Life Sciences Commons^™

Target Selection And Enhancement During Attentional Tracking, Marvin R. Maechler

Dartmouth College Ph.D Dissertations

At any waking moment, we are bombarded with more sensory information than we can fully process. Attention is necessary to deal with the dynamic world we live in. One fundamental function of vision and attention is to keep track of moving objects, but what are the targets of attention during tracking?

One of the first theories of attentional tracking predicted that targets would be selected at early processing stages. By employing the double-drift illusion, which dissociates physical and perceived positions of moving objects, we investigated which of these positions is selected for tracking. Contrary to earlier theories and in line …

Accelerated Forgetting In People With Epilepsy: Pathologic Memory Loss, Its Neural Basis, And Potential Therapies, Sarah Ashley Steimel Phd

Dartmouth College Ph.D Dissertations

While forgetting is vital to human functioning, delineating between normative and disordered forgetting can become incredibly complex. This thesis characterizes a pathologic form of forgetting in epilepsy, identifies a neural basis, and investigates the potential of stimulation as a therapeutic tool. Chapter 2 presents a behavioral characterization of the time course of Accelerated Long-Term Forgetting (ALF) in people with epilepsy (PWE). This chapter shows evidence of ALF on a shorter time scale than previous studies, with a differential impact on recall and recognition. Chapter 3 builds upon the work in Chapter 2 by extending ALF time points and investigating the …

Mapping The Malleable Self: How Self-Views Are Represented And Learned Within The Social Brain, Sasha Carmela Brietzke

Dartmouth College Ph.D Dissertations

Humans possess a unique and wide-ranging ability to self-reflect that takes center stage in our everyday cognition. While many people believe their own self to be immutable, different contexts may warp how we perceive the self. The goal of this dissertation is to investigate two lenses through which we may view the self: (1) across time in the past and future, and (2) through the eyes of others via evaluative feedback. In Studies 1-3, I demonstrate that people’s ratings of their own personality become increasingly less differentiated as they consider more distant past and future selves. This effect was preferential …

Genetic Heterogeneity In Schizophrenia And Contribution Of Context To Vowel Recognition, Eva Childers

Dartmouth College Ph.D Dissertations

This dissertation is composed of three chapters that address two distinct topics. Chapter 2 addresses the use of consonantal context in vowel perception. Previous studies have demonstrated that context is important for vowel identification, however, this effect may be an artifact of stimuli production. To address this potential confound, we used stimuli extracted from an audiobook and asked subjects to identify vowels encased in consonants and isolated by themselves. We show that subjects had improved vowel identification when the vowel is presented with a consonantal framing, suggesting there is information contained in the surrounding context that is important for phoneme …

Beyond Homogenous Decision-Making Models: Role Of Brain Areas Interaction And Heterogeneity, Mohsen Rakhshan

Dartmouth College Ph.D Dissertations

Most existing mechanistic models of decision making consider microcircuits within a homogenous brain area and fail to consider the distributed nature of this cognitive process. More specifically, these models do not take into account: a) how different types of information might influence choice in different stages of the process; and b) how interactions and the heterogeneity between circuits across different brain areas might be essential for the process. In this dissertation, I present a combination of experimental and modeling approaches to study distributed nature of the decision-making by examining both the distributed processing of information as well as the interaction …