 |
 |
Dear Sophie, You have two within-subjects factors with two levels each here so I would recommend to compute a contrast image for each main effect and interaction for each subject and enter these in a one-sample t-test at the second level, ie at first level, compute: main effect of drug: [1 1 -1 -1] main effect of cardiac: [1 -1 1 -1] drug x cardiac interaction: [1 -1 -1 1] Best regards, Guillaume. On 03/05/18 09:31, Sophie Betka wrote: > Dear Spm users, > > > > Could you let me know if what I did is correct? Thanks a lot > > > > So I am using a 2*2 flexible design (within-subjects design with > Subjects, Drug:2 Levels ; CardiacTiming:2 Levels). > > > > > > 1) I attached a screen shot of my batch. The variance of Drug and > Cardiac should be unequal right? > > I am interested in main effect of Drug, main effect of > Cardiac and the interaction. > > > > 2) I attached a screen shot of the design matrix. > > Following the Glascher’s paper, I created contrasts. > > > > Could confirm/correct my contrasts: > > > > > > > > Drug1 > > > > Durg2 > > > > Card1 > > > > Card2 > > > > D1C1 > > > > D1C2 > > > > D2C1 > > > > D2C2 > > Main effect of Drug > > > > 1 > > > > -1 > > > > 0 > > > > 0 > > > > 0.5 > > > > 0.5 > > > > -0.5 > > > > -0.5 > > Main effect of Cardiac > > > > 0 > > > > 0 > > > > 1 > > > > -1 > > > > 0.5 > > > > -0.5 > > > > 0.5 > > > > -0.5 > > Interaction Drug*Cardiac > > > > 0 > > > > 0 > > > > 0 > > > > 0 > > > > 0.5 > > > > -0.5 > > > > -0.5 > > > > 0.5 > > Test single repressor Drug1 > > > > 1 > > > > 0 > > > > 0.5 > > > > 0.5 > > > > 0.5 > > > > 0.5 > > > > 0 > > > > 0 > > Test single repressor D2C2 > > > > 0 > > > > 1 > > > > 0 > > > > 1 > > > > 0 > > > > 0 > > > > 0 > > > > 1 > > > > The main effect of cardiac gives me a massive cluster; this a bit odd > (enclosed). > > > > > > Thank you for your help, > > S. > > > > > > > > > > *Sophie BETKA* > *Ph.D Student* > *Neuropsychologist* > > *Brighton and Sussex Medical School* > > Neurosciences Department - CritchleyLab > > /Trafford Centre, 202 (Brighton, UK)/ > > University of Sussex, Falmer, BN1 9RR > +44 (0)1273 873132 > > *SCALab - Cognitive and Affective Sciences Laboratory* > /DEEP Team - Emotional Dynamics and Pathology (Lille, FR)/ > Faculté de Medecine, Pôle Recherche > 1, Place de Verdun, 59045 Lille cedex > > +33 (0)3.20.62.68.13 > > _Twitter @SophieBetka <https://twitter.com/SophieBetka>___ > > _ResearchGate <https://www.researchgate.net/profile/Sophie_Betka>___ > > _Linkedin <https://www.linkedin.com/in/sophie-betka-54b149155/>___ > > > > > > > ___________________________________________________________ > This email has been scanned by MessageLabs' Email Security System > on behalf of the Brighton & Sussex Medical School. For more information see: > https://staff.brighton.ac.uk/is/computing/Pages/Email/spam.aspx -- Guillaume Flandin, PhD Wellcome Centre for Human Neuroimaging University College London 12 Queen Square London WC1N 3BG