In the isolated CNS, GABA activated (1) motor neurons in the cerebral ganglion responsible for protraction of the tentacles, or buccal cones (see also Norekian and Satterlie, 1993); (2) the feeding rhythm generator in the buccal ganglion; and (3) efferent input to statocyst
A statolith is contained within a sac called a statocyst
and aids the animal in gravity perception as it moves within the statocyst
Removing a whole beak from the buccal mass is much easier than extracting a statolith from the statocyst
. The beak, therefore, has been identified as an appropriate structure for studies of squid biology and ecology (Jackson et al., 1997; Groger et al., 2000; Martinez et al., 2002; Cherel and Hobson, 2005; Guerra et al., 2010).
Unidirectional response to angular acceleration recorded from the middle cristal nerve in the statocyst
of Octopus vulgaris.
located in antero-ventral region of pedal ganglia (sy).
Type-T photoreceptor cells send processes to the cerebral ganglion and terminate close to the end of statocyst
"I think of a statocyst
as an inside-out tennis ball," explained Dr Mooney.
In the present study, we surgically removed the apical complex, which houses the photoreceptor and the statocyst
(a balance organ), from the experimental comb jelly and compared its behavior in altered gravity to that of the control with the apical complex intact.
Then the shaking causes the snails statocyst
to release GABA, which binds to the neuron.
Both species use a statocyst
to detect changes in gravity (geotaxis) and a photoreceptor to detect changes in light (phototaxis).
Hands-on student activities include manipulation of a model statocyst
, the invertebrate equivalent to the human inner ear, and a chair-spinning experiment that demonstrates the disorienting effects of microgravity on the human body.
9A): Uniramous; peduncle three-segmented: 1st segment with one large ventral spine, one small proximal spine, 27 plumose setae and statocyst
; 2nd segment with 12 plumose setae; 3rd segment with seven plumose setae; outer ramus with eight aesthetascs; inner ramus unchanged.