Introduction to Cognitive Neuroscience Flashcards
Neurons, Glia and the Axon potential
What is an action potential?
A rapid electrical signal in neurons caused by ion movement across the membrane.
What is an axon terminal (bouton)?
The endpoint of an axon where neurotransmitters are released to communicate with other neurons.
What is a dendrite?
A neuron’s branched extension that receives signals from other neurons.
What is the soma?
The cell body of a neuron, containing the nucleus and essential organelles.
What is resting membrane potential?
The charge difference across the membrane when the neuron is inactive.
What is an ion?
A charged particle; cation is positive (e.g., Na⁺), anion is negative (e.g., Cl⁻).
What is a phospholipid bilayer?
The double-layered membrane structure that controls ion movement.
What is an ion channel?
A protein that allows specific ions to pass through the membrane.
What is an ion pump?
A protein that actively moves ions, such as the sodium-potassium pump (Na⁺/K⁺ exchange).
What is diffusion?
Movement of molecules from high to low concentration.
What is a concentration gradient?
The difference in ion concentration across a membrane.
What is equilibrium potential?
The membrane voltage at which no net ion movement occurs.
What is the Nernst equation?
Calculates equilibrium potential for a specific ion.
What is depolarization?
A decrease in membrane potential, making the inside of the cell less negative.
What is the blood-brain barrier?
A protective filter controlling substance entry into the brain.
What is threshold in neuronal activity?
The membrane potential where enough sodium channels open, making sodium permeability higher than potassium.
What occurs during the rising phase of an action potential?
Na⁺ rushes in due to a strong driving force, rapidly depolarizing the membrane.
What is overshoot in the context of action potentials?
High Na⁺ permeability drives the membrane potential above 0 mV, near Eₙₐ.
What happens during the falling phase of an action potential?
Na⁺ channels inactivate, K⁺ channels open, and K⁺ exits, repolarizing the membrane.
What is undershoot in neuronal activity?
Extra K⁺ permeability causes hyperpolarization until K⁺ channels close.
What is the absolute refractory period?
Na⁺ channels inactivate and cannot reopen until the membrane repolarizes.
What is the relative refractory period?
The membrane stays hyperpolarized, requiring more depolarization to reach threshold.
