In 2006, two curious regions of the human brain were described by Larsson and Heeger, two New York scientists. These areas, known simply as lateral occipital areas 1 and 2 (LO1 and LO2), were deduced to be two visual areas. This initial conclusion was reached due to the functional properties and location of the areas. Less than a decade later, University of York researchers have utilised an, almost literally, mind-blowing technique to unravel the functions of LO1 and LO2.
Enter Edward Silson, a York student who undertook the research as part of his PhD; the project itself having been designed by Professor Tony Morland of the University and Dr Declan McKeefry of the University of Bradford. By utilising Functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS), whilst also taking advantage of some of the high tech equipment at the York Neuroimaging Centre (YNiC), the roles that LO1 and LO2 play were revealed.
Initially, fMRI was utilised in order to locate the tiny areas within each of the participants’ brains. Once located, TMS could be applied. This intriguing technique works non-invasively to temporarily activate or inhibit the activity of a chosen subset of neurons in the living brain. By targeting a rapidly changing magnetic field at specific areas of the brain, their functions can be disrupted and therefore determined. In this case, participants performed orientation and shape discriminations whilst having LO1 or LO2 activity disrupted.
With LO1 activity disrupted, it was discovered that the ability for participants to discriminate between the orientations of an object was reduced. In regards to LO2, a similar reduction was apparent when attempting to discriminate between the shapes of objects. The data therefore suggests that LO1 and LO2 have vital roles in the effective processing of orientation and shape respectively.
Concerning the project, Dr McKeefry stated that “The combination of modern brain scanning technology along with magnetic neurostimulation techniques provide us with a powerful means by which we can study the workings of the living human brain.” With Professor Morland further explaining that “Measuring activity across the brain with fMRI can’t tell us what causal role different areas play in our perception. It is disrupting brain function in specific areas that allows the causal role of that area to be assessed.”
It is hoped that future work will reveal exactly how information from all relevant visual areas in the brain, including the LO1 and LO2, come together to produce object recognition. Four further areas, which house currently unknown functions, have already been pencilled in for investigation.