Daniel tammet is a fairly average person with an incredible memory. in one feat of memory, tammet set the european record for remembering and recounting the number pi to 22,514 decimal places. interestingly, he also experiences synesthesia, a neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. for example, in one common form of synesthesia, known as color-graphemic synesthesia, letters or numbers are perceived as inherently colored or having specific geometric shapes. the same shapes and/or colors are consistently with certain numbers. so, for example, the number one may always appear like a blue oval to someone with this type of synesthesia. what is the most likely aspect of daniel’s brain that can explain both his amazing memory and synesthesia?