Wednesday, December 17, 2008

More about Locus Ceruleus

Deric Bownds at Mindblog posted about this new article today: Modafinil Shifts Human Locus Coeruleus to Low-Tonic, High-Phasic Activity During Functional MRI. Not exactly a catchy title, but what the abstract implies is pretty exciting - LC seems to be involved in cognition.

Cognition? Cognition. Fascinating.

Here is the abstract, viewable by clicking on Deric's post, How a cognition enhancing drug works.
"Models of cognitive control posit a key modulatory role for the pontine locus coeruleus–norepinephrine (LC-NE) system. In nonhuman primates, phasic LC-NE activity confers adaptive adjustments in cortical gain in task-relevant brain networks, and in performance, on a trial-by-trial basis. This model has remained untested in humans. We used the pharmacological agent modafinil to promote low-tonic/high-phasic LC-NE activity in healthy humans performing a cognitive control task during event-related functional magnetic resonance imaging (fMRI). Modafanil administration was associated with decreased task-independent, tonic LC activity, increased task-related LC and prefrontal cortex (PFC) activity, and enhanced LC-PFC functional connectivity. These results confirm in humans the role of the LC-NE system in PFC function and cognitive control and suggest a mechanism for therapeutic action of procognitive noradrenergic agents."

Thank you so much for bringing this to this reader's avid attention, Deric. I was interested in the pain-downregulating capacity of LC, its role in sleep, and its extensive connection to everything else in the brain. Now it looks like there may be a direct link between it and actual, functional cognition, not just anatomical noradrenergic pathways between it and parts of the brain one might be forgiven for having assumed were involved in actual, functional cognition.

Here is a link to posts I made earlier in the year, about locus ceruleus.

It has become one of those brain part names that leaps out at me, as does the insula.

Tuesday, December 2, 2008

More about virtual bodies

In reference to More about glia, and a Neurophilosophy post on Moseley:

Today's post is short, because Mo has already written it. :-D He's called it The body-swap illusion.

In it Mo explains new work by Henrik Ehrsson, now in Stockholm, the paper If I Were You: Perceptual Illusion of Body Swapping, by Valeria Petkova and Henrik Ehrsson.

Thanks Mo, thumbs up for a great post.

I don't know what more evidence could be found to support the idea that the perceptual brain is in charge of autonomic outflow than to persuade it by means of illusion, both visual and tactile, that it was responsible for maintaining the bodily integrity of a mannequin, then physically threaten the mannequin and measure autonomic alarm as represented by evoked skin conductance response (SCR).

UPDATE Dec 16: Rubber hands feel real for amputees. Thank you again, Mo from Neurophilosophy.