B.S. (Biology), B.S.(Electrical Engineering) and M.S., Massachusetts Institute of Technology (M.I.T.)
M.D. and Ph.D. (Physiology), University of Pennsylvania
Residency (Neurology), Johns Hopkins Hospital
Assistant Professor (Neurology), University of Pennsylvania
Professor (Neurology and Physiology), University of Maryland
Feedforward memory: There are two fundamentally distinct means to hold information of events of the immediate past. The information can be held as an “echo” within a feedback or attractor network. Alternatively, the information can be held by the propagation of the information within a feedforward network that can be viewed as the forward movement of ripple in a still pool of water after a series of pebbles has been dropped into it. There is a time to space transform which encodes the past perturbations. Feedforward networks have distinct advantages for holding arbitrary time encoded signals. Indeed, this strategy has been found to be the best means for buffering and holding inputs arriving over time at the input stage of CPUs of modern digital computers.
We postulate that the brain may use a similar strategy for implementing short term memory buffer functions, an indispensible function for any computational system that has to process information that does not arrive instantaneously. We believe the molecular substrate for this function is the voltage dependent block of the NMDA receptor and that the cellular substrate is the terminal dendrites of pyramidal neurons in a process we call “dendritic hold and read” or “DHR” (Santos et al., 2012). Furthermore, we postulate that the network substrate for feedforward memory are linear chains of identical pyramidal neurons that form a “delay line” type circuitry.
“FingerSight”: This technology is conceived as a user friendly and intuitive means to decrease the disability of visually impaired individuals. One end of a medical endoscopy fiber bundle (with appropriate imaging optics) is secured to the index finger of the user. The other end is optically coupled to the camera port of a smart phone. We wrote a computer vision algorithm for the smart phone that allows the user to use voice commands to “see” and interact with the environment. This system will allow one with poor sight to read by scanning the index finger over a page, to identify predetermined objects, and to detect critical edges for navigation.
After the introductory video of the hardware and the hallway, this video provides three parts to illustrate the three stages of the computer vision algorithm: (1) the raw video feed into the smart phone from the fiber bundle, (2) Canny edge detection of the video, and (3) edge detection of a vertical edge of a certain length without interruptions. When this edge (green line) crosses the center of the image a brief audio signal is provided to the user. A left turn is particularly hard for the blind because one can’t tap the edge with the white cane. (Collaborators, Rama Chellappa, Lee Stearns, and Leah Findlater)
Development and clinical applications of coherence gated Doppler (CGD) and transmission laser Doppler. (Collaborators: Yu Chen, Joe Schmitt, and Ashraf Fouad)
Catheter based optical coherence tomography (OCT) for stereotactic neurosurgery (Collaborators: Samir Jafri and Joe Schmitt)
Development of anisotropic scattering imaging (ASI) as a novel high resolution means to map white matter tracts in human brain.
Development and application of a tandem DMD-holographic photostimulation system (collaborator, Valentina Emiliani)
Integration of virtual reality and eye tracking technologies as an objective means of monitoring the severity of TBI and sports concussions (Collaborators: Ziggy Majumdar, Robert Shin, Chimene Richa)
Development and testing of a robotic neck brace for ALS patients and for airline travelers who wants to sleep in coach class
Sterilization of urinary catheter drains to decrease urinary tract infections (Collaborators: Paul Bigeleisen)
Tang, C-M., Presser, F., Morad, M. (1988) Amiloride selectively blocks the low threshold (T) calcium channel. Science 240: 213-215.
Tang, C-M., Dichter, M., Morad, M. (1989) Quisqualate activates a rapidly inactivating high conductance ionic channel in hippocampal neurons. Science 243: 1474-1477.
Tang, C-M., Dichter, M., Morad, M. (1990) Modulation of the NMDA channel by extracellular H+. Proc. Nat. Acad. Sci. 87:6445-6449.
Tang, C-M., Shi, Q-Y., Katchman, A. and Lynch, G. (1991) Modulation of the time course of fast EPSCs and glutamate channel kinetics by aniracetam. Science 254:288-290.
Yamada, K.A. and Tang, C-M. (1993) Benzothiadiazides inhibit rapid glutamate receptor desensitization and enhance glutamatergic synaptic currents. J. Neurosci. 13:3904-3915.
Tang, C-M., Margulis, M., Shi, Q-Y. and Fielding, A. (1994) Saturation of postsynaptic glutamate receptors after quantal release of transmitter. Neuron 13:1385-1393, 1994.