Summary: Astrocytes, star-shaped glial cells located in the brain, play a crucial role in learning and memory by regulating synaptic plasticity. Researchers have developed a biophysical model showing how astrocytes interact with nerve cells to facilitate rapid adaptation to new information.
The study reveals that astrocyte dysfunction can significantly impair cognitive processes. This research bridges the gap between theoretical models of plasticity and experimental results, offering new therapeutic possibilities targeting astrocytes to improve cognitive functions.
Highlights:
- Astrocytes regulate synaptic plasticity, which is essential for learning and memory.
- The biophysical model highlights the role of astrocytes in the regulation of the neurotransmitter D-serine.
- Astrocyte dysfunction can lead to significant cognitive impairment.
Source: University of Bonn
Star-shaped glial cells called astrocytes are much more than just support cells in the brain. They are actively involved in learning processes and interact with nerve cells. But what exactly do astrocytes do?
Researchers from the University Hospital Bonn (UKB) and the University of Bonn use a biophysical model to clarify how astrocytes interact with nerve cells to regulate rapid adaptation to new information.
The results of the study have now been published in Biology of communications.
In the brain, synaptic plasticity (the ability to change neuronal connections over time) is fundamental to learning and memory. Traditionally, science has focused on nerve cells and their synapses. The discovery of intracellular calcium2+ Signaling in astrocytes has led to the idea that astrocytes are more than just glue that holds the brain together and play a crucial role in this process.
“Astrocyte dysfunction can significantly impair our learning ability, thus highlighting their importance in cognitive processes. However, the exact functions of astrocytes have long remained a mystery,” says Professor Tatjana Tchumatchenko, co-senior author and head of the research group at the Institute for Experimental Research on Epileptology and Cognition at the UKB and member of the Transdisciplinary Research Area (TRA) “Modeling” at the University of Bonn.
Deciphering the complex dance of cellular interactions during learning
“Our job as computational neuroscientists is to use the language of mathematics to interpret experimental observations and build coherent models of the brain,” says Dr. Pietro Verzelli, co-senior author and postdoctoral researcher in Professor Tchumatchenko’s group.
In this case, the researchers developed a biophysical model of learning based on a biochemical feedback loop between astrocytes and neurons recently discovered by Dr. Kirsten Bohmbach, Professor Christian Henneberger and other researchers from DZNE and UKB.
The biophysical model explains the learning deficits observed in mice with impaired astrocytic regulation and highlights the crucial role that astrocytes play in rapid adaptation to new information. By regulating levels of the neurotransmitter D-serine, astrocytes may facilitate the brain’s ability to efficiently adapt and rewire its synaptic connections.
“Our mathematical framework not only explains the experimental observations, but also provides new testable predictions about the learning process,” says first author Lorenzo Squadrani, a PhD student in Tchumatchenko’s group.
This research bridges the gap between theoretical models of plasticity and experimental findings on neuron-glial cell interactions. It highlights astrocytic regulation as the physiological basis of dynamic synaptic adaptations, a central concept of synaptic plasticity.
“Our results contribute to a better understanding of the molecular and cellular mechanisms underlying learning and memory and offer new opportunities for therapeutic interventions targeting astrocytes to improve cognitive functions,” explains Professor Tchumatchenko.
About this news on learning and memory research
Author: Lorenzo Squadrani
Source: University of Bonn
Contact: Lorenzo Squadrani – University of Bonn
Picture: Image credited to Neuroscience News
Original research: Free access.
“Astrocytes enhance the plasticity response during reversal learning” by Lorenzo Squadrani et al. Biology of communications
Abstract
Astrocytes enhance plasticity response during reversal learning
Astrocytes play a key role in regulating synaptic strength and are thought to orchestrate synaptic plasticity and memory. However, how astrocytes and their neuroactive transmitters specifically control learning and memory remains an open question.
Recent experiments have highlighted an astrocyte-mediated feedback loop in CA1 pyramidal neurons, which is triggered by endocannabinoid release from active neurons and closed by astrocytic regulation of D-serine levels at dendrites. D-serine is a co-agonist of the NMDA receptor regulating the strength and direction of synaptic plasticity.
Astrocyte-mediated activity-dependent D-serine release is therefore a candidate for mediating synaptic long-term depression (LTD) and potentiation (LTP) during learning.
Here, we show that the mathematical description of this mechanism leads to a biophysical model of synaptic plasticity consistent with the phenomenological model known as the BCM model.
The resulting mathematical framework can explain the learning deficit observed in mice after disruption of the D-serine regulatory mechanism. It shows that D-serine enhances plasticity during reversal learning, ensuring rapid responses to changes in the external environment.
The model provides novel testable predictions about the learning process, improving our understanding of the functional role of neuron-glia interaction in learning.