The use of immature rodents to study physiologic aspects of cortical development requires high-quality recordings electroencephalography (EEG) with simultaneous video recording (vEEG) of behavior. Normative developmental vEEG data in control animals are fundamental for the study of abnormal background activity in animal models of seizures or other neurologic disorders. Electrical recordings from immature, freely behaving rodents can be particularly difficult because of the small size of immature rodents, their thin and soft skull, interference with the recording apparatus by the dam, and other technical challenges. In this report of the TASK1 Working Group 2 (WG2) of the International League Against Epilepsy/American Epilepsy Society (ILAE/AES) Joint Translational Task Force, we provide suggestions that aim to optimize future vEEG recordings from immature rodents, as well as their interpretation. We focus on recordings from immature rodents younger than 30 days old used as experimental controls, because the quality and correct interpretation of such recordings is important when interpreting the vEEG results of animals serving as models of neurologic disorders. We discuss the technical aspects of such recordings and compare tethered versus wireless approaches. We also summarize the appearance of common artifacts and various patterns of electrical activity seen in young rodents used as controls as a function of behavioral state, age, and (where known) sex and strain. The information herein will hopefully help improve the methodology of vEEG recordings from immature rodents and may lead to results and interpretations that are more consistent across studies from different laboratories.

Department of Developmental Epileptology Institute of the Czech Academy of Sciences Czech Academy of Sciences Prague Czech Republic

Department of Epilepsy Movement Disorders and Physiology Kyoto University Graduate School of Medicine Kyoto Japan

Department of Neurosurgery University of Utah School of Medicine Salt Lake City Utah U S A

Department of Pediatrics University of Toronto Toronto Ontario Canada

Department of Physiology Faculty of Medicine Istanbul Bilim University Istanbul Turkey

Division of Neurology Department of Pediatrics School of Medicine Translational Epilepsy Research Program University of Colorado Aurora Colorado U S A

Division of Neurology The Hospital for Sick Children Toronto Ontario Canada

Epilepsy Unit Carlo Besta Neurological Institute Foundation Milan Italy

Laboratory of Developmental Epilepsy Saul R Korey Department of Neurology Dominick P Purpura Department of Neuroscience Isabelle Rapin Division of Child Neurology Albert Einstein College of Medicine Einstein Montefiore Epilepsy Center Montefiore Medical Center Bronx New York U S A

Program of Neurosciences and Mental Health Peter Gilgan Center for Research and Learning SickKids Research Institute Toronto Ontario Canada

PROTECT INSERM UMR1141 APHP University Paris Diderot Sorbonne Paris Cité Paris France

University Hospital Robert Debré Service of Pediatric Neurology Paris France

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The role of electroencephalography in epilepsy research-From seizures to interictal activity and comorbidities