AU, Riken join hands to demystify human brain

Japan’s institute also gifts eye scanner worth Rs 25 lakh to CBCS

SCIENTISTS OF Allahabad University's Centre for Behavioural and Cognitive Sciences (CBCS) will soon undertake in-depth studies to demystify the dynamics of the human brain and also find the reasons for the duration of judgements of the visual perceptions found varying from person to person.

The new researches are being undertaken as part of a collaborative effort between the CBCS and the experts of the Riken Brain Science Institute of Japan  for which the proposal has been approved recently.

Explaining the two studies, CBCS's Dr Narayanan Srinivasan— who has just returned from a visit to the Laboratory for Perceptual Dynamics (PDL) at Riken Brain Science Institute, Japan after finalising the project— said, "One way to study brain activity is through recordings made from the scalp called electroencephalograms (EEG). EEG reflects summated electrical activity of the neural networks in the brain and is used for clinical research as well as cognitive science research. Various techniques are available to analyse EEG signals."

Dr Srinivasan, who has also been offered a position of visiting scientist at Riken from June 2006 to March 2007, said that one way to do it is by finding the presence of alpha rhythms (8-13 Hz) when a person is at resting state with eyes closed.

"One possible way to look into the dynamic interactions between brain areas is through phase synchronisation. Prof Van Leeuwen, who heads the PDL at Riken, and his colleagues have studied phase synchronisation in spontaneous EEG alpha activity during the resting state with eyes closed," he said.

"Two specific patterns involving various brain areas have been observed.

However, these studies have been done with adults. It is also important to understand the dynamic interactions in children and see how these specific patterns develop. And this is what we plan to do at CBCS now," Dr Srinivasan added.

Dr Srinivasan said that for this, EEG recordings when participants are resting with eyes closed will be obtained from adults as well as children at the Cognitive Neuroscience Lab at CBCS.

"Phase synchronisation will be evaluated for children and compared with adults which will enable us to understand dynamic interactions among different brain areas in children. One of the most interesting puzzles in cognitive science is perceptual experience. A possible solution is the so-called laminar intervals which are defined based on concepts from non-linear dynamics," Dr Srinivasan explained.

He said that the laminar intervals have certain duration and this is related to the psychological present.

"A common example of multi-stability is the Necker cube that can be seen in two forms and these forms alternate in time. Perceptual switching is said to occur when a person goes from seeing one version of the Necker cube to the next version," he added.

The proposal is that during switching the system is between two laminar intervals, so there is no persistent synchrony and hence no duration. "This proposal suggests that duration judgements will be affected depending on whether perceptual switching occurs during the duration to be judged. To study this hypothesis, experiments will be performed in the Visual Cognition Lab in CBCS with multi-stable stimuli like Necker cube," he said.

Dr Narayanan Srinivasan informed that the decision to undertake collaborative researches with Riken Institute's lab has been taken as studying the dynamic nature of perception using different methodological approaches is common between both the CBCS and the Japanese lab.

As part of the collaboration between CBCS and PDL, an eye-tracker has been given to CBCS for conducting experiments at the Visual Cognition Lab of CBCS.

The eye tracker is worth around Rs 25 lakh and will enable the faculty and students of CBCS to study eye movements to find where the person is looking at or focusing his attention. Study of eye movements is important to study various cognitive processes including attention and reading.