Not much. Though the topics of the course overlap considerably (e.g. with both covering visual perception, language, and consciousness), the specific approaches and material discussed hardly overlap at all. Brain & Thought is devoted almost entirely to neuroscientific perspectives on these topics, whereas Introduction to Cognitive Science covers many higher-level perspectives in addition to neuroscience – and even the bits of this course that do explicitly focus on neuroscience do so with a different perspective. Introduction to Cognitive Science also includes lectures on several topics that are not discussed in Brain & Thought (e.g. modularity, innateness, computation, reasoning and decision-making, infant cognition, and the cognitive science of love/sex/attraction), and the reverse is also true (e.g. motor behavior, olfaction, taste, and Alzheimer’s Disease). In addition, Introduction to Cognitive Science includes material drawn from several different fields beyond neuroscience, including Linguistics, Computer Science, and Psychology. Both courses are thus strongly recommended for all majors.