title: Spontaneous activity and functional connectivity in the developing cerebellorubral system.
abstract: The development of the cerebellar system depends in part on the emergence of functional connectivity in its input and output pathways. Characterization of spontaneous activity within these pathways provides insight into their functional status in early development. In the present study we recorded extracellular activity from the interpositus nucleus (IP) and its primary downstream target, the red nucleus (RN), in unanesthetized rats at postnatal days 8 (P8) and P12, a period of dramatic change in cerebellar circuitry. The two structures exhibited state-dependent activity patterns and age-related changes in rhythmicity and overall firing rate. Importantly, sensory feedback (i.e., reafference) from myoclonic twitches (spontaneous, self-generated movements that are produced exclusively during active sleep) drove neural activity in the IP and RN at both ages. Additionally, anatomic tracing confirmed the presence of cerebellorubral connections as early as P8. Finally, inactivation of the IP and adjacent nuclei using the GABAA receptor agonist muscimol caused a substantial decrease in neural activity in the contralateral RN at both ages, as well as the disappearance of rhythmicity; twitch-related activity in the RN, however, was preserved after IP inactivation, indicating that twitch-related reafference activates the two structures in parallel. Overall, the present findings point to the contributions of sleep-related spontaneous activity to the development of cerebellar networks.
authors.affiliation: Department of Psychological & Brain Sciences, University of Iowa, Iowa City, Iowa;
authors.forename: Carlos
authors.identifier: 0000-0002-1036-1673
authors.initials: C
authors.lastname: Del Rio-Bermudez
authors.affiliation: Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa;
authors.forename: Alan M
authors.initials: AM
authors.lastname: Plumeau
authors.affiliation: Department of Psychological & Brain Sciences, University of Iowa, Iowa City, Iowa;
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Sattler
authors.affiliation: Department of Psychological & Brain Sciences, University of Iowa, Iowa City, Iowa; DeLTA Center, University of Iowa, Iowa City, Iowa.
authors.forename: Greta
authors.identifier: 0000-0003-3651-1980
authors.initials: G
authors.lastname: Sokoloff
authors.affiliation: Department of Psychological & Brain Sciences, University of Iowa, Iowa City, Iowa; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa; Department of Biology, University of Iowa, Iowa City, Iowa; and DeLTA Center, University of Iowa, Iowa City, Iowa mark-blumberg@uiowa.edu.
authors.forename: Mark S
authors.identifier: 0000-0001-6969-2955
authors.initials: MS
authors.lastname: Blumberg
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D004576:Electromyography; D005260:Female; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D008297:Male; D008839:Microelectrodes; D009068:Movement / Q000187:drug effects / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010507:Periodicity; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism; D012012:Red Nucleus / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*
chemical_list: D058785:GABA-A Receptor Agonists; D011963:Receptors, GABA-A; D009118:Muscimol
keywords: cerebellum; myoclonic twitching; red nucleus; rhythmicity; sleep