Abstract
Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB) has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far. Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice). We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra) in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi), the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment.
Highlights
To adapt to the surrounding environment, neural circuits rearrange by means of strengthening or weakening of their synapses
To determine whether changes in whisker inputs induce the activation of the transcription factor cAMP response element binding protein (CREB) in related somatosensory cortex, we quantified the expression of total CREB (CREB) and phosphorylated CREB in barrel cortex of young adult mice unilaterally deprived of vibrissae
The transcription factor CREB is an important player in activity-dependent neuronal plasticity, and several evidences reported the activation of CREB-mediated gene transcription in relation to experience-mediated plasticity within neocortical regions [26,27,28,29,30,31]
Summary
To adapt to the surrounding environment, neural circuits rearrange by means of strengthening or weakening of their synapses. Modifications in connectivity are supported by variations in number and size of dendritic spines, small protrusions along dendritic branches that host excitatory postsynaptic sites. Most spines formed in adult individuals are transient. In cortical regions of young adult rodents, the vast majority of newly formed spines shrink and disappear rapidly. A small minority (20%) of new spines persist over the 48 hours following their formation [1] and an even smaller proportion (3%) last up to 30 days [2, 3]. The occurrence of a synaptic contact, as identified by the presence of a postsynaptic density (PSD) opposed to an active synaptic zone [4], is a key determinant for the persistence of a spine
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have