Pial arteriolar vasomotion changes during cortical activation in rats

Area of Science:

• Neuroscience
• Vascular Biology
• Physiology

Background:

• Pial arteriole vasomotion, an oscillatory pattern, has been known since the 1980s.
• The influence of neural activation on vasomotion during neurovascular coupling (NVC) remains underexplored.
• Sciatic nerve stimulation is a validated model for investigating NVC, showing increased pial arteriolar diameter with neural activity.

Purpose of the Study:

• To investigate changes in pial arteriole vasomotion during NVC using a novel analytical approach.
• To characterize the spectral properties of vasomotion in response to neural activation.
• To explore the potential involvement of vasomotion in the mechanisms controlling NVC.

Main Methods:

• Utilized sciatic nerve stimulation to induce NVC in a rodent model.
• Analyzed pial arteriole oscillations by evaluating total spectral power in the 0.02-2.00 Hz range.
• Subdivided the frequency spectrum into seven overlapping bands to characterize oscillatory changes.

Main Results:

• A significant increase in total spectral power of pial arterioles was observed specifically over the stimulated hindlimb cortex, not the control whisker barrel cortex.
• The increase in total power was primarily driven by low-frequency oscillations (peaks at 0.03 and 0.08 Hz) and high-frequency oscillations (0.60-2.00 Hz).
• These spectral changes suggest the involvement of at least three distinct oscillatory mechanisms in NVC control.

Conclusions:

• Total spectral power is a viable metric for assessing vascular responses in NVC.
• Evidence suggests multiple frequency-dependent feedback loops (two low-frequency, one high-frequency) regulate NVC.
• Vasomotion plays a potential role in NVC, underscoring the oscillatory nature of neurovascular control mechanisms.