How the Brain Learns and Remembers

 By Tayren Ben-Abraham MPH, MSc, M.A. M.A. Founder & Principal Investigator, Ben-Abraham Center for Environmental Health Sciences (BAEHS)

                 Figure 1. Child learning through reading a book. Source: powerofpositivity.com

                                              

Learning begins when an organism encounters an experience. The nervous system receives information from the external and internal environment, processes that information, and changes in response to it. Through learning, organisms can change behavior based on experience, gain information, develop skills, recognize patterns, form associations, and respond to environmental changes (Fuchs et al., 2023).

The fundamental biological property that makes learning possible is neural plasticity which is the capacity of the nervous system to change in response to experience (Asuku et al., 2025). Neural plasticity includes changes in neuronal communication and activity, gene expression, protein production, cellular structure, and synaptic strength (Alberini, 2025). Some changes occur within seconds (Madar et al., 2025), whereas others develop over hours, days, months, or years (Marom & Marder, 2023). Learning therefore emerges from biological processes operating across multiple timescales.

Experience Enters the Nervous System

                  Figure 2. The human brain as seen here in an MRI image. Source: qaqooking.wiki

The human brain contains approximately 86 billion neurons (Lent, 2025), connected through structures called synapses (Luo, 2020). Our sensory systems continuously provide information about the environment, while internal systems provide information about the body's physiological and emotional state (Demenko et al., 2022). However, the brain does not process all incoming information equally. Our sensory organs receive an enormous amount of sensory and internal information, yet only a small number of our experiences receive sufficient processing to produce lasting changes (Vuong, 2022). This is known as the Mind Sponge Theory.

                                 Figure 3. Labelled synapse model. Source: Speechneurolab.ca  

What causes our brains to rank certain stimuli over others?  Attention therefore plays an important role at the beginning of learning. Information receiving greater attention is generally processed more strongly, whereas information receiving little attention may not be encoded effectively (Liu et al., 2026). Learning is also influenced by motivation, arousal, reward, stress, and the significance of an experience (Peng et al., 2024). Several neuromodulatory systems contribute to these processes. Dopamine is involved in reward-related learning, motivation, action selection, and synaptic plasticity (Parra-Abarca et al., 2025). Acetylcholine contributes to attention, arousal, and plasticity, while norepinephrine contributes to arousal, attention, and responses to important or unexpected events (Slater et al., 2022). These chemicals should not be described simply as “learning chemicals.” Their effects depend on where and when they act, the receptors involved, their concentration, and the individual's behavioral state (Liu, 2026). Dopamine, for example, is often associated with pleasure, but it also contributes to reward learning and updating expectations (Parra-Abarca et al., 2025). The brain's chemical environment therefore influences how strongly experiences modify neural circuits.

Attention and Prior Knowledge Shape the Experience

Once information receives sufficient attention, it is processed in relation to what the brain already knows. Learning does not occur in an empty brain. New experiences are processed through neural systems shaped by previous experience (Clark, 2024). Prior knowledge can facilitate learning when new information connects with existing representations. New information can also conflict with established expectations, requiring existing representations to change. New information is therefore not simply added as an isolated fact. It can become integrated with, and sometimes modify, what is already known. This reflects a fundamental property of the nervous system: it must balance stability and change (Banerjee et al., 2023). The brain must preserve useful information while remaining flexible enough to respond to new experiences.

Encoding Turns Experience Into Neural Information

Before information can become a lasting memory, it must be encoded. Encoding involves processing information and creating a neural representation of an experience (Fernandino et al., 2022). At this stage, the brain is beginning to transform an experience into patterns of neuronal activity that can potentially be modified and maintained. Learning is therefore not the storage of information in a single location; rather, it changes the activity and connections of groups of neurons (Luczak et al., 2022). Different kinds of experiences recruit different neural systems. There is no single “learning center” in the brain.

Figure 4. Brain areas associated with learning and memory. The thalamus is the gateway of our sensory organs to different centers like the cortex in these areas of the brain associated with memory and others. 

The hippocampus is important for forming many new declarative memories, including facts and events (Yadav et al., 2026). Physical skill learning involves networks that include the cerebral cortex, basal ganglia, and cerebellum (Roth & Ding, 2024). The basal ganglia contribute to action selection and learning from rewards and consequences, while the cerebellum is important for movement coordination and motor adaptation (Yoshida et al., 2024). Emotional learning involves regions including the amygdala, hippocampus, and prefrontal cortex (Jacobson et al., 2025). Sensory learning involves changes within the neural systems responsible for processing vision, hearing, touch, and other sensory information (Demenko et al., 2022). Thus, what is being learned influences which neural systems participate in the learning process.

Neural Activity Changes Synapses

Once an experience has been encoded, neural activity can modify the connections between neurons. Synaptic plasticity refers to changes in the strength or function of synapses in response to neural activity (Applebaum et al., 2023). Synaptic connections can strengthen or weaken according to patterns of activity and previous experience, allowing the brain to acquire new information while maintaining previously learned skills (Fuchs et al., 2024).

Two important forms of synaptic plasticity are long-term potentiation (LTP), a long-lasting increase in synaptic strength, and long-term depression (LTD), a long-lasting decrease (Rodriguez-Moreno & Paulsen, 2026). LTP and LTD are not equivalent to learning itself, but they provide important mechanisms through which experience can produce lasting changes in the nervous system (Toader et al., 2025). At the synapse, neurons communicate by releasing neurotransmitters into the space between neurons. These chemical messengers bind to receptors on receiving neurons and alter their activity (Borroto-Escuela et al., 2024; Luo, 2020).

Glutamate and Calcium Initiate Molecular Changes

One of the major neurotransmitters involved in learning and memory is glutamate (Andersen & Schousboe, 2023). This neurotransmitter acts on two different receptors to produce two different neural states. Two important glutamate receptors are AMPA and NMDA receptors. AMPA receptors support fast excitatory communication, while NMDA receptors can allow calcium ions to enter the receiving neuron under appropriate conditions (Pampaloni & Plested, 2022; Jewett & Thapa, 2022). The function of calcium is important in cellular communication especially in learning. Calcium acts as an important intracellular signal (Pikor et al., 2024). Once it enters the neuron, it can activate signaling pathways that alter existing proteins and change the number or function of AMPA receptors (Pampaloni & Plested, 2022). These changes can strengthen synaptic responses. Thus, an experience can begin with neural activity and neurotransmitter release and progress to intracellular molecular changes that alter how strongly neurons communicate. Longer-lasting plasticity can also involve changes in gene activity, protein production, and synaptic structure, providing a pathway from brief experience to lasting neural change (Zha & Sossin, 2022).

Synaptic Changes Alter Neural Networks

Changes at individual synapses are important, but they do not fully explain learning. Complex behaviors and memories depend on neural networks, in which groups of neurons interact through coordinated patterns of activity (Yuste et al., 2024). As synapses change, the patterns of communication within neural circuits can also change. Experience can alter which neurons participate in these patterns, their connectivity, and how readily they become active together.  The concept of a memory engram describes a population of neurons and associated changes that contribute to the physical representation of a memory (Guskjolen & Cembrowski, 2023). An engram should not be viewed as a complete memory permanently stored in one small group of neurons because memories can involve multiple brain regions and change over time. Learning therefore progresses across interconnected levels, beginning with experience that produces neural activity, which leads to molecular changes, synaptic changes, circuit changes, and ultimately altered patterns of network activity (Chaudhary, 2025). At the same time, these levels continuously influence one another. Molecular changes alter neurons, neuronal changes alter circuits, circuits alter communication between brain regions, and activity across brain regions can influence molecular and cellular processes (Chaudhary, 2025).

Newly Learned Information Must Be Consolidated

Newly learned information can initially be fragile. Memory consolidation refers to processes that stabilize memories over time (Goto, 2022). At the molecular and synaptic levels, consolidation can involve changes in gene activity, protein production, synaptic function, and synaptic structure (Khan et al., 2025). Consolidation also involves changes in communication among brain regions. The hippocampus contributes importantly to the organization and consolidation of many forms of declarative memory (Yadav et al., 2026). It does not simply serve as a permanent storage site. Instead, it interacts with regions of the cerebral cortex as memories are stabilized and integrated (Sridhar et al., 2023). The precise relationship between hippocampal and cortical representations remains an active area of research, and different forms of memory may undergo different consolidation processes.

9. Repeated Experience Strengthens and Refines Learning

Learning does not end when information has initially been encoded or consolidated. Repeated experience can produce additional changes in the neural systems involved in learning. Repeated practice can produce lasting changes in neural systems involved in learning. However, repetition alone does not guarantee effective learning. Attention, feedback, task difficulty, timing, and spacing of practice influence learning and memory (Carpenter et al., 2022). With practice, neural circuits involved in skills can become more coordinated and efficient, allowing behavior to become faster and increasingly automatic (Florio, 2025). Learning can also change the physical structure of neural circuits.

Figure 5. This figure shows an axon with dendrites being highlighted. Dendritic spines are found on dendrites and participate in neuronal communication and learning. Source: Med.libretexts.org

One site where changes occur is at the dendritic spines. Dendritic spines are small structures on dendrites that contain many excitatory synapses (Luo, 2020). Experience and neural activity can influence their size, shape, number, and stability (Kasai, 2023). Experience causes synaptic proteins and patterns of neuronal connectivity changes which help to form memories and facilitate learning (Choudhary et al., 2024). This process is like a gardener arranging trees, flowers, and plants to specific locations and through time, the gardener may come back to prune the plants, move certain plants around, and even remove some of the plants. These structural changes can contribute to long-lasting neural plasticity, although not every structural change represents a permanent memory (Rodriguez-Moreno & Paulsen, 2026). Effective learning requires both mechanisms that permit change and mechanisms that maintain existing neural functions. Without such regulation, widespread permanent changes could destabilize neural circuits.

Learning and Memory Are Related but Not the Same

Learning refers broadly to relatively lasting changes resulting from experience, whereas memory refers to the persistence and later expression of acquired information (Cherry, 2026; Sridhar et al., 2023). Memory is not a single system. Declarative memories, motor skills, emotional associations, perceptual learning, and other forms of memory can depend on different brain systems and biological mechanisms (Sridhar et al., 2023). Consequently, a person can learn something without consciously remembering the experience through which it was learned, and some forms of learning may remain intact when another form of memory is impaired. Distinguishing learning from memory prevents both from being treated as a single process controlled by one brain region.

The Brain Learns by Changing

The central principle of the neuroscience of learning is that experience changes the brain. Learning is consequently an ongoing biological process rather than a single event. Neural plasticity allows the nervous system to respond to experience, while synaptic plasticity can strengthen or weaken connections between neurons. Changes in neuronal activity alter neural networks, and interactions among brain regions support different forms of learning, memory, attention, movement, emotion, and reward.

Learning is therefore a balance between plasticity and stability (Yamada et al., 2024). The brain must preserve useful information while remaining flexible enough to respond to new experiences. Experience can change synapses, neurons, neural networks, and interactions among brain regions, while later experiences can strengthen, weaken, or modify those changes. The brain does not simply collect information. It changes as a result of experience. Those changes allow information gained from the past to influence what the brain can recognize, remember, predict, and do in the future.

 

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