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Title page for ETD etd-09042010-004354


Type of Document Dissertation
Author Asplund, Christopher L.
URN etd-09042010-004354
Title The Coordination and Control of Attention in Lateral Prefrontal Cortex
Degree PhD
Department Neuroscience
Advisory Committee
Advisor Name Title
Mark Wallace Committee Chair
Frank Tong Committee Member
John Rieser Committee Member
René Marois Committee Member
Keywords
  • inferior frontal junction
  • fMRI
  • cognitive control
  • attention
  • stimulus-driven
  • goal-directed
Date of Defense 2010-08-20
Availability unrestricted
Abstract
Our world constantly bombards us with more information than we can process. To ensure that we can act in accordance with our goals and relevant events, we use attention to select and enhance aspects of our environment. Attention is not unitary, able to be captured by salient events (stimulus-driven) or deployed under voluntary control (goal-directed). These two forms of attention rely on largely distinct ventral and dorsal fronto-parietal networks. While these networks have been extensively studied, their control and coordination is poorly understood. Using functional neuroimaging and a variety of behavioral tasks, this dissertation shows that the inferior frontal junction (IFJ) of the prefrontal cortex may be a key region in the control and coordination of attention. I employ a novel ‘Surprise-induced Blindness’ paradigm to show that the IFJ and temporo-parietal junction (TPJ), core members of the ventral attention network, support stimulus-driven attention. I then demonstrate that the IFJ co-activates with the dorsal attention network--including the frontal eye field (FEF) and intra-parietal sulcus (IPS)--for goal-directed attention. This result suggests that the IFJ may coordinate stimulus-driven and goal-directed attention. The remainder of the dissertation functionally distinguishes the IFJ from other regions within the ventral and dorsal attention networks. I first dissociate the function of the IFJ from the ventral attention network’s TPJ by demonstrating that only the latter is activated during a task in which participants reason about others' mental states (Theory of Mind) and while resting between the attention-demanding periods of a search task (Default Mode of Processing). Using an endogenous Posner cueing task, I next show that the IFJ is involved in cue interpretation for setting goal-directed attentional weights, but not in the maintenance of these weights. The FEF and IPS, by contrast, are involved in both processes. I conclude that the IFJ’s primary function may be to connect incoming sensory information with appropriate behavioral or dispositional responses, coordinating the activity of widespread brain regions to do so. Consequently, the IFJ influences central aspects of human information processing and even the contents of consciousness.
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