title: The Nature of the Sensory Input to the Neonatal Rat Barrel Cortex.
abstract: Sensory input plays critical roles in the development of the somatosensory cortex during the neonatal period. This early sensory input may involve: (1) stimulation arising from passive interactions with the mother and littermates and (2) sensory feedback arising from spontaneous infant movements. The relative contributions of these mechanisms under natural conditions remain largely unknown, however. Here, we show that, in the whisker-related barrel cortex of neonatal rats, spontaneous whisker movements and passive stimulation by the littermates cooperate, with comparable efficiency, in driving cortical activity. Both tactile signals arising from the littermate's movements under conditions simulating the littermates' position in the litter, and spontaneous whisker movements efficiently triggered bursts of activity in barrel cortex. Yet, whisker movements with touch were more efficient than free movements. Comparison of the various experimental conditions mimicking the natural environment showed that tactile signals arising from the whisker movements with touch and stimulation by the littermates, support: (1) a twofold higher level of cortical activity than in the isolated animal, and (2) a threefold higher level of activity than in the deafferented animal after the infraorbital nerve cut. Together, these results indicate that endogenous (self-generated movements) and exogenous (stimulation by the littermates) mechanisms cooperate in driving cortical activity in newborn rats and point to the importance of the environment in shaping cortical activity during the neonatal period.
  
  
  
  Sensory input plays critical roles in the development of the somatosensory cortex during the neonatal period. However, the origins of sensory input to the neonatal somatosensory cortex in the natural environment remain largely unknown. Here, we show that in the whisker-related barrel cortex of neonatal rats, spontaneous whisker movements and passive stimulation by the littermates cooperate, with comparable efficiency, in driving cortical activity during the critical developmental period.
authors.affiliation: Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia.
authors.forename: Dinara
authors.identifier: 0000-0001-8161-5012
authors.initials: D
authors.lastname: Akhmetshina
authors.affiliation: Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia.
authors.forename: Azat
authors.initials: A
authors.lastname: Nasretdinov
authors.affiliation: Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia.
authors.forename: Andrei
authors.initials: A
authors.lastname: Zakharov
authors.affiliation: Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia.
authors.forename: Guzel
authors.identifier: 0000-0001-6745-059X
authors.initials: G
authors.lastname: Valeeva
authors.affiliation: Laboratory of Neurobiology, Kazan Federal University, Kazan 420008, Russia, INMED/INSERM U901, Marseille 13273, France, and Aix-Marseille University, Marseille 13273, France roustem.khazipov@inserm.fr.
authors.forename: Roustem
authors.identifier: 0000-0002-6763-2841
authors.initials: R
authors.lastname: Khazipov
mesh_terms: D000344:Afferent Pathways / Q000502:physiology*; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005154:Facial Nerve / Q000502:physiology; D005260:Female; D008297:Male; D009068:Movement / Q000502:physiology; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000502:physiology*; D018709:Statistics, Nonparametric; D014110:Touch; D014738:Vibrissae / Q000294:innervation
keywords: EEG; barrel; development; neonate; whisker