
¹⁴Detect harsh body touch, e.g., with a platinum wire (O’Hagan and Chalfie, 2006).
¹⁵Motor neuron stretch receptors. May be sensing body posture and tension generated along the body by muscles (White et al., 1986; O’Hagan and Chalfie, 2006). The sensory mechanotransduction channel is hypothesized to be formed by UNC-8/DEL-1/MEC-6. The signal may directly translate into localized changes in motor activity.
¹⁶Long, thin tailspike is thought to be a large sensory organ without the sheath and socket cells that characterize normal sensilla. May be sensing flexion of tail tip (Bird and Bird, 1991).
¹⁷Putative mechanosensory.
¹⁸Muscle may also function in stretch sensation through its own stretch receptor complexes that contain UNC-105 (Jospin et al., 2004).
¹⁹Avoidance (quinine). t Involved in navigation of movement (control of omega turns, reversals, sinusoids, etc.) through AIB and AIY interneurons (Gray et al., 2005).
²⁰Control of life span (Alcedo and Kenyon, 2004; Bargmann, 2006).
²¹Involved in aggregation behavior (Rogers et al., 2006).
²²Contains unexposed ciliated endings in the lips. Putative harsh touch sensor in the head.
²³AFD is the major thermosensor while AWC is supportive (Mori and Ohshima, 1995; Kuhara et al, 2008; Ohnishi et al, 2011).

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