What is the function of the dendritic spine?

What is the function of the dendritic spine?

A dendritic spine (or spine) is a small membranous protrusion from a neuron’s dendrite that typically receives input from a single axon at the synapse. Dendritic spines serve as a storage site for synaptic strength and help transmit electrical signals to the neuron’s cell body.

What is an important advantage of dendritic spines?

These observations suggest that one function of dendritic spines is to standardize local EPSP properties throughout the dendritic tree, thereby allowing neurons to use similar voltage-sensitive postsynaptic mechanisms at all dendritic locations.

What do different shaped dendritic spines mean?

Changes in size, shape, and density of synaptic spines are associated with learning and memory, and observed after drug abuse in a variety of neurodegenerative, neurodevelopmental, and psychiatric disorders.

Does dendritic spines affect memory?

Importantly, dendritic spines are where some of the key processes that facilitate learning and memory take place (4,5). (A) Repeated long-term potentiation causes spines to become larger and heartier. This process is thought to be important in the creation of memories.

Why are dendritic spines so important for the normal functioning of the nervous system?

6.1 Introduction. Dendritic spines are the principal site for excitatory transmission in the brain. First, dendritic spines exhibit important activity-dependent forms of plasticity that affect both their strength and structural organization, contributing in this way to information processing.

What does growing new dendritic spines do?

Growth of new dendritic spines contributes to experience-dependent circuit plasticity in the cerebral cortex. Yet the signaling mechanisms leading to new spine outgrowth remain poorly defined. Increasing evidence supports that the proteasome is an important mediator of activity-dependent neuronal signaling.

Are dendritic spines postsynaptic?

Introduction. Dendritic spines are the postsynaptic sites of most excitatory synapses, found along the dendrites of neurons. Ramón y Cajal in 1888 was the first to observe these small protrusions 1.0–1.5 μm in length in Golgi stainings (Cajal, 1888). He proposed them to be points of contact between neurons.

Are there voltage gated sodium channels in dendrites?

Voltage-gated sodium channels were found throughout GP dendrites and furthermore exhibited a specific clustering at sites of excitatory synaptic inputs.

Do dendrites change shape?

Increased neural activity and the establishment of long-term potentiation at dendritic spines change the sizes, shape, and conduction. Dendritic branching can be extensive and in some cases is sufficient to receive as many as 100,000 inputs to a single neuron.

What is dendritic spine turnover?

At the cellular level, the best-established morphological correlate of synaptic plasticity is the turnover of dendritic spines. 1-2 micrometers in size) that comprise the post-synaptic part of the cortical synapses (primarily glutamatergic). …

What causes dendritic spine abnormalities in Fragile-X syndrome?

While it may be that the dendritic spine abnormalities seen in fragile-X syndrome are due directly to the absence of FMRP, particularly at synapses, it must be kept in mind that altered afferent input can also lead to abnormal neuronal structure.

What is the pathophysiology of Fragile X brain?

Similar to ‘pure’ autism, the fragile X brain is characterized by elevated spine density, which is thought to result from pruning deficits, with elongated, tortuous spine morphologies 11, indicative of altered function. Together, these findings underscore the profound spine pathology exhibited by ASDs and comorbid disorders.

What is fragile-X syndrome (FXS)?

Fragile-X syndrome is a common form of mental retardation affecting nearly one in 2000 males and roughly half as many females ( Brown, 1996 ). It is caused by the insertion of extra DNA into the X chromosome that silences the gene encoding FMRP.

What is the role of synaptic plasticity in Fragile-X syndrome?

In investigating molecular mechanisms of synaptic plasticity, it was discovered that the fragile-X mental retardation protein (FMRP), the protein absent in those afflicted with fragile-X syndrome, is synthesized in synaptoneurosome preparations in response to neurotransmitter stimulation ( Weiler et al., 1997 ).