Lecture 5 Central Pattern Generators (CPGs) and Rhythmic Behaviors

Flashcards covering the foundational concepts, experimental techniques, and specific cellular/network examples of Central Pattern Generators as discussed in Lecture 5.

Central Pattern Generator (CPG)

An elementary unit of behavior that generates rhythmic motor patterns without requiring feedback from sense organs.

Deafferentation

An experimental technique used to demonstrate central generation of rhythmic behaviors by removing sensory nerve input.

Immobilization

An experimental technique, usually involving neuromuscular blockade, used to study fictive motor patterns in the absence of movement.

Isolation

In vitro studies in which a portion of the nervous system is completely removed from the body to demonstrate the presence of a CPG.

Don Wilson

The researcher who first demonstrated the central generation of the basic flight motor pattern in locusts and used the term "central pattern generator" in 1965.

Fictive flight motor patterns

Rhythmic motor outputs recorded from central stumps of nerves in highly reduced preparations where all sensory feedback from wings has been eliminated.

Interneuron 501

A locust flight interneuron that is active during wing depression (downstroke) and can reset the timing of the entire flight rhythm.

Interneuron 301

A locust flight interneuron active during wing elevation (upstroke) that excites interneuron 501 via disinhibition.

Disinhibition

A circuit mechanism where one neuron (like 301) inhibits an inhibitory neuron to excite a third neuron (like 501).

Pure network oscillator

A system, such as the Tritonia swim CPG, in which oscillations result entirely from network interactions between neurons rather than intrinsic bursting properties.

Multi-component PSPs

Post-synaptic potentials involving parallel excitation and inhibition that are crucial for pattern generation in the Tritonia swim network.

Endogenous burster

A neuron capable of producing rhythmic bursts of action potentials in isolation.

Mutual excitation

A network building block where neurons excite each other to synchronize synergists.

Reciprocal inhibition

A network building block that requires relief from inhibition to cycle and is often used to alternate antagonistic muscles.

Székely ring

A cyclic inhibition network that must contain an odd number of elements to produce cycling or patterned activity.

Post-inhibitory rebound (PIR)

Also known as anode-break excitation, it is a brief self-excitation that follows the offset of hyperpolarizing inhibition, often involving the activation of $I_h$ current.

Plateau potentials

Prolonged depolarizing responses to a brief input, dominated by persistent inward currents such as $I_{NaP}$ and $I_{Ca(L)}$.

Spike frequency adaptation

An intrinsic cellular property where the frequency of action potentials decreases over time during a constant stimulus.

Reset experiment

A procedure where brief excitation or inhibition of a single neuron produces a permanent change in the timing of the whole motor pattern.

Entrainment

A condition where the motor pattern is locked to the timing of a neuron's activity, such that changing the neuron's burst frequency changes the whole motor pattern timing.

Photo-inactivation

A technique invented in the Selverston lab used to study the roles of individual cells by inactivating them using light.

$$I_h$$

A hyperpolarization-activated cation current (consisting of $Na^+$ and $K^+$) that contributes to post-inhibitory rebound.