Neurons & Neural Firing

This set of vocabulary flashcards covers the anatomy of neurons, the physiological steps of action potentials, and the different methods used by the nervous system to code for stimulus intensity and quality.

Neurons

Cells that are not physically connected and come in many different types varying in shape, size, and connections.

Main parts of a neuron

The three components consisting of the soma, dendrites, and axons.

Soma

The cell body of a neuron from which processes like dendrites and axons extend.

Receptor cells

Sensory neurons that receive signals in either a physical form or a chemical form.

Action Potentials

A process occurring only in axons that can travel at speeds up to $100\,\text{meters/sec}$ and remains constant in strength as it moves.

Resting Potential

The electrical state of most neurons between $-60$ and $-80\,\text{millivolts}$ relative to extracellular space.

Depolarization

The phase in an action potential that occurs when sodium channels open.

Hyperpolarization

The phase in an action potential that occurs as potassium channels begin to open.

Ion pump

A mechanism that restores the normal distribution of $Na^+$ and $K^+$ ions after an action potential.

Refractory Period

A specific period in the steps of an action potential that follows hyperpolarization and the restoration of ion distribution.

Myelin

A wrapping around axons where ion channels are unable to open, affecting how the action potential travels.

All or None Law

The principle stating that a neuron either fires completely or does not fire at all.

Synapse

The junction where the release of neurotransmitters occurs to pass a signal to the next neuron.

Intensity Coding

The process of representing how strong a stimulus is within the nervous system.

Quality Coding

The process of representing what type of stimulus is being perceived (e.g., through specificity, sparse, or population coding).

Temporal Codes

A possibility for quality coding that relies on the timing or rhythm of neural firing, such as "tap, tap, tap" versus "tap tap … tap tap."

Feature Detectors

Neurons in the visual system that respond to specific qualities of a stimulus.

Specificity Coding

A type of quality coding where a single neuron might respond to a complex stimulus, such as a specific face.

Sparse Coding

One of the three mentioned types of neural coding used to represent the quality of a stimulus.

Population Coding

A type of neural coding for stimulus quality involving the pattern of firing across a large group of neurons.