Effect of auditory deafferentation on the synaptic connectivity of a pair of identified interneurons in adult field crickets.
In adult crickets, Teleogryllus oceanicus, unilateral auditory deafferentation causes the medial dendrites of an afferent-deprived, identified auditory interneuron (Int-1) in the prothoracic ganglion to sprout and form new functional connections in the contralateral auditory neuropil. The establishment of these new functional connections by the deafferented Int-1, however, does not appear to affect the physiological responses of Int-1's homolog on the intact side of the prothoracic ganglion which also innervates this auditory neuropil. Thus it appears that the sprouting dendrites of the deafferented Int-1 are not functionally competing with those of the intact Int-1 for synaptic connections in the remaining auditory neuropil following unilateral deafferentation in adult crickets. Moreover, we demonstrate that auditory function is restored to the afferent-deprived Int-1 within 4-6 days following deafferentation, when few branches of Int-1's medial dendrites can be seen to have sprouted. The strength of the physiological responses and extent of dendritic sprouting in the deafferented Int-1 progressively increase with time following deafferentation. By 28 days following deafferentation, most of the normal physiological responses of Int-1 to auditory stimuli have been restored in the deafferented Int-1, and the medial dendrites of the deafferented Int-1 have clearly sprouted and grown across into the contralateral auditory afferent field. The strength of the physiological responses of the deafferented Int-1 to auditory stimuli and extent of dendritic sprouting in the deafferented Int-1 are greater in crickets deafferented as juveniles than as adults. Thus, neuronal plasticity persists in Int-1 following sensory deprivation from the earliest juvenile stages through adulthood.
Brodfuehrer
P D
PD
Section of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853.
Hoy
R R
RR
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology* / Q000648:ultrastructure; D003712:Dendrites / Q000502:physiology; D005260:Female; D005456:Fluorescent Dyes; D006135:Gryllidae / Q000502:physiology*; D007395:Interneurons / Q000502:physiology* / Q000648:ultrastructure; D007546:Isoquinolines; D008297:Male; D009473:Neuronal Plasticity; D009987:Orthoptera / Q000502:physiology*; D013569:Synapses / Q000502:physiology
D005456:Fluorescent Dyes; D007546:Isoquinolines; C017475:lucifer yellow