Neurobiology of Synaptic Plasticity: Understanding Protein Synthesis and LTP

Short-lasting LTP (S-LTP or early LTP) and long-lasting LTP (L-LTP or late LTP) exhibit distinct characteristics in terms of induction mechanisms and underlying processes.

Gene expression involves a series of steps including transcription, translation, and post-translation, each serving a specific purpose in synthesizing proteins from the genetic information in DNA. The correct answer describes these processes accurately, while the incorrect answers provide misleading information to test comprehension of the topic.

The correct answer describes how synaptic activity triggers signaling molecules to induce new protein synthesis through the phosphorylation of transcription factors, specifically CREB. The incorrect answers provide inaccurate statements about the genomic signaling hypothesis.

CREB, or cAMP Response Element Binding protein, is a transcription factor that plays a crucial role in gene expression. It is activated by phosphorylation, not released in stress or anxiety response, involved in carbohydrate digestion, or regulating temperature in the skin.

The correct answer explains the essential role of CREB in L-LTP by highlighting the consequence of knocking out or inhibiting CREB. The incorrect answers are designed to mislead by providing inaccurate reasons regarding CREB's involvement in L-LTP, ultimately emphasizing the importance of CREB in this process.

The difference between synapse-to-nucleus and soma-to-nucleus signaling lies in the mode of transmission - synapse-to-nucleus signaling is mediated by synaptic activity, while soma-to-nucleus signaling is mediated by action potentials.

The correct answer involves a specific mechanism that should be referred to in a picture. The incorrect answers focus on other processes related to synaptic activity but do not directly address how the signal is sent to the nucleus for generating new plasticity products.

The correct answer describes the specific experimental setup where weak stimulation alone is insufficient to induce L-LTP, but the combination of weak stimulation and antidromic stimulation can trigger L-LTP. This supports the soma-to-nucleus hypothesis as it suggests the importance of integrating signals from different parts of the neuron. Additionally, this experiment can be considered an example of synaptic tagging because it shows how a specific synaptic event (weak stimulation) can 'tag' a synapse for future potentiation when combined with another event (antidromic stimulation).

The correct answer highlights that blocking protein synthesis using specific inhibitors like anisomycin or emetine can prevent the long-term potentiation (L-LTP) process, indicating the dependence of L-LTP on protein synthesis. The incorrect answers propose strategies that do not align with the known mechanisms of L-LTP.

The correct answer highlights the specific effect of actinomycin-D on LTP and its components, distinguishing the molecular requirements of E-LTP and L-LTP.

Local or dendritic protein synthesis refers to the translation of mRNAs that are already present near dendrites, rather than importing proteins from the cell body or synthesizing proteins in the axon.

The correct answer clarifies that there can indeed be distinct waves of protein synthesis during synaptic activity and how they contribute to the support of long-lasting LTP.

The Kang and Shuman experiment involved separating dendrites from the soma, stimulating Schaffer Collaterals, and still observing long-term potentiation (L-LTP). The key finding was that proteins were translated locally in the dendrite, highlighting the role of local protein synthesis in synaptic plasticity.

Bradshaw et al. conducted experiments by applying emetine to different parts of the neuron to observe its effects on dendritic protein synthesis, as outlined in the correct answer. The incorrect answers suggest alternative methods or approaches that were not employed in the study.

Ribosomes are responsible for protein synthesis within a cell, by translating messenger RNA (mRNA) into amino acid chains and ultimately proteins. They do not store genetic information, produce energy, or regulate cell growth and division.

The correct answer humorously dismisses the question and implies that understanding the methodology requires going to a specific place, Hopkins, as suggested by Bradshaw et al. The incorrect answers provide alternative scenarios that do not align with the actual methodology used in the study.

The correct answer implies that genomic signalling may not be necessary for L-LTP, as there could be another pathway involved in this process.

A strong high-frequency inducing stimulus can lead to two rounds of protein synthesis by activating proteins synthesis either locally at the dendrite using pre-existing mRNAs or triggering the synthesis later with newly-transcribed mRNAs from the nucleus.

The correct answer highlights that even without the transcription and translation processes, E-LTP can still be observed, indicating that existing proteins are being modified rather than newly synthesized.

Frey and Morris's synaptic tagging theory specifically focuses on the mechanism by which plasticity products can target and strengthen specific synapses.

The correct answer highlights the key concept of synaptic tagging theory, which involves the tagging of stimulated synapses to capture plasticity products.

Synaptic tagging theory suggests that specific synapses are 'tagged' by the initial strong stimulation, allowing them to capture plasticity-related proteins produced by genomic signalling.

The correct answer is a play on words indicating that the complex nature of synaptic tagging cannot be easily summarized by a simple methodology. Counting vesicles, measuring resistance, and observing neurotransmitter movement are all unrelated to studying synaptic tagging.

Only when there is temporal overlap of weak and strong stimuli at different synapses, can tagging occur. This mechanism is crucial in demonstrating how synaptic plasticity can be selectively induced based on specific conditions.

The correct answer 'yay! plasticity products!' refers to the fact that tagging proteins can lead to changes in the plasticity of neurons, which can impact local protein synthesis.

The Kelleher et al. experiment indicated a role for local protein synthesis in L-LTP based on the timing of when Anisomycin and Actinomycin-D blocked L-LTP, suggesting translation occurs before transcription.