Stephen Cowen, Ph.D.

Stephen Cowen, Ph.D.

Stephen Cowen headshot_secondary

The University of Arizona 
Life Sciences North, Rm 347
1501 N. Campbell Ave., Tucson, AZ 85724-5115
(520) 626-2615


A fundamental and unresolved question in neuroscience is how the billions of interconnected neurons in our brains coordinated their activity with one another to support learning, decision making, and sleep. Resolving this question is important as disrupted coordination between neurons contributes to conditions such as epilepsy, Parkinson’s disease, Alzheimer's disease, and schizophrenia. My research seeks to understand the mechanisms by which the activities of ensembles of neurons and dopamine release are organized during learning, motor control, and sleep. To illustrate, data from our lab indicates that normal aging is associated with reduced reliability and precision of by which neurons fire during sleep and that these changes may impact sleep-associated memory consolidation. Our research also investigates how drugs such as ketamine impact neuronal coordination throughout the brain and how ketamine in particular may correct pathological patterns of coordination associated with Parkinson's disease and levodopa-induced dyskinesia. Finally, our group works to develop new technologies for measuring brain activity and the release of neuromodulators such as dopamine in behaving animals.

Research Interests

  • Determining the neural origins of age-associated memory loss and the role of sleep in the memory formation process.
  • Identifying neural mechanisms underlying Parkinson’s disease and its treatment. 
  • Understanding how interacting groups of neurons represent the value of anticipated outcomes, planned actions, and physical space.
  • Developing new technologies to 1) advance the measurement of neuromodulator release (e.g., dopamine) and the activities of large groups of neurons, and 2) for the non-invasive imaging of electrical activity deep within the brain (with Dr. Russel Witte, UA).

Methods used in the laboratory include Neuropixels extracellular recording, optogenetics, fast-scan voltammetry, and novel behavioral tasks. Our investigations target the hippocampus, striatum, motor cortex, and prefrontal cortex.

Lab Members

Glow Track

A photo with some glowing artistic effects that illustrates one of the decision-making mazes that we use in the lab to assess reward and effort-guided decision making.

Effort Rate Map

This heatmap represents the firing activity (the rate of action potentials) of a single neuron in the rat prefrontal cortex. The neuron was recorded as the animal ran around a maze (illustrated in the picture above). The neuron was most active during the approach the the choice-zone of the maze.


Neural ensemble recordings from Neuropixels electrodes implanted in the ventral hippocampus (vHC+) and medial prefrontal cortex (mPFC). Left: Tic marks indicate action potentials for individual neurons (rows). Right: Correlations (Pearson's r) between neurons.

Publications & News

  • Ye T, Bartlett MJ, Sherman SJ C, Falk T C, Cowen SL. (2021) Spectral Signatures of L-DOPA-Induced Dyskinesia Depend on L-DOPA Dose and are Suppressed by Ketamine. Exp. Neurology. In Press.
  • Ondek K, Pevzner A, Tercovich K, Schedlbauer AM, Izadi A, Ekstrom AD, Cowen SL, Shahlaie K, Gurkoff GG C. (2020). Recovery of Theta Frequency Oscillations in Rats Following Lateral Fluid Percussion Corresponds With a Mild Cognitive Phenotype. Front Neurol [Internet] 11:600171. Available from:
  • Seaton BT, Hill DF, Cowen SL, Heien MLC (2020) Mitigating the Effects of Electrode Biofouling-Induced Impedance for Improved Long-Term Electrochemical Measurements In Vivo. Anal Chem 92:6334–6340. Available from:
  • Siegenthaler JR, Gushiken BC, Hill DF, Cowen SL, Heien ML C (2020) Moving Fast-Scan Cyclic Voltammetry toward FDA Compliance with Capacitive Decoupling Patient Protection. ACS sensors 5:1890–1899.
  • Bartlett MJ, Flores AJ, Ye T, Smidt SI, Dollish HK, Stancati JA, Farrell DC, Parent KL, Doyle KP, Besselsen DG, Heien ML C, Cowen SL, Steece-Collier K, Sherman SJ  C, Falk T C (2020) Preclinical evidence in support of repurposing sub-anesthetic ketamine as a treatment for L-DOPA-induced dyskinesia. Exp Neurol 333.
  • Crown LM, Bartlett MJ, Wiegand J-PL, Eby AJ, Monroe EJ, Gies K, Wohlford L, Fell MJ, Falk T C, Cowen SL (2020) Sleep Spindles and Fragmented Sleep as Prodromal Markers in a Preclinical Model of LRRK2-G2019S Parkinson’s Disease. Front Neurol [Internet] 11. Available from:
  • Cowen SL, Gray DT, Wiegand, J-PL, Schimanski, LA, Barnes CAC (2020) Age-associated changes in waking hippocampal sharp-wave ripples Hippocampus, 30:28–38,  doi:10.1002/hipo.23005, Epub (2018)
  • Spanó G, Gómez RL, B. Demara M, Cowen SL, Edgin JE (2018) To Nap or Not to Nap?: Sleep-dependent Memory Consolidation in Typical and Atypically Developing Preschoolers. (In Press, Proc. Natl. Acad. Sci.)
  • Ye T, Bartlett MJ, Schmit MB, Sherman SJ, Falk T, Cowen SL (2018) Ten-Hour Exposure to Low-Dose Ketamine Enhances Corticostriatal Cross-Frequency Coupling and Hippocampal Broad-Band Gamma Oscillations. Front. Neural Circuits 12, 61. doi: 10.3389/fncir.2018.00061
  • Cowen SL, Gray DT, Wiegand, J-PL, Schimanski, LA, Barnes CA (2018) Age-associated changes in waking hippocampal sharp-wave ripples Hippocampus, July 5 (ePub available ahead of print) doi:10.1002/hipo.23005
  • Cowen SL, Phelps, CE, Navratilova E, McKinzie DL, Okun A, Husain, BS, Gleason SD, Witkin JM, Porreca F (2018) Chronic pain impairs cognitive flexibility and engages novel learning strategies in rats. Pain doi:10.1097/j.pain.0000000000001226 (Editor’s Choice article)
  • Hill DF, Parent KL, Atcherley CW, Cowen SL, Heien ML (2017). Differential release of dopamine in the nucleus accumbens evoked by low-versus high-frequency medial prefrontal cortex stimulation. Brain Stimul 11: 426–434.
  • Lewis SA, Negelspach DC, Kaladchibachi S, Cowen SL, Fernandez F (2017). Spontaneous alternation: A potential gateway to spatial working memory in Drosophila. Neurobiol Learn Mem 142: 230–235.
  • Parent KL, Hill DF, Crown LM, Wiegand J-P, Gies KF, Miller MA, Atcherley CW, Heien ML, Cowen SL (2017) Platform to Enable Combined Measurement of Dopamine and Neural Activity. Anal Chem:acs.analchem.6b03642.
  • Okun A, McKinzie DL, Witkin JM, Remeniuk B, Husein O, Gleason SD, Oyarzo J, Navratilova E, McElroy B, Cowen S, Kennedy JD, Porreca F (2016) Hedonic and motivational responses to food reward are unchanged in rats with neuropathic pain. Pain. 
  • Wiegand J-PL, Gray DT, Schimanski LA, Lipa P, Barnes CA, Cowen SL (2016) Age Is Associated with Reduced Sharp-Wave Ripple Frequency and Altered Patterns of Neuronal Variability. J Neurosci 36:5650–5660.
  • Cowen S.L., Nitz D.A. (2014) Repeating Firing Fields of CA1 Neurons Shift Forward in Response to Increasing Angular Velocity, Journal of Neuroscience, 34(1):232-41.
  • Miller M.A., Thomé A, Cowen S.L. (2013) Intersection of Effort and Risk: Ethological and Neurobiological Perspectives, Frontiers in Neuroscience, 7:208.
  • Cowen S.L., Davis G.A., Nitz D.A. (2012) Anterior cingulate neurons in the rat map anticipated effort and reward to their associated action sequences. Journal of Neurophysiology 107(9):2393–2407.
  • Cowen, S.L. and McNaughton, B.L (2007) Selective delay activity in the medial prefrontal cortex of the rat: The contribution of sensory-motor information and contingency. Journal of Neurophysiology, 98(1):303-16.
  • Maurer, A.P., Cowen, S.L., Burke, S.N., Barnes, C.A. and McNaughton, B.L. (2006) Phase precession in hippocampal interneurons showing strong functional coupling to individual pyramidal cells. The Journal of Neuroscience, 26:13485-13492.
  • Maurer, A.P., Cowen, S.L., Burke, S.N., Barnes, C.A. and McNaughton, B.L. (2006) Organization of hippocampal cell assemblies based on theta phase precession. Hippocampus, 16:785-794.
  • Battaglia, F.P., Sutherland, G.R., Cowen, S.L., McNaughton, B.L. and Harris, K.D. (2005). Firing rate modulation: A simple statistical view of memory trace reactivation. Neural Networks, 18:1280-1291.
  • McNaughton, B.L., Barnes, C.A., Battaglia, F.P., Bower, M.R., Cowen, S.L., Ekstrom, A.D., Gerrard, J.L., Hoffman, K.L., Houston, P.F., Karten, Y., Lipa, P., Pennartz, C.M.A. and Sutherland, G.R. (2003) Off-line reprocessing of recent memory and its role in memory consolidation: A progress report. In: P. Maguet, C. Smith and B. Stickgold (Eds.) Sleep and Brain Plasticity. Oxford University Press: United Kingdom, pp. 225-246.

6/27/2019 - Our very own Allison Eby was just interviewed for "Thesis Thursday". 

8/30/2018 - Erin Mamaril was interviewed on KXCI about the work she does in the lab with Dan Hill, and it is fantastic. Congratulation Erin! You are a master communicator.

7/12/2018 - Four Questions: Chronic Pain and How It Affects the Brain

A UA interview on our chronic pain just went live: Four Questions: Chronic Pain and How It Affects the Brain

JP and I have a little piece in the AZ Star... (you need to dig through a number of  articles to find it...)

1/28/2017 - Just accepted....
Parent K, Hill D, Crown L, Wiegand J, Gies K, Miller MMM, Atcherley CA, Heien ML, Cowen SL, (2017) A platform to enable combined measurement of dopamine and neural activity (DANA), Analytical Chemistry, in press.

9/18/2016 - Our collaborative work with Dr. Russ Witte to develop a new ultrasound imaging device:

4/7/2016 - Our ripple and aging paper was just accepted at the Journal of Neuorscience! 
Wiegand JL, Gray DT, Schimanski LA, Lipa P, Barnes CA, Cowen SL (2016) Age is associated with reduced sharp-wave ripple frequency and altered patterns of neuronal variability, In press: J Neurosci.

1/27/2016 - A Science Cafe talk at Magpies Pizza: Riding the (Brain) Waves: How Brains and Drugs Produce Hallucinations

1/20/2016 - Our work was just showcased through an interview with Dr. Leslie Tolbert on NPR 89.1: Arizona Spotlight Episode 11: How our brain makes up its mind.

12/16/2015 - Our collaboration with Dr. Russ Witte was just highlighted on UA Now!

10/16/2015 - A video of me and Dr. Michael Heien about our NSF Brain Initiative grant to develop new technologies for the simultaneous recording of both dopamine release and ensemble activity in the brain.

9/22/2015 - Cowen, S.L., Heien, M.A. Video interview for UA Now regarding collaborative research and technology development:

12/1/2013 - Cowen, S.L. “Is memory in your brain, body or both?” Arizona Daily Star, Sunday Dec. 1, 2013.

Updated: 03/08/24