The Journal of Neuroscience, December 1, 2001, 21(23):9280-9290
Synaptic Reorganization Induced by Selective Photoablation of an
Identified Neuron
Adi
Mizrahi and
Frederic
Libersat
Zlotowski Center for Neuroscience and Department of Life Sciences,
Ben-Gurion University of the Negev, Beer-Sheva, 84105 Israel
The maintenance of synaptic strength and specificity in the CNS may
depend on interactions among postsynaptic dendrites. We examined the
effect of removing a neuron on synaptic organization. A single
identified postsynaptic neuron in the adult cercal system of the
cockroach was removed with photoablation. After a 30 d recovery
period, the synaptic connectivity and morphology of the intact
presynaptic and postsynaptic neurons were analyzed. The synaptic
connectivity was reorganized in a manner that was consistent with
functional plasticity.
To associate anatomical changes with this reorganization, we analyzed
the morphology of the presynaptic and postsynaptic neurons by
quantitative morphometry. Both presynaptic and intact postsynaptic neurons maintained a stable morphology after removal of a neighboring postsynaptic neuron. Using the Hausdorff Match method (HM) (Mizrahi et
al. 2000), we found that the spatial organization of the intact dendritic and axonal trees after ablation of a postsynaptic neuron remained stable. Thus, interactions with neighboring neurons were not
necessary for maintaining dendritic morphology in the adult nervous
system. However, adult central synapses were capable of adjusting to
maintain normal function.
Key words:
plasticity; photoablation; insect; dendrites; quantitative morphology; Hausdorff match
Copyright © 2001 Society for Neuroscience 0270-6474/01/21239280-11$05.00/0