以前的研究表明,，腦部結(jié)構(gòu)變化和感官體驗(yàn)之間有一個關(guān)聯(lián),，但類似變化是否也伴隨著學(xué)習(xí)卻并不確定。對正在學(xué)習(xí)成鳥鳴叫模式的斑胸草雀幼鳥的聲音控制核HVC（higher vocal centre）中的單個神經(jīng)元所做的高分辨率雙光子活體成像表明,，學(xué)習(xí)的確涉及這樣的變化,。在學(xué)習(xí)它們第一首歌的24小時內(nèi)，斑胸草雀幼鳥HVC中在正常情況下處于動態(tài)的樹狀脊會變得更大,、更穩(wěn)定,，突觸活動得到增強(qiáng)。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 463, 948-952 (18 February 2010) | doi:10.1038/nature08759
Rapid spine stabilization and synaptic enhancement at the onset of behavioural learning
Todd F. Roberts1, Katherine A. Tschida1, Marguerita E. Klein1 & Richard Mooney1
1 Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
Behavioural learning depends on the brain’s 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 brain1, 2, 3, 4, 5, 6, 7. 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 formation8, 9, 10, 11, 12. 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 period13, 14. Spine dynamics were measured in the forebrain nucleus HVC, the proximal site where auditory information merges with an explicit song motor representation15, 16, 17, 18, 19, immediately before and after juvenile finches first experienced tutor song20. 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.
