Microglia, Learning, Memory & Autism

Does your child have learning issues?

Do they seem to forget things that they knew well one day?

Are you concerned about their brain health?

Understanding the microglia which are brain cells will help you answer those questions.

Welcome to my series on microglia. I’ll teach you what microglia are, what they do, and how things change related to autism. In this blog post, we’re going to focus on plasticity, learning, and memory all related to microglia and autism. Learn about the microglia so that you have up-to-date information. Let me get my slides so you can see what I’m talking about.

I just want to give a quick warning that this is an advanced topic. The information is useful after beginning steps have been taken in the autism journey, there are many beginner steps to take. If you haven’t done beginner steps, then focus on those. You certainly can read this post and learn about what might be relevant in the future. But by doing advanced steps too early, it really doesn’t make the impact that many people think it will. Really take those beginner steps first. If you’ve taken them, then definitely advanced steps are things to do.

Microglia

Microglia exist mainly in a resting state and constantly monitor their microenvironment and survey neuronal and synaptic activity. Microglia are in the brain. And if you want to learn some of the basics about microglia and autism, then certainly check out my microglia and autism video. Microglia are highly sensitive to environmental cues. They can detect, in a way, inflammation, regardless if it’s in the brain or elsewhere in the body. And that’s really important to remember that our bodies are connected. If there’s inflammation in a particular part of the body, the microglia might be able to be sensing that even though they’re located all the way in the brain.

You can also watch my microglia and microbiota autism video to learn more because microbiota definitely has an influence on microglia.

Brain Development

Synaptic pruning is necessary for precise neuronal circuitry during development (when we’re a child as well as when we’re adults). Microglia frequently interact with neurons. So the cells in our body interact with each other. Microglia interact with neurons. There’s communication going back and forth. There are these signaling molecules. That’s what we mean by communication. They communicate through chemistry. One is called brain-derived neurotrophic factor and there certainly are others. Microglia are able to communicate with the neurons to mediate their neuronal function. Microglia aren’t just randomly doing certain things to neurons. There’s communication there and BDNF is one molecule that is used as a signaler. Microglia play an important role in the identification and removal of unnecessary neural connections. You can think of it as a clean-up process. Autophagy is the scientific-technical term and autophagy is this clean-up process. Synaptic pruning is the process of synapse removal that occurs during childhood and all throughout adulthood. The signals that microglia and neurons use to regulate this synaptic pruning are not entirely known.

What happens is the neurons give off some type of signal that says, okay, this neuron needs to go, and then the microglia pick up on that signal and they’re the ones that actually clean it up and process it out through the body. And that process is autophagy. However, it’s important to determine the particular indications or instructive signals that recruit microglia to certain synapses. Right? How does that happen? How does the Microglia clean up one neuron as opposed to the one sitting next to it? And microglia need to get it right. Synapse elimination is an activity-dependent process and this “tagging” allows for elimination specificity by microglia. The microglia really needs to be very specific. This is not a process that has a lot of room for error.

As a result, active synapses are selectively maintained, while non-essential synapses are eliminated with the microglia. Phosphatidylserine is used by some cells to regulate this process. Now, if your child has neuro-inflammation, not every child or person with autism has neuro-inflammation. But if your child has neuro-inflammation and you know that based upon different tests that have been done, you could certainly ask your doctor “Would Phosphatidylserine be beneficial for us?” That would be a very good specific question that can really help with the dialogue in the partnership building between you and the doctor.

Microglia and Autism

Here’s a quote directly from a research article and it says

“Microglia activation or dysfunction is associated with the progression of cognitive deficits in normal aging, neurodegenerative and neurological diseases such as Alzheimer’s, traumatic brain injury and HIV associated neurocognitive disorder and mental disorders, including autism, stress, and depression.”

I will say I don’t like autism being classified as a mental disorder because even if you’re just basing that categorization on microglia, we know microglia are really sensitive to the environment. So to just put it in the small box of mental disorders I think is quite limiting and quite harmful and also not really fully descriptive of the entire situation on a molecular level.

However, regardless of all that, the science here says microglia activation or dysfunction is associated with autism. So this is cutting-edge science. I’m sure many regular practitioners are not aware of this. This is information that is on the cutting edge.

Have studies been done on Autism about the Microglia?

Yes. Post-mortum human studies showed elevated microglia and a particular mouse model that utilized gene knockouts showed dysfunction in microglia Synapse pruning immature and impaired synaptic connectivity resulting in autistic-like behavior. So studies have been done in humans as well as in an animal model here in mice.

Altogether, the impaired autophagy and remember, that is just the cleanout process in microglia disrupts the neuronal connectivity and causes autistic-like behaviors. And it’s so unfortunate that we don’t have some type of lab test for autism because we have to wait so long until behaviors are actually occurring. The chemistry is happening so much earlier before we actually see autistic-like behaviors. It would be absolutely wonderful to get a better understanding of chemistry so that a lab test can be done. And again, not every person with autism has neuro-inflammation. So this is not something that is universal to everyone with autism. That’s how autism gets complex.

Conclusion

“Due to the importance of microglia in synaptic pruning and symptoms, plasticity and learning and memory, it is not surprising that abnormal microglia activation and the resulting neuro-inflammation have been shown to be a main causal mechanism of the cognitive deficits associated with normal aging and different diseases including AD, TBI, HAND, and mental disorders such as autism, depression, and PTSD.”

This is a direct quote from a scientific publication. If your child is struggling with neuro-inflammation, if something showed up on the MRI or a variety of other different ways of measuring neuro-inflammation, then please work with a well-informed healthcare practitioner that can help guide you through this process. Again, microglia activation – this is all cutting-edge research, so you really want to work with a knowledgeable person.

Reference

And here is the reference in case you want to read the paper yourself.

  1. Neural Regen Res. 2022 Apr; 17(4):705-716.