UC Berkeley

A major goal of cognitive neuroscience is to understand the link between anatomical brain structure and cognition. In the work that follows, I characterize patterns of cortical folding in the prefrontal cortex and its relation to reasoning skill. A central thread running through this work is that by exploring the relationship between variability in anatomy and cognition, we can establish a link among cortical structure, function, and behavior.In Chapter 1, I test a classic hypothesis and ask whether small, variable structures known as tertiary sulci have cognitive relevance. By combining precise neuroanatomical techniques with a modern data-driven analysis pipeline, I show that these structures can be reliably identified in individuals across childhood and adolescence and that the depth of a subset of tertiary sulci explains additional variance in reasoning not accounted for by age. In Chapter 2, I further examine variability in the presence and prominence of cognitively relevant tertiary sulci in prefrontal cortex. I show that the variability in the presence of these structures is associated with variability in behavior and that these sulcal components have discernable functional connectivity profiles that relate to reasoning skill. Finally, in Chapter 3, I take a modern comparative anatomy approach and show that while these structures exist in chimpanzees, they are notably smaller, shallower, and more variable. This work lays out a methodological approach to compare structure, function, and behavior across individuals, age groups, and species. I show that sulci, particularly tertiary sulci, can be reliably identified across individuals and that variability in the presence and morphology of these structures can be linked to variability in cognition. The goal of these studies is not to claim that a single sulcus predicts a specific cognitive process, but rather to demonstrate that sulci are useful landmarks that can provide valuable insights into the relationship among cortical structure, function, and cognition.