Research Interests

My burning question concerns how "thinking" is accomplished by humans.  In order to make the jump from philosophy to neuroscience (although I am still informally interested in philosophy of the mind), I have narrowed my formal research interests to the following question(s): How does the human brain (a) acquire information from the environment, (b) store and process that information, and (c) retrieve stored and processed information and output behavior?  In order to study information extraction, I have focused on the visual system.  In order to explore how information is stored and processed, and what sorts of behaviors come from studying that information, I am focusing on learning and memory.  I employ a wide variety of techniques to study these questions.

How do we learn and remember?

• I'm analyzing (a) electrical activity recorded from neurosurgical patients and (b) fMRI activity recorded from healthy people as they study and recall lists of words.  I'm trying to gain a better understanding of how these words, and the contexts in which they are encountered, are represented by the brain during memory tasks.  I'm also interested in modeling these processes.  You can read more about the details this project here, here, and here.  You can also read high-level descriptions of the project here, here, and here.
• Examining fundamental patterns in the brain's electrical activity can yield valuable insights into how the brain does its computations.  I'm currently working on this problem by analyzing intracranial EEG recorded from neurosurgical patients who participate in various memory-related experiments.  You can read a recent paper here.
  
• I am involved in a joint project with the Sekuler Lab at Brandeis University. The goal of the project is to design and implement a computational model which will mimic human subjects who played a virtual taxicab game. You can read more about the high-level ideas of this project here.  If you want the details, read this paper.

How do we see?

In the Brainard Lab, I'm working on a Bayesian model for vision. We know that photoreceptors cannot capture all photons which hit the retina, and so the activation of photoreceptors undersamples the light reflected off objects in one's environment. Plus, there's all kinds of blurring and other sources of noise that make photoreceptor measurements unreliable. This means that in order to estimate what's actually "out there" in the world, the brain needs to do some guesswork.  We've implemented a Baysian estimator for images which explicitly represents the photoreceptor layout on the retina -- this allows us to test how "good" different retinal designs are at guessing about the visual world. So far, we're using this model to answer questions about how and why the visual system might have evolved as it did.  If you're interested, check out this paper.

The next question I'm working on in this line of research is to ask whether details about the types of each photoreceptor need to be genetically encoded, or whether the types can be learned by observing receptor responses.  We're using an expectation-maximization-like algorithm to simultaneously estimate the statistical properties of the stimulus distribution (i.e., the world) and the types of each photoreceptor.

How do our developing brains know how to wire themselves?

In the Raper Lab, I studied axon guidance in E7 chick DRG's in vitro. The brain contains many chemical cues that tell neurons how and where to grow, and where to link up with other neurons. I worked with a simple assay to measure the effectiveness of various signalling molecules. In parallel, I developed a (cross platform) computer program to automate the image analysis component of my experiment and some other experiments in the lab.

Other interests

My other research interests include artificial intelligence, machine learning, neural networks, knowledge representation, database systems, and computer graphics.

Aside from my research:

• I really like to read. Science fiction has always held a special place in my heart, although I enjoy a good thriller, mystery, or adventure book, too.  I tend to latch onto a particular author, read everything they've ever written, and then move on to the next candidate.  Some of my favorite authors (and books) are:
• Robert Sawyer (pretty much anything he writes!)
• Greg Bear (EON series)
• Robert Ludlum (Bourne series)
• Orson Scott Card (Ender series)
• Philip K. Dick (especially his short stories)
• Frank Herbert (Dune series)
• Neal Stephenson (Snow Crash, Diamond Age, The Cobweb, Interface)
• I like to run/bike.  My most recent events were the Philly Rock and Roll Half Marathon and the Boilermaker 15K.
• I enjoy customizing my Droid X to the n^th degree.  I've recently started playing around with the Android Development Kit, so maybe I'll be posting an app soon!  Current ROM of choice: MIUI.
  
• Modular origami is is one of my longest-standing hobbies. The best book for learning how to do this stuff is Unit Origami: Multidimensional Transformations, by Tomoko Fuse.  It's also a great book even if you just like geometry but aren't that interested in origami.
  
• I am also a PADI-certified open water diver. I have been on some neat dives, including a shipwreck dive. I enjoy other water-related activities such as sailing, snorkling, swimming, jet-skiing, water-skiing, etc. as well.  Just sitting on the beach and watching the water is also nice.
• As an undergrad at Brandeis I started learning Okinawan Uechi-Ryu karate. I haven't been keeping up with this formally while in New Jersey, although I've been practicing my kata (forms) and drills when I can.
• I also like playing chess (untimed). If you ever want an easy match, let me know and I'll be glad to play (even over the internet via email) provided I don't have a myriad of other pressing things to do (although I can be easily distracted from my work for a good game).
• I enjoy playing the trumpet. In high school I played in the school's jazz band, although since then I've played only infrequently.  More recently, I've been trying to teach myself to play the guitar.  A long time ago, I played the viola and the piano as well.
  
• I have been making computer art for a while now. I used to be a big 2D fan (using Photoshop, Photopaint, Illustrator, Draw, etc.), however In the past couple years I've started to move into the 3D world (Dream3D, Blender, Cinema4D, Lightwave, Maya, etc.).
• A few of my favorite video games are Unreal Tournament, Freelancer, Tribes, BZFlag, Grand Theft Auto, and Frozen Bubble.
• Near the end of my senior year in college, I started getting interested in Rubik's Cubes. I am more interested in generalizeable puzzle-solving algorithms than speed-solving. You can watch a movie of me solving a Rubik's cube using the layer-by-layer method. I also enjoy writing and reading about puzzle-solving computer algorithms.  I'm planning to put up a tutorial on Rubik's cube solving at some point, so stay tuned!