Do you believe in magic? Want to know more about DSRF? We would be happy to give you a tour of our unique facility. Please contact Dawn to set up an individualized or group tour....more
DSRF - Making Dreams Happen
The Down Syndrome Research Foundation is proud to present our brand new promotional video aimed at raising awareness for our organization as well as providing information on our various programs for individuals with developmental disabilities of all ages....more
Waiting for a Snowflake to Land on my Tongue
DSRF Receives Kiwanis Club Grant (2013)
About the MEG
Peering into the Brain
At the DSRF we have a specialized imaging tool that records these small magnetic fields called magnetoencephalography (MEG). The MEG installed at DSRF is a 151-channel whole cortex system manufactured by CTF Systems, Inc. (Canada). The system is placed inside a magnetically shielded room that protects it from the strong environmental fields such as the Earth field, industrial electromagnetic noise, etc. We use the MEG to conduct numerous studies .
How does the MEG work?
The liquid helium vessel has a helmet-shaped bottom and the sensor array inside the vessel follows the shape of the helmet. When a person sits inside, their head is placed in the helmet with the sensors very close to the scalp to allow the detection of the electromagnetic activity of the brain.
MEG is a completely non-invasive technology. It does not involve any physical, electromagnetic or chemical intervention with the subject. The system is just passively “listening” to the natural brain activity. This technology is particularly suited for children and other populations who may be more sensitive to noise and small confined spaces.
What happens once the information from the brain has been collected?
Looking at this data we can get some basic information about the signals and how these signals change with different conditions. For example this image shows 3 examples displaying the signals when a person is sitting quietly with their eyes closed (A), eyes open (B) and when they are looking at an image on the computer screen (C). The qualitative differences in the rhythms of the brain under the different conditions are quite apparent in these plots.
Once we have looked at these plots we use sophisticated signal processing methods to estimate the location of the activity within the brain. This is referred to as the inverse problem. The main issue is that the inverse problem does not have a unique solution. In other words there are many, many possible solutions to where the activity is located in the brain. Our signal processing scientists use various models and techniques that are based to find the best solution. These models are based on specific assumptions that are made about the shape of the head, knowledge about neurophysiology, etc.
Once the locations of brain activity are determined, we then look at the relationship between different locations and the timing of this activity. Below is a figure that shows the areas of activation during a motor task involving pressing a button with the index finger. The top plot shows the average from a group of typically developing adults; the bottom plot shows the average from a group of adults with Down syndrome. Differences and similarities in the active areas of the brain between the two groups can be clearly seen.