Akinetopsia

My last post got me thinking about the visual perception of motion.  This is obviously a broad topic that has been explored for decades by neuroscientists.  One of the most interesting aspects of the visual perception of motion is what happens when things go wrong and people lose their ability to see movement.

This is a GREAT video that gives a little background on the topic, plus a visual demonstration of what it's like to live in a stop-motion world:

http://www.youtube.com/watch?v=tYFhDzQ1rYU&feature=related

One of the most famous patients with akinetopsia was described by Zihl et al. (1991).  They studied patient L.M., a woman with bilateral lesions of the lateral occipital cortex and area V5 (she had brain damage to both sides of the visual cortex that is involved with motion perception).  Because of this, she was unable to cross a street without traffic lights (because she could not perceive how fast cars were moving), and averse to watching people’s mouths as they spoke (she found the movement disturbing).   Oddly, L.M. was able to see a target was constantly changing position, but unaware of any sensation of movement.  L.M. described this phenomenon as, “First the target is completely at rest.  Then it suddenly jumps upwards and downwards” (Zihl et al., 1991, p 2244).  L.M. could see objects changing position; only the object’s movement between two positions was undetectable.  In other words, she perceived the world as if she was in a low-frequency stop-motion animation.  Such a life is not only distressing but dangerous, as people with akinetopsia cannot perceive any moving dangers, thus putting them at constant danger of being hit by a car.  

Motion changes the way we see

This summer I will be working at the Vision Sciences Laboratory at Harvard University.  I'm really interested to learn more about vision and cognition, so I was digging through their website and found this:

http://visionlab.harvard.edu/silencing/

There are a ton of cool visual illusions that I'm sure you've seen before.  This one is especially cool because you know exactly what's happening (objects are changing shape, size, color and brightness), but once they start moving you stop seeing the changes.  This phenomenon is called silencing. 


The silencing of changes in favor of paying attention could make evolutionary sense; after all, isn't it more important for you to pay attention to the fact that a predator is moving toward you than it is to know what color said predator is?

Attack of the tongues!

One of the classes I am taking this term is called Language and Cognition.  During lecture, the professor showed us a real-time MRI of a diva and an emcee singing.  While the point of the demonstration was to show us how the tongue, larynx and lips moved during speech production, all I could think of was how crazy the tongues looked... It's like there's a hyper sea creature hanging out in our mouths!

Check it out: http://vimeo.com/12251154

                      

Cyborg Babies!

One of the coolest things about Neuroscience is its ability to read your mind.  Well, read the activity in your mind.  This is especially useful when studying babies, as you can't really ask them what they're thinking.  Optical topography, which involves shining near infrared light through the skull and measuring the diffraction patterns, is especially useful as it involves no radiation and works perfectly well when the baby is moving.

Also, the head gear involved makes the kids look like CYBORG BABIES.