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Krystal L. Parker, PhD

Specialty: Neuroscience
Assistant Professor of Psychiatry

Contact Information

Primary Office
2336 PBDB
200 Hawkins Dr.
Iowa City, IA 52242


BS, Psychology, Minors: Biology and French, Iowa State University
PhD, Neuroscience, Iowa State University

Research Summary

My long-term goal is to understand the cerebellar contribution to cognitive and affective processes. In pursuit of this goal, I combine neurophysiology, pharmacology and optogenetics in animals performing behavioral tasks to dissect cerebellar neural circuitry. I study the potential for cerebellar stimulation to rescue cognitive impairments and mood in humans using EEG but also in animals with pharmacologically- and genetically-induced phenotypes of disease. My training in psychology, systems neurophysiology, and clinical psychiatry allows me to target the cerebellum for novel treatments of diseases involving cognitive and affective dysfunction.


Heskje, J., Heslin, K., De Corte, B. J., Walsh, K. P., Kim, Y., Han, S., Carlson, E. S. & Parker, K. L. (2019). Cerebellar D1DR-expressing neurons modulate the frontal cortex during timing tasks. Neurobiology of Learning and Memory, 107067. DOI: 10.1016/j.nlm.2019.107067.

Emmons, E. B., De Corte, B. J., Kim, Y., Parker, K. L., Matell, M. S. & Narayanan, N. S. (2017). Rodent medial frontal control of temporal processing in the dorsomedial striatum. J Neurosci, 37(36), 8718-8733.

Parker, K. L., Kim, Y. C., Kelley, R. M., Nessler, A. J., Chen, K. H., Muller-Ewald, V. A., Andreasen, N. C. & Narayanan, N. S. (2017). Delta-frequency stimulation of cerebellar projections can compensate for schizophrenia-related medial frontal dysfunction. Molecular psychiatry, 22(5), 647-655. PMID: 28348382.

Messingham, K. A., Aust, S., Helfenberger, J., Parker, K. L., Schultz, S., McKillip, J., Narayanan, N. S. & Fairley, J. A. (2016). Autoantibodies to Collagen XVII Are Present in Parkinson’s Disease and Localize to Tyrosine-Hydroxylase Positive Neurons. The Journal of Investigative Dermatology, 136(3), 721–723. PMID: 27015458.

Parker, K. L., Kim, Y., Alberico, S. L., Emmons, E. B. & Narayanan, N. S. (2016). Optogenetic approaches to evaluate striatal function in animal models of Parkinson disease. Dialogues in Clinical Neuroscience, 18(1), 99–107. PMID: 27069384.

Parker, K. L., Kim, Y., Alberico, S. L., Emmons, E. B. & Narayanan, N. S. (2016). Optogenetic approaches to evaluate striatal function in animal models of Parkinson disease. Dialogues in clinical neuroscience, 18(1), 99-107. PMID: 27069384.

Emmons, E. B., Ruggiero, R. N., Kelley, R. M., Parker, K. L. & Narayanan, N. S. (2016). Corticostriatal Field Potentials Are Modulated at Delta and Theta Frequencies during Interval-Timing Task in Rodents. Frontiers in Psychology, 7, 459. PMID: 27092091.

Parker, K. L., Chen, K. H., Kingyon, J. R., Cavanagh, J. F. & Narayanan, N. S. (2015). Medial frontal ~4-Hz activity in humans and rodents is attenuated in PD patients and in rodents with cortical dopamine depletion. Journal of neurophysiology, 114(2), 1310-20. PMID: 26133799.

Parker, K. L., Ruggiero, R. N. & Narayanan, N. S. (2015). Infusion of D1 Dopamine Receptor Agonist into Medial Frontal Cortex Disrupts Neural Correlates of Interval Timing. Frontiers in Behavioral Neuroscience, 9. DOI: 10.3389/fnbeh.2015.00294.

Parker, K. L. (2015). Timing Tasks Synchronize Cerebellar and Frontal Ramping Activity and Theta Oscillations: Implications for Cerebellar Stimulation in Diseases of Impaired Cognition. Frontiers in Psychiatry, 6. DOI: 10.3389/fpsyt.2015.00190.

Parker, K. L., Chen, K. H., Kingyon, J. R., Cavanagh, J. F. & Narayanan, N. S. (2014). D1-dependent 4 Hz oscillations and ramping activity in rodent medial frontal cortex during interval timing. The Journal of neuroscience : the official journal of the Society for Neuroscience, 34(50), 16774-83. PMID: 25505330.

Koziol, L. F., Budding, D., Andreasen, N., D'Arrigo, S., Bulgheroni, S., Imamizu, H., Ito, M., Manto, M., Marvel, C., Parker, K., Pezzulo, G., Ramnani, N., Riva, D., Schmahmann, J., Vandervert, L. & Yamazaki, T. (2014). Consensus paper: the cerebellum's role in movement and cognition. Cerebellum (London, England), 13(1), 151-77. PMID: 23996631.

Parker, K. L., Narayanan, N. S. & Andreasen, N. C. (2014). The therapeutic potential of the cerebellum in schizophrenia. Frontiers in systems neuroscience, 8, 163. PMID: 25309350.

Parker, K. L., Andreasen, N. C., Liu, D., Freeman, J. H. & O'Leary, D. S. (2013). Eyeblink conditioning in unmedicated schizophrenia patients: a positron emission tomography study. Psychiatry research, 214(3), 402-9. PMID: 24090512.

Parker, K. L., Lamichhane, D., Caetano, M. S. & Narayanan, N. S. (2013). Executive dysfunction in Parkinson's disease and timing deficits. Frontiers in integrative neuroscience, 7, 75. PMID: 24198770.

Parker, K. L., Alberico, S. L., Miller, A. D. & Narayanan, N. S. (2013). Prefrontal D1 dopamine signaling is necessary for temporal expectation during reaction time performance. Neuroscience, 255, 246-54. PMID: 24120554.

Parker, K. L., Andreasen, N. C., Liu, D., Freeman, J. H., Ponto, L. L. & O'Leary, D. S. (2012). Eyeblink conditioning in healthy adults: a positron emission tomography study. Cerebellum (London, England), 11(4), 946-56. PMID: 22430943.

Parker, K. L., Bracha, V. (2009). Inactivating the middle cerebellar peduncle abolishes the expression of short-latency conditioned eyeblinks. Brain research, 1303, 32-8. PMID: 19747462.

Parker, K. L., Zbarska, S., Carrel, A. J. & Bracha, V. (2009). Blocking GABAA neurotransmission in the interposed nuclei: effects on conditioned and unconditioned eyeblinks. Brain research, 1292, 25-37. PMID: 19635470.

Bracha, V., Zbarska, S., Parker, K., Carrel, A., Zenitsky, G. & Bloedel, J. R. (2009). The cerebellum and eye-blink conditioning: learning versus network performance hypotheses. Neuroscience, 162(3), 787-96. PMID: 19162131.

Parker, K. ’. (2009). The role of cerebellar nuclear GABAergic neurotransmission in eyeblink motor control. United States – Iowa: Iowa State University.

Ryan, S. B., Detweiler, K. L., Holland, K. H., Hord, M. A. & Bracha, V. (2006). A long-range, wide field-of-view infrared eyeblink detector. Journal of neuroscience methods, 152(1-2), 74-82. PMID: 16257057.