Boston University Medical Campus
Biomedical Imaging

Louis J. Toth, Ph.D.

Current Interests:

Studying the physiology of how the mammalian brain computes information at the level of neuronal ensembles. Systems studied include the representation of object features in the visual pathway, and behavioral modulation in cortex. Developing novel techniques, including primate fMRI, correlation of fMRI signals with neuronal activity, other imaging techniques (voltage-sensitive dye, intrinsic signal, 2-DG) and studying the neural consequences of transcranial magnetic stimulation in animal models. Studying comparative functional neurophysiology in mammals in order to learn how cortical function has been shaped by evolution.

Experience:

Developed techniques of in vivo whole-cell recording and optical imaging of intrinsic signals. Experienced in neurosurgery and histology of monkey, cat, ferret, squirrel and rat. Wrote software for experimental control, data collection, visual stimulus display, data and image analysis, using C++ and MATLAB on Macintosh and PC platforms. Built setup for neuronal recording from awake behaving primates. Experience with high-field fMR imaging of neuronal activity.

Degrees:

S.B. Mass. Inst. of Tech. 1989, Aeronautical & Astronautical Eng.
Ph.D., Mass. Inst. of Tech. 1995, Systems Neurosci. (Brain & Cog. Sci.)

Positions Held:

Physiologist, The Daedalus Project (human-powered aircraft)
Massachusetts Institute of Technology 1987-88
Postdoctoral Associate, Department of Brain and Cognitive Sciences,
Massachusetts Institute of Technology 1995-96
Research Fellow, Department of Neurobiology,
Harvard Medical School 1996-2001
Research Assistant Professor, Department of Anatomy and Neurobiology
Boston University Medical School 2002-present
Visiting Assistant Professor, Center for Magnetic Resonance Research,
Department of Radiology, University of Minnesota 2002-present

Honors and Awards:

National Merit Scholarship, 1986
Sigma Xi national honor society, elected in 1992
Angus N. MacDonald Award for Dedication in Teaching
The Medical Foundation, research award 1999-2001.

Member of:

Society for Neuroscience, 1991-present
International Society for Magnetic Resonance in Medicine, 2002-present

Publications:

Kim DS, Ronen I, Olman C, Kim SG, Ugurbil K, Toth, LJ (2003) Spatial relationship between neuronal activity and BOLD functional MRI Neuroimage (in press)

Williams ZM, Elfar JC, Eskandar EN, Toth LJ, Assad JA (2003) Parietal activity and the perceived direction of ambiguous apparent motion Nat. Neurosci. 6:616-623.

Ugurbil K, Toth LJ, Kim DS (2003) How accurate is magnetic resonance imaging of brain function? TINS 26:108-114.

Toth LJ, Assad JA (2002) Dynamic coding of behaviorally relevant stimuli in parietal cortex Nature 415:165-8.

Somers DC, Todorov EV, Siapas AG, Toth LJ, Kim DS, Sur M (1998) A local circuit approach to understanding integration of long-range inputs in primary visual cortex. Cer. Ctx. 8:204-217.

Toth LJ, Kim DS, Rao SC, Sur M (1997) Integration of local inputs in visual cortex. Cer. Ctx. 7:703-710.

Rao SC, Toth LJ, Sur M (1997) Optical maps of orientation preference in primary visual cortex of cats and ferrets: organizing principles and rules of representation. J. Comp. Neurol. 387:358-370.

Toth LJ, Rao SC, Kim DS, Somers DC, Sur M. (1996) Subthreshold facilitation and suppression in primary visual cortex revealed by intrinsic signal imaging. Proc. Nat. Acad. Sci. USA 93:9869-9874.

Toth LJ (1995) Layout and connectivity of orientation domains in mammalian visual cortex: a physiological description. Ph.D. Thesis in Brain and Cog. Sci., Mass. Inst. of Tech.

Nelson S, Toth L Sheth B, Sur M (1994) Orientation selectivity of cortical neurons during intracellular blockade of inhibition. Science 265:774-7. (5 Aug.)

Kwon YH, Nelson SB, Toth LJ, Sur M (1991) Effect of stimulus contrast and size on NMDA receptor activity in the cat lateral geniculate nucleus. J. Neurophys. 68(1):182-96.

Book Chapters

Somers DC, Toth LJ, Todorov E, Rao SC, Kim DS, Nelson SB, Siapas AG, Sur M (1995) Variable gain control in local cortical circuitry supports context-dependent modulation by long-range connections. In Sirosh, J., Miikkulainen, R., and Choe, Y., eds., Lateral Interactions in the Cortex: Structure and Function. The UTCS Neural Networks Research Group, Austin, TX, 1996. Electronic book, ISBN 0-9647060-0-8, http://www.cs.utexas.edu/users/nn/web-pubs/htmlbook96

Invited Talks

2001 Minnesota Workshop on MR Imaging of Brain Function 7-8 Oct. 2001

Abstracts

Toth LJ, Van Hooser SD, Chung S, Heimel JAF, Nelson SB (2003) Functional organization of squirrel visual cortex revealed by intrinsic signal imaging Soc. Neurosci. Abstr.29 (125.10)

Park JC, Ronen I, Toth LJ, Ugurbil K, Kim DS (2003) Comparison of lateral point spread function of BOLD and CBF based functional MRI in cat visual cortex Soc. Neurosci. Abstr.29 (69.8)

Toth LJ, Ronen I, Ugurbil K, Kim DS (2002) Neural correlate of functional MRI at columnar resolution Soc. Neurosci. Abstr. 28: (325.10)

Ronen I, Toth LJ, Ugurbil K, Kim DS (2002) Investigating the Point Spread Function of BOLD and CBF fMRI in the Cat Visual Cortex ISMRM meeting

Toth LJ, Ronen I, Kim SG, Ugurbil K, Kim DS (2002) Neural correlate of CBF-based functional MRI ISMRM meeting

Kim DS, Ronen I, Toth LJ, Olman C, Duong T, Merkle H, Kim SG, Ugurbil K (2001) Neural correlate of BOLD functional MRI ISMRM meeting.

Toth LJ, Ronen I, Olman C, Ugurbil K, Kim DS (2001) Spatial correlation of BOLD activity with neuronal responses. Soc. Neurosci. Abstr. 27: (783.1)

Toth LJ, Assad JA (2000) Behavioral relevance dynamically increases color selectivity in LIP. Soc. Neurosci. Abstr. 26: (249.14)

Toth LJ, Assad JA (1999) Visual stimulus selectivity during an association task in LIP. Soc. Neurosci. Abstr. 25:1546 (618.6)

Toth LJ, Kim DS, Sur M (1996) Do cortical cells integrate local inputs linearly? Short-range lateral interactions revealed by intrinsic signal and single-unit activity. Soc. Neurosci. Abstr. 22:491. (198.10)

Toth LJ, Kim DS, Rao SC, Sur M (1995) GABA iontophoresis modifies the intrinsic signal orientation map in cat area 18. Soc. Neurosci. Abstr. 21:1655. (650.14)

Kim DS, Toth LJ, Rao SC, Sur M (1995) Orientation dynamics in adult visual cortex: focal infusion of bicuculline modifies optically imaged maps. Soc. Neurosci. Abstr. 21:771 (311.4)

Rao SC, Toth LJ, Kim DS, Sur M (1995) Direction selective patches revealed by optical imaging of intrinsic signals in cat primary visual cortex. Soc. Neurosci. Abstr. 21:392 (162.2)

Toth LJ, Rao SC, Sur M (1994) Orientation-specific spread of activation in primary visual cortex measured by optical recording of intrinsic signals. Soc. Neurosci. Abstr. 20:836. (349.2)

Rao SC, Toth LJ, Sur M (1994) Invariance of orientation domains in area 17 of cat visual cortex revealend by intrinsic signal imaging. Soc. Neurosci. Abstr. 20:836. (349.1)

Toth LJ, Nelson SB, Rao SC and Sur M (1993) Synaptic potentials in visual cortical neurons : temporal variability and spatial structure. Soc. Neurosci. Abstr. 19:1576. (648.8)

Sheth BR, Rao SC, Toth LJ and Sur M (1993) Patchy intrinsic connections within ferret primary visual cortex. Soc. Neurosci. Abstr. 19:333. (139.8)

Toth LJ, Nelson SB, Sheth BR, Sur M (1992) Orientation selectivity of synaptic currents during intracellular blockade of inhibition in visual cortex in vivo. Soc. Neurosci Abstr. 18:209. (99.5)

Nelson SB, Toth LJ, Sur M (1992) Spatial and temporal integration of synaptic inputs by visual cortical neurons. Soc. Neurosci. Abstr. 18:209. (99.4)

Kwon YH, Nelson SB, Toth LJ, Sur M (1991) Effect of stimulus contrast and size on NMDA receptor activity in the cat lateral geniculate nucleus. Soc. Neurosci Abstr. 17:709. (282.3)