Optogenetics - Studying the Nervous System

Recently I've been digesting a lot of newspaper articles and online seminar talks regarding neuroscience. Although I have known about the Connectome project which from my knowledge was given life by Sebastian Seung at MIT only recently have I seen it pop up in news articles. The idea of the Connectome parallels in many senses the various other "-omes" that are either in progress or have been completed within our lifetimes, most notably the Human Genome Project. An arduous task that took several years, and whose implications will likely not be fully felt for several more. So the question is whether or not to -"ome". Like many others I understand that it needs to get done at somepoint, but just like in the field of bioinformatics I worry about the prospect of unraveling all this information, developing novel ways to speed it up and make the data collecting more commonplace and not having the manpower to analyze it and put in layman's terms. Now for those who are not familiar with the Connectome Project, it is trying to establish a map of a human brain. In Seung's lab I believe it is being done part by brain imaging and dissection, and in large part by computational methods. If interested here is their website - http://www.humanconnectomeproject.org/. If anything just go and check out the gallery, the images are just unreal and will give you a sense of the major connections wiring certain portions of the brain together.

Much of this has been possible due to Jeff Lichtman, neuroscience professor at Harvard, who first created brainbows by genetically altering neurons to express certain fluorescent colors. He cleverly placed these segments of DNA near vital proteins which varied in expression from neuron to neuron and through this was able to distinguish individual neurons by fluorescence.

This leads me into optogenetics, a fascinating new method of studying neurobiology. It incorporates the fact that our nervous system has the most diverse population of cells, and that each cell differs in the receptors, and proteins that it expresses. With gene therapy researchers are able to incorporate a transmembrane protein which can transmit electrical signals when exposed to certain wavelengths of light to the desired cells. Now those cells may be activated under the researcher's control allowing actions potentials, connections, and synaptic potentials to be studied. The research is being done in vivo in mice, I have not dived further into any dense papers that this field has published but I am skeptical about the process of being able to activate only portions of the brain. We know that the brain is constantly firing, and that its connections are immense, so if your looking to study one area of the brain in live animals how do you incorporate the activation of your area of study from different brain areas? My idea is that you would have to implement some sort of measuring device to allow you to measure potentials at least initially when the light is on and when it is off to allow you to set a baseline and ensure a difference between the two scenarios.

Here is the TED video of Ed Boyden explaining the theory behind his idea, and the potential it has for various brain disorders. http://www.ted.com/talks/ed_boyden.html

How good are our brains on weighing value?

Recently I was at a convention for neuroscience and there was a talk given on our abilities to weigh values at different points. The main speaker, Dr. Louie Kenway, is a cognitive neuroscientist at NYU focusing his research on normalization in the parietal cortex. Dr. Kenway discussed the area in the parietal cortex known as lateral intraparietal cortex (LIP), an area in the parietal cortex that responds to both general visual stimuli and saccade eye movements (eye movements that jump). He began to show that in this area, the brain has an ability to weight the values of the saccadic eye movements. Dr. Kenway's lab focuses on value in a relative term based in the parietal cortex similar to that of somatosensory areas.
LIP neurons respond to a specific visual receptive field, but also encorporate the surrounding context and previous saccades. So, individual parietal neurons need the response of neighboring neurons to contextualize the saccade movement. Additionally, inhibition by the receptive field neurons not being used enhances the strength and response of the receptive field neurons which are active, similar to that of general visual processing giving value and different weights. What was interesting is that as the number of alternative distractors in neighboring visual fields increased the value firing in the LIP neurons was not as strong.
The talk was quite fascinating as it encorporated both physiological and cognitive elements. My curiosity was to that of dislexia. If this applied to visual stimuli in general, perhaps there is some problems in LIP neurons of those with dislexia.

For anyone who's interested, I'm posting a link to his original research. It was tough to get through, but quite interesting.

http://www.jneurosci.org.flagship.luc.edu/content/31/29/10627.full.pdf

Can Facebook Friends Increase Brain Regions?

The next time your parents tell you to, “Get off Facebook!” at the dinner table, you will have a more neuroscientifically plausible response, “I’m working on expanding the amount of grey matter in my right entorhinal cortex!” … or not?

Facebook has become the epicenter of social networking. With more than 800 million active users worldwide, “friending” an old classmate from preschool and swapping pictures seems quicker, easier, and more interactive than planning out a reunion only to find yourself once again going your separate ways at the end of the night.

Reuters has published a bold new article titled, “More Facebook friends linked to bigger brain areas.” The article goes on to propose that the number of online friends a person has may affect the size of certain regions of the brain. The focus of this article is whether the internet will change the structure of the human brain over time. Ryota Kanai, a researcher from the University College London, and colleagues used MRI to examine the brains of students. In their study they used 125 students who were active Facebook users. They went on to cross – check their data with 40 other students later on. In their research they found that the amount of friends a person had on Facebook strongly suggested a connection with the grey matter of four regions in the brain: the amygdala, the right superior temporal sulcus, the right entorhinal cortex, and the left middle temporal gyrus.

However, they also found that the thickness of the grey matter when it came to the amygdala was also related to “real – world” friends. Although, the other three brain regions were linked to the “online” friendships. Typically the students in their research varied in the number of friends each one had from roughly 300 to upwards of 1,000.

There is still more research to be done in relation to social networking and the brain and with all of this research it is still not clear whether a person is “hard – wired” to be more social. Heidi Johansen Berg, a researcher not involved in the study from the University of Oxford, said, “If you got yourself 100 new Facebook friends today then your brain would not be bigger tomorrow.”

Despite the controversy and the on-going dilemma of the goodness or evil of modern – day technology, it is good to know that perhaps we can begin to be a little more “guilt – free” while expanding our friend circles on Facebook!

Source: http://www.reuters.com/article/2011/10/19/uk-science-facebook-idUSLNE79I02020111019