Cortical cells driven by the low-threshold tooth pulpal afferent in cats

Area of Science:

• Neuroscience
• Sensory processing
• Cortical mapping

Background:

• The somatosensory cortex processes sensory information from the body.
• Understanding the neural pathways for dental sensation is crucial for orofacial function.
• Previous research has not fully detailed the cortical representation of tooth pulp afferents.

Purpose of the Study:

• To investigate the input pattern and spatial distribution of tooth pulp-driven neurons (TPNs) in the cat cerebral cortex.
• To determine the functional properties and potential roles of TPNs in specific cortical areas.

Main Methods:

• Unitary activities of neurons were recorded in response to tooth pulp stimulation.
• Stimulation targeted upper and lower canine and molar tooth pulps.
• Neuronal responses were analyzed for location, response threshold, and afferent inputs.

Main Results:

• TPNs were identified in the deep layers of cortical areas 3a and 3b.
• Ipsilateral TPNs were located anteroventrally to contralateral TPNs; bilateral TPNs were situated between them.
• Area 3a TPNs exhibited lower activation thresholds than area 3b TPNs.
• Most area 3a TPNs received input from both tooth pulp afferents and low-threshold masseteric muscular afferents.

Conclusions:

• TPNs are spatially organized within the coronal gyrus based on stimulation laterality.
• Area 3a TPNs possess distinct properties, including lower thresholds and dual sensory inputs.
• These findings suggest a role for area 3a TPNs in orofacial motor functions.