PSYC 456: Advanced Biological Psychology - Action Potentials and Synapses

Flashcards covering key vocabulary related to action potentials, synaptic transmission, and neural modeling from the Advanced Biological Psychology lecture.

Action Potentials

The product of a neuron releasing its stored energy in a cascade down the axon, representing a rapid change in membrane potential.

Invasive Extracellular Recording

A method using an electrode array implanted in vivo to record electrical activity from neurons.

Ex Vivo Extracellular Recording

A method to record electrical activity from neurons using techniques like patch-clamp, including cell-attached, inside-out, whole-cell, and outside-out configurations.

Neurons as Capacitors

A conceptualization where neurons store energy by accumulating two electrical charges near one another but separated, releasing energy by removing this separation.

Phospholipid Bilayer

The lipid membrane that surrounds a neuron, making it difficult for ions to flow through directly.

Resting Membrane Potential

The electrical potential difference across the neuron's membrane when it is not actively transmitting a signal, typically around -70 mV.

Threshold of Excitation

The critical level of depolarization that must be reached for an action potential to fire, usually around -65 mV.

Refractory Period

A period following an action potential during which the neuron is less likely or unable to fire another action potential, due to the inactivation of Na+ channels and continued K+ efflux.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration across a membrane.

Electrostatic Pressure

The force exerted by electrical charges that causes ions to move towards areas of opposite charge.

Sodium-Potassium Transporter (Na-K Pump)

A protein pump that actively transports 3 sodium ions out of the cell and 2 potassium ions into the cell, maintaining the ionic concentration gradients necessary for neural activity.

Rate Law

The principle that variations in the intensity of information conveyed by a neuron are encoded by its firing rate, not by the amplitude of individual action potentials.

Myelin Sheath

An insulating layer of fatty material that surrounds axons, allowing for faster and more efficient propagation of action potentials.

Nodes of Ranvier

Gaps in the myelin sheath along an axon where action potentials are regenerated.

Synapse

The junction between two neurons where electrical or chemical signals are transmitted from one neuron to another.

Synaptic Vesicles

Small, spherical sacs in the presynaptic terminal button that contain neurotransmitters.

Neurotransmitter Release

The process by which synaptic vesicles fuse with the presynaptic membrane, facilitated by calcium entry, to release neurotransmitters into the synaptic cleft.

Kiss and Run

A mode of synaptic vesicle recycling where vesicles briefly fuse with the presynaptic membrane to release neurotransmitters, then detach and are refilled without fully collapsing.

Ionotropic Receptors

Receptors that are ligand-gated ion channels, opening directly in response to neurotransmitter binding to allow ion flow.

Metabotropic Receptors

Receptors that are G protein-coupled, indirectly affecting ion channels or activating second messengers inside the cell upon neurotransmitter binding.

Excitatory Postsynaptic Potentials (EPSPs)

Depolarizations of the postsynaptic membrane that increase the likelihood of the neuron firing an action potential, often mediated by Na+ or Ca2+ influx.

Inhibitory Postsynaptic Potentials (IPSPs)

Hyperpolarizations of the postsynaptic membrane that decrease the likelihood of the neuron firing an action potential, often mediated by K+ efflux or Cl- influx.

Reuptake

The process by which neurotransmitters are reabsorbed into the presynaptic terminal, often via transporter proteins, to terminate their action.

Enzymatic Deactivation

The process by which enzymes in the synaptic cleft break down neurotransmitters, terminating their action (e.g., Acetylcholinesterase breaking down Acetylcholine).

Autoreceptors

Receptors located on the presynaptic neuron that respond to the neurotransmitter released by that neuron, typically providing inhibitory feedback.

Gap Junctions

Electrical synapses where the membranes of two neurons are in direct contact, allowing direct ionic flow and electrical coupling between cells.

Hodgkin-Huxley Model

A mathematical model developed in 1952 that explicitly describes how neurons function and produce action potentials based on ion flow measured from squid axons.

Markov Kinetic Models

Mathematical models used to describe the state shifts of receptors (e.g., unbound, bound, open, closed) and their transitions in response to neurotransmitter binding.

Runge-Kutta Method

A numerical method used to solve initial value problems for differential equations, commonly employed in neuroscience to model phenomena that change over time.