| The functional contribution of medial temporal lobe has been studied in the human brain for over half a century. Insight into the nature of this extraordinary structure was discovered when epileptic patient H.M. had an experimental operation to surgically resect his bilateral medial temporal lobes. The procedure resulted in profound anterograde amnesia, demonstrating the critical role of medial temporal lobe in forming new long-term memories; yet a variety of other capacities remained intact (e.g., intelligence, personality, and skills). The notion that medial temporal lobe function was isolated to the formation of new long-term memories persisted for several decades until the development of new methodologies. It has been the endeavor of cognitive neuroscience to further our understanding of the structural organization of complex cognition and behavior. The focus of this dissertation is to provide evidence supporting the functional contribution of medial temporal lobe sub-regions, namely perirhinal cortex and hippocampus, to a variety of capacities classically considered outside the domain of memory. Several studies are presented that demonstrate the contribution of these regions to certain aspects of perception, language, and creativity. In Chapter 3, we investigated the ability of perirhinal cortex to support complex object (i.e. fused) perceptual representations in healthy young adults using a novel approach - functional magnetic resonance adaptation (Rubin, Chesney, Cohen, & Gonsalves, 2013). In Chapter 4, we investigated whether hippocampus and its role in forming arbitrary associations are necessary to form visual and linguistic common ground (Rubin, Brown-Schmidt, Duff, Tranel, & Cohen, 2011). Eye-movements of participants with hippocampal amnesia were monitored during real-time language comprehension. In Chapter 5, we investigated whether hippocampus and its role in flexibly expressing information contribute to creativity (Duff, Kurczek, Rubin, Cohen, & Tranel, 2013). Performance was assessed in participants with hippocampal amnesia on standardized tests of verbal and figural creativity (i.e. Torrance Tests of Creative Thinking). The results from these studies emphasize that there are many areas of cognition, which are typically considered outside the domain of memory, that engage the characteristic processing features of medial temporal lobe. These regions retain their functionality irrespective of timescale and contribute to many complex cognitive functions. |
