Alejandro Grau-perales, PhD
Postdoctoral Fellow

Alejandro obtained his M.Sc in Neuroscience in 2015 and his Ph.D. in 2019 at the Gallo Lab from the Institute of Neurosciences of the University of Granada (Spain) where he focused on identifying the brain circuit responsible for safe taste recognition memory in rodents and how its activity is altered with non-pathological aging as an early indicator of mild cognitive decline. In 2020, he joined the Fenton Lab at NYU, where he studied the role of atypical protein kinases (PKMz and PKCi/l) in the molecular and physiological long-term maintenance of synaptic mechanisms in the hippocampus that allow episodic-like memories to be maintained across long periods of time, so they can be in principle retrieved in the future as information for guiding behavior. As a postdoc in the Castellano lab, he is interested in understanding the role of extracellular matrix remodeling proteins (MMPs and TIMPs) in the development of functional changes in hippocampal circuits that can lead to imbalanced cell excitability, causing changes that lead to accumulation of amyloid-beta and ultimately cognitive decline.


Samuele Petridis
Associate Researcher

Samuele Petridis graduated from Providence College in 2023 with a B.S. in Biology, a B.A. in Psychology, and a Neuroscience Certificate. In his undergraduate years, he worked in the Rhode Island Resilience Lab at Warren Alpert Medical School at Brown University under Dr. Nicole Nugent on a project that examines the interplay between social context and physiology on psychological outcomes in trauma-exposed adolescents. In addition, he worked under Dr. Ileana Soto at Providence College on the role of VGLUT transporters in Niemann-Pick Disease Type C. In his time in the Castellano Lab, he will examine the effects of blood-borne factors, such as TIMP2, on mechanisms of adult neurogenesis and the implications for plasticity in aged mice. Outside of lab, Samuele enjoys cooking, traveling, and playing basketball.


Brittany Hemmer
PHD Student

Brittany received her B.S. in Biology, B.A. in Psychology, and Neuroscience Certificate from Providence College in 2017. As an undergraduate, Brittany spent 3 years in the Neuroscience and Animal Cognition laboratory studying the effects of aging and social housing on learning and memory. After graduation, to explore her burgeoning interest in neuroimmunology, she worked in the Laboratory for Aging Neuroscience at Brigham and Women’s Hospital and examined the neurobiological and immunological basis of memory dysfunction in the aged brain following anesthesia and surgery. As a PhD student and current NRSA/F31 fellow in the Castellano lab, Brittany aims to elucidate how blood-borne factors influence glial cells to shape brain aging and affect the development of neurodegenerative diseases like Alzheimer’s disease. Outside of research, Brittany enjoys participating in neuroscience outreach, traveling with friends, and scuba diving (when the opportunity arises)


Sarah Philippi
PhD Student

Sarah received her B.S. in Cellular & Molecular Biology, Psychology, and minor in Chemistry from the University of Wisconsin-Milwaukee (UWM) in 2019. From 2016-2020, Sarah worked in Dr. Karyn Frick's Neuroendocrinology of Memory Lab where she studied the neurobiology of learning and memory using sex-steroid hormones in mouse models of menopause and Alzheimer's disease pathology. During this time, she contributed to work investigating the influence of sex, APOE genotype, and 17β-estradiol on behavioral and molecular phenotypes in EFAD-tg mice. As a graduate student in the Castellano lab, Sarah's primary research interests involve investigating peripheral factors that may be protective, or deleterious, in normal aging and Alzheimer's disease. When she's not in the lab, Sarah is most likely exploring New York's restaurant scene with friends or practicing her embroidery.


Kevin spehar
Md/phd student

Kevin graduated from Washington University in St. Louis in 2019 majoring in Biomedical Engineering and Biochemistry with minors in computer science, electrical engineering, and bioinformatics. At WashU, he developed a novel super-resolution imaging method to study amyloid structures at nanometer resolution for extended time periods in the Bieschke and Lew Labs. Afterwards, he worked at the National Institute on Aging, where he studied aging in hematopoietic stem cells in the Beerman Lab. As an MD-PhD student in the Castellano Lab, Kevin aims to better characterize glial biology in aging and Alzheimer's disease. Outside the lab, Kevin enjoys playing badminton, playing board games, and exploring restaurants.


ralphyn pallikunnath
Masters Student/Research Assistant

Ralphyn Pallikunnath received her B.S. in Biology and minor in Chemistry from University of San Francisco in 2020. During her undergraduate years, Ralphyn studied changes in emotion regulation across a range of neurodegenerative disorders. As a masters student in the Castellano lab, Ralphyn has been interested in blood-borne factors that affect the development of Alzheimer's disease pathology. In her free time, Ralphyn enjoys exploring New York, traveling, dancing, and spending time with friends.


Suhani yerapathi
Masters Student

Suhani received her B.A in Psychology, Cognitive Science, and minor in Biology from Rutgers University in 2023. During her undergraduate degree, Suhani researched the role of microglia in opioid addiction with Dr. Mark West. She also worked on a project with Dr. Pinar Ayata at the Advanced Science Research Center (CUNY) focusing on the epigenetic effects of climate change on microglial metabolism and stress. In 2023, Suhani completed her undergraduate thesis with Dr. Alexander Kusnecov studying how the nociceptin/orphanin FQ receptor regulates microglia-astrocyte responses during illness. As a masters student in the Castellano lab, Suhani is interested in studying how blood-borne factors affect the integrity of the blood-brain-barrier and glial cells in the context of Alzheimer’s pathology. Outside of the lab, Suhani enjoys traveling, cooking, learning new hobbies, and spending time with her dog.


Laura HIRSCHFIELD
undergraduate research assistant

Laura is a rising junior at Princeton University, pursuing a BA in Neuroscience. After her freshman year at Princeton, Laura took a covid-gap-year, during which time she worked in Michael Levine’s lab at Princeton’s Lewis Sigler Institute for Integrative Genomics. There, she worked on constructing a brain map for a proto-vertebrate using scRNA-seq technology. Laura has also worked in Peter Heeger’s Lab at Mount Sinai doing transplant immunology research. In the Castellano Lab, she is interested in exploring the effects of TIMP2 on the microglial response to neuroinflammation. She is excited to apply her past studies and research experiences to investigate neuroimmunology and neurodegeneration, especially in the context of AD. After college, Laura plans to continue doing neuroscience research and later work towards an MD or MD/PhD. Outside of the lab, Laura enjoys cooking and baking, playing piano and guitar, and spending time with her dog.