Neural Dynamics at NSI

Patrick David Roberts
Neurological Sciences Institute
Oregon Health Sciences University
505 N.W. 185th Avenue, Beaverton, OR 97006 USA
Phone: (503) 418-2620

PRESENT RESEARCH INTERESTS (detailed description)
To develop appropriate mathematical methods, both analytical and computational, to study the dynamics of neural activity patterns, and to help understand the relationship between these dynamics and behavior. Using mathematical methods drawn from statistical physics, the specific areas of research are as follows:
The storage of temporal patterns in cerebellum-like structures: In collaboration with experimentalist Dr. Curtis Bell, we are investigating the dynamics of synaptic plasticity at the site of initial electrosensory information processing in mormyrid electric fish. Using mathematical analyses and computer simulations, results from different experiments performed in Dr. Bell's lab are combined to predict changes in responses of neurons in the ELL during changing sensory conditions (Click here for an introduction to the ELL and spike-timing dependent plasticity presented at CNS*00 meeting, Brugge, Belgium).
Dynamics of neural activity in the cerebellum: This collaborative project with experimentalist Dr. Neal Barmack will test various hypothetical mechanisms underlying neuronal activity patterns in the cerebellum. The modeling effort will help to bridge the gap between cellular- and systems-level experimental findings.
Biological learning rules: A research program is presently underway to analyze the neural dynamics that result from different biological learning rules. Since the timing relations of biological learning rules result from molecular events at the synapse, this line of research helps to link the implications of dynamics at the molecular level, through dynamics at the network level, to the behavior of whole organisms.

PUBLICATIONS
C.V Portfors, P.D. Roberts (2007) Temporal and Frequency Characteristics of Cartwheel Cells in the Dorsal Cochlear Nucleus of the Awake Mouse. J Neurophysiol 98: 744-756. (PDF)

P.D. Roberts, R. Santiago, C. Mello, T. Velho (2007) Storage of Auditory Temporal Patterns in the Songbird Telencephalon. Neurocomputing 70: 2030-2034. (PDF)

O. Iancu, P.D. Roberts, J. Zhang, C.C. Bell (2007) Postsynaptic modulation of electrical EPSP size investigated using a compartmental model. Neurocomputing 70: 1685-1688. (PDF)

P.D. Roberts (2007) Stability of Complex Spike Timing-Dependent Plasticity in Cerebellar
Learning. J Compu Neurosci 22: 283-296.(PDF)

Sawtell NB, Williams A, Roberts PD, von der Emde G, Bell CC (2006) Effects of sensing behavior on a latency code. J Neurosci. 26:8221-34. (PDF)

P. D. Roberts, C.V. Portfors, N. Sawtell, and R. Felix (2006) Model of auditory prediction in the dorsal cochlear nucleus via spike-timing dependent plasticity. Neurocomputing, 69:1191–1194. (PDF)

P. D. Roberts, G. Lafferriere, N. Sawtell, A. Williams, C.C. Bell (2006) Dynamic regulation of spike-timing dependent plasticity in electrosensory processing. Neurocomputing, 69: 1195–1198. (PDF)

P. D. Roberts (2005) Recurrent neural network generates a basis for sensory image cancellation. Neurocomputing, 65-66: 237–242. (PDF)

C. V. Mello and P. D. Roberts (2005) Neuronal substrates of sensory processing for songperception and learning in songbirds: Lessons from the mormyrid electric fish. In J. S. Kanwaland G. Ehret, editors, Behavior and Neurodynamics for Auditory Communication, pp 265-293, Cambridge England, Cambridge University. (PDF)

McCollum G, Roberts PD (2004) Dynamics of everyday life: rigorous modular modeling in neurobiology based on Bloch's dynamical theorem. J Integr Neurosci. 3:397-413. (PDF)

Williams A, Leen TK, Roberts PD (2004) Random walks for spike-timing-dependent plasticity. Phys Rev E 70:021916 (PDF)

Roberts PD (2004) Recurrent biological neural networks: the weak and noisy limit. Phys Rev E 69:031910. (PDF)

Williams A., Roberts P.D., Leen, T.K.(2003) Stability of Negative Image Equilibria in Spike-Timing Dependent Plasticity, Phys. Rev. E 68, 021923 (arXiv.org:physics/0304062)

C. Mohr, P. D. Roberts, and C. C. Bell (2003) Cells of the mormyrid electrosensory lobe: I. Responses to the electric organ corollary discharge and to electrosensory stimuli. J. Neurophysiology 90: 1193-1210. (PDF)

C. Mohr, P. D. Roberts, and C. C. Bell (2003) Cells of the mormyrid electrosensory lobe: II. Responses to input from central sources. J. Neurophysiology 90: 1211-1223. (PDF)

Roberts PD (2003) Recurrent Biological Neural Networks: The Weak and Noisy Limit, (in press) Phys. Rev. E (arXiv.org:cond-mat/0305515) (PDF)

Roberts P. D. (2003) Effects of noise on recurrence in networks of spiking neurons. Neurocomputing 52-54:893-899. (PDF)

P. D. Roberts and C. C. Bell (2003) Active Control of Spike-Dependent Synaptic Plasticity inan Electrosensory System. J.Physiol. (Paris), 96: 445-449. (PDF)

P. D. Roberts and C. C. Bell (2002) Spike-Timing Dependant Synaptic Plasticity: Mechanisms and Implications. Biol. Cybern. 87, 392–403. (PDF) (The original publication is available at http://link.springer.de or at http://link.springerny.com.)

P. D. Roberts and C. C. Bell (2001) Mutual Inhibition Increases Adaptation Rate in an Electrosensory System. Neurocomputing 38-40:845-850. (PDF)

PD Roberts (2001) Cooperative field theory is critical for embodiment, Beh. Brain Sci. 24:59-60 (PDF)

P. D. Roberts (2000) Modeling Inhibitory Plasticity in the Electrosensory System of Mormyrid Electric Fish. J. Neurophys.84: 2035-2047(PDF)

P. D. Roberts (2000) Dynamics of temporal learning rules. Phys. Rev. E 62: 4077-4082 (PDF)

P. D. Roberts (2000) Electrosensory response mechanisms in mormyrid electric fish. Neurocomputing 32-33:243-248. (PDF)

P. D. Roberts and C. C. Bell (2000) Computational consequences of temporally asymmetric learning rules: II. Sensory image cancellation. J. Compu. Neurosci. 7: 67-83. (PDF)

P. D. Roberts (1999) Computational consequences of temporally asymmetric learning rules: I. Differential Hebbian learning. J. Compu. Neurosci. 7: 235-246. (PDF)

P. D. Roberts (1998) Rhythmic behavior generated by neural ensembles. Int. J. Theor Phys. 37: 3051-3068. (PDF)

P. D. Roberts (1998) Classification of temporal patterns in dynamic biological networks, Neural Comp. 10: 1831-1846. (PDF)

P. D. Roberts (1997) Stochastic recruitment in parallel fiber activity patterns. Beh. Brain Sci. 20: 263-264. (PDF)

P. D. Roberts (1997) Classification of temporal patterns in the stomatogastric ganglion, Neuroscience 81: 281-296. (PDF)

P. D. Roberts, G. McCollum, and J. E. Holly (1996) Cerebellar rhythms: Exploring another metaphor, Beh. Brain Sci. 19: 146-147. (PDF)

P. D. Roberts and G. McCollum (1996) The stomatogastric nervous system: A formal approach, Neuroscience 72: 1089-1105. (PDF)

P. D. Roberts and G. McCollum (1996) Dynamics of the sit-to-stand movement, Biol. Cybern. 74: 147-157. (PDF)

String Theory Publications:
S. Hwang and P. Roberts (1993) Interaction and modular invariance of strings on curved manifolds, In Pathways to Fundemental Theories L. Brink and R. Marnelius (eds.) World Scientific, Singapore, pp. 61-75. (LaTex version)

P. Roberts and H. Terao (1992) Modular invariants of Kac-Moody algebras from covariant lattices, Int. Jour. of Mod. Phys. A7: 2207-2218. (LaTex version, references)

M. Henningson, S. Hwang, P. Roberts and B. Sundborg1 (1991) Modular invariance of SU(1,1) strings, Phys. Lett. B267: 350-355. (LaTex version)

P. Roberts, (1990) Modular invariant partition functions of minimal models from self-dual lattices, Phys. Lett. B244: 429-434. (LaTex version, references)

B.E.W. Nilsson, P. Roberts and P. Salomonson (1989) Standard model-like string theories from covariant lattices, Phys. Lett. B222: 35-42. (LaTex version, references)

P.D. Roberts and C.C. Bell (2000) Electrosensory response mechanisms in mormyrid electric fish. Featured presentation at Ninth Annual Computational Neuroscience Meeting, Brugge, Belgium. (presentation)

P.D. Roberts (1999) Electrosensory response mechanisms in mormyrid electric fish. Presented at Eighth Annual Computational Neuroscience Meeting, CNS*99, Pittsburgh, PA.

P.D. Roberts (1999) Dynamics of temporal learning rules in adaptive biological networks. Presented at the American Physical Society Centennial Meeting, Atlanta, GA.

P.D. Roberts and C.C. Bell (1998) Consequences of temporal order in synaptic plasticity. Presented at the Electroreception and Electrocommunication, San Diego, CA.

P.D. Roberts and C.C. Bell (1997) Computational consequences of temporal order in synaptic plasticity. Presented at the Dynamical Neuroscience Satellite Symposium , New Orleans, LA.(poster)

P.D. Roberts (1996) Rhythms in dynamic biological networks. Presented at the Society for Mathematical Biology Annual Meeting, Seattle, WA.

P.D. Roberts and G. McCollum (1995) Temporal pattern generation in dynamic biological networks, Soc. Neurosci. Abstr. 21(1): 225.

P. Roberts and G. McCollum (1994) A formal approach to the function and behavior of the stomatogastric nervous system, Soc. Neurosci. Abstr. 20(1): 324. (poster)

P. Roberts and G. McCollum (1993) The dynamics of rising from a seated position, Soc. Neurosci. Abstr. 19(2): 1687. (poster)