Marcia Hillary Ratner, PhD, DABT

Biography

Dr. Ratner is a Board-Certified Toxicologist and Behavioral Neuroscientist. She earned her doctoral degree in Behavioral Neuroscience from the Chobanian and Avedisian School of Medicine where she trained in the Department of Neurology under the supervision of Drs. Robert G. Feldman, MD and Raymon Durso, MD. During her doctoral training, she was an active member of the Environmental and Occupational Neurology Program where she gained her expertise in neurotoxicology. Dr. Ratner’s dissertation research which revealed a younger age at onset of sporadic Parkinson’s disease among subjects occupationally exposed to metals such as manganese and pesticides has been replicated by other investigators demonstrating the enduring importance as well as the rigor and reproducibility of her research (see Ratner et al., 2015 and Gamache et al., 2019). Dr. Ratner subsequently completed a three-year National Institute on Aging funded Post-Doctoral Fellowship in the Biochemistry of Aging under the supervision of Dr. David H. Farb, here in the Department of Pharmacology, Physiology and Biophysics. Her postdoctoral training has provided Dr. Ratner with the additional expertise necessary to use preclinical animal models combined with in vivo electrophysiological techniques to effectively investigate how chemical exposures modulate neural network activity in vivo.

Her training at the bench and bedside has provided Dr. Ratner with genuine translational research experience in clinical as well as preclinical neuroscience and neurotoxicology. This unique combination of experience enables Dr. Ratner to effectively evaluate how chemicals modify neurological function and the progression of neurodegenerative disease in humans and animal models.

Dr. Ratner’s research currently focuses on clinical and preclinical investigations of how chemicals alter neurological function in healthy subjects and those with neuropsychiatric and age-related neurodegenerative diseases. She and her clinical colleagues are currently investigating the use of serum exosomal alpha synuclein levels as a biomarker for differentiating young onset Parkinson’s disease from parkinsonism in welders exposed to manganese (see Rutchik and Ratner, 2019). Her preclinical research employs basic behavioral and in vivo electrophysiological techniques to investigate how chemicals modify hippocampal neural network activity and disease progression in animal models of age-related amnestic mild cognitive impairment and Alzheimer’s disease. The major advantages of in vivo electrophysiology over noninvasive measures of neurological function such as surface electroencephalogram and functional imaging studies of regional cerebral blood flow is found in the ability of this powerful technology to differentiate the activity of inhibitory interneurons from that of excitatory pyramidal cells both across brain regions and within subregions. This highly translational approach is well suited for target-based as well as repurposing studies of drug-induced changes in both single unit activity and local field potentials. Dr. Ratner’s paper looking at the effects of co-administration of low doses of the FDA approved anti-epileptic drugs levetiracetam and valproic acid demonstrates that these compounds improve aspects of place cell firing dynamics including increasing spatial information content in aged rats (Hippocampus, 2015). The observations of Dr. Ratner and her colleagues suggest that the specificity with which, not just the rate at which, a neuron fires plays an important role in learning and memory function and, that interventions designed to increase the specificity with which hippocampal pyramidal cells fire may improve memory function in subjects with age-related amnestic mild cognitive impairment (aMCI). She and her colleagues have also demonstrated that pharmacologically decreasing tonic inhibition in wild type rats increases place cell firing rates without abolishing place cell remapping while at the same time increasing the amplitude of sharp wave ripples implicated in memory consolidation. The observed augmentation of ripple amplitude in wild type rats is not seen in TgF344-AD rats implicating disrupted tonic inhibition in the early stages of AD (Heliyon, 2021). Her work has played a key role in promoting and advancing the use of in vivo electrophysiology as an applied science in preclinical neurotoxicology research (Frontiers in Toxicology, 2022).

Dr. Ratner is an active member of the American Academy of Clinical Toxicology, American Academy of Neurology, American Psychological Association and the Society of Toxicology. Dr. Ratner is a Review Editor for the journal Frontiers in Toxicology and, she serves as an ad hoc peer reviewer for several other professional medical and scientific journals including: Neurology, Toxicology, Clinical Toxicology, Food and Chemical Toxicology, and BMC Pharmacology and Toxicology. Dr. Ratner has also served as a scientific advisor, on the role of occupational exposures to chemicals in Parkinson’s disease, to the Workplace Safety Insurance Board of Ontario, Canada. In addition, she regularly serves as an ad hoc advisor to the pharmaceutical and legal services industries.

Dr. Ratner has expertise and training in the following areas:

Toxicology (Board Certified in Toxicology)
Stereotactic Brain Surgery (Rodents)
In vivo Electrophysiology and EEG
Preclinical Animal Models of Behavior
Neurophysiology
Clinical Neurological Assessment
Human Neuropsychological Assessment
Neuroimaging