Diagram
fMRI : block design paradigm
A block design fMRI paradigm requires that the subject perform a certain task in time blocks which are interleaved with time blocks of rest.
For example, in this case the language task was to look at a letter presented on a screen and to generate as many words as possible starting with the letter: the Orthographic Lexical Retrieval (OLR) paradigm.
During rest, the person was asked to refrain from practising the task.