Mini Encyclopedia

Glossary of Neuroscience

Core concepts from neuroscience and pedagogy, explained without heavy jargon — with real-life everyday examples.

15 terms

⬡ Cells & Signals

Neuron

Νευρώνας

The fundamental structural and functional cell of the nervous system. It consists of a cell body, dendrites that receive signals, and an axon that transmits them. It communicates via electrical impulses within the cell and chemical signals at synapses.

Example:When you touch something hot, neurons carry that signal to your brain in fractions of a second.
⬡ Cells & Signals

Synapse

Σύναψη

The specialized junction between two neurons where signals are transmitted. The pre-synaptic neuron releases neurotransmitters into the synaptic cleft, which bind to receptors on the post-synaptic neuron.

Example:Think of a synapse as the gap between two hands that don't quite touch — the message leaps the gap as a chemical messenger.
⬡ Cells & Signals

Myelination

Μυελίνωση

The process by which fatty material (myelin) incrementally wraps around neuronal axons. It dramatically increases signal transmission speed and the efficiency of communication between brain regions. Completes in the prefrontal cortex around age 25.

Example:Think of myelin as plastic insulation around an electrical cable — without it, the signal leaks and slows significantly.
⬡ Cells & Signals

Mirror Neurons

Καθρεπτικοί Νευρώνες

Neurons that fire both when an action is performed and when the same action is observed in another person. They are considered the neurological basis of empathy, imitation, and social learning.

Example:The feeling of "pain" when you see someone get hurt, or contagious yawning — these are linked to mirror neuron activity.
◎ Brain Structures

Amygdala

Αμυγδαλή

An almond-shaped structure in the medial temporal lobe, critical for processing intense emotions — particularly fear, anxiety, and reward. It functions as the brain's alarm system: it activates before rational analysis.

Example:The amygdala reacts in milliseconds — long before you consciously "think" that something is frightening.
◎ Brain Structures

Hippocampus

Ιππόκαμπος

A seahorse-shaped structure in the medial temporal lobe. Essential for converting short-term experiences into long-term memories and for spatial navigation. Vulnerable to chronic stress.

Example:When a song vividly brings back a memory, the hippocampus played a key role in creating that connection.
◎ Brain Structures

Prefrontal Cortex

Προμετωπιαίος Φλοιός

The front region of the frontal lobe, responsible for higher cognitive functions: decision-making, planning, impulse control, and understanding social consequences. Fully mature only at age 25 — which explains many adolescent behaviors.

Example:When you hold back an impulsive reaction and choose a calmer response, your prefrontal cortex is "putting on the brakes".
⬦ Brain Chemistry

Neurotransmitters

Νευροδιαβιβαστές

Chemical substances released from the pre-synaptic neuron that diffuse across the synaptic cleft and bind to specialized receptors. There are dozens of types — each with a distinct role in regulating mood, movement, and cognition.

Example:Each neurotransmitter is like a "key" that only fits its own receptors — the wrong "messenger" can't open the door.
⬦ Brain Chemistry

Dopamine

Ντοπαμίνη

A neurotransmitter critical for motivation, reward, and learning. It's not just about pleasure — it's primarily about anticipation and the drive to pursue reward.

Example:The eager, restless feeling before opening a gift or starting a game — that's dopamine at work.
⬦ Brain Chemistry

Cortisol

Κορτιζόλη

A hormone secreted by the adrenal glands in response to stress. Short-term, it mobilizes the body for action. When chronically elevated, it impairs memory, growth, and the immune system.

Example:Cortisol before an exam keeps you alert. But if stress is daily, chronic exposure begins to affect even the hippocampus.
◈ Cognitive Functions

Executive Functions

Εκτελεστικές Λειτουργίες

A set of higher cognitive processes that coordinate purposeful, adaptive behavior: planning, working memory, cognitive flexibility, and impulse control. They are primarily based in the prefrontal cortex.

Example:When you switch strategy because the first one isn't working, you're using cognitive flexibility — one of the executive functions.
◈ Cognitive Functions

Working Memory

Εργαζόμενη Μνήμη

A system for temporarily storing and actively processing a limited amount of information during task execution. It serves as the brain's "working surface" — capacity ~7 (±2) items.

Example:When you hold an address in mind while looking it up on the map — that's working memory.
↻ Adaptation & Change

Neuroplasticity

Νευροπλαστικότητα

The brain's ability to modify its structure and function in response to experience, learning, or injury. Most pronounced in childhood, but remains active throughout life.

Example:Every time you practice something new — a musical instrument, a foreign language — the brain literally reorganizes itself at the neuronal level.
↻ Adaptation & Change

Circadian Rhythm

Κιρκάδιος Ρυθμός

An internal ~24-hour biological cycle that regulates sleep, wakefulness, body temperature, and hormone secretion. Synchronized primarily by light and controlled by the suprachiasmatic nucleus.

Example:Jet lag — the inability to sleep after crossing time zones — results from a disconnect between your internal clock and external light.
↻ Adaptation & Change

Epigenetics

Επιγενετική

Studies mechanisms that regulate gene expression without changing the DNA sequence — through chemical modifications to chromatin. Experiences and environment can switch genes on or off.

Example:Some effects of chronic childhood stress are reflected in epigenetic changes that alter how the brain responds to anxiety later in life.