Irina Topchiy, PhD

Research Interests
Neurophysiology of Sleep
Central Mechanisms of Respiration and Breathing Disorders
Neuropharmacology
Animal Models for Mechanisms of Cognitive Dysfunction in Sleep Apnea

My research interests are focused on the neurophysiology of sleep and its role in normal and pathological respiratory regulation. Particularly, I investigate the role of pontine structures of the brain in respiratory control and mechanisms of sleep apnea.

In my current project, I explore the mechanisms of cognitive dysfunctions in sleep apnea syndrome. Sleep-related breathing disorders, including sleep apnea, are often associated with cognitive deficits such as impaired attention, reduced working and long-term memory, impaired learning, and cognitive flexibility. Cognitive impairments can be worsened by acute apnea exacerbation that occurs regularly in individuals with sleep apnea.

We and others demonstrated that the group of cholinergic neurons in the pons - pedunculopontine tegmentum (PPT) – is engaged both in sleep/wake homeostasis and respiration. Besides, PPT is a powerful source of ascending and descending cholinergic projections relevant to cognition, memory, and autonomic function. A central hypothesis of my research is that acute increase of spontaneous sleep-related apnea perturbs brain cholinergic signaling, contributing impaired cognitive functioning.

I investigate how apnea exacerbation affects cholinergic signaling in PPT and its projections related to memory, learning and cognitive flexibility in a rat model of sleep apnea. Understanding these mechanisms will provide new insights into the pathophysiology of sleep related breathing disorders and can translate into better and individualized treatment approaches to alleviate cognitive deficits attendant to apnea exacerbation.

Education & Training
MS Biology Rostov State University, Russia
PhD Physiology Rostov State University, Russia
Post-doctoral Fellow Washington State University
Post-doctoral Fellow Harvard University

Professional Memberships
Society for Neuroscience
Sleep Research Society

Kang D, Ding M, Topchiy I, Kocsis B. Reciprocal interactions between medial septum and hippocampus in theta generation: Granger causality decomposition of mixed spike-field recordings. Frontiers in Neuroanatomy. 2017; 11, 120.

Kang D, Ding M, Topchiy I, Shifflett L, Kocsis B. Theta-rhythmic drive between medial septum and hippocampus in slow wave sleep and microarousal: A Granger causality analysis. J Neurophysiol. 2015; 114(5):2797-803.

Topchiy I, Amodeo D, Ragozzino M, Waxman J, Radulovacki M, Carley DW. Acute Exacerbation of Sleep Apnea by Hyperoxia Impairs Cognitive Flexibility in Brown-Norway Rats, Sleep.2014; 37(11):1851-1861.

Fink AM, Topchiy I, Ragozzino ME, Amodeo, DA, Waxman JA, Radulovacki M, Carley DW. Brown Norway and Zucker Lean Rats Demonstrate Circadian Variation in Ventilation and Sleep Apnea. Sleep. 2014, 37(4): 715-721.

Topchiy I, Radulovacki M, Waxman J, Carley DW. Impact of the vagal feedback on cardiorespiratory coupling in anesthetized rats. Resp. Physiol. Neurobiol. 2011, 175(3):375-82.

Topchiy I, Waxman J, Radulovacki M, Carley DW. Functional topography of respiratory, cardiovascular and pontine-wave responses to glutamate microstimulation of the pedunculopontine egmentum of the rat. Resp. Physiol.Neurobiol. 2010, 173(1):64-70.

Topchiy I, Radulovacki M, Waxman J, Carley DW. Cardiorespiratory effects of intertrigeminal area stimulation in vagotomized rats. Brain Research, 2009, 1250:120-129.

Topchiy IA, Wood RM, Peterson B, Navas JA, Rojas MJ, Rector DM. Conditioned lick behavior and evoked responses using whisker twitches in head restrained rats. Behav Brain Res 2009,197(1):16-23.

Li S, Topchiy I, Kocsis B. The effect of atropine administered in the medial septum or hippocampus on high and low frequency theta rhythms in the hippocampus of urethane anesthetized rats. Synapse. 2007, 61(6):412-419.

Kocsis B and Topchiy I. Intermittent coupling between cardiorespiratory oscillations and neuronal discharge in the medulla of freely moving rats. FASEB Journal, 2007, 21:582.45.

Rector DM, Topchiy IA, Carter KM, Rojas MJ. Local functional state differences between rat cortical columns. Brain Res. 2005, 1047(1):45-55.