The front of the shirt bears the first line of Chapter 3, “The neuron is my second favorite cell.”
To learn the identity of Sebastian’s favorite cell, you can read Connectome. You can also guess the answer if you know that the shirt front pays homage to Woody Allen’s 1973 science fiction comedy Sleeper. Here is the scene when Woody discovers he has woken up 200 years in the future.
The back of the shirt displays the book cover. This was drawn by the famous illustrator Christoph Niemann, who has a charming blog at the New York Times.