I actually find these results extremely misleading -- there is no way that these three processes occur in complete isolation across these three areas. The recognition and recall task has been shown to rely on hippocampal regions (through lesion studies). A correlative finding is very weak.
What a horrible task to demonstrate consciousness.
The linked task is nothing but adaptation and/or attention. Adaptation occurs as early as the retina, and attention effects have been shown in V1. So if I were to subtract activity of when the yellow disk is percieved and when it is not it would pretty much show the entire brain.
MEG, like EEG, does have fairly fine temporal resolution, and using many electrodes and fancy signal processing, you can often get good spatial resolution as well (mm resolution). MEG does have better spatial resolution than EEG because the skull/scalp actually distorts/spreads the E fields.
However, MEG also has the same problems as EEG -- the signals are mainly derived from cortical areas. Because you are measuring magentic fields, you must measure orthogonal to the direction of current -- therefore MEG only measures current that is parallel to the skull surface. The human brain is heavily folded (each fold being a sulcus), and much of the important areas lay within these sulci.
Also, I believe MEG is a fairly expensive technique, and doesn't have the dual-use of functional MRI, so they are more difficult to find.
Slashdot Mirror
Not only has the recognition and category task been done in primates (http://www.sciencemag.org/cgi/content/abstract/29 1/5502/312) but all three of these areas have been found in previous fMRI experiments.
I actually find these results extremely misleading -- there is no way that these three processes occur in complete isolation across these three areas. The recognition and recall task has been shown to rely on hippocampal regions (through lesion studies). A correlative finding is very weak.
What a horrible task to demonstrate consciousness. The linked task is nothing but adaptation and/or attention. Adaptation occurs as early as the retina, and attention effects have been shown in V1. So if I were to subtract activity of when the yellow disk is percieved and when it is not it would pretty much show the entire brain.
MEG, like EEG, does have fairly fine temporal resolution, and using many electrodes and fancy signal processing, you can often get good spatial resolution as well (mm resolution). MEG does have better spatial resolution than EEG because the skull/scalp actually distorts/spreads the E fields. However, MEG also has the same problems as EEG -- the signals are mainly derived from cortical areas. Because you are measuring magentic fields, you must measure orthogonal to the direction of current -- therefore MEG only measures current that is parallel to the skull surface. The human brain is heavily folded (each fold being a sulcus), and much of the important areas lay within these sulci. Also, I believe MEG is a fairly expensive technique, and doesn't have the dual-use of functional MRI, so they are more difficult to find.