In a remarkable study researchers have been able to intrepret the activity in people’s visual cortex and correlated this with video images. These results are a convincing demonstration of the validity of functional Magnetic Resonance Imaging (although there are various nuances in the interpretation of the results). To get to these results the researchers used large datasets and long training periods for the subjects which consisted of the researchers themselves. Firstly the researchers needed to correlate activity in multiple areas of the visual cortex with large numbers of video segments. For this the subjects had to watch a lot of video clips whilst being scanned to build up the library of video clip-activity pairs. The researchers developed an understanding of the relationship of perception of different line orientations and other basic visual information to brain activity. Then the researchers’ program scanned through 18 million seconds of video footage from YouTube generating likely brain activity correlates. Then the subjects watched a new set of previously unseen clips and the software translated the brain activity into the nearest matches from the 18 million second sample set. The end results are the blurry images seen below. The researchers however could sharpen up the videos by refining the program. There are many obvious questions to ask here. For instance when we use imagination one hypothesis states that imagination utilises the visual cortex rather than higher association areas. The researchers would be able to investigate this by asking subjects to imagine a scene whilst recording brain activity before translating this. These results would also be incredibly important for researchers investigating the causes of visual hallucinations in people with Schizophrenia and Dementia.
One of the questions asked in Alzheimer’s Disease research is just how important are the neurofibrillary tangles in the aetiology? This is a useful question to ask because there are a number of people who are found to have significant neurofibrillary tangles in the brain at autopsy but were not diagnosed with dementia during lifetime. The obvious inference would be that tangles do not necessarily result in Alzheimer’s Disease and there must be other factors playing a protective role. Santacruz and colleagues have tried to answer the question by looking at data from two studies – the Nun study and the Adult Changes in Thought study (combined n=821). Using the Braak staging for grading the pathology at autopsy the researchers found that people with severe Braak staging (V-VI) who were not diagnosed with dementia prior to death did have evidence of significant memory impairment. The data was consistent with the Tau hypothesis* which state that the neurofibrillary tangles play a central role in the disease process.
In an interesting development, a group at Oxford have used a new scoring system for small vessel disease to show a correlation with cognitive scores. None of the people involved in the study had pathological evidence of Alzheimer’s Disease using Braak staging and the researchers used both a simple measure of cognition (the MMSE) as well as the CAMCOG. Thus the group have shown results which may contribute to a better understanding of the contribution of small vessel disease to cognition with potentially useful clinical applications.
In another development the cost of personal genomics has come down with one company offering 80 x coverage (meaning that the genome is covered 80 times to reduce the risk of errors). It will be interesting to see how this will be linked in with mainstream health services.
There is an interview with Professor Simon Baron-Cohen on his book ‘The Science of Evil’ here.
In a paper in the American Journal of Human Genetics, Stoneking and colleagues have looked at the genomes of people from 33 populations in Asia for similarities to the genome of Denisovans. Denisovans are an extinct hominid with one specimen being identified in Siberia dating back to over 30,000 years ago. The researchers found evidence of Denisovan DNA in people living in countries including Australia and Indonesia. They have suggested that the Denisovans were likely to have inhabited a vast range from Siberia to Australia thought to be possible only for modern humans. However other researchers have suggested that hybridisation may have occured in Central Asia with the migration of subsequent generations. The Denisovan specimen was found with a necklace and is more closely related to Neanderthal (although distinct) than humans although such generalisations should be viewed with caution without a sufficient sample size.
Researchers have used obtained evidence that Marmosets can intentionally meditate in order to receive a reward (see write-up here which also features footage). The researchers used an EEG to record brain activity. The Marmoset would appear to focus at a distance and this would correspond to a 12-16 Hz frequency of cortical activity. Once the reward was received there would be a return to waking brain activity. This raises important questions about intelligence, cognitive abilities and consciousness in New World Monkeys whose ancestors diverged from ours some 40 million years ago.
There is a new Wiki site – CognoPedia where you can ‘learn more about the brain, cognition, neuroscience and brain health’. More articles are being contributed to the site.
* Part of the Amyloid Cascade Hypothesis
Appendix – Annual News Roundups
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