TY - JOUR
T1 - Rapid spine stabilization and synaptic enhancement at the onset of behavioural learning
AU - Roberts, Todd F.
AU - Tschida, Katherine A.
AU - Klein, Marguerita E.
AU - Mooney, Richard
N1 - Funding Information:
Acknowledgements We thank M. Ehlers and L. Katz for access to the two-photon microscope and support in making lentivirus, K. Hamaguchi for peak detection and analysis software and D. Kloetzer for animal husbandry and laboratory support. D. Fitzpatrick, D. Purves and M. Ehlers provided comments on the manuscript. This work was supported by grants from the US National Science Foundation (NSF) and the US National Institutes of Health (NIH) (R.M.). T.F.R. was supported by a National Research Service Award from the NIH, K.A.T. was supported by a pre-doctoral award from the NSF and M.E.K. was supported by the Howard Hughes Medical Institute (Investigator, M. Ehlers).
PY - 2010/2/18
Y1 - 2010/2/18
N2 - Behavioural learning depends on the brains capacity to respond to instructive experience and is often enhanced during a juvenile sensitive period. How instructive experience acts on the juvenile brain to trigger behavioural learning remains unknown. In vitro studies show that forms of synaptic strengthening thought to underlie learning are accompanied by an increase in the stability, number and size of dendritic spines, which are the major sites of excitatory synaptic transmission in the vertebrate brain. In vivo imaging studies in sensory cortical regions reveal that these structural features can be affected by disrupting sensory experience and that spine turnover increases during sensitive periods for sensory map formation. These observations support two hypotheses: first, the increased capacity for behavioural learning during a sensitive period is associated with enhanced spine dynamics on sensorimotor neurons important for the learned behaviour; second, instructive experience rapidly stabilizes and strengthens these dynamic spines. Here we report a test of these hypotheses using two-photon in vivo imaging to measure spine dynamics in zebra finches, which learn to sing by imitating a tutor song during a juvenile sensitive period. Spine dynamics were measured in the forebrain nucleus HVC, the proximal site where auditory information merges with an explicit song motor representation, immediately before and after juvenile finches first experienced tutor song. Higher levels of spine turnover before tutoring correlated with a greater capacity for subsequent song imitation. In juveniles with high levels of spine turnover, hearing a tutor song led to the rapid (24-h) stabilization, accumulation and enlargement of dendritic spines in HVC. Moreover, in vivo intracellular recordings made immediately before and after the first day of tutoring revealed robust enhancement of synaptic activity in HVC. These findings suggest that behavioural learning results when instructive experience is able to rapidly stabilize and strengthen synapses on sensorimotor neurons important for the control of the learned behaviour.
AB - Behavioural learning depends on the brains capacity to respond to instructive experience and is often enhanced during a juvenile sensitive period. How instructive experience acts on the juvenile brain to trigger behavioural learning remains unknown. In vitro studies show that forms of synaptic strengthening thought to underlie learning are accompanied by an increase in the stability, number and size of dendritic spines, which are the major sites of excitatory synaptic transmission in the vertebrate brain. In vivo imaging studies in sensory cortical regions reveal that these structural features can be affected by disrupting sensory experience and that spine turnover increases during sensitive periods for sensory map formation. These observations support two hypotheses: first, the increased capacity for behavioural learning during a sensitive period is associated with enhanced spine dynamics on sensorimotor neurons important for the learned behaviour; second, instructive experience rapidly stabilizes and strengthens these dynamic spines. Here we report a test of these hypotheses using two-photon in vivo imaging to measure spine dynamics in zebra finches, which learn to sing by imitating a tutor song during a juvenile sensitive period. Spine dynamics were measured in the forebrain nucleus HVC, the proximal site where auditory information merges with an explicit song motor representation, immediately before and after juvenile finches first experienced tutor song. Higher levels of spine turnover before tutoring correlated with a greater capacity for subsequent song imitation. In juveniles with high levels of spine turnover, hearing a tutor song led to the rapid (24-h) stabilization, accumulation and enlargement of dendritic spines in HVC. Moreover, in vivo intracellular recordings made immediately before and after the first day of tutoring revealed robust enhancement of synaptic activity in HVC. These findings suggest that behavioural learning results when instructive experience is able to rapidly stabilize and strengthen synapses on sensorimotor neurons important for the control of the learned behaviour.
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U2 - 10.1038/nature08759
DO - 10.1038/nature08759
M3 - Article
C2 - 20164928
AN - SCOPUS:77249161242
SN - 0028-0836
VL - 463
SP - 948
EP - 952
JO - Nature
JF - Nature
IS - 7283
ER -