This may NOT be a specific answer to this important Question posed unto the mathematical model.
My impression and personal opinion that the paper published recently by Riedl et al. (2014) will offer some important biophysiological clues.
The brain arterial blood supply tree of life and its intricate infrastructure is the ground zero basis to the whispers within the Kuppe.
Someone else also asked today for a Project, well it is almost 2015 and yet the Brain does not know how the Brain works..., these are the kind of directions and foundations I hope the new Neuroscientsists will build their stronger edifices over...
Riedl V, Bienkowska K, Strobel C, Tahmasian M, Grimmer T, Förster S, Friston KJ, Sorg C, Drzezga A. Local activity determines functional connectivity in the resting human brain: a simultaneous FDG-PET/fMRI study. J Neurosci. 2014;34(18):6260-6.
http://www.jneurosci.org/content/34/18/6260.full.pdf+html
Khader M Hasan, PhD
Associate Professor of Radiology
MSE 168, Tel 713 500 7690 (FAX 713 500 7684)
University of Texas Health Science Center at Houston
Medical School
Diagnostic and Interventional Imaging
Magnetic Resonance Imaging Research Division
Diffusion Tensor Imaging Lab, Tel 713 500 7683
http://www.uth.tmc.edu/radiology/faculty/khader-m-hasan/index.html
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From: SPM (Statistical Parametric Mapping) [[log in to unmask]] on behalf of Mouthon Michaël [[log in to unmask]]
Sent: Thursday, December 04, 2014 12:53 PM
To: [log in to unmask]
Subject: [SPM] DCM: How to interpret intrinsic connections values computed by DCM12
Dear SPM and DCM user,
I would like to have a confirmation of the way how to interpret the intrinsic connections value between regions (DCM.A) compute by the last version of DCM (DCM12).
A previous post from Rainer Bögle in 2011 explained that:
“-connections in DCM are change rates, i.e. a12 tells you how much of the current state/activation (on neuronal level) at time t of region 2 is added to the change in region 1 (at time t). There might be influences from other regions on region 2 which have to be considered, but if if a12 is the sole connection, we can say:
*** a12=0.1 means 10% of the state in region 2 is added to the state (activity) of region 1
and analog for a12=-0.1, this corresponds to a subtraction by 10% of the state in region 2 from the state in region 1.”
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FA2-3Dspm-3B7834fcd0.1102&d=AAIFaQ&c=6vgNTiRn9_pqCD9hKx9JgXN1VapJQ8JVoF8oWH1AgfQ&r=unPeqwYYiM8GN9mYrGGQ8nfQhlBmdvoiED0CP2jF6T4&m=H6xtA3BtLEryiZUkNTi2p91SzCY6Q_Crq0MJKjZHQ-4&s=3nB3TFEcKsMUMUVgp8nYuhwwc9Nv_JfOhozpaHsehd4&e=
Does this explanation still work with the changes in DCM12?
If it is not the case, how do you interpret the relation between region 1 and 2 if the connection value is positive or negative?
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