Thank you Matthew and Arnold for the speedy reply! But the AP and PA type of acquisition are not in any of the HCP 900 data release though, right? So seems there is no way to correct this intrinsic hemispheric connectivity differences introduced by the RL vs LR encoding?, even though demean and variance normalization make the two runs overall comparable and have better coverage, it automatically make left and right hemisphere more similar in terms of intra hemisphere connections, so more difficult to pull out connectivity laterality as conventional AP and PA resting state data reveals for language network..
Any field map correction might help this at all? or do you think it will help if to normalize variance for each hemisphere separately within each run, and then concatenate across RL and LR, for the purpose of calculating hemispheric connectivity? Thanks again for all your help and thoughtful comments! Xiaozhen You, PhD Research Faculty Center for Neuroscience Research Children's National Medical Center 111 Michigan Ave. NW M7634 Washington D.C. 20010 Phone: 2024764294 Email: [email protected] Developmental Cognitive Neuroscience Lab Georgetown University Phone: 202-687-9133 Email: [email protected] On Nov 11, 2016, at 3:47 PM, Glasser, Matthew <[email protected]> wrote: > The recommended approach is to use a balanced amount of RL and LR data in > your analysis. This should not be biased in either direction and should > actually have a somewhat better coverage as far as dropout goes. > > The reason LR and RL were used was that they allowed for some more favorable > scanner settings on our customized HCP Skyra. On commercial Prisma scanners > there is no advantage to LR and RL, so we have been using AP and PA (still > balanced so that one gets the benefits of better coverage regarding dropout. > > Peace, > > Matt. > > From: <[email protected]> on behalf of Xiaozhen You > <[email protected]> > Date: Friday, November 11, 2016 at 1:29 PM > To: "[email protected]" <[email protected]> > Subject: Re: [HCP-Users] Phase Encoding left-to-right and right-to-left > systematically affect intra hemisphere connections > > Hi HCP experts, > I noticed the very different effect from the RL or LR phase encoding on > within subject intrahemisphere connections, is there a way to correct for > this objectively if someone is interested in looking at any metric related to > hemispheric connections? > Here is a sample subject’s intrahemisphere connection map to language area > for RL at Rest1 and Rest2, and then LR at Rest1 and Rest2. > > _______________________________________________ > HCP-Users mailing list > [email protected] > http://lists.humanconnectome.org/mailman/listinfo/hcp-users > <PastedGraphic-16.png> > <PastedGraphic-18.png> > then LR > > <PastedGraphic-19.png> > <PastedGraphic-20.png> > > I also then tried to concatenated the RL and LR within the same session by > demean and variance normalization but then it artificially make it more > bilateral. Here is what I have for just a single run resting state data from > our lab's regular rsfmri acquisition which does reveal left hemispheric > language dominance for connectivity for adult. > > Any help will be highly appreciated. > Thanks! > Xiaozhen You, PhD > > Research Faculty > Center for Neuroscience Research > Children's National Medical Center > 111 Michigan Ave. NW > M7634 > Washington D.C. 20010 > Phone: 2024764294 > Email: [email protected] > > Developmental Cognitive Neuroscience Lab > Georgetown University > Phone: 202-687-9133 > Email: [email protected] > > > > The materials in this message are private and may contain Protected > Healthcare Information or other information of a sensitive nature. If you are > not the intended recipient, be advised that any unauthorized use, disclosure, > copying or the taking of any action in reliance on the contents of this > information is strictly prohibited. If you have received this email in error, > please immediately notify the sender via telephone or return mail. > <PastedGraphic-16.png><PastedGraphic-18.png><PastedGraphic-19.png><PastedGraphic-20.png> _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
