Cryptography

Why "cortical cryptography"? A fundamental question of Cognitive Neuroscience is the question of how information is represented in the neurons and synapses of the human brain. In cognitive psychology studies of learning and memory, we attempt to identify and control the type of information being acquired and we then observe the behavioral consequences that follow to verify the learning.

What is happening in-between the presentation of controlled information to the participant and the observation of their subsequent responses is essentially the encryption of information into the brain of the participant. So we can say that trying to understand the representation of information in neural systems is analogous to attempting to determine the encryption/decryption algorithm that the brain uses.

In basic research that we've been doing for awhile in the lab, I frequently find myself describing one of the goals of the research as identifying the operating characteristics of specific memory systems that we believe we can isolate. We attempt to find boundary conditions on the rate of learning, the applicability of the information (flexibility), the limitations on complexity of information to be acquired, the effect of passage of time (memory decay, forgetting).

Internally, I think of this as being something like a timing channel attack on this mysterious encryption algorithm.

From Wikipedia, http://en.wikipedia.org/wiki/Timing_attack

In cryptography, a timing attack is a side channel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms. Every logical operation in a computer takes time to execute, and the time can differ based on the input; with precise measurements of the time for each operation, an attacker can work backwards to the input.

I think I'd state the last bit a little differently -- I want to try to work out the characteristics (including time) of the encryption algorithm not to identify the input (we control the input), but to figure out the algorithm itself.

We are currently looking at perceptual-motor sequence learning, which we believe is largely supported by cortico-striatal circuit loops (from the basal ganglia to the cortex and back). There are a fair number of neurons in the circuit, but I have this hunch that if we can get some basic characteristics of the learning ability of the system, e.g., the bandwidth of the learning rate, that will rule out some possible encoding algorithms and constrain the set of plausible encryption algorithms.