Non-awaking basal forebrain stimulation enhances auditory cortex responsiveness during slow-wave sleep

Area of Science:

• Neuroscience
• Sleep Research
• Auditory Processing

Background:

• The basal forebrain (BF) plays a crucial role in modulating cortical activity, including during sleep.
• Cholinergic pathways originating from the BF are known to influence cortical plasticity and responsiveness.
• Understanding how BF input affects sensory processing during specific sleep stages like slow-wave sleep (SWS) is important for cognitive function.

Purpose of the Study:

• To investigate the effect of non-arousing basal forebrain (BF) stimulation on auditory cortex responses during slow-wave sleep (SWS).
• To determine the role of cholinergic pathways in mediating BF-induced facilitation of cortical responses during SWS.

Main Methods:

• Multi-unit recordings were performed bilaterally in the auditory cortex of subjects during SWS.
• Unilateral BF stimulations were delivered, paired with auditory tone presentations.
• The effect of BF stimulation on tone-evoked responses was assessed, and the role of cholinergic input was examined using atropine.

Main Results:

• Non-arousing BF stimulations significantly facilitated tone-evoked responses in the ipsilateral auditory cortex during SWS.
• This ipsilateral facilitation was blocked by atropine, indicating a cholinergic mechanism.
• No significant effect was observed in the contralateral auditory cortex.

Conclusions:

• Non-arousing cholinergic input from the basal forebrain can selectively enhance cortical responsiveness in the ipsilateral auditory cortex during SWS.
• These findings highlight a mechanism by which sleep-specific brainstem inputs modulate sensory processing.
• The study demonstrates that BF cholinergic projections are sufficient to increase cortical excitability during SWS without causing arousal.