Tagged: neuroscience

A Bug in fMRI Software Could Invalidate 15 Years of Brain Research

As more and more in training is based on fMRI-based brain studies, this is notable:

Functional MRI (fMRI) is 25 years old, yet surprisingly its most common statistical methods have not been validated using real data. Here, we used resting-state fMRI data from 499 healthy controls to conduct 3 million task group analyses. Using this null data with different experimental designs, we estimate the incidence of significant results. In theory, we should find 5% false positives (for a significance threshold of 5%), but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. These results question the validity of some 40,000 fMRI studies and may have a large impact on the interpretation of neuroimaging results. [Emphasis added]

Read coverage from Science Alert

Paper: Cluster failure: Why fMRI inferences for spatial extent have inflated false-positive rates by Anders Eklunda, Thomas E. Nicholsd, and Hans Knutsson

Paper: First Direct Evidence for Ultra-Fast Responses in Human Amygdala to Fear

For the first time, an international team of scientists has shown that the amygdala in the human brain is able to detect possible threats in the visual environment at ultra-fast time scales. By measuring the electrical activity in the amygdala of patients that had been implanted with electrodes in order to better diagnose their epilepsy, the researchers provide new data on how information travels between the visual and emotional networks…

Continue reading at Science Daily

The Empty Brain

In The Empty Brain, Robert Epstein asserts that “your brain does not process information, retrieve knowledge or store memories. In short: your brain is not a computer.”

Long but interesting read that covers a lot of ground. A few choice points:

Recognition vs explicit recall:

The difference between the two diagrams reminds us that visualising something (that is, seeing something in its absence) is far less accurate than seeing something in its presence. This is why we’re much better at recognising than recalling. When we re-member something (from the Latin re, ‘again’, and memorari, ‘be mindful of’), we have to try to relive an experience; but when we recognise something, we must merely be conscious of the fact that we have had this perceptual experience before.

Stimulus/response, reward/punishment:

As we navigate through the world, we are changed by a variety of experiences. Of special note are experiences of three types: (1) we observe what is happening around us (other people behaving, sounds of music, instructions directed at us, words on pages, images on screens); (2) we are exposed to the pairing of unimportant stimuli (such as sirens) with important stimuli (such as the appearance of police cars); (3) we are punished or rewarded for behaving in certain ways.

That could leave a mark…

Because neither ‘memory banks’ nor ‘representations’ of stimuli exist in the brain, and because all that is required for us to function in the world is for the brain to change in an orderly way as a result of our experiences, there is no reason to believe that any two of us are changed the same way by the same experience. If you and I attend the same concert, the changes that occur in my brain when I listen to Beethoven’s 5th will almost certainly be completely different from the changes that occur in your brain. Those changes, whatever they are, are built on the unique neural structure that already exists, each structure having developed over a lifetime of unique experiences.

Continue reading at AEON…