Tag Archives: Electroencephalography

The brains of mathematicians

9 May

A post at Scientific American asks: “How Does a Mathematician’s Brain Differ from That of a Mere Mortal?”

“The team used functional magnetic resonance imaging (fMRI) to scan the brains of 15 professional mathematicians and 15 nonmathematicians of the same academic standing. While in the scanner the subjects listened to a series of 72 high-level mathematical statements, divided evenly among algebra, analysis, geometry and topology, as well as 18 high-level nonmathematical (mostly historical) statements. They had four seconds to reflect on each proposition and determine whether it was true, false or meaningless.
The researchers found that in the mathematicians only, listening to math-related statements activated a network involving bilateral intraparietal, dorsal prefrontal, and inferior temporal regions of the brain.”


Images of a brain on LSD

18 Apr


From the New Scientist:

“The team gave 20 volunteers infusions on two days, once containing 75 micrograms of LSD, the other a placebo. Then volunteers lay in a scanner and had their brains imaged with three different techniques, which together built up a comprehensive picture of neural activity, both with the drug and without.”

This work is yielding important findings:

“LSD also made the brain more unified in its activity, and there was more communication between regions that normally work separately. “The brain is functioning in a simpler way,” says Carhart-Harris.

The results also go some way to explaining how LSD causes dreamlike visual hallucinations. Although the primary visual cortex usually communicates mainly with other parts of the vision system, many other brain areas contributed to the processing of images in volunteers who received LSD.”


The effect of tea on brain waves

30 Apr


Here is the abstract from the relevant paper:

Tea has been associated with many mental benefits, such as attention enhancement, clarity of mind, and relaxation. These psychosomatic states can be measured in terms of brain activity using an electroencephalogram (EEG). Brain activity can be assessed either during a state of passive activity or when performing attention tasks and it can provide useful information about the brain’s state. This study investigated the effects of green and black consumption on brain activity as measured by a simplified EEG, during passive activity.
Eight healthy volunteers participated in the study. The EEG measurements were performed using a two channel EEG brain mapping instrument – HeadCoach™. Fast Fourier transform algorithm and EEGLAB toolbox using the Matlab software were used for data processing and analysis.
Alpha, theta, and beta wave activities were all found to increase after 1 hour of green and black tea consumption, albeit, with very considerable inter-individual variations.
Our findings provide further evidence for the putative beneficial effects of tea. The highly significant increase in theta waves (P < 0.004) between 30 minutes and 1 hour post-consumption of green tea may be an indication of its putative role in cognitive function, specifically alertness and attention. There were considerable inter-individual variations in response to the two teas which may be due genetic polymorphisms in metabolism and/or influence of variety/blend, dose and content of the selected products whose chemistry and therefore efficacy will have been influenced by ‘from field to shelf practices’.”

Brainwave signature for autism?

25 Sep

A paper, published in The Journal of Autism and Developmental Disorders, suggests that autism may be associated with a unique pattern of brainwave activity.

Here is the abstract:

“Atypical processing and integration of sensory inputs are hypothesized to play a role in unusual sensory reactions and social-cognitive deficits in autism spectrum disorder (ASD). Reports on the relationship between objective metrics of sensory processing and clinical symptoms, however, are surprisingly sparse. Here we examined the relationship between neurophysiological assays of sensory processing and (1) autism severity and (2) sensory sensitivities, in individuals with ASD aged 6–17. Multiple linear regression indicated significant associations between neural markers of auditory processing and multisensory integration, and autism severity. No such relationships were apparent for clinical measures of visual/auditory sensitivities. These data support that aberrant early sensory processing contributes to autism symptoms, and reveal the potential of electrophysiology to objectively subtype autism.”

And here is the press release giving a summary of the findings.

Finally, here is a video overview:



A switch for consciousness?

7 Sep

From the journal Epilepsy & Behavior, a paper describing a how a woman’s conscious awareness could be turned on or off by electrical stimulation of certain brain structures. Here is the abstract:


“The neural mechanisms that underlie consciousness are not fully understood. We describe a region in the human brain where electrical stimulation reproducibly disrupted consciousness. A 54-year-old woman with intractable epilepsy underwent depth electrode implantation and electrical stimulation mapping. The electrode whose stimulation disrupted consciousness was between the left claustrum and anterior-dorsal insula. Stimulation of electrodes within 5 mm did not affect consciousness. We studied the interdependencies among depth recording signals as a function of time by nonlinear regression analysis (h2 coefficient) during stimulations that altered consciousness and stimulations of the same electrode at lower current intensities that were asymptomatic. Stimulation of the claustral electrode reproducibly resulted in a complete arrest of volitional behavior, unresponsiveness, and amnesia without negative motor symptoms or mere aphasia. The disruption of consciousness did not outlast the stimulation and occurred without any epileptiform discharges. We found a significant increase in correlation for interactions affecting medial parietal and posterior frontal channels during stimulations that disrupted consciousness compared with those that did not. Our findings suggest that the left claustrum/anterior insula is an important part of a network that subserves consciousness and that disruption of consciousness is related to increased EEG signal synchrony within frontal–parietal networks.”

Wikipedia has a good description of the claustrum. Francis Crick and Christof Koch have suggested that the claustrum might be the seat of consciousness.

This research opens up the possibility that transcranial direct current stimulation might be used as tool to study consciousness.


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