Increasing fMRI resolution

Neuroimaging techniques are limited by their spatial and temporal resolution. fMRI has a spatial resolution of about 3-4mm. Now researchers have developed statistical techniques to narrow fMRI resolution down to less than a millimeter, fine enough to see the “orientation columns” in the primary visual cortex (V1), so named because each reacts to lines and edges at a particular orientation.

The research is described in an article in Nature Neuroscience, Decoding the visual and subjective contents of the human brain. The authors conclude their abstract with the observation

Our approach provides a framework for the readout of fine-tuned representations in the human brain and their subjective contents.

Much more of science than people realize is about computers processing massive amounts of data. Theories of the cosmos are basically just computers crunching numbers; the Hubble photos we see are massively computer enhanced. From an information theoretic point of view, it’s highly likely that orders of magnitude of additional useful information can be extracted from even the current generation of fMRI hardware, given the right algorithms. That’s the approach these researchers have taken, highlighting the importance of the field called computational neuroscience.

V1 is the part of the visual cortex at the back of your head which takes the first crack at signals coming in from your eyeballs. It’s just one synapse away from the retina. The interesting thing about this research was not just the ability to look at individual orientation columns, but how this ability was used. Subjects were told to focus on one of two overlapping grids of lines of different orientations. The researchers then used the enhanced scanning technique to verify that the relevant orientation columns were activated. This demonstrates how higher-level, conscious functioning (“attention”) can drive lower-level brain functions—the sort of top-down mechanism that Jeff Hawkins focuses on in On Intelligence.

I do have to object to the headline the NYT came up with for its article about this news: “Improved Scanning Technique Uses Brain as Portal to Thought”.

Now, we just have to hone in on the “God” columns in the temporal lobe, or wherever they are.

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