Mapping the Human Brain To “See” What Makes You Unique




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The Matrix may not be fantasy anymore. The virtual reality shown in Avatar could be with us any time now, and at the same time, scientists are getting closer to decoding what goes on inside our brains. In fact, they are well on their way to mapping the human brain.

This means that you could really peek into the brain and “see” how it works for yourself — the domino effect of memory cells firing up to take you back to your childhood home and its smell of freshly-baked bread, or the flurry of activity in the learning center as you try to pick up the notes and play them on the piano.

Scientists have long known that the structural connectivity of the brain influences the functional performance of individuals. In other words, given the structural similarities of the human brain, it is the neural and synaptic connections within our brains that make us the unique individuals that we are. But what they want to do now is to create a complete map of the brain to discover how memories are stored, how personality traits develop, and how people learn skills. It looks as if they are well on their way.

Enter the connectome!

Mapping the Connectome

The network of connections in the brain — up to 10,000 for each of the 85 billion cells — is known as the “connectome.”

It is a complex but organized system of wires unique to every person. Scientists believe that wiring faults hamper the way cells connect and signal to each other. This may lead to mental disorders such as depression, schizophrenia and learning disabilities.

So, scientists need a comprehensive model that not only shows the neuronal structures but also details the connections — how your brain figures out the moves when you play Diablo; how do you remember, recall, and apply knowledge; how do you sense changes in temperature and color.

The human brain comprises structurally distinct but functionally interdependent components. Scientists have to mine data at the neuronal level (microscale) where there are connections between individual cells, as well as connections between several groups of neurons (mesoscale), and at the regional level (macroscale), where different structures of the brain interact with one another. Combining the findings from these disparate sets of data will ultimately help scientists create a comprehensive map of the brain.

There have been quite a few connectome studies aimed at creating such mental maps.

How the Eye Detects Motion

One connectome study has decoded how the human eyes sense motion. It is interesting to note that neurological data for the study was gleaned from more than 2,000 volunteers who took part in an online game, EyeWire. The results of the study busted the myth, long held in visual neuroscience circles, that we see with the brain. Scientists now know for sure that visual stimuli is first processed (somewhat) by cells in the retina before being transmitted to the brain.

The photoreceptor cells in the eye capture light, but on their own they are not capable of sensing motion. They are connected to the starburst amacrine cells that are in turn connected to the optic nerve that transmits signals to the brain to be interpreted. The photoreceptor cells are connected to the amacrine cells in such a way that the visual stimulus hits the latter at different times, or with a time lag. The brain interprets the delay in receiving the signals as coming from a moving object.

The findings from the above study represent a step in the right direction for scientists engaged in finding ways to map the brain. The task is not easy because deciphering neuronal characteristics and behavior demands that researchers study a large number of neurons, ideally individually, in different areas of the brain. Scientists expect that continual advances in micro-electrode technology will enable them to target the teeny-weeny neurons. They also believe that the way computational technology is progressing, they will soon be able to process the data mined from the billions of cells and the almost countless neural pathways effectively enough to create a map of the whole brain.

Implications of Brain Mapping Studies

Scientists, physicians, psychiatrists, and the common man on the street have much to be excited about the brain-mapping studies that are currently underway. The implications are wide-ranging.

As already mentioned, neuroscientists believe that many psychiatric disorders are caused by faulty wiring in the brain. Being able to pinpoint where the connection has gone awry can help them explore effective therapeutic methods. Brain-mapping studies also hold promise for people who have suffered traumatic brain injuries.

Knowing how neural structures and behavior influence function can also help scientists understand the basis of cognitive processes. Their conclusions can help educationalists devise curriculum that best meets the learning needs and preferences of specific groups of students or those who are suffering from learning disabilities.

The findings from such brain-mapping studies are already being utilized to explore the scope of neural prosthetics. These findings will enrich the brain-computer interface (BCI) studies that are currently underway. Right now, scientists are at work to devise sophisticated, powerful, and sensitive BCI systems that can capture and process neural data in real time and use this to control specific areas of the brain. These BCI systems can forge an artificial connection, which should mimic a neural pathway, between a set of implantable electrodes embedded within a prosthetic limb and the brain. Such BCI systems have already been tested on monkeys, and it is not hard to fathom how eagerly amputees or those who are paralyzed are awaiting developments in this field!

In fact, scientists around the world are already excited by the advances made in neuromorphic computing. Researchers have developed a computer chip that simulates the brain and can replicate synaptic connections. They believe that when this device integrates data from more comprehensive brain maps, it will become powerful enough to help blind people move around physically with ease.

Brain-mapping studies are the latest buzz in the medical fraternity. The brain may not have revealed all its secrets, but hopes run high.

References

Kim, J., Greene, M., Zlateski, A., Lee, K., Richardson, M., Turaga, S., Purcaro, M., Balkam, M., Robinson, A., Behabadi, B., Campos, M., Denk, W., & Seung, H. (2014). Space–time wiring specificity supports direction selectivity in the retina Nature, 509 (7500), 331-336 DOI: 10.1038/nature13240

Kipke, D., Shain, W., Buzsaki, G., Fetz, E., Henderson, J., Hetke, J., & Schalk, G. (2008). Advanced Neurotechnologies for Chronic Neural Interfaces: New Horizons and Clinical Opportunities Journal of Neuroscience, 28 (46), 11830-11838 DOI: 10.1523/JNEUROSCI.3879-08.2008

Service, R. (2014). The brain chip Science, 345 (6197), 614-616 DOI: 10.1126/science.345.6197.614

Sporns, O., Tononi, G., & Kötter, R. (2005). The Human Connectome: A Structural Description of the Human Brain PLoS Computational Biology, 1 (4) DOI: 10.1371/journal.pcbi.0010042

Zuo, X., Ehmke, R., Mennes, M., Imperati, D., Castellanos, F., Sporns, O., & Milham, M. (2011). Network Centrality in the Human Functional Connectome Cerebral Cortex, 22 (8), 1862-1875 DOI: 10.1093/cercor/bhr269

Image via solarseven / Shutterstock.

Viatcheslav Wlassoff, PhD

Viatcheslav Wlassoff, PhD, is a scientific and medical consultant with experience in pharmaceutical and genetic research. He has an extensive publication history on various topics related to medical sciences. He worked at several leading academic institutions around the globe (Cambridge University (UK), University of New South Wales (Australia), National Institute of Genetics (Japan). Dr. Wlassoff runs consulting service specialized on preparation of scientific publications, medical and scientific writing and editing (Scientific Biomedical Consulting Services).
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