Lecture 22: Motor 4: Rhythmic Outputs

TL;DR

This content discusses the role of different brain regions and neural circuits in controlling movement and locomotion, including the influence of the cerebellum, corpus striatum, and neocortex.

Transcript

GERALD SCHNEIDER: This is where we were at the end of the last lecture. I think I said a little bit about how the cerebellum can fit into this kind of scheme and the corpus striatum. Now, concerning the corpus striatum, in this book of readings, there are some very interesting chapters here at the end about pathologies of corpus striatum. It starts... Read More

Key Insights

• 🎮 The neocortex plays a significant role in motor control, with connections to the corpus striatum and thalamus.
• ❓ The limbic system influences movement and motivation through its connections with the neocortex and thalamus.
• 🧑‍🦼 Reflexes are important modulators of movement but are not critical for pattern generation and motor control.
• 🔠 Deafferentation studies reveal that central pattern generators can generate movement patterns even without sensory input.
• 🚜 Command neurons and command tracts are responsible for initiating specific movements, while central pattern generators contribute to generating rhythmic movements.

Questions & Answers

Q: How does the neocortex influence movement in higher mammals?

The neocortex has a direct output to the brainstem and spinal cord, as well as a larger output to the thalamus, which then projects to the motor cortex. This suggests that the neocortex plays a crucial role in motor control and movement.

Q: What are some examples of abnormal movements related to the corpus striatum?

Apart from Huntington's chorea and Parkinson's disease, there are other pathologies of the corpus striatum that can cause abnormal movements, such as dyskinesias. These include specific chapters in the suggested readings, "Newton's Madness, Further Tales of Clinical Neurology" by Harold Klawans.

Q: How does the respiratory rhythm occur and what factors influence it?

The respiratory rhythm is generated by a central pattern generator in the brainstem, specifically the inspiratory and expiratory centers. Feedback from stretch receptors in the lungs and CO2 levels in the blood modulate the respiratory rhythm.

Q: How do locomotor patterns and interlimb coordination occur?

Locomotor patterns and interlimb coordination are attributed to central pattern generators in the spinal cord. Coordinating neurons connect different levels of the spinal cord to ensure proper movement coordination.

Summary & Key Takeaways

• The content emphasizes the importance of the neocortex in mammals, highlighting its extensive connections with the corpus striatum and thalamus.

• It discusses the role of the limbic system in controlling movement and its connections with the neocortex.

• The content also addresses other motor systems, such as reflex swallowing and the respiratory rhythm.