As other members of my class have posted before me, we are giving presentations on synesthesia. I will be presenting possible mechanisms of grapheme-color synesthesia. Grapheme-color syesthesia is where a person sees numbers or letters as specific colors. One possible mechanism is local crossactivation. In the thalamus is the lateral geniculate nucleus (LGC). The LGC is a sensory relay nucleus. It has six layers, and the fourth layer (V4) is specifically involved in color analysis. It also happens to be next to the visual word form area (VWF). The VWF is responsible for processing strings of letters. In fetal brains 70-90% of the connections made to V4 are from regions of higher brain function including the VWF. Whereas only 20-30% of the connections are made to higher brain function areas in adults. Knowing that, it has been hypothesized that a gene mutation could lead to the persistance of these connections. Including connections between V4 and VWF. Greater connectivity between the area involved in color analysis and the area involved in letter sequence processing could be a mechanism for grapheme-color synesthesia.