Balancing Structure and Function at Hippocampal Dendritic Spines (original) (raw)

Examining form and function of dendritic spines

Neural plasticity, 2012

The majority of fast excitatory synaptic transmission in the central nervous system takes place at protrusions along dendrites called spines. Dendritic spines are highly heterogeneous, both morphologically and functionally. Not surprisingly, there has been much speculation and debate on the relationship between spine structure and function. The advent of multi-photon laser-scanning microscopy has greatly improved our ability to investigate the dynamic interplay between spine form and function. Regulated structural changes occur at spines undergoing plasticity, offering a mechanism to account for the well-described correlation between spine size and synapse strength. In turn, spine structure can influence the degree of biochemical and perhaps electrical compartmentalization at individual synapses. Here, we review the relationship between dendritic spine morphology, features of spine compartmentalization and synaptic plasticity. We highlight emerging molecular mechanisms that link str...

Analysis of activity-dependent morphological plasticity of dendritic spines on hippocampal neurons

2003

Dendritic spines are the main sites of synaptic input onto excitatory neurons. As recent experiments showed that synaptic activity and especially long-term potentiation (LTP) can modify spine morphology and number, I studied the effect of long-term depression (LTD) on these parameters. I used a local stimulation approach in combination with intracellular recordings and 2-photon-laser-microscopy to spatially restrict the area of induced synaptic activity. My experiments indicate that spine morphology was stable over time with only very little changes occurring following the induction of LTD. The number of large, prominent spine changes was very low. Only small, stubby spines disappeared significantly after local LTD induction.

Structural and functional plasticity of astrocyte processes and dendritic spine interactions

The Journal of neuroscience : the official journal of the Society for Neuroscience, 2014

Experience-dependent plasticity of synaptic transmission, which represents the cellular basis of learning, is accompanied by morphological changes in dendritic spines. Astrocytic processes are intimately associated with synapses, structurally enwrapping and functionally interacting with dendritic spines and synaptic terminals by responding to neurotransmitters and by releasing gliotransmitters that regulate synaptic function. While studies on structural synaptic plasticity have focused on neuronal elements, the structural-functional plasticity of astrocyte-neuron relationships remains poorly known. Here we show that stimuli inducing hippocampal synaptic LTP enhance the motility of synapse-associated astrocytic processes. This motility increase is relatively rapid, starting <5 min after the stimulus, and reaching a maximum in 20-30 min (t(1/2) = 10.7 min). It depends on presynaptic activity and requires G-protein-mediated Ca(2+) elevations in astrocytes. The structural remodeling ...