Learning and the development of memory are processes that cannot be strictly separated from psychology and sociology. Thus, this article deals with the physiology of learning and memory. Topics include understanding the relationship between experience and storage of acquired knowledge, how the brain deals with “useless” knowledge, and how a baby starts to understand its surroundings.
Limbic Lobe

Picture: “Illustration from Anatomy & Physiology” by Anatomy & Physiology, Connexions Web site. Licence: CC-BY 3.0

What is learning?

The word learning is originally related to “teaching somebody” and “trick.” Furthermore, learning also etymologically related to “tracing something.” The conclusion is that learning is a process to acquire new knowledge. Learning is the precondition for the brain to store experiences and to use those experiences in our actions to gain benefits and prevent damage.

Formation of synapses

Learning processes during the first six months of a baby’s life hold great significance for the development of the nervous system. Environmental stimuli and experiences also play a role in this process since they lead to the formation of new synapses and the improvement of already existing synaptic connections. The ability for the brain to from and improve these connections is referred to as neuroplasticity, whether they are based on physiological or neuroanatomical conditions.

How do infants learn?

Most brain cells are already formed during pregnancy. However, an infant’s nerve cells still cannot communicate at the time of birth, since they are not yet connected with each other. These connections are developed during the first three years of life. This process takes place by developing dendrites, which enable cells to absorb information. Moreover, synaptic connections, which are responsible for relaying information, are formed. The extent of these connections is far greater than what is required. This makes it easy to make adjustments later on anywhere they are needed.

Learning capacity of babies

Babies react strongly to stimuli. This is also an important indication that a learning process is carried out. Besides, these stimuli are necessary for the brain to even be able to develop at all. This means that an environment with few stimuli hinders the development of babies.

During this development stage, the ability to differentiate faces and vocal sounds is better developed than it is in adults, which enables the baby to differentiate between close reference persons, intimates, and strangers. After the first imprinting to the personal surroundings, the baby loses a certain amount of flexibility considering its mental abilities. However, learning processes become more specific. This development takes place during the first six months of life.

How does the brain work?

The brain uses neurons to communicate and, to a large extent, manage itself. However, the development of neurons and the resulting brain capacities depend on environmental and sensory stimuli. The brain works in connection with the spinal cord to send and receive information via the neurons. The brain processes all perceptions, which are also connected with each other. For this process, the brain uses already stored experiences. However, most perceptions are suppressed. Perceptions that have to be processed during the learning process are differentiated by the brain according to:

  • Relevance
  • Value of new knowledge
  • Significance
  • Meaningfulness
The Neuron

Picture: “Parts of a Neuron” by philschatz.de. Licence: CC BY 4.0

Importance of emotions during the learning process

Cognition and emotions play a major role in the process of learning. Sensations are used as somatic markers, which influence processing, storage and memory. Learning also includes the strengthening of the most used neuronal pathways so they can be used longer and above all faster.

Learning as formation and deformation inside the brain

The process of learning starts with processing external influences. Learning leads to changes inside the brain that can be classified into four categories: expanding, tuning, re-constructing and pruning.

Expanding means to improve the number and strength of neuronal connections by developing a network between already existing information. Tuning describes the process of creating new connections.  During the process of re-constructing, relearning takes place. In this time-consuming and exhausting process, preexisting learning achievements (motor patterns and routine processes) are replaced by new ones that are better suited for the respective task. Pruning describes the regression of neuronal potential, which is used little or not at all. During this process, connections can be changed in such a way that they cannot be activated anymore.

Learning is differentiated into:

  • Intentional learning
  • Individual learning
  • Collective learning
  • Physical learning
  • Social learning

Significance of social interaction and physical activity

Humans need social interactions. This also applies for the brain. Mirror neurons inside the brain are responsible for the development of the required cognitive orientation pattern. Physical activity is important for brain performance as well. This particularly applies in the first years of life.

Localization of learning processes and memory

Cerebrellum Animation

Picture: “Cerebellum (rot dargestellt)” by Database Center for Life Science(DBCLS). Licence: CC-BY-SA-2.1

Temporal Lobe Animation

Picture: “Temporallappen (rot dargestellt)” by Database Center for Life Science(DBCLS). Licence: CC-BY-SA-2.1

Motor learning is located in the neurons of the cerebellum and basal ganglia. The declarative memory is located in the medial temporal lobe. A lesion of the hippocampus leads to an anterograde amnesia. This means that new information cannot be stored anymore.

Memory systems

The procedural memory is located in the striatum and uses the pathway of the neurocortex. Associative learning takes place inside the amygdala for emotional processes and in the cerebellum for motor processes. Non-associative learning occurs in the form of habituation and sensitization (both via reflex circuits).

Hebbian theory

Hebbian theory explains how the connection between certain neurons can be strengthened.

If an axon of neuron A is located close enough to neuron B so that neuron B can be stimulated by neuron A repeatedly or continuously, the efficiency of neuron A for the stimulation by neuron B is increased by growth processes or changes in metabolism in both or one of the two neurons. This means that experience-related changes of the nervous systems depend on certain conditions.


Development of memory and the Papez circuit

Limbic SystemThe Papez circuit is of great importance for the development of memory. The circuit is located in the center of the limbic system. The limbic system is located above the brain stem and exists in all mammals. It has an important role for social behavior, solicitude, love, fear and learning by imitation.

Papez circuit

The Papez circuit is a chain of neurons, named after its discoverer, James Papez. Research on the tasks of the Papez circuit for memory performance is still ongoing. However, the assumption that the circuit controls anger and rage are already outdated, since it has been discovered that the circuit is even more complex than Papez himself thought.

These days, it is assumed that the Papez circuit serves the storage of memories by transferring information from the primary memory (short-term memory) to the secondary memory (long-term memory) or to the tertiary memory (an independent part of the long term memory).

The Papez circuit proceeds as follows: hippocampus → fornix → mammillary body inside the hypothalamus (corpora mamillaria) → cingulate cortex → hippocampus

Papez Circuit

The different types of memory

The specialist term for mind and memory is called mnestic function. Some things are easier to remember than other things. For example, important things are easier to remember than events that hold no meaning and positive experiences are easier to remember than neutral experiences. Moreover, the process of remembering is easier in positive prevailing mood. This also means that remembering things is more difficult in a state of fatigue or grief.

Not all memories can be explained

Humans have a declarative memory (explicit memory) and a procedural memory (implicit memory). The declarative memory stores information that can be reproduced because we are conscious of the experience/information. The procedural memory on the other hand contains experiences for which one has no direct memory of the learning process. Still, this type of memory has an influence on our behavior. A classic example is the process of learning a new language.

Ultra short-term memory (sensory memory)

The ultra short-term memory receives stimuli from sensory organs in the form of a neuronal excitation. This process has a duration of less than one second, and the perception can take place via the eyes or ears. The ultra short-term memory via the eye is also referred to as iconic memory, and via the ears, echoic memory (and it perishes just as fast). Only stimuli that reach the short-term memory remain because the ultra short-term memory has no storage capabilities.

Primary memory

Memories in the primary memory (short-term memory) are available as long as we occupy ourselves with them. If that process is interrupted, the memory is lost too. Memories that begin in the primary memory can be available permanently but only if they are transferred to the long-term memory. It is assumed that the short-term memory is a transit for experiences into the long-term memory.

The hippocampus, located in the cerebral cortex, is apparently involved in the process of transmitting information from the primary memory to the long-term memory.  The Hippocampus is thought to be involved in this process because when lesions appear in the hippocampus, only the short-term memory remains intact. Another term for primary memory is “labile memory” since it is very unstable. One distraction is enough to forget the perceived or heard information. Calcium has a major importance for these processes.

Long-term memory

For storing memories in the long-term memory, repetition is particularly important. This is easily understandable when one considers the high amount of repetition required to learn new movement patterns, e.g. when learning a new sport.

The process of learning inside the brain

The hippocampus also plays an important role in the process of learning. There exists a connection between nerve cells and the neuronal mechanism which is assumed to be the physiologic substrate of learning. This physiologic substrate consists of continuous electrophysiologic, morphologic and molecular changes of nerve cells. For information to be available long-term, long-term potentiation (LTP) is necessary. LTP facilitates the stimulation of afferent axons over a period of weeks as well as a stronger Ca-influx.

Everything stored inside the long-term memory is available during one’s entire life. The processes of the long-term memory take place under the influence of the neurotransmitter glutamate (glutamic acid).

Pathology of memory performance

The highly complex system of learning and memory is susceptible to malfunctions. If anomalies occur, differential diagnosis has to be made with the greatest care. This is also because even changes in the mineral balance of the body can lead to disorders that give the impression of a disease (e.g. calcium deficiency). Furthermore, cases of dementia are increasing, which is partly due to increasing life expectancy. Currently, approximately 1.5 million people with dementia are estimated to live in Germany.


Amnesia is one type of memory disorder in which a patient loses access to stored information. The term “amnesia” originates from the Greek a (without ) and mnémē (memory). Amnesia is not an independent disease but is the symptom of a disease or the consequence of an influence on the brain. This influence can be internal or external.

In the case of amnesia, it is not possible for patients to store experiences or learned knowledge. This can affect all types of information or only certain parts, for example patients can lose access to memories from certain stages of their lives. In most cases, the patient is able to remember events that happened long ago rather than events that occurred just lately. There are different forms of amnesia. However, they cannot be strictly separated from each other. The following forms are of importance:

  • Retrograde amnesia
  • Global amnesia
  • Transient global amnesia
  • Congrade amnesia
  • Psychogenic amnesia

Alzheimer’s Disease

Alzheimer‘s Disease is characterized by a regression of nerve cells, which can result in the brain shrinking up to 20%. The consequence is an impaired relay of information. Furthermore, Alzheimer’s may make processing information nearly impossible. At the same time, plaques of protein fragments form. Particularly affected by Alzheimer’s are those brain regions responsible for processing information and memory performance.

Left: healthy brain; right: brain with alzheimer

Popular exam questions for learning and memory

Solutions can be found below the references.

1. Which statement concerning short-term memory is true?

  1. It is available for about one hour.
  2. It relays all information to the long-term memory.
  3. It depends on the functionality of the hippocampus.
  4. It stores the most important information.
  5. It does not absorb information from the ear.

2. Which statement is true?

  1. Newborns have yet to develop nerve cells.
  2. Newborns still have no connections between nerve cells.
  3. Connections between nerve cells develop during the third year of life.
  4. The development of connections is fixed and unchangeable.
  5. Dendrites are responsible for relaying information inside the brain.

3. The brain processes information according to:

  1. Amount
  2. Experience
  3. Significance
  4. Individual impression
  5. Duration of the time it remains inside the short-time memory
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