Ruwe manier describes loose painting, characterized by visible brushwork that is casually or even crudely exposed. Although Rembrandt did not invent ruwe manier, his late style is practically synonymous with highly developed surface texture. The goal of this study is to help develop historical context for understanding Rembrandt’s characteristic approach to thick paint, as well as to attempt to locate what is so distinctive about Rembrandt’s expressive brushwork. The ruwe manier is particularly prominent in Rembrandt’s 1658 Self-Portrait housed in the Frick Collection in New York City. The Frick Self-Portrait thus operates as a case study and as a point of departure from which to discuss notions of the rough manner in this period. Through detailed formal analysis and primary texts, I propose how the emotional impact of impasto, as understood in Rembrandt’s time, might have served as motivation for Rembrandt’s painting approach in his later years. In the last section, I apply these discussions about Rembrandt’s ruwe manier to a current neuroscience research about visual and tactile perception. This final, exploratory chapter is more of an inquiry of neuroaesthetic methodology than of Rembrandt’s painting. I ultimately suggest that the assertion of self is manifest not only in the Rembrandt’s presentation of himself as a subject, but also as it is imbued on a conscious and fundamental level—in the very tactility of the paint itself. / text