Actin dynamics in dendritic spines: A form of regulated plasticity at excitatory synapses

Abstract

Dendritic spines form the postsynaptic element at most excitatory synapses in the brain. The spine cytoskeleton consists of actin filaments which, in time‐lapse recordings of living neurons expressing actin labeled with green fluorescent protein, can be seen to undergo rapid, dynamic changes. Because actin dynamics are associated with changes in cell shape, these cytoskeletal rearrangements may form a molecular basis for the morphological plasticity at brain synapses. The rapidity of these dynamic events in dendritic spines raises new questions. First, do the changes in actin cytoskeleton that are visible by light microscopy really correspond to changes in spine morphology, or do they represent changes in the relationship between actin and its many binding partners at postsynaptic sites? Second, how are these changes regulated by synaptic transmission? Third, to what extent do these changes occur in organized brain tissue? Answers to these questions are now beginning to emerge. Hippocampus 2000;10:555–560. © 2000 Wiley‐Liss, Inc.

Nogo receptor 1 regulates formation of lasting memories

“…First demonstrated as reactive sprouting in response to injury (1), structural synaptic plasticity in the adult brain is known to be a normal feature of gray matter (2,3) and may be how lasting memories are formed and maintained. Thus perturbations of sensory input, such as monocular deprivation, leave lasting traces in the cerebral cortex in the form of changes of synaptic contacts (4) and involves dynamic changes of the actin cytoskeleton (5).…”

Nogo receptor 1 regulates formation of lasting memories

“…First demonstrated as reactive sprouting in response to injury (1), structural synaptic plasticity in the adult brain is known to be a normal feature of gray matter (2,3) and may be how lasting memories are formed and maintained. Thus perturbations of sensory input, such as monocular deprivation, leave lasting traces in the cerebral cortex in the form of changes of synaptic contacts (4) and involves dynamic changes of the actin cytoskeleton (5).…”

Dynamics of learning‐induced spine redistribution along dendrites of pyramidal neurons in rats

“…First, training cessation may lead to relative lack of afferent activation causing stimulation of AMPA receptors to fall below a critical threshold. This lack of activation may eventually lead to spine pruning (McKinney et al, 1999;Matus et al, 2000). Interestingly, similarly to the present results, spine pruning due to axon loss also occurs within a few days, and is often followed by recovery of spine density (Fiala et al, 2002).…”

TRIM67 Implicates in Regulating the Homeostasis and Synaptic Development of Mitral Cells in the Olfactory Bulb

“…It is known that dendritic spines are one of the basic elements of synapses, and form complete synaptic connections with projected axons. The morphology and structure of dendritic spines are characterized by significant plasticity, and changes in dendritic spine morphology and structure often lead to alterations in synaptic function [35,36]. We found that the number of dendritic spines and synapses was reduced in the OB mitral cells of TRIM67 KO mice, which explained well the phenotype of diminished olfactory function in TRIM67-deficient mice.…”

Nogo receptor 1 regulates formation of lasting memories

“…First demonstrated as reactive sprouting in response to injury (1), structural synaptic plasticity in the adult brain is known to be a normal feature of gray matter (2,3) and may be how lasting memories are formed and maintained. Thus perturbations of sensory input, such as monocular deprivation, leave lasting traces in the cerebral cortex in the form of changes of synaptic contacts (4) and involves dynamic changes of the actin cytoskeleton (5).…”

Dynamics of learning‐induced spine redistribution along dendrites of pyramidal neurons in rats

“…First, training cessation may lead to relative lack of afferent activation causing stimulation of AMPA receptors to fall below a critical threshold. This lack of activation may eventually lead to spine pruning (McKinney et al, 1999;Matus et al, 2000). Interestingly, similarly to the present results, spine pruning due to axon loss also occurs within a few days, and is often followed by recovery of spine density (Fiala et al, 2002).…”

TRIM67 Implicates in Regulating the Homeostasis and Synaptic Development of Mitral Cells in the Olfactory Bulb

“…It is known that dendritic spines are one of the basic elements of synapses, and form complete synaptic connections with projected axons. The morphology and structure of dendritic spines are characterized by significant plasticity, and changes in dendritic spine morphology and structure often lead to alterations in synaptic function [35,36]. We found that the number of dendritic spines and synapses was reduced in the OB mitral cells of TRIM67 KO mice, which explained well the phenotype of diminished olfactory function in TRIM67-deficient mice.…”

Nogo receptor 1 regulates formation of lasting memories

“…First demonstrated as reactive sprouting in response to injury (1), structural synaptic plasticity in the adult brain is known to be a normal feature of gray matter (2,3) and may be how lasting memories are formed and maintained. Thus perturbations of sensory input, such as monocular deprivation, leave lasting traces in the cerebral cortex in the form of changes of synaptic contacts (4) and involves dynamic changes of the actin cytoskeleton (5).…”

Dynamics of learning‐induced spine redistribution along dendrites of pyramidal neurons in rats

“…First, training cessation may lead to relative lack of afferent activation causing stimulation of AMPA receptors to fall below a critical threshold. This lack of activation may eventually lead to spine pruning (McKinney et al, 1999;Matus et al, 2000). Interestingly, similarly to the present results, spine pruning due to axon loss also occurs within a few days, and is often followed by recovery of spine density (Fiala et al, 2002).…”

TRIM67 Implicates in Regulating the Homeostasis and Synaptic Development of Mitral Cells in the Olfactory Bulb

“…It is known that dendritic spines are one of the basic elements of synapses, and form complete synaptic connections with projected axons. The morphology and structure of dendritic spines are characterized by significant plasticity, and changes in dendritic spine morphology and structure often lead to alterations in synaptic function [35,36]. We found that the number of dendritic spines and synapses was reduced in the OB mitral cells of TRIM67 KO mice, which explained well the phenotype of diminished olfactory function in TRIM67-deficient mice.…”