Neuroscience
The idea that your brain contains information that ‘you’ cannot access is, of course, not new – Freud wrote about that years ago; and neither is it an unfamiliar phenomenon in our everyday lives – how often do we struggle to find a word that we know is in there somewhere? But what is new, is the demonstration by scientists that they can use a scan to read off information from your brain that you are unable to access yourself.
Using functional imaging, John-Dylan Haynes and Geraint Rees at University College London first showed that some parts of the brain involved in early visual processing are activated more than others, depending on the particular angular orientation (e.g. / or \ ) of the visual pattern being looked at. That some brain cells are organised according to sensitivity to different orientations is well-known from the direct recording of individual neurons in monkeys, but this is the first time it has been shown in humans using brain scanning.
Next, Haynes and Rees presented participants with ‘invisible’ visual patterns. The patterns were invisible because they were presented so briefly, and because each one was followed by a visual mask – a second stimulus that interferes with processing of the first. This meant that when asked, a participant couldn’t say what orientation a pattern had – they could only guess. But although a pattern was invisible to a participant, its orientation still left a signature trace of activity in their brain. This meant the researchers could discern the orientation of the pattern by observing the distribution of activity in the participant’s brain (in their early visual cortex, called ‘V1’). So the researchers could read information in a participant’s brain that was inaccessible to the participant herself. “Human V1 can represent information about the orientation of visual stimuli that cannot be used by participants to make a simple behavioural discrimination”, the authors concluded.
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Haynes, J-D. & Rees, G. (2005). Predicting the orientation of invisible stimuli from activity in human primary visual cortex. Nature Neuroscience, 8, 686-691.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Neuroscience
Are you thinking what I say you're thinking?
The idea that your brain contains information that ‘you’ cannot access is, of course, not new – Freud wrote about that years ago; and neither is it an unfamiliar phenomenon in our everyday lives – how often do we struggle to find a word that we know is in there somewhere? But what is new, is the demonstration by scientists that they can use a scan to read off information from your brain that you are unable to access yourself.
Using functional imaging, John-Dylan Haynes and Geraint Rees at University College London first showed that some parts of the brain involved in early visual processing are activated more than others, depending on the particular angular orientation (e.g. / or \ ) of the visual pattern being looked at. That some brain cells are organised according to sensitivity to different orientations is well-known from the direct recording of individual neurons in monkeys, but this is the first time it has been shown in humans using brain scanning.
Next, Haynes and Rees presented participants with ‘invisible’ visual patterns. The patterns were invisible because they were presented so briefly, and because each one was followed by a visual mask – a second stimulus that interferes with processing of the first. This meant that when asked, a participant couldn’t say what orientation a pattern had – they could only guess. But although a pattern was invisible to a participant, its orientation still left a signature trace of activity in their brain. This meant the researchers could discern the orientation of the pattern by observing the distribution of activity in the participant’s brain (in their early visual cortex, called ‘V1’). So the researchers could read information in a participant’s brain that was inaccessible to the participant herself. “Human V1 can represent information about the orientation of visual stimuli that cannot be used by participants to make a simple behavioural discrimination”, the authors concluded.
___________________________________
Haynes, J-D. & Rees, G. (2005). Predicting the orientation of invisible stimuli from activity in human primary visual cortex. Nature Neuroscience, 8, 686-691.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
- Brain Scan Can Read Your Intentions
Researchers have shown they can read a person's intentions from the patterns of activity in the front of their brain. John-Dylan Haynes and colleagues said their findings could have important technical and clinical applications, “such as the further...
- Invisible Nudes?
From Dr Gerry Quinn: Dynamic Visual Noise You can't see them here, because the authors exploited the phenomenon of binocular rivalry to present different images to each eye separately. Specifically, dynamic visual noise and nude male or female images...
- I Am What I See
Schematic representation of the two streams of visual processing in human cerebral cortex (taken from Goodale & Westwood, 2004). There is no pattern, yet there is The configuration lies within --Single Gun Theory, I Am What I See How does the brain categorize...
- Predicting Stimuli From Fmri Data
Though the headline and subhead they use are unfortunately over-dramatic, this from the BBC:'Thoughts read' via brain scans The researchers monitored activity in the brain. Scientists say they have been able to monitor people's thoughts via...
- Fmri And The Primary Visual Cortex
Improved Scanning Technique Uses Brain as Portal to Thought By NICHOLAS WADE The New York Times Published: April 25, 2005 By peering not into the eyes but into the brain, an improved scanning technique has enabled scientists to figure out what people...