Abstract
0287 The Cortex and Parafacial Zone of Infant Rats Exhibit Parallel Homeostatic Responses to Sleep Deprivation
Sleep (New York, N.Y.), Vol.48(Supplement_1), pp.A125-A125
05/19/2025
DOI: 10.1093/sleep/zsaf090.0287
Abstract
Introduction
Beginning around postnatal day 12 (P12) in rats, quiet sleep (QS, or NREM sleep) increases at the expense of active sleep (AS, or REM sleep). The developmental increase in QS is accompanied by the sudden emergence of cortical delta (0.5-4 Hz). We recently discovered a novel delta rhythm in a medullary structure, the parafacial zone (PZ), a region implicated in regulating QS in adults. At P12, PZ delta was generated locally and was highly coherent with cortical delta. We hypothesized that if PZ delta is a homolog of cortical delta, then the two rhythms should exhibit parallel homeostatic responses to sleep deprivation.
Methods
P12 rats (n=8) were deprived of sleep for 30 minutes while recording from the PZ and frontal cortex. Cold stimuli were applied to the snout to induce arousal whenever cortical delta was observed. After deprivation, pups were allowed to sleep undisturbed for an additional 60 minutes for recovery. Control pups (n = 8) were matched for sex and age and were left undisturbed for 90 min. PZ and cortical LFP, PZ unit activity, respiration, and behavioral measures (EMG, video) were obtained for each pup.
Results
Sleep deprivation produced intense sleep pressure, as operationalized by the need to increase the rate of arousing stimulations over the 30-minute deprivation period. Over the recovery period, PZ and cortical delta showed parallel homeostatic responses consisting of initially increased delta power that decreased in lock-step toward baseline over time. The durations of QS and AS showed a similar pattern. Brief arousals (< 10 s) occurred more often during the recovery period; these arousals elicited simultaneous decreases in delta power in PZ and cortex. Surprisingly, pups breathed more deeply at the start of the recovery period, providing additional evidence of a link between respiration and delta power at this age.
Conclusion
These results support the notion that PZ and cortical delta are closely linked components within the sleep-regulatory system. Also, the findings suggest intimate connections between delta- and respiration-generating structures in the brainstem, a possibility that is currently being investigated.
Details
- Title: Subtitle
- 0287 The Cortex and Parafacial Zone of Infant Rats Exhibit Parallel Homeostatic Responses to Sleep Deprivation
- Creators
- Midha Ahmad - University of IowaGreta Sokoloff - University of IowaMark Blumberg - University of Iowa
- Resource Type
- Abstract
- Publication Details
- Sleep (New York, N.Y.), Vol.48(Supplement_1), pp.A125-A125
- Publisher
- Oxford Academic; CARY
- DOI
- 10.1093/sleep/zsaf090.0287
- ISSN
- 0161-8105
- eISSN
- 1550-9109
- Grant note
- NIH: R37-HD081168
NIH grant R37-HD081168 to M.S.B.
- Language
- English
- Date published
- 05/19/2025
- Academic Unit
- Psychological and Brain Sciences; Iowa Neuroscience Institute
- Record Identifier
- 9984824331802771
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