Comments on: “Different” Brain Connectivity Linked to Social Impairments

By: Patrick

Patrick — Fri, 13 Jun 2008 18:48:29 +0000

This kind of reporting has been going on for at least 2 years that I know of, volume calculations, fmris, etc, linked to processing functional areas. I hope something useful comes of it all.

@daedulus2u, isn’t that pelvis statement a bit shallow considering pelvic expansion and c-sections?

By: Marcie

Marcie — Fri, 13 Jun 2008 13:01:07 +0000

This study actually sounds a lot like what I keep saying about the connection with frontal lobe syndrome (disconnection of emotion and intellect) and autism. The connection of emotions and intellect is where social intuition comes from. Antonio Damasio describes frontal lobe syndrome (though not autism) in “Descartes’ Error”.

By: daedalus2u

daedalus2u — Fri, 13 Jun 2008 11:15:38 +0000

There is a gigantic difference between “actual” connectivity and “functional” connectivity.

Each neuron has ~10,000 connections (or more). Those are the actual connections.

When a neuron fires, on average only one downstream neuron fires in response. If more than one fired (on average), the number of neurons firing would increase exponentially until they were all firing (a massive seizure). That doesn’t happen, so we know the average is 1. Those are the functional connections.

The actual connections control what it is possible for that brain to do, the functional connections are what that brain is actually doing.

Actual connections are extremely difficult to determine even on postmortum. Functional connections are too, but with fMRI patterns of activity can be mapped in the brain and when activity in one area follows from activity in another area, the inference is that the first activity caused the second and so there is functional connectivity between them.

The mapping that fMRI does is no where close to the single cell level. The volumes seen to be activated contain many cells, at least hundreds of thousands. The details of what is going on with each of those cells is completley smeared out in the averaging that goes on during the measurement.

By: Kristina Chew, PhD

Kristina Chew, PhD — Fri, 13 Jun 2008 02:42:23 +0000

I noted the “faulty”—-I was rushing because Charlie had been waiting too long to go swimming. Checked the html but obviously not the spelling.

Or maybe it’s my faulty wiring in action.

By: Xeno

Xeno — Fri, 13 Jun 2008 02:39:25 +0000

(Matt asked: “‘witing?’ I’m figuring that this is either a new word to me, a mispelling of ‘writing’…”)

It’s “wiring” of course. Not sure if you were joking…

Since they used functional MRI, they must have been measuring “functional connectivity”, which is the tendency for brain areas to be activated at the same time, just as you described. The assumption is that functional connectivity reflects the way two areas are physically “wired” (the more correlated the activity, the more efficient or numerous the “wires.”)

I’m not sure this assumption is warranted, and I’m very skeptical of fMRI in general. There’s even less justification for assuming that any difference in activity is a defect. (The actual title was “‘Faulty’ Brain Connections May Be Responsible For Social Impairments In Autism.”)

By: Kristina Chew, PhD

Kristina Chew, PhD — Fri, 13 Jun 2008 02:12:59 +0000

Need to look up that study you cite, Matt.

I also wonder, why is it so often “facial identification” that gets tested? As noted in this thread, there are plenty of other ways to recognize people.

By: Kristina Chew, PhD

Kristina Chew, PhD — Fri, 13 Jun 2008 02:10:00 +0000

“witing” could be–

1) whiting?
2) writing?
3) wit thing
4) wiring…

5) wot hapns wen ur son hs waitd long enuf 2 go 2 the pool.

By: M

Fri, 13 Jun 2008 01:37:56 +0000

Hee. You win points.

By: Ms. Clark

Ms. Clark — Fri, 13 Jun 2008 01:32:04 +0000

M, One thing about door knobs, they’re a-door-bell.

By: M

Fri, 13 Jun 2008 01:09:36 +0000

(i adoor them.)