Hi Angela,
Interesting to have a topic on interpretation of results. It's always good to share some knowledge and discuss. I did some research on healthy brain aging.
Your analysis is on gray matter in various area's as you state. First you notice a significant loss of gray matter in the patient group, which is interesting. Are you sure about matching your groups on age, gender, handedness, education, IQ and such? Variables may influence your results. Another question is on normalizing your results. Different subjects have different intra-cranial volume (ICV). To make sure you compare correctly, you should normalize the specific areas to the ICV.
It is known that gray matter volume decreases in healthy aging (and cerebrospinal fluid increases). Different structures in the brain age differently. There is a theory based on the frontal-occipital way of aging where the frontal part ages quicker than the occipital part. Consider checking my paper on healthy aging: http://www.ncbi.nlm.nih.gov/pubmed/20483378
How do you define the connectivity in the GM areas you investigated? Usually connectivity (like FA, MD, ADC) is investigated in white matter. In this respect I can't say what's right. Your finding might be a compensation mechanism of the brain, getting less matter but 'better' connections. If you assume that the increase of connectivity is presented because of the atrophy, you might check for a relation with illness duration/age of onset/severity. A hypothesis like "A longer the illness duration makes an increase of connectivity" can be used. And is the increase in connectivity significant between your two groups?
Let me know what you think!
Kind regards,
Stijn Michielse
Research Assistant
Dept. Psychiatry and Neuropsychology
Maastricht University
E-mail: [log in to unmask]
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Hi FSL masters,
I (again) need some advice on analyses/interpretation of my data.
I am analysing a sample of patients with atrophy of GM in various brain
areas due to malnutrition and weight loss (it is a sample of anorexia
nervosa subjects). I have used ICA and dual regression to identify
networks and analyse differences between patients and controls.
I have found an increase in connectivity in areas that (on a voxel based
morphometry) have a significant loss of GM.
Is this a contradictory finding? Is it possible to observe an increase of
connectivity as a 'compensation' of brain atrophy? Or may I consider this
finding as an increase of connectivity due to the psychiatric illness
observable despite atrophy?
It is not easy to disentangle the effects of weight loss, brain atrophy
and what is due to (or at the origin of) the psychiatric disorder
I know that interpretation is up to me (and my clinical data), but I am
wondering if something similar has been observed in other patients
populations with brain atrophy.
thank you for any help!
Angela
Angela Favaro, MD, PhD, MSc
Psychiatric Clinic
Department of Neurosciences
via Giustiniani 3
35128 Padova
Italy
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