Which Parts Of The Brain Affect Memory Function?

The brain is a complex organ, and experts are still learning about how it functions.

Memory helps us learn, socialize, make decisions, and interpret the world around us. So, it can be helpful to understand how the brain manipulates memory, particularly when faced with memory disorders, a head injury, or similar memory-related challenges. Below, we’re going to discuss the parts of the brain that are implicated in: 

• Memory creation
• Memory storage
• Memory recall
• Memory loss

How memory works on a cellular level

Neurons, or nerve cells, are responsible for much of our functioning. Neurons are not like other cells. They do not divide, and in the case of cell death, they are not replaced. (This is why most memory loss is permanent.) On average, the human brain has around 86 billion neurons or brain cells.

Neurons communicate with one another through synaptic connectors, often called synapses. There are over a trillion synapses in the brain that facilitate the transfer of information between neurons. With this complex system, it is estimated that humans have a memory capacity of up to 2,500 terabytes worth of data.

The neurons work together through the synapses to facilitate encoding memories and retrieving information from memory. The process is electrical as well as electrochemical, with neurotransmitters like dopamine and serotonin helping the neurons communicate.

What part of the brain creates and stores memories? The role of the hippocampus

Understanding how memory works requires knowledge of how the hippocampus functions. The hippocampus is a small organ of its own situated in the medial temporal lobe of the brain. The hippocampus is responsible primarily for memory, specifically normal recognition memory, but also for spatial memory and behavioral inhibition. A healthy hippocampus is vital to the creation of new memories and the retrieval of stored memories.

Damaging this part of the brain

A damaged hippocampus can lead to the failure of short-term memory, making it difficult for new memories to be formed and encoded into the brain. This is one reason why people with Alzheimer’s disease start to lose their short-term memory and fail to create new memories—the hippocampus is often the first part of the brain to be affected by the disease.

Generally, the hippocampus plays a role in short-term and declarative long-term memory; in other words, the memory that allows you to state facts and figures. Some patients with damage to the hippocampus can recall memories from early life, but they may not be able to remember newer information or form new memories.

Types of memory and associated brain regions

There are three main types of memory—sensory memory, short-term memory, and long-term memory—each of which can be further divided into several different subtypes. Below, we are discussing the different forms of memory, their associated brain regions, and how they impact your ability to function. 

Sensory memory

Sensory memory is an ultra-short-term form of memory that usually lasts less than one second. As your brain takes in information through the five senses, it relays that information to sensory memory. From there, it makes a snap decision as to whether to store the information in short-term memory or discard it.

There are five senses, and most people would assume that there is a sensory memory type for each. However, only three types of sensory memory have been studied sufficiently for us to know in which parts of the brain they’re processed.

• Iconic memory refers to visual memory—which is related to things you see. It is primarily processed through the occipital lobe. 
• Echoic memory refers to audio memory—which is related to things you hear. It is primarily processed through the primary auditory cortex of the temporal lobe. 
• Haptic memory refers to tactile memory—which is related to things you touch. It is primarily processed through the parietal lobe.

Short-term memory

Short-term memory is where information is stored for a brief time before it is either relayed to long-term memory or discarded. While short-term memory lasts longer than sensory memory, it still has a much lower capacity than long-term memory.

The part of the brain that is primarily responsible for short-term memory functioning is the prefrontal lobe. The prefrontal lobe holds information in short-term memory until the hippocampus passes it from short-term to long-term memory.

Long-term memory

Long-term memory is divided into multiple categories, the function of which can be facilitated by different parts of the brain (though some brain regions, such as the hippocampus, have been implicated in the processing of all types of long-term memory). 

As you take in information, it is passed through the hippocampus and then relegated back to other parts of the brain. Typically, the more times a piece of information passes through the hippocampus, the longer it will be stored in long-term memory. This is why studying the same information repeatedly can make it more likely that you will remember it in the future.

According to a theory called arousal theory, information with very strong emotional associations are typically easier to remember than weaker emotional experiences. When processing emotional information, strong emotions trigger the release of certain chemicals and hormones in the brain that “tag” the emotional event as important and leave a physical trace. Moreover, an atypical or unusual event might be associated with stronger memories, while everyday or routine events are linked to weaker memories. 

Explicit memory

Explicit memory, also known as declarative memory, is the type of long-term memory that involves consciously recalling stored information (e.g., object recognition). You are using explicit memory when you want to remember the name of your high school science teacher or are trying to recall the answer to a test question.

Explicit memory is primarily formed and stored in the cerebellum, though it is thought that we use a different part of our brains to access that information (studies have linked the right frontal region of the prefrontal cortex to our ability to retrieve information from explicit memory). There are two types of explicit memory, episodic and semantic, which are discussed below. 

Episodic memory

Episodic memory is the memory you have of events that have happened to you throughout your life. Your wedding day, your high school graduation, the birth of your child, and special memories of holidays are all examples of experiences that are stored in episodic memory.

The hippocampus and prefrontal cortex have been implicated in declarative and episodic memory. Researchers are divided on whether episodic memories are stored in the hippocampus for a long period or are relegated to the neocortex. More studies are being done to determine exactly how episodic memories are stored and retrieved.

Semantic memory

Semantic memory is your memory of certain facts and figures that you have learned over your lifetime. Examples of information recalled by semantic memory are the names of past presidents, how addition works, or that the sky is blue.

Semantic memory works slightly differently from episodic memory. The part of the brain used most for semantic memory is the anterior temporal lobe. The hippocampus is also thought to contribute to semantic memory function. 

Implicit memory

When you create implicit memories, your brain automatically recalls the information when it is needed, without conscious thought. Information processed through implicit memory is stored in various structures of the brain, depending on what type of information it is. While most experts recognize four types of implicit memory, we’re going to focus on the primary type, procedural memory, below.

Procedural memory

Procedural memory is the most well-known type of implicit memory. This is your memory of how to do certain things. You use procedural memory when you: 

• Ride a bike
• Drive a car
• Walk
• Talk
• Use a fork

You do not have to think about doing those things—your procedural memory recalls information on how to complete the action automatically.

The main part of the brain used for processing procedural memory is the cerebellum. The cerebellum stores the knowledge of how to perform a particular task and then relays that information to the regions of the brain and central nervous system that are responsible for helping us physically engage in it. 

Procedural memory is one of the only forms of memory thought to not be affected by the hippocampus. Studies have shown that people without a fully functioning hippocampus can learn new skills, such as playing the guitar. 

Addressing cognitive functioning with online therapy

Studies suggest that online therapy can help participants improve cognitive functions that may be affecting their memory. For example, in one trial, researchers found that an online intervention led to cognitive rehabilitation and improved mood in people with memory-impairing brain injuries. Researchers have also pointed out that online therapy can be more cost-effective than traditional therapy and that it offers access to care to people who may live in remote areas.

If you’d like to address the emotional challenges that may accompany memory loss or similar concerns, know that help is available. With an online therapy platform like BetterHelp, you can schedule therapy appointments easily, online or through the app, and receive regular reminders of upcoming sessions. Your therapist can also connect you with useful resources, such as articles on memory enhancement.