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 areas of the brain that are implicated in memory creation, storage, recall, and 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 if they die, 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 encode or retrieve information from memory. The process is electrical as well as electrochemical, with neurotransmitters like dopamine and serotonin helping the neurons communicate.
The role of the hippocampus
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, but also spatial navigation and behavioral inhibition. A healthy hippocampus is vital to the creation of new memories and retrieval of stored memories.
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 senfeel a greater sense of personal coherencesory 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 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.
Explicit memory
Explicit memory is the type of long-term memory that involves consciously recalling stored information. 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 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 than 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
With implicit memory, 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. When you ride a bike, drive a car, walk, talk, or use a fork, you are using procedural memory. 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 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 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.
Memory can play an important role in your emotional wellness
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.
Takeaway
What part of the brain controls memory?
Memory is a complex, multifaceted function that may involve many different brain regions. Investigation of the brain with technologies like PET scans and MRIs has identified several key neurological structures that appear crucial for memory:
- The hippocampus, a portion of the limbic system, is critical for memory formation and retrieval
- The thalamus, a region involved with sensory processing, may also help stabilize memories for long-term encoding
- The amygdala, which is important for processing emotions, also seems to be involved in strengthening long-term memories and their emotional associations — especially fear memories
- The cerebellum is involved in motor coordination as well as learning and remembering how to perform complex tasks, a process often called implicit motor learning
- The basal ganglia also seem to be essential for motor control and motor learning, as well as forming learned reactions to stimuli (AKA implicit memories)
- The prefrontal cortex, a part of the brain involved in conscious planning and self-control, is important for temporary information storage, AKA “working memory”
Long term memories may be stored as patterns of connections distributed widely throughout the cerebral cortex. This large brain structure contains many substructures and serves many important functions in higher cognition, such as reasoning, planning, visual information processing, social processing, and the use of language.
How does the brain remember things?
Neurological researchers are still working to uncover the exact mechanisms of memory storage within the brain. Current evidence suggests that permanent memory storage involves changes in the strength of the connections between various nerve cells. These changes cause certain neurons to be more easily activated by others, leading to the formation of large networks of brain cells that tend to “fire” together. These patterns of increased reactivity can encode specific memories.
When a new stimulus activates one of these nerve networks, the memories stored in the pattern are brought back to the forefront of the mind. This can happen due to sensory information coming from your environment or in response to your own thoughts. This process is known as memory retrieval or recall. The hippocampus appears to be the part of the brain most directly involved in memory retrieval.
What causes memory loss?
Memory loss can have many different causes. Certain illnesses may temporarily interfere with the brain’s ability to form or retrieve memories — these include thyroid problems, depression, and dementia, among others. Infections of brain cells may also disrupt your ability to remember and recall information. Health issues such as lack of sleep or poor nutrition may also impair the brain functions involved with memory.
Physical damage to the brain may also cause loss of memory functions. This can involve the inability to form new memories (anterograde amnesia) or the loss of old memories (retrograde amnesia). Head injuries, strokes, and malnutrition are common sources of brain damage. Intoxicating substances like alcohol and marijuana can also suppress memory functioning. Prolonged, excessive substance use may also carry a risk of long-term brain damage and memory loss.
Some medications may also sometimes cause memory loss as a side effect. Many chemotherapy drugs used in cancer treatment are known to produce this effect, as are anticonvulsants, benzodiazepines, and selective serotonin reuptake inhibitors (SSRIs).
Finally, some degree of memory loss can be a normal part of aging. However, persistent and severe memory troubles could also be an early indicator of dementia. Older adults can often benefit from talking with a doctor when experiencing memory difficulties.
Can my memory improve?
You may be able to improve your memory by improving your physical health. For example, studies suggest that regular physical activity can strengthen the brain’s capacity for storing and recalling memories.
It might also be possible to improve your memory through techniques such as:
- Using mnemonic devices like rhymes or colorful mental pictures to make memories more vivid
- Paying attention to multiple senses when trying to remember something
- Placing memories within an imagined visual space
- Repeated practice of memory games and exercises
While memory tends to decline rather than improve as people get older, research indicates that individuals can protect against this effect. The key may be engaging in activities that challenge their minds and force them to learn new things. This can build up a “cognitive reserve” that acts as a buffer against the impairments of memory that are common in old age.
How does the memory system work?
The human memory system is extremely complex and may contain many distinct but partly overlapping subsystems. In broad terms, memory seems to involve a sequence of interactions between the prefrontal cortex (PFC) and the hippocampus, moderated by other structures like the amygdala.
A memory often begins as sensory information and related thoughts within the cerebral cortex. These are passed to the hippocampus through two distinct pathways in the PFC, which process different types of information about memories. The perirhinal cortex and lateral entorhinal area appear to identify the content of the memory — the objects, sensations, and people involved in an event. The context — when, where, and why the event occurred — seems to be identified in the parahippocampal cortex and medial entorhinal area.
The hippocampus then generates links between the various streams of information, signaling the cortex to encode these links for storage as long-term memory. The prefrontal cortex, in particular, seems to store the information used to organize memories based on their context (for example, which memories are linked to a particular time or place).
When a person later has a thought or receives a sensory impression that’s linked to one of these long-term memories, the prefrontal cortex identifies the memory based on its content or context. It then prompts the hippocampus to reactivate the related networks of brain cells, triggering the recollection of a memory.
How much can your brain remember?
The current upper limit of the brain’s capacity for memory is not known. Based on the total number of synapses (nerve cell connections) in the brain, and the amount of information each synapse can encode, some researchers have proposed that the total storage capacity of a brain might be several petabytes. This means, in theory, a single brain could store as much information as several large municipal libraries.
However, not all of the information stored in the brain consists of facts and memories. A substantial amount may encode for sequences of tasks like throwing a baseball or riding a bike. There’s also quite a bit of information stored in the form of emotional association with people, places, and situations.
Still, it may be possible for the brain to remember a great deal more than most people are capable of recalling in day-to-day life. There are documented cases of people who have explicit memories of every single day of their lives stretching back to early adolescence. It’s possible that no human being has yet reached the limits of the brain’s memory storage capacity.
Why do some people have better memory?
Some differences in memory capacity may be due to physical differences in the brain. Research on people with highly superior autobiographical memory (HSAM) indicates that these individuals have more brain tissue in the left temporoparietal junction and left posterior insula. These two areas are known to be linked with recall of past events.
A person’s thinking styles, personality, and habits of thought also appear to make a difference. Those who frequently go back over their memories or tell stories from their lives might remember them more vividly (though not always more accurately). Some people may also employ mnemonic techniques to improve their memory for factual information, such as linking particular numbers or letters with colors or sounds.
Why is it important to have a strong memory?
Having a robust memory capacity can be important for several reasons. It may improve your functioning in many areas of life, including social connections, career performance, and creative capabilities.
Many people also feel a greater sense of personal coherence when they can recall events from their lives in greater detail. The loss of memory in dementia can be one of the primary factors behind the feeling that people are “losing themselves” as they age. There’s also some evidence that depression may be associated with decreased specificity in personal memories, so a strong memory might be good for your mental health.
Working memory, the capacity to hold information in the brain in the short term, can also be important. Researchers believe working memory may be crucial for learning and other cognitive skills.
How can I improve my memory and focus?
Certain kinds of brain-training practices may be able to improve memory capacity. Simply practicing remembering various facts may help, as can learning techniques like:
- Chunking: Clustering information into larger units, like grouping letters or numbers into larger strings
- Multi-coding: Thinking about multiple sensory streams (sight, texture, sound, etc.) when remembering something
- Association: Focusing on links between pieces of information
- Narrativizing: Coming up with strange, memorable stories to help you memorize details
Practicing the use of your visual imagination may also boost your memory capacity. Many people who engage in competitive memory challenges develop imaginary inner spaces in which they “store” information. Many of these individuals can recall long sequences of numbers in detail after only a few repetitions. Cultivating mindfulness through meditation may also improve both your memory and your ability to focus.
Is memory ability genetic?
Studies of twins suggest that memory capability is somewhat heritable, meaning it has a strong genetic component. The size of brain areas associated with memory formation seems to be similar between parents and children. However, there also appears to be a significant environmental component to these capabilities. Even people without the genes for strong memory may be able to improve their abilities with practice.
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