Hippocampal Memory Formation

The hippocampus consists of two sheets of densely packed neurons deep within the brain. This collection of grey matter is an essential component of the limbic system as well as a contributor to memory. Due to its central location within the brain, the hippocampus relays information to the thalamus and eventually cerebral cortex. Neuroscientists, intrigued by hippocampal memory formation, have studied this deep brain structure at the cellular level, looking for patterns within neuronal firing. Neuroscientist Neil Burgess has built upon prior hippocampal research targeting spatial memory processing.
Every time a neuron within the brain fires it emits a small electrical spike called an action potential. Using modern techniques, neuroscientists have been able to record the electrical activity of the brain at the cellular level. Neil Burgess monitored individual neurons within the hippocampus of rats. The experiment examined a rat’s rate of neural firing within one hippocampal neuron while they were looking for food.
In his rat studies, Burgess found a striking neuronal response to boundary conditions. If two sides of the box were lengthened, forming a rectangle, the neuron corresponding to the changed location also elongated. Similar tests were done using additional boundaries placed within the original space, contributing analogous results. Thus, the type of boundary did not seem to matter because the rats responded uniformly in all situations. Boundary conditions seem to be crucial for sensing distances and direction. Just as before, similar studies were also conducted using human test subjects. Brain activity was monitored via MRI while human test subjects explored a virtual world and marked significant locations. Changing the dimensions of the environment resulted in outcomes comparable to the prior rat