Edward M. Merricks, Ph.D.

Edward M Merricks
PhD

About me

Ed is a research scientist. He's an Instructor in the Department of Neurology at Johns Hopkins Medicine and Neurodevelopmental Medicine at Kennedy Krieger Institute, splitting his time between NYC and Baltimore.

Outside being a nerd who enjoys coding for fun (see the pseudo-terminal version of this site!), he also:

Does some art (linocuts and paintings, primarily)
Plays a bit of music (trumpet and bass, mostly... fan of jazz)
Enjoys strolling around New York's parks (preferably with his dog)

Science!

My research focuses on the activity of populations of single neurons in epilepsy patients, particularly how the firing patterns of individual cells play a role in seizure onset and propagation, and how we might restrain seizures from spreading through cortex. To do this, I maintain continuous micro-electrode recordings in patients undergoing surgery to remove pathological tissue, and develop analytical methods to track individual neurons and explore their activity over days to weeks in order to interrogate the neuronal firing underlying a range of pathological activities.

I'm fortunate also to collaborate with various lab groups using these methods, exploring a range of neurological questions: from cell-type specific activity at the boundary of brain tumors, to auditory processing of music, to mechanisms underlying loss of consciousness.

For more details on all of these projects, see below for the peer-reviewed publications, book chapters and pre-prints or a selection of the software tools I've developed, or check out my GitHub, Google Scholar profile, ResearchGate profile, or my full academic CV.

Cover art for Agopyan-Miu et al 2023 paper in Brain

Cover art for Merricks et al 2021 paper in JNeurosci

Depending on time available, I also enjoy making "cover art" for some of our publications, made entirely in MATLAB using camera manipulations on real data (though with some panels and text assembled in "post" using Pixelmator). Above are a couple of examples from recent(-ish) first-author papers...

Similar camera manipulations can be used to produce videos entirely from code. For example, if you've ever wanted to "fly" through the action potentials of a neuron that is being recruited to a seizure to get a sense of scale (and who hasn't? Each action potential here is over in under 2 milliseconds and is less than half a millivolt in amplitude), here you go:

Or perhaps get a feel for when a full population of neurons are firing action potentials during a spontaneous human seizure:
(Here, each dot is a single action potential, with inhibitory activity in red and excitatory in white. For a proper breakdown of this activity see our pre-print below, and example code to create this animation from scratch is also available on my GitHub!)
Animation of neuronal firing during a spontaneous human seizure

Animation of neuronal firing during a spontaneous human seizure

Or maybe finding zen through focusing on how the relationship between frequency bands in the brain evolves over time is more your thing.

Software: (a selection)

Publications: 866 total citations, h-index = 13

Book chapters:

Human Single-Neuron Recordings in Epilepsy

Edward M Merricks and Catherine A Schevon

(2024) in Jasper's Basic Mechanisms of the Epilepsies, 5th edn.

eds.: Noebels, J.L., Avoli, M., Rogawski, M.A., Vezzani, A., Delgado-Escueta, A.V.

Oxford University Press

Pre-prints:

(Submitted)

Aberrant fast spiking interneuronal activity precedes seizure transitions in humans

Edward M Merricks, Sarita S Deshpande, Alexander H Agopyan-Miu, Elliot H Smith, Emily D Schlafly, Guy M McKhann, Robert R Goodman, Sameer A Sheth, Bradley Greger, Paul A House, Emad N Eskandar, Joseph R Madsen, Sydney S Cash, Andrew J Trevelyan, Wim Van Drongelen, Catherine A Schevon

(2024) medRχiv, pre-print doi.org/10.1101/2024.01.26.24301821

(Submitted)

Spectral-switching analysis reveals real-time neuronal network representations of concurrent spontaneous naturalistic behaviors in human brain

Hongkun Zhu, Andrew J Michalak, Edward M Merricks, Alexander H Agopyan-Miu, Joshua Jacobs, Marla J Hamberger, Sameer A Sheth, Guy M McKhann, Neil A Feldstein, Catherine A Schevon, Elizabeth MC Hillman

(2024) bioRχiv, pre-print doi.org/10.1101/2024.07.08.600416

Peer-reviewed publications:

19. Cell-type-specific responses to single-pulse electrical stimulation of the human brain

Rhiannon L. Cowan, Tyler S. Davis, Edward M. Merricks, Bornali Kundu, Ben Shofty, Shervin Rahimpour, Catherine A. Schevon, John D. Rolston, Elliot H. Smith

(2025) Brain Stimulation, 18 (4) 1266–1278

18. Protocol for detecting and analyzing non-oscillatory traveling waves from high-spatiotemporal-resolution human electrophysiological recordings

Veronica M Zarr, Jyun-You Liou, Edward M Merricks, Tyler S Davis, Kyle Thomson, Bradley Greger, Paul A House, Ronald G Emerson, Robert R Goodman, Guy M McKhann, Sameer A Sheth, Catherine A Schevon, John D Rolston, Elliot H Smith

(2025) STAR protocols, 6 (1) 103659

17. Glioma-induced alterations in excitatory neurons are reversed by mTOR inhibition

Alexander R Goldberg, Athanassios Dovas, Daniela Torres, Brianna Pereira, Ashwin Viswanathan, Sohani Das Sharma, Angeliki Mela, Edward M Merricks, Cristina, Megino-Luque, Julie J McInvale, Markel Olabarria, Leila Abrishami Shokooh, Hanzhi T Zhao, Cady Chen, Corina Kotidis, Peter Calvaresi, Matei A Banu, Aida Razavilar, Tejaswi D Sudhakar, Ankita Saxena, Cole Chokran, Nelson Humala, Aayushi Mahajan, Weihao Xu, Jordan B Metz, Eric A Bushong, Daniela Boassa, Mark H Ellisman, Elizabeth MC Hillman, Gunnar Hargus, Jose Javier Bravo-Cordero, Guy M McKhann, Brian JA Gill, Steven S Rosenfeld, Catherine A Schevon, Jeffrey N Bruce, Peter A Sims, Darcy S Peterka, Peter Canoll

(2025) Neuron, 113 (6) 858–875.E10

16. A selective small-molecule agonist of G protein-gated inwardly-rectifying potassium channels reduces epileptiform activity in mouse models of tumor-associated and provoked seizures

Robert A Rifkin, Xiaoping Wu, Brianna Pereira, Brian JA Gill, Edward M Merricks, Andrew J Michalak, Alexander R Goldberg, Nelson Humala, Athanassios Dovas, Ganesha Rai, Guy M McKhann, Paul A Slesinger, Peter Canoll, Catherine Schevon

(2025) Neuropharmacology, 265 110259

^* co-first authors

15. Cell-type specific and multiscale dynamics of human focal seizures in limbic structures

Alexander H Agopyan-Miu^*, Edward M Merricks^*, Elliot H Smith, Guy M McKhann, Sameer A Sheth, Neil A Feldstein, Andrew J Trevelyan, Catherine A Schevon

(2023) Brain, 146 (12) 5209-5223

14. Spatiotemporal spike-centered averaging reveals symmetry of temporal and spatial components of the spike-LFP relationship during human focal seizures

Somin Lee, Sarita S Deshpande, Edward M Merricks, Emily Schlafly, Robert Goodman, Guy M McKhann, Emad N Eskandar, Joseph R Madsen, Sydney S Cash, Michel JAM van Putten, Catherine A Schevon, Wim van Drongelen

(2023) Communications Biology, 6 (1) 317

13. Distinct signatures of loss of consciousness in focal impaired awareness versus tonic-clonic seizures

Elsa Juan, Urszula Górska, Csaba Kozma, Cynthia Papantonatos, Tom Bugnon, Colin Denis, Vaclav Kremen, Greg Worrell, Aaron F Struck, Lisa M Bateman, Edward M Merricks, Hal Blumenfeld, Giulio Tononi, Catherine Schevon, Melanie Boly

(2023) Brain, 146 (1) 109–123

^* co-first authors

12. Single unit analysis and wide-field imaging reveal alterations in excitatory and inhibitory neurons in glioma

Brian JA Gill^*, Farhan A Khan^*, Alexander R Goldberg^*, Edward M Merricks^*, Xiaoping Wu, Alexander A Sosunov, Tejaswi D Sudhakar, Athanassios Dovas, Wudu Lado, Andrew J Michalak, Jia Jie Teoh, Jyun-you Liou, Wayne N Frankel, Guy M McKhann, Peter Canoll, Catherine A Schevon

(2022) Brain, 145 (10) 3666–3680

11. Multiple sources of fast traveling waves during human seizures: resolving a controversy

Emily D Schlafly, François A Marshall, Edward M Merricks, Uri T Eden, Sydney S Cash, Catherine A Schevon, Mark A Kramer

(2022) Journal of Neuroscience, 42 (36) 6966–6982

10. Multiscale temporal integration organizes hierarchical computation in human auditory cortex

Sam V Norman-Haignere, Laura K Long, Orrin Devinsky, Werner Doyle, Ifeoma Irobunda, Edward M Merricks, Neil A Feldstein, Guy M McKhann, Catherine A Schevon, Adeen Flinker, Nima Mesgarani

(2022) Nature Human Behaviour, 6 (3) 455–469

9. Human interictal epileptiform discharges are bidirectional traveling waves echoing ictal discharges

Elliot H Smith, Jyun-you Liou, Edward M Merricks, Tyler Davis, Kyle Thomson, Bradley Greger, Paul House, Ronald G Emerson, Robert Goodman, Guy M McKhann, Sameer Sheth, Catherine Schevon, John D Rolston

(2022) eLife, 11 e73541

8. Neuronal firing and waveform alterations through ictal recruitment in humans

Edward M Merricks, Elliot H Smith, Ronald G Emerson, Lisa M Bateman, Guy M McKhann, Robert R Goodman, Sameer A Sheth, Bradley Greger, Paul A House, Andrew J Trevelyan, Catherine A Schevon

(2021) Journal of Neuroscience, 41 (4) 766-779

7. Dual mechanisms of ictal high frequency oscillations in rhythmic onset seizures

Elliot H Smith, Edward M Merricks, Jyun-You Liou, Camilla Casadei, Lucia Melloni, Daniel Friedman, Werner Doyle, Robert Goodman, Ronald Emerson, Guy McKhann, Sameer Sheth, John Rolston, Catherine Schevon

(2020) Scientific Reports, 10 (1) 1-14

^* co-first authors

6. Role of paroxysmal depolarization in focal seizure activity

Andrew K Tryba^*, Edward M Merricks^*, Somin Lee, Tuan Pham, SungJun Cho, Douglas R Nordli Jr, Tahra L Eissa, Robert R Goodman, Guy M McKhann Jr, Ronald G Emerson, Catherine A Schevon, Wim van Drongelen

(2019) Journal of Neurophysiology, 122 (5) 1861-1873

5. Multiscale recordings reveal the dynamic spatial structure of human seizures

Catherine A Schevon, Steven Tobochnik, Tahra Eissa, Edward Merricks, Brian Gill, R Ryley Parrish, Lisa M Bateman, Guy McKhann, Ronald G Emerson, Andrew J Trevelyan

(2019) Neurobiology of Disease, 127 303-311

4. The ictal wavefront is the spatiotemporal source of discharges during spontaneous human seizures

Elliot H Smith, Jyun-you Liou, Tyler S Davis, Edward M Merricks, Spencer S Kellis, Shennan A Weiss, Bradley Greger, Paul A House, Guy M McKhann II, Robert R Goodman, Ronald G Emerson, Lisa M Bateman, Andrew J Trevelyan, Catherine A Schevon

(2016) Nature Communications 7 11098

3. Single unit action potentials in humans and the effect of seizure activity

Edward M Merricks, Elliot H Smith, Guy M McKhann, Robert R Goodman, Lisa M Bateman, Ronald G Emerson, Catherine A Schevon, Andrew J Trevelyan

(2015) Brain 138 (10) 2891-2906

2. The role of inhibition in epileptic networks

Andrew J Trevelyan, Sarah F Muldoon, Edward M Merricks, Claudia Racca, Kevin J Staley

(2015) Journal of Clinical Neurophysiology 32 (3) 227-234

1. The contribution of raised intraneuronal chloride to epileptic network activity

Hannah Alfonsa, Edward M Merricks, Neela K Codadu, Mark O Cunningham, Karl Deisseroth, Claudia Racca, Andrew J Trevelyan

(2015) Journal of Neuroscience 35 (20) 7715-7726