Dr. Dorval applies the tools of engineering to study the nervous system
and design ways to improve the health and quality of life for persons
with neural disorders. Dorval's research
activities include: engineering novel treatments to alleviate the
symptoms of neurological diseases; quantifying information processing
in the brain and interpreting informational changes induced by disease
and treatment states; and elucidating the relationships between the
structural elements of neurons and neural tissue, their physiological
dynamics and their behavioral responses. Pursuing these
interests, Dorval performs experimental studies, recording and
stimulating neurons and neural tissue while
assessing symptom severity in computational systems, animal models and
human participants with neurological disorders.
I conduct research in the field of neural engineering, oriented toward designing devices that will alleviate the symptoms of neurological diseases and disorders by modulating neural activity. In most cases, intelligent construction of neuromodulatory devices requires a more complete understanding of how neural activity relates to behavior than exists currently. Hence the goals of my specific research projects are often two stage: first, to better understand how neural activity corresponds to behavior and symptoms, and second to engineer interventions that will modify neural activity to improve function.
Projects
- Dorval AD, Panjwani N, Qi RY, Grill WM; 2009. "Deep brain
stimulation that abolishes parkinsonian activity in basal ganglia
improves thalamic relay fidelity in a computational circuit." Proc IEEE Eng Med Biol Soc,
31(1):4230-4233. [abstract]
[pdf]
- Dorval AD, Russo GS, Hashimoto T, Xu W, Grill WM, Vitek JL; 2008.
"Deep
brain stimulation reduces neuronal entropy in the MPTP-primate model of
Parkinson's disease." Journal of
Neurophysiology, 100(5):2807-2818. [abstract] [pdf]
- Birdno MJ, Kuncel AM, Dorval AD, Turner DA, Gill WM; 2008. "Tremor varies as a function of the temporal regularity of deep brain stimulation." NeuroReport, 19(5):599-602. [abstract] [pdf]
- Dorval AD, Kuncel AM, Birdno MJ, Turner DA, Grill WM. “Deep brain stimulation that regularizes neural activity alleviates parkinsonian motor symptoms.” Neural Interfaces Conference, biannual meeting, Jun 2008. [abstract] [poster]
- Dorval AD, Grill WM. "High frequency stimulation reduces disordered activity and alleviates parkinsonian symptoms in the 6-OHDA rat model." Society for Neuroscience, annual meeting, Oct 2009. [abstract][poster]
- Birdno MJ, Kuncel AM, Dorval
AD, Turner DA, Gross RE, Grill WM. "Stimulus features underlying
reduced tremor suppression during deep brain stimulation (DBS) with
temporally irregular patterns." Society
for
Neuroscience,
annual meeting, Oct 2009. [abstract]
Variable yet Reliable Neuronal Responses to Natural and Artificial
Input. A neuron
transmits information by firing spikes of membrane potential along its
axon as a signal to downstream neurons. The information a neuron
can transmit is limited by the spike rate, the variability of the
membrane potential waveform, and the fidelity with which inputs are
reliably transformed into outputs. In this project we elucidate
fundamental constraints on how rate, variability and reliability limit
the processing of synaptic and externally
applied information. We quantify those concepts with a measure of
firing pattern entropy, and explore methods to best estimate that
entropy. We also examine how various neuronal
elements (e.g., ion channels, dendritic spines) and electrical
stimulation affect rate, variability, reliability and the information
to which they give rise.
For
this
project
thus far, we have used computational neuronal
models and in vitro rodent neurons.
- Dorval AD; 2008. "Probability distribtutions of the logarithm of inter-spike intervals yield accurate entropy estimates from small datasets." Journal of Neuroscience Methods, 173(1):129-139. [abstract] [pdf] [supplement]
- Haas JS, Dorval AD, White JA; 2007. “Contributions of Ih to feature selectivity in layer II stellate cells of the entorhinal cortex.” Journal of Computational Neuroscience, 22(2):161-171. [abstract] [pdf]
- Dorval
AD, White JA; 2006. “Synaptic input statistics tune the variability and
reproducibility of neuronal responses.” Chaos, 16(2):26105.
**selected as highlight publication 7/1/2006: Virtual
Journal of Biological Physics Research.
[abstract] [pdf]
- White JA, Dorval AD; 2005. “Neuro-electric principles.” The Electrical Engineering Handbook, 3rd edition. Dorf RC (Ed.), CRC Press, Boca Raton.
- I use the Neuronal Spike Train Analysis Toolkit (Neuro-STAT, neuroanalysis.org/toolkit) for Matlab® to perform information theoretic analysis on spike trains recorded from computational and animal models. I run Neuro-STAT under Octave (octave.org). To compile Neuro-STAT under mex within Octave, required a number of patches, which you can dowload to try for yourself (Neuro-STAT patch for Octave).
Random Fluctuations in Ion Channel States Enables Rhythmic
Activity. The
mammalian brain is rife with rhythmic activity at many frequencies and
across various brain regions. In the hippocampus in particular,
periodic activity in the 4-12 Hz range is highly correlated with active
exploration and location identification. While there may be
several mechanisms contributing to the generation of this oscillatory
activity, we focus on contributions provided by the random (i.e.,
thermal noise driven) openings and closings of membrane spanning
proteins that, when open, channel Na+ ions across the neuronal
membrane. The small number of these so called persistent Na+
channels suggests that neurons may control their oscillatory activity
by increasing or decreasing the pool of available channels over time.
- Dorval AD; 2006. “The rhythmic consequences of ion channel stochasticity.” The Neuroscientist 12(5):442-448. [abstract] [pdf]
- Dorval AD, White JA; 2005. “Channel noise is essential for perithreshold oscillations in entorhinal stellate neurons.” Journal of Neuroscience, 25(43):10025-10028. [abstract] [pdf]
Controlling Abstract Properties of Neuronal Behavior, In Vitro.
Electrophysiologists have
traditionally relied upon two techniques to assa the membrane and
response properties of neurons: current and voltage clamp, which
control the current through an intracellular electrode and the voltage
across the neuronal membrane, respectively. The modern technique
of dynamic clamp supercedes those more traditional methods, enabling:
the addition or subtraction of less straighforward quantities including
conductance or capacitance; the control of more abstract qualities
including firing rate and membrane potential variability; and the
generation of arbitrarily complicated hybrid networks in which living
neurons are connected to entirely artificial constructs. This
technique harbors great potential for future scientific discovery.
- Dorval
AD, Bettencourt JB, Netoff TI, White JA; 2007. “Hybrid Neuronal Network
Studies Under Dynamic Clamp.” Methods
in Molecular Biology: Applied Patch Clamp,
Humana Press, Totowa, NJ. [abstract]
- Netoff TI, Banks MI, Dorval AD, Acker CD, Haas JS, Kopell N, White JA; 2005. “Synchronization in hybrid neuronal networks of the hippocampal formation.” Journal of Neurophysiology, 93(3):1197-1208. [abstract] [pdf]
- Dorval AD, Netoff TI, White JA; 2003. “Real-time experimental control in cellular neurophysiology.” Proc IEEE Eng Med Biol Soc Neural Eng, 1:71-74. [pdf]
- Dorval
AD, Christini DJ, White JA; 2001. “Real-time linux dynamic clamp: a
fast
and flexible way to construct virtual ion channels in living cells.” Annals of
Biomedical
Engineering, 29:
897-907. [abstract]
[pdf]
- Applicable for dynamic clamping and controlling other biological
systems, the Real-Time eXperimental Interface (RTXI.org)
is
under
continuing
development by Jonathan Bettencourt, under the direction of David Christini,
John
White and Robert
Butera. RTXI runs under Real-Time Application Interface Linux
(RTAI.org) and uses the Linux COntrol and
MEasurement Interface Device (COMEDI.org)
driver
package
to
interface with the data acquisition boards.
Education
- Postdoctoral studies, Biomedical Engineering, Duke University,
Durham NC, 2008. Research: Examining
the
relationships
between
neuronal firing patterns, deep brain
stimulation (DBS) and Parkinson's disease.
- Marine Biological Laboratory, Woods Hole, 2001. Course: Methods in Computational Neuroscience.
- Ph.D., Biomedical Engineering, Boston University, Boston MA, 2004. Dissertation: Probing the role of noise in the superficial medial entorhinal cortex.
- B.S., Biomedical Engineering, Rensselaer Polytechnic Institute, Troy NY, 1997. Senior Research: Constructed software tool for the statistical analysis of functional magnetic resonance imaging (fMRI) data.
Employment
- 2009-present USTAR
Assistant
Professor.
Department of Bioengineering, Program in Neurosciences, Brain Institute, University of Utah, Salt Lake City, UT
- 2004-2008 Reseach Associate with Dr. Warren Grill.
Department of Biomedical Engineering, Duke University, Durham NC - 1997-2004 Research Assistant & Graduate Student Fellow with
Dr. John White.
Department of Biomedical Engineering & Center for BioDynamics, Boston University, Boston MA. - 1996-1997 Research Assistant with Dr. T. J. Holmes.
AutoQuant Imaging, Inc., Watervliet NY.
Teaching Experience
Professor/Instructor:
- Bioengineering Senior Project I & II (2009, 2010) University
of Utah, Salt Lake City UT.
Teaching
Assistant/Fellow (TA/TF)
- Post-graduate student courses
- Neural Systems and Behavior (TA-2004) Marine Biological Laboratories, Woods Hole MA.
- Methods in Computational Neuroscience (TA-2003) Marine Biological Laboratories, Woods Hole MA.
- Graduate student courses
- Quantitative Studies of Excitable Membranes (TF-1998, TA-2000, TA-2002) Boston University, Boston MA.
- Advanced Signals and Systems (TF-1999) Boston Universtiy, Boston MA.
- Biomedical Instrumentation (TF-1999) Boston University, Boston MA.
- Quantitative Studies of Cardiovascular & Respiratory Systems (TF-1998) Boston University, Boston MA.
- Undergraduate student courses
- Physics I (TA-1997) Rensselaer Polytechnic Institute, Troy NY.
Professional Activities
- Ad hoc reviewer for:
- Annals of Biomedical Engineering
- Journal of Neural Engineering
- Journal of Neurophysiology
- Journal of Neuroscience Methods
- Neural Computation
- Open Neuroscience Journal
- Service
- National Postdoctoral Association, Advocacy Committee &
Meetings Committee, 2008-2009
- Duke University Postdoctal Association, Board of Chairs:
2006-2008, President 2008
- Boston University, Student Association of Graduate Engineers, Officers' Committee: 1998 - 2003
- Societies
- since 2000 Society for Neuroscience, Member
- since 2003 BioMedical Engineering Society, Member
- since 2009 IEEE
Engineering in Medicine and Biology Society, Member
- 2008-2007 National Postdoctoral Association, Member
Publications
- Dorval AD, Kuncel AM, Birdno MJ, Turner D, Grill WM. “Deep brain stimulation that regularizes activity in the basal ganglia thalamic circuit alleviates parkinsonian bradykinesia." (submitted, January 2010)
- Birdno MJ, Kuncel AM, Dorval AD, Turner DA, Gross RE, Grill WM. "Stimulus features underlying reduced tremor suppression during deep brain stimulation (DBS) with temporally irregular patterns." (submitted, January 2010)
- Dorval AD, Panjwani N, Qi R, Grill WM. "Deep brain stimulation that abolishes parkinsonian activity in the basal ganglia improves thalamic relay fidelity in a computational circuit." Proc IEEE Eng Med Biol Soc, 31(1):4230-4233, 2009. [abstract] [pdf]
- Dorval AD, Russo GS, Hashimoto T, Xu W, Grill WM, Vitek JL. "Deep brain stimulation reduces neuronal entropy in the MPTP-primate model of Parkinson's disease." Journal of Neurophysiology, 100(5):2807-2818, 2008. [abstract] [pdf]
- Dorval AD. "Probability distribtutions of the logarithm of inter-spike intervals yield accurate entropy estimates from small datasets." Journal of Neuroscience Methods, 173(1), 2008. [abstract] [pdf] [supplement]
- Birdno MJ, Kuncel AM, Dorval AD, Turner DA, Grill WM. “Tremor varies as a function of the temporal regularity of deep brain stimulation." NeuroReport, 19(5):599-602, 2008. [abstract] [pdf]
- Haas JS, Dorval AD, White JA. “Contributions of Ih to feature selectivity in layer II stellate cells of the entorhinal cortex.” Journal of Computational Neuroscience, 22(2):161-171, 2007. [abstract] [pdf]
- Dorval AD, Bettencourt JB, Netoff TI, White JA. “Hybrid Neuronal Network Studies Under Dynamic Clamp.” Methods in Molecular Biology: Applied Patch Clamp, Humana Press, Totowa, NJ, 2007. [abstract]
- Dorval AD. “The rhythmic consequences of ion channel stochasticity.” The Neuroscientist 12(5):442-448, 2006. [abstract] [pdf]
- Dorval AD, White JA. “Synaptic input statistics tune the variability and reproducibility of neuronal responses.” Chaos, 16(2):26105, 2006. **selected as highlight publication 7/1/2006: Virtual Journal of Biological Physics Research. [abstract] [pdf]
- Dorval AD, White JA. “Channel noise is essential for perithreshold oscillations in entorhinal stellate neurons.” J ournal of Neuroscience, 25(43):10025-10028, 2005. [abstract] [pdf]
- White JA, Dorval AD. “Neuro-electric principles.” The Electrical Engineering Handbook, 3rd edition. Dorf RC (Ed.), CRC Press, Boca Raton, 2005.
- Netoff TI, Banks MI, Dorval AD, Acker CD, Haas JS, Kopell N, White JA. “Synchronization in hybrid neuronal networks of the hippocampal formation.”Journal of Neurophysiology, 93(3):1197-1208, 2005. [abstract] [pdf]
- Dorval AD, Netoff TI, White JA. “Real-time experimental control in cellular neurophysiology.” Proc IEEE Eng Med Biol Soc Neural Eng, 1:71-74, 2003. [pdf]
- White JA, Netoff TI, Dorval AD, Banks MI. “Assessing neuronal synchronization properties using spike time response methods.” Proc IEEE Eng Med Biol Soc, 25:2235-2238, 2003.
- White JA, Netoff TI, Acker CD, Dorval AD, Haas JS. “The biophysical bases of synchronous activity in the hippocampal formation.” Proc IEEE Eng Med Biol Soc, 24:1958-1959, 2002.
- Dorval AD, Christini DJ, White JA. “Real-time linux dynamic clamp: a fast and flexible way to construct virtual ion channels in living cells.” Annals of Biomedical Engineering, 29(10): 897-907, 2001. [abstract] [pdf]
- White JA, Haas JS, Dorval AD. “Stochastic dynamic clamping as a method for studying the effects of biological noise sources.” Proc IEEE Eng Med Biol Soc, 21:880, 1999.