RT Journal Article
SR Electronic
T1 Activity-dependent structural dynamics of insect sensory fibers
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 6946
OP 6955
DO 10.1523/JNEUROSCI.14-11-06946.1994
VO 14
IS 11
A1 HJ Pfluger
A1 S Hurdelbrink
A1 A Czjzek
A1 M Burrows
YR 1994
UL http://www.jneurosci.org/content/14/11/6946.abstract
AB This report analyses the role of neuronal activity in shaping the axonal arborizations of sensory neurons from individually identified filiform hairs on the prosternum of locusts (Locusta migratoria), and their connections with a pair of identified interneurons (A4I1). Afferents from lateral filiform hairs terminate in the ipsilateral neuropil and connect only with the ipsilateral interneuron in all instars. Afferents from ventral filiform hairs possesses ipsi- and contralateral branches and make monosynaptic connections with both interneurons in first instars. In later instars, the ipsilateral branch, and its synaptic connection to the ipsilateral interneuron, is gradually reduced until it is lost in the adult, whereas the contralateral branch, and its synaptic connection with the contralateral interneuron, is strengthened. Therefore, after an initial overgrowth of fibers and synapses, segregation of fibers occurs involving the loss of synaptic connections. This loss of branches and synapses was prevented by immobilizing a subpopulation of ventral and lateral filiform hairs, or each group independently, so that their normal activity was blocked. In such treated animals afferents from ventral filiform hairs retain their ipsi- and contralateral branches until adulthood. We therefore conclude that afferent activity plays an important role in shaping the final structure and connectivity of afferents, as neither the peripheral position of the receptors nor the hormonal environment was changed by these manipulations.