RT Journal Article
SR Electronic
T1 BDNF Signaling during Learning Is Regionally Differentiated within Hippocampus
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 15097
OP 15101
DO 10.1523/JNEUROSCI.3549-10.2010
VO 30
IS 45
A1 Lulu Y. Chen
A1 Christopher S. Rex
A1 Danielle T. Pham
A1 Gary Lynch
A1 Christine M. Gall
YR 2010
UL http://www.jneurosci.org/content/30/45/15097.abstract
AB Learning-induced neurotrophic signaling at synapses is widely held to be critical for neuronal viability in adult brain. A previous study provided evidence that unsupervised learning of a novel environment is accompanied by activation of the TrkB receptor for brain-derived neurotrophic factor (BDNF) in hippocampal field CA1b of adult rats. Here we report that this effect is regionally differentiated, in accord with “engram” type memory encoding. A 30 min exposure to a novel, complex environment caused a marked, NMDA receptor-dependent increase in postsynaptic densities associated with activated (phosphorylated) Trk receptors in rostral hippocampus. Increases were pronounced in field CA3a, moderate in the dentate gyrus, and absent in field CA1a. Synapses with Trk activation were significantly larger than their neighbors. Surprisingly, unsupervised learning had no effect on Trk phosphorylation in more temporal sections of hippocampus. It thus appears that commonplace forms of learning interact with regional predispositions to produce spatially differentiated effects on BDNF signaling.