Plateau potentials

Definition

Plateau potentials are prolonged depolarizations in neurons that can sustain action potentials over extended periods. This phenomenon is crucial in the functioning of central pattern generators, where rhythmic motor patterns, such as locomotion, are generated. The ability of plateau potentials to maintain neuronal excitability supports the generation of rhythmic outputs essential for coordinated movements.

5 Must Know Facts For Your Next Test

1. Plateau potentials can be triggered by various inputs, including synaptic stimulation and intrinsic membrane properties of the neuron.
2. They help facilitate sustained firing of neurons in central pattern generators, allowing for the continuous output necessary for rhythmic activities like locomotion.
3. The presence of certain ion channels, particularly calcium channels, plays a crucial role in the generation and maintenance of plateau potentials.
4. Unlike typical action potentials, plateau potentials can last seconds to minutes, contributing to the prolonged excitability of neurons involved in motor control.
5. Dysregulation of plateau potentials may lead to abnormal motor patterns or contribute to neurological disorders affecting movement.

Review Questions

• How do plateau potentials contribute to the function of central pattern generators in controlling locomotion?
  • Plateau potentials enable neurons within central pattern generators to maintain prolonged depolarization, which allows them to sustain action potentials necessary for producing rhythmic motor patterns. This sustained excitability supports continuous output during locomotion, facilitating coordinated movements essential for walking or running. Without plateau potentials, these circuits would struggle to maintain the rhythmic activity required for such tasks.
• Discuss the role of ion channels in generating and maintaining plateau potentials in neurons.
  • Ion channels, particularly voltage-gated calcium channels and certain potassium channels, play a vital role in generating and maintaining plateau potentials. When neurons receive stimuli that depolarize their membranes, these calcium channels open, allowing calcium ions to enter the cell. This influx of calcium contributes to a sustained depolarization that prolongs the action potential phase. The balance between opening and closing various ion channels determines the duration and strength of the plateau potential.
• Evaluate the implications of abnormal plateau potentials on locomotor functions and potential neurological disorders.
  • Abnormalities in plateau potentials can disrupt normal locomotor functions by impairing the ability of central pattern generators to produce rhythmic outputs effectively. Such dysregulation might manifest as abnormal movement patterns or conditions like spasticity or ataxia. Investigating these disturbances could provide insights into various neurological disorders, highlighting the importance of understanding plateau potentials in both healthy and diseased states.

Related terms

Central pattern generators:

Neuronal circuits that produce rhythmic outputs without requiring sensory feedback, vital for controlling repetitive movements like walking or swimming.

Action potential: A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane, which is fundamental for neuronal signaling.

Neurotransmitter: Chemical messengers released by neurons that transmit signals across synapses, playing a key role in modulating neuronal activity and influencing plateau potentials.