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Tiny microscope and fluorescent dye allow a fascinating glimpse inside rodent memory

Mouse models are often used to evaluate pre-clinical human medical techniques.  In a recent study, Stanford University Biology and Applied Physics Professor Mark Schnitzer used a neuro implant -- a tiny microscope -- and fluorescent dye to literally "read" a mouse's thoughts by visualizing firing neurons.

Neurons flood with calcium ions when they fire.  Via some clever genetic engineering, Professor Schnitzer spliced in gene systems to express green fluorescent proteins when calcium was present.  As a result the cells light up when they're firing.

The microscope was implanted into the hippocampus, a part of the brain responsible for spatial reasoning and episodic memory in mice and men.  The microscope's digital imaging chip captured images of over 700 neurons.

The seemingly chaotic resulting patterns of "green fireworks" -- neuron firings -- actually were discovered to have regular patterns.  Even after months of not seeing it, a mouse would recognize a certain spot or familiar stimulus, and the neurons would fire off in a predictable pattern.

Green neural patterns
The firing neurons create distinctive patterns. [Image Source: Stanford University]

In that regard, the experiment functioned as rodent "mind reading" of a sort -- although the limitation is that the researchers had to first record which neurons fired upon certain stimuli, in order to develop a langauge set.

Professor Schnitzer explains, "We can literally figure out where the mouse is in the arena by looking at these lights.  The hippocampus is very sensitive to where the animal is in its environment, and different cells respond to different parts of the arena.  Imagine walking around your office. Some of the neurons in your hippocampus light up when you're near your desk, and others fire when you're near your chair. This is how your brain makes a representative map of a space."

Mice
The rodent mind-reading technique could be used to study brain disease.
[Image Source: Gawker]

The technique could be applied to studying degenerative brain diseases like Alzheimer's Disease in mouse models.  Such diseases are still poorly understood on a cellular level.  The procedure could also lead to experimental techniques in humans, though clearly the requirements of gene splicing and brain implants would make such an application unlikely in the near term.

The work was published in the prestigious peer-reviewed journal Nature Neuroscience.

The results are promising enough that Professor Schnitzer is spinning off a startup to manufacture and sell the device to pharmaceutical and biomedical research firms.

Sources: Nature [abstract], Stanford University



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Fascinating...
By MrBlastman on 2/20/2013 3:46:15 PM , Rating: 2
As much as we can image/record/visualize with current sensors and instruments, we understand so little about how the brain actually operates. Stuff like this is fascinating because it helps us understand the one thing we've had the hardest time figuring out--the individual neurons and their sequencing/interactions.

Yeah, we can witness the broad flow of activity across a brain... but to see which individual neurons activate and discharge versus others... this is the stuff that will truly let us figure things out. I love our green rats. :)

It is only 700 neurons out of billions (in a Human brain) but it is a start.




RE: Fascinating...
By mik123 on 2/20/2013 4:00:21 PM , Rating: 1
If you want to understand how the brain operates, read "On Intelligence" by Jeff Hawkins.


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