Using fMRI data and experience sampling data to map ongoing thought patterns onto brain activity during movie-watching. Left to Right - One sample of participants was scanned while watching movies (Sample 1), and a different set of participants responded to experience sampling probes (Sample 2) while watching the same movies in the laboratory. Decomposition of mDES data into low-dimension experiential patterns using principal component analysis (PCA) produced a set of dimensions that describe experience during movie-watching (a “thought space” within which the dynamics of the movie-watching experience unfold). Word clouds illustrate how the experience sampling questions map onto each dimension that describes this space. In these word clouds, the font size describes their importance (bigger = more important), and the colour describes their polarity (red = positive, blue = negative). Similarly, we created a brain space to describe the movie-watching experience by comparing each moment in the film to validated dimensions of brain variation. For this purpose, we used the dimensions defined from the resting states of the HCP conducted by Margulies [43] (often referred to as gradients): Gradient 1 (Association to Primary cortex), Gradient 2 (Visual to Motor cortex), Gradient 3 (Frontoparietal to Default Mode Networks) and Gradient 4 (Dorsal Attention Network (DAN)/Visual to Default Mode Networks) of brain variation dimensions illustrated by colour to map activity in state space analysis (purple = low, yellow = high) (not shown: Gradient 5 (Lateral Default Mode to Primary sensory cortex)) [43]. Two 3D scatter plots illustrating two examples from our data of how the movie-watching can be seen as two complimentary trajectories through a “Brain Space” (focusing on Gradients 1, 2 and 3, shown at the top) and a “Thought Space” (focusing on“Episodic Knowledge,” “Verbal Detail,” and “Sensory Engagement,” shown at the bottom). The cooler (blue) points occur earlier in the movie clip and the warmer (red) points occur later.