A group of researchers from the University of Texas Health Science Center at Houston and UC Davis have reported some exciting findings in regards to how the brain works to recall memories, discovered by research made possible by utilizing cutting edge methods to record brain activity. Rather than relying on the slow and often indirect processes of the past this group of scientists monitored several parts of the brain simultaneously, and in much closer detail, in order to determine what parts are working together when one recollects a past event. The lead author in the study is Andrew Watrous, a UC Davis graduate student. According to The California Aggie, using these much more detailed recordings allowed researchers to:
” . . . record not only which parts of the brain were activated, but when they were activated as well…The approach of graphing the recordings of areas of the brain provided a fresh perspective for the study of memory recollection. In order to record the activity, electrodes were placed inside the skull…The patients were individuals suffering from epilepsy. Due to their history, the researchers understood what parts of their brain were affected by epilepsy and how they might have been involved in recollecting memories.”
The first group to combine graph theory and recordings in the study of memory, the researchers also worked in conjunction with neurosurgeons in order to apply the electrodes. ““[We] recorded different areas of the brain simultaneously such as the frontal and parietal lobe and areas that were thought to be key in memory retrieval. [The] advantage is that we’re recording brain activity in various areas while we are spatially aware of them,” Watrous explains.
The Aggie article goes on to quote the University of Texas’ Christopher Conner:
“Think of a wave on the ocean. A surfer at the top of the wave has a lot of potential energy that they use as they ride down. We can use these recordings to estimate the frequency components using a variety of methods, such as Fourier transform and wavelet transform,” said Conner, a researcher on the University of Texas team responsible for data collection.
“Low frequency waves have very high amplitude. These are the huge waves the surfer actually rides. They come once every 10 to 20 seconds. Very high frequency waves have small amplitude. These are the little ripples you see on the top of the wave — just a couple inches tall, hundreds of them per second,” Conner said. “If you look at the wave, there are more ripples at the top than the bottom. It’s the same way with our recordings. What we did was to see how the high amplitude, low frequency waves coordinated the smaller ripples between areas. To push the metaphor to the extreme: Tsunamis travel thousands of miles, ripples don’t. So if you want to send information a long way, use the low frequency range to do it.”
The work completed for this study reveals another insightful look into how the human brain functions. Going forward, researchers hope to build on the knowledge gained by conducting experiments involving MRIs to map graphs, and they are also interested in possible research that looks into what happens when the brain’s memory recall network is disturbed.