Feedback signal from dendritic spine to the presynaptic neuron
In short:
Feedback signals from the postsynaptic dendritic spine to the presynaptic neuron (often called retrograde signaling) modulate presynaptic function — typically by regulating neurotransmitter release.
🧠 More precisely:
- After the postsynaptic neuron is activated (e.g., a spine depolarizes strongly), it can release molecules (like nitric oxide (NO), endocannabinoids, or neurotrophins like BDNF) that travel backward across the synapse.
- These molecules influence the presynaptic terminal, often by:
- Changing the probability of neurotransmitter release
- Modulating presynaptic plasticity mechanisms (e.g., long-term potentiation (LTP) or long-term depression (LTD))
- Adjusting the number or function of presynaptic vesicle release sites
⚡ Typical effects:
| Type of retrograde signal | Effect on presynaptic neuron |
|---|---|
| Nitric oxide (NO) | Increases neurotransmitter release (facilitates LTP) |
| Endocannabinoids | Decrease neurotransmitter release (induce LTD or inhibition) |
| BDNF (Brain-derived neurotrophic factor) | Strengthens presynaptic function or promotes growth |
🧩 Why is this important?
- It allows the postsynaptic neuron to actively regulate how much input it gets — not just passively receive.
- It fine-tunes synaptic strength during learning and memory.
- It provides a mechanism for local homeostasis, preventing runaway excitation or depression.
In short:
The feedback from the dendritic spine to the presynaptic neuron adjusts how much and how reliably neurotransmitter is released, depending on the postsynaptic neuron’s experience.
This creates a dynamic, two-way conversation — not just a one-way “fire and forget” mechanism.
Would you like me to also show you a quick schematic diagram to visualize this (presynaptic → postsynaptic → retrograde loop)? 🚀
see also
Tags: neurobiology science
Superlink: 051 ☣Neurobiology 050 🧠Neuroscience
Neuron Cell
Source
Created: 29-04-25 16:13