Functional organization of crayfish abdominal ganglia. III. Swimmeret motor neurons.
J Comp Neurol
; 419(2): 233-43, 2000 Apr 03.
Article
en En
| MEDLINE
| ID: mdl-10723001
Swimmerets are limbs on several segments of the crayfish abdomen that are used for forward swimming and other behaviors. We present evidence that the functional modules demonstrated previously in physiological experiments are reflected in the morphological disposition of swimmeret motor neurons. The single nerve that innervates each swimmeret divides into two branches that separately contain the axons of power-stroke and return-stroke motor neurons. We used Co(++) or biocytin to backfill the entire pool of neurons that innervated a swimmeret, or functional subsets whose axons occurred in particular branches. Each filled cell body extended a single neurite that projected first to the Lateral Neuropil (LN), and there branched to form dendritic structures and its axon. All the motor neurons that innervated one swimmeret had cell bodies located in the ganglion from which their axons emerged, and the cell bodies of all but two of these neurons were located ipsilateral to their swimmeret. Counts of cell bodies filled from selected peripheral branches revealed about 35 power-stroke motor neurons and 35 return-stroke motor neurons. The cell bodies of these two types were segregated into different clusters within the ganglion, but both types sent their neurites into the ipsilateral LN and had their principle branches in this neuropil. We saw no significant differences in the numbers or distributions of these motor neurons in ganglia A2 through A5. These anatomical features are consistent with the physiological evidence that each swimmeret is controlled by its own neural module, which drives the alternating bursts of impulses in power-stroke and return-stroke motor neurons. We propose that the LN is the site of the synaptic circuit that generates this pattern.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ganglios de Invertebrados
/
Astacoidea
/
Abdomen
/
Extremidades
/
Neuronas Motoras
Límite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos