Hippocampus Brain Injury: Functions, Side Effects, and Recovery

A brain injury that damages the hippocampus can cause problems with the formation of new memories. It can also cause people to forget older memories.

Today you will learn more about the function of the hippocampus and what to expect after an injury to it. We will also show you how you can help your hippocampus repair itself after injury.

Hippocampus Function

The hippocampus is a small, curved structure in the brain that is part of the limbic system. It is found deep in the temporal lobe below the cerebral cortex.

The limbic system supports a variety of functions including emotion, behavior, motivation, and memory. The hippocampus is the part of the limbic system involved in consolidating memories.

The hippocampus helps us process two kinds of memory:

• Declarative memories. These are related to facts and events. For example, memorizing a speech uses declarative memory. So does remembering what you did on the weekend.
• Spatial memories. These involve remembering pathways and routes. Examples include memorizing your way home from work or being able to visualize where everything in your room is from memory.

Your hippocampus also converts short-term memories into long-term memories.

Side Effects of Hippocampus Brain Injury

The hippocampus plays a vital role in encoding memory. Therefore, most of the side effects of hippocampal damage revolve around memory.

The following are two of the most common symptoms of hippocampus brain injury.

Anterograde Amnesia

Damage to the hippocampus can cause a person to lose their ability to create new memories. This fact was discovered in the 1950s by the famous case of Henry Molaison.

Henry, who suffered from severe epilepsy, underwent surgery to eliminate his seizures. During that surgery, much of Henry’s hippocampus was removed.

Because of the loss of his hippocampus, Henry would suffer from severe anterograde amnesia for the rest of his life. This meant that his ability to form new memories was impaired. He could remember facts and experiences from before his surgery, but nothing afterward.

Most TBI patients do not have near as extreme of symptoms as Henry did. They can still create some new memories, but they will have a much harder time doing so. For example, they might need to ask the same question multiple times because they cannot remember the answer.

Depression

While the hippocampus mainly controls declarative memory, damage to it can also cause symptoms of depression.

In patients with depression and PTSD, brain scans reveal that their hippocampal volume is actually reduced. Not only that, but their hippocampus appears to be smaller during periods of depression than during periods of remission.

To explain this fact, some psychologists developed a theory of depression known as the neurogenic hypothesis.

This hypothesis suggests that an impaired ability to produce new neurons contributes to depression. Interestingly, the hippocampus actually plays a role in the production of new neurons. Therefore, the fact that hippocampus activity decreases during depression supports this idea.

Next, we will discuss exactly how the hippocampus plays a role in neuron production, and how that helps with recovery for hippocampus brain injury patients.

The Hippocampus and Neurogenesis

One of the most fascinating things about the hippocampus is the role it plays in neurogenesis, which refers to the creation of new brain cells.

Many neuroscientists call the hippocampus the “regeneration center” of the brain. That is because it is one of the only areas in the adult brain that produces progenitor cells.

These cells can transform into different types of brain cells and migrate into brain regions that need replenishing.

Thus, the hippocampus can help brain injury patients heal their brain damage by replacing damaged nerve cells.

Neurogenesis provides a pathway for recovery after a brain injury.

Treating Hippocampus Brain Injury (Helping the Brain Repair Itself)

Because the hippocampus is so intimately involved in neurogenesis, activating that process may help reverse some of the damage.

You can help your hippocampus do this by boosting the production of brain-derived neurotrophic factor (BDNF) in your brain. BDNF acts as fuel to activate neurogenesis.

The following are a few effective ways to increase your BDNF levels and promote neurogenesis.

1. Exercise

Exercise, particularly aerobic exercise, is one of the best ways to boost BDNF levels and improve hippocampal function.

For example, a now-famous study compared the brains of two groups of mice. One group had access to a running wheel, and one did not. The researchers found that the mice that used the wheel had an abundance of new neurons in their hippocampus compared to the mice that did not exercise.

In addition, a study on humans found that moderate exercise increased the size of the hippocampus and led to enhanced memory.

Therefore, if you want to help reverse some of the damage done to your hippocampus, make sure you exercise regularly.

2. Stimulate Your Brain

Keeping your brain stimulated can also increase hippocampus function.

The more you stimulate your brain, the more neurons your brain will fire. This increases the production of BDNF and helps your brain create new neural pathways.

Some of the best ways to keep your brain stimulated include:

• Crossword puzzles
• Cognitive training
• Memory strategies
• Games such as chess and sudoku

Another good way to stimulate your brain is to pay close attention to your surroundings. Next time you go outside, write down all the sounds, sights, and smells you can notice. This will help keep your memory sharp.

3. Change Your Diet

Certain foods can also stimulate BDNF and enhance your memory. These foods include:

• Fatty fish, such as salmon
• Blueberries
• Turmeric root
• Dark chocolate

In addition, some foods that contain saturated fat and processed sugar can reduce BDNF levels and decrease hippocampal function. Therefore, you’ll want to avoid them as much as possible.

Foods that are particularly high in saturated fat include:

• Dairy products
• Fatty meat cuts
• Processed meat

However, it’s important to note that this isn’t an absolute prohibition. Some of these foods (such as dairy) have important health benefits. The key is to practice moderation if you want to improve your hippocampal function.

Hippocampus Brain Injury: Key Points

The hippocampus is one of the most crucial structures of the brain. Not only does it play a pivotal role in the formation of new memories, but it also helps the brain produce new nerve cells.

An injury to the hippocampus can cause serious memory problems. But fortunately, physical and cognitive exercises can help reverse some of the worst effects of hippocampal damage and improve your memory skills.  

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