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Updated: Jun 26, 2026
07:52
Electroencephalography Measurements in Awake Marmosets Listening to Conspecific Vocalizations
Published on: July 26, 2024
Sensory responses during sleep in primate primary and secondary auditory cortex
1Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21025, USA.
Summary
Sensory signals reach the auditory cortex during sleep, challenging the idea that the thalamus blocks them. Auditory cortical responses are preserved, suggesting altered sensory processing may occur during sleep.
Area of Science:
- Neuroscience
- Sleep Science
- Auditory Neuroscience
Background:
- Sensory stimuli typically do not reach conscious perception during sleep.
- The thalamus has been traditionally viewed as a gatekeeper preventing sensory relay to the cortex during sleep.
- The impact of sleep on cortical responses to sensory signals remains incompletely understood.
Purpose of the Study:
- To investigate the impact of natural sleep on auditory cortical responses.
- To determine if the thalamus effectively gates sensory information flow to the cortex during sleep.
- To characterize neural activity patterns in auditory cortical areas during different sleep stages.
Main Methods:
- Electrophysiological recordings from primary and secondary auditory cortical areas in naturally sleeping marmoset monkeys.
- Comparison of single-neuron responses to acoustic stimulation during wakefulness and sleep (slow-wave and rapid-eye movement sleep).
- Analysis of neural discharge patterns and response preservation across sleep cycles.
Main Results:
- Single neurons in primary auditory cortex exhibited bidirectional response changes (increases or decreases) during sleep compared to wakefulness.
- Secondary auditory cortex (lateral belt) also showed bidirectional response modulation without a clear depressive effect of sleep.
- Averaged sound-evoked activity in both auditory cortical areas was well-preserved during sleep, with similar discharge patterns to wakefulness.
- Neural responses were consistently observed across multiple sleep cycles and stages.
Conclusions:
- The thalamus may be less effective at gating sensory information to the cortex during sleep than previously assumed.
- A dynamic pattern of neuronal activation and deactivation occurs in the auditory cortex during sleep.
- Preserved neural signaling in secondary auditory cortex suggests the possibility of altered auditory information processing during sleep.
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