Autism, Optics, & Books (oh my)
Autism & Human Brain Mapping
I am currently in the midst of my whirlwind pre-summer conference schedule. I enjoyed attending the International Meeting for Autism Research in Philadelphia this past week, where I presented a poster on autistic brain responses to novelty in their environment. (I’m attaching a JPEG of the poster to this blog post–click on the image to see it enlarged.)
The basic take home message is that the anterior cingulate cortex was less active in autistic brains during response to novelty than were non-autistic brains. This is just a starting point for further comparisons to explore network differences between autistic and non-autistic brains. I received some terrific feedback during the poster session and plan to do some follow-up connectivity analysis this summer. I’m en route to Barcelona right now for the 2010 Human Brain Mapping conference, where my lab will be presenting some of our findings on functional relationships between the default mode network and the task positive network. Specifically, we’ve been looking at the regions in the brain that are the communication points between these two networks, and how these communication points are differentially affected in disease pathologies. Stay tuned for more details!
The biggest news story for fMRI last week came from a Nature article vindicating the causal effect of neural activity in BOLD signal. In other words, it’s long been an assumption that the “lighting up” of the brain seen in fMRI is caused by neural firing. A group at Stanford finally proved that the “lighting up” is indeed directly caused by neuron firing. They inserted a protein called a channel-rhodopsin into neurons. When blue light is shined on the neuron, the channel protein opens, causing the neuron to fire. When this was done under the observation of fMRI, it was observed that those blotchy brain activation maps we are all familiar with were indeed caused directly by neuron firing. Because of the widespread popularity and acceptance of fMRI as a technique to monitor brain activity, it might surprise many people to learn that the there have been questions about the connections between brain activity and fMRI “lighting up” (properly called the BOLD signal, for “blood oxygen-level dependent signal”). After a quarter of a million fMRI publications, it was a sigh of relief to have the cause and effect relationship of the BOLD signal definitively nailed down.
An exciting spin-off of this technique is the newly-available opportunity for single-neuron network mapping. In other words, it is now possible to stimulate an individual neuron using the optical stimulation technique, and then to watch via fMRI what regions of the brain that individual neuron stimulates. It’s hard to exaggerate how much added mapping power this confers on brain scientists in order to begin higher-precision traces of brain wiring patterns.
My slew of summer reading material arrived this week from Amazon. I’m super-excited about several of the books I ordered, particularly Melvin Konner’s The Evolution of Childhood: Relationships, Emotions, and Mind. Unfortunately, at a bulky 900+ pages of hardcovered material, the book was way too hefty to haul in a backpack around Europe. I settled on Konner’s The Tangled Wing: Biological Limitations on the Human Spirit, and The Compassionate Instinct by UC Berkeley’s Center for the Greater Good as my travel reading. I’ll be sure to report back what my impressions are for the books.