Where is Memory Stored in the Brain?

This article answers the question ‘Where is Memory Stored in the Brain?’ The article also sheds light on different kinds of memories as well as the different brain areas involved in memory formation and storage. The article will also address some frequently asked questions in the end.

Where is Memory Stored in the Brain?

Explicit memories are stored in the hippocampus, the neo-cortex, and the amygdala. Implicit memories are stored in the basal ganglia and the cerebellum. Working memory is operated upon by the Prefrontal Cortex.

Long-term Memory

The majority of our knowledge is stored in long-term memory. Generally, any information that can be recollected after 30 seconds is considered to be a long-term memory. 

There is no limit on how much information can be stored in the long-term memory and how long it will remain there. Long-term Memory can be of two types: explicit and implicit long-term memory. 

Explicit Long-term Memory 

The memories that we consciously store and take time to memorise and form are known as explicit memories. This can include remembering your phone number, your friend’s birthday, childhood events, academic information, etc. 

There are two types of explicit memory: Episodic Memory, which contains information about your life events, for example, when you received your first A grade in school.

Semantic Memory holds information about general knowledge and facts that you have acquired over the years. 

Implicit Long-term Memory 

Explicit memories are not the only memories that we form and use. Implicit memories are formed without any conscious awareness. It also tends to influence how we behave and think. 

Implicit memories involve the learning of motor skills like walking, riding a bike, or writing. Thus, even if you ride a bike after 10 years, you will still remember it with the help of implicit memory.

Working Memory

Working memory refers to the retention of small bits of information. But this retention is done in a readily accessible form. Working memory helps in facilitating planning, comprehension, reasoning, as well as problem-solving. 

Working memory includes the central executive system, visuospatial sketchpad, and phonological loop. It helps in integrating information from short-term memory and long-term memory in a more usable fashion.

Working memory is considered to be the fourth distinct kind of memory by some experts, while others are of the view that working memory and short-term memory can be used interchangeably.

Parts of the Brain that Process Memories

Below, we discuss what part of the brain plays what role in the formation and storage of memories.

Prefrontal Cortex

The prefrontal cortex is involved in the storage of short-term memory. It functions from both the left and the right sides to collectively work on short-term working memory. The prefrontal cortex is also involved in working memory.

Neocortex

This area of the brain helps in processing information. It is involved in reasoning and learning as it is a part of the cerebral cortex. This part of the brain helps in the storage of explicit memories in the hippocampus for enabling reasoning and logic.

Basal Ganglia

This part of the brain functions in maintaining implicit and involuntary learning from the information given by the brain.

Amygdala

The amygdala is majorly responsible for the formation of emotional memories. Since the amygdala is closer to the hippocampus and is known to have shared connections, the two work together for the formation of more memorable memories.

Since the amygdala attributes emotions to cognitive processes, it also includes memories. Thus, the more emotions the memory invokes, the better it is remembered. 

For instance, when the mother gives birth to her child, the entire process is remembered in clear detail because it has highly positive emotions attached to the experience. Whereas, everyday mundane tasks that do not invoke emotional attachment are usually forgotten.

The amygdala stores good and bad memories, but is involved especially in storing emotional traumas. This is when the functions of the amygdala in memory formation can be detrimental as emotional traumas are difficult to overcome. The emotions attached to those traumas make it especially difficult for them to get weak.

People who have been victims of emotional trauma can also find it affecting their cognitive reasoning, this is because the amygdala is also connected to the prefrontal cortex.

Emotional memories are generally stored in the synapses between the neurons in the brain. There is evidence which claims that multiple neuromodulators in the amygdala mediate emotional memory formation (Tang et al., 2020). These neural connections have the emotion of fear embedded in them.

Hippocampus

The hippocampus plays an essential role in creating long-term episodic memories. The hippocampus is also involved in storing and processing short-term memories. Damage to the hippocampus can greatly affect the formation of newer memories and storing them.

Conclusion 

This article answered the question, “how does the brain store data?” and also covered what memory is, the different types of memory, as well as the brain areas involved in the processing, formation, and maintenance of memories. The article also answers some frequently asked questions about memory in the end.

Why is sleep important for memory formation?

Sleep plays a crucial role in memory storage. When we are asleep, the hippocampus and neocortex play out a dialogue, wherein the hippocampus replays all the recent events that take place. This is why hippocampal neurons are active during slow-wave sleep and they help the neocortex to store important information by playing the events over and over again. This replay can only happen when you are asleep, and thus lack of sleep leads to problems in memory consolidation.

How Much Memory Does Your Brain Have?

The human brain’s capacity for memory is equivalent to trillions of bytes of information. A study at Stanford found that our cerebral cortex alone has the space to hold 125 trillion synapses. Another study found that one synapse in the human brain can hold up to 4.7 bits of information. 

Neurons are brain cells that make up the brain. Neurons are responsible for transmitting messages that they carry to the brain from the body and vice versa. Synapses bridge the gap between the neurons in the brain and help them carry the messages to be transmitted. 

Hence, if there are 125 trillion synapses in the human brain, and one synapse can carry an average of 4.7 bits of information, then we can say that the human brain’s memory capacity equals 1 trillion bytes or 1 TB. 

The human brain is a marvellous organ and has many more capabilities apart from memory. More and more studies are highlighting the brilliance of the human brain, and it is only a matter of time till we discover all of its capabilities. 

There are about 1 billion neurons in the human brain and each of these neurons has 1,000 other connections with other neurons accounting for more than trillions of connections. 

Here’s where it gets interesting, if each neuron could only store a single memory, we would run out of space to store memories and might only have a few GBs of storage. Hence, our brain would store just as much memory as an iPod or a USB drive. 

However,  the human brain’s neurons are smarter than that, and they combine so that each one of the billion neurons can hold many complex memories together. This is what helps the human brain have a storage capacity of 2.5 petabytes, or in simpler terms, a million gigabytes. 

If we compare our brain to the television, this would be equivalent to holding 3 million hours’ worth of TV shows. Moreover, we’d have to let the TV run continuously for over 300 years to run out of 2.5 petabytes worth of storage. 

It is difficult to calculate the precise storage capacity of the human brain. This is in part because scientists are unaware of how to exactly measure the size of memory.

Secondly, some memories are more complex and detailed and may take up more space compared to other simpler memories. Moreover, some information is not remembered by the brain because it doesn’t deem it to be important. The human brain can hold as much information as available on the entire Internet in its memory, as has been suggested by newer research. 

Conclusion

This article answered the question ‘Where is Memory Stored in the Brain?’ The article shed light on different kinds of memories as well as the different brain areas involved in memory formation and storage. The article will also address some frequently asked questions in the end.

Frequently Asked Questions: Where is Memory Stored in the Brain?

What are the three basic functions of memory?

The three basic functions of memory include encoding, storing, and retrieving information. 

Who discovered Working Memory?

Baddeley and Hitch (2003) discovered Working Memory and elaborated on the same.

What are the main models of memory?

The main models of memory include the Information Processing Model (Atkinson & Shiffrin, 1968), Level of Processing Model (Craik & Tulving, 2002) and Parallel Distributed Processing (Rumelhart & McCleland, 1988).

References

Atkinson, R. C., & Shiffrin, R. M. (1968). Chapter: Human memory: A proposed system and its control processes. In Spence, K. W., & Spence, J. T. The psychology of learning and motivation (Volume 2). New York: Academic Press. pp. 89–195.

Baddeley A (October 2003). “Working memory: looking back and looking forward”. Nature Reviews Neuroscience. 4 (10): 829–39. doi:10.1038/nrn1201. PMID 14523382. S2CID 3337171

Craik, F. I. (2002). Levels of processing: Past, present… and future?. Memory, 10(5-6), 305-318.

Rumelhart, D. E., McClelland, J. L., & PDP Research Group. (1988). Parallel distributed processing (Vol. 1, pp. 354-362). New York: IEEE.

What was missing from this post which could have made it better?