Inhibitory synaptic input to edge cells during fictive locomotion

Area of Science:

• Neuroscience
• Spinal Cord Physiology
• Sensory Receptors

Background:

• Edge cells are stretch receptors located in the lateral margin of the lamprey spinal cord.
• Their activity is hypothesized to influence the spinal central pattern generator (CPG), which controls locomotion.
• Understanding this interaction is crucial for comprehending motor control mechanisms.

Purpose of the Study:

• To investigate the functional relationship between lamprey edge cells and the spinal central pattern generator (CPG).
• To determine if spinal CPG activity modulates the sensitivity of edge cells.

Main Methods:

• Intracellular recordings were performed on edge cells in the lamprey spinal cord.
• Recordings were conducted during episodes of fictive locomotion, a model for CPG activity.
• The presence and nature of postsynaptic potentials in edge cells were analyzed.

Main Results:

• All recorded edge cells exhibited numerous chloride-sensitive inhibitory postsynaptic potentials (IPSPs).
• These IPSPs indicate a direct influence of neuronal activity on edge cells.
• The chloride-sensitivity suggests a specific inhibitory neurotransmitter system is involved.

Conclusions:

• The study provides evidence that edge cell sensitivity is modulated by the activity of the spinal CPG.
• This modulation occurs via inhibitory synaptic input to the edge cells.
• These findings reveal a feedback mechanism within the lamprey spinal cord circuitry.