Wednesday, February 29 2012

Time Talks
All day
 
12:00 pm
12:00pm - 01:00pm
Todd Horowitz - Remembering the present: Multiple Object Tracking as a continuous visual working memory taskTodd Horowitz, Visual Attention Lab, Brigham and Women's
Classical accounts assume that multiple object tracking is a purely spatial task, involving spatial indexes, spatial attention, or spatial grouping processes which encode little or no information about target features. Yet the ability to track the positions of multiple targets but not their identity would be a pyrrhic accomplishment by the visual system. Indeed, multiple identity tracking experiments demonstrate that the visual system does know which objects are where. I will describe studies demonstrating that identity (featural) and spatial information are encoded in a common representation during tracking. Prioritizing location information reduces fidelity of identity information and vice versa. Improving encoding of identity information frees up space for positional information. Electrophysiological, and neuroimaging studies demonstrate a substantial overlap between the brain networks implicated in visual working memory tasks and those implicated in tracking (particularly in intraparietal sulcus); though tracking evokes additional activity presumably reflecting updating processes. Tracking can be seen as a continuous visual working memory task; alternatively, we can see visual working memory as a degenerate tracking task.


12:00pm - 01:00pm
Amy Cuddy - Fake it ‘til You Make It: Power Posing Change Hormones, Risk Tolerance, and Job Interview SuccessAmy Cuddy (Harvard Business)

http://www.hcs.harvard.edu/decision-ws/Spring_2012.html
12:00pm - 01:00pm
Keith Johnson - Molecular, structural and functional imaging in preclinical Alzheimer's diseaseKeith A. Johnson, M.D.
Radiology and Neurology, Harvard Medical School
Division of Nuclear Medicine and Molecular Imaging, MGH

Abstract:

Converging evidence suggests that the pathophysiological process of Alzheimer’s disease (AD) begins more than a decade before the clinical stage we now recognize as AD dementia. Even by the stage of mild impairment, the neurodegeneration of AD is thought to be well entrenched, and amyloid deposition has already been present for years. Attempts to clarify the pathogenetic chain of events have proceeded in parallel with the related task of human AD biomarker development. In this talk, I will review recent data from normal older adults in which amyloid deposition is related to brain volume and brain glucose metabolism, in an attempt to characterize the preclinical state and to develop therapeutic trial endpoints.
01:00 pm
01:00pm - 02:00pm
Timothy Buschman - Evidence from Capacity Limitations for a Dual-Model of Working MemoryTimothy Buschman (MIT, Miller Lab)

Abstract:

Cognition has a severely limited capacity: Adult humans can retain only about four items “in mind”. This limitation is fundamental to human brain function: Individual capacity is highly correlated with intelligence measures and capacity is reduced in neuropsychiatric diseases. Although human capacity limitations are well studied, their mechanisms have not been investigated at the single-neuron level. Simultaneous recordings from monkey parietal and frontal cortex revealed that visual capacity limitations occurred immediately upon stimulus encoding and in a bottom-up manner. Capacity limitations were found to reflect a dual model of working memory. The left and right halves of visual space had independent capacities and thus are discrete resources. However, within each hemifield, neural information about successfully remembered objects was reduced by adding further objects, indicating that resources are shared. Together, these results suggest visual capacity limitation is due to discrete, slot-like, resources, each containing limited pools of neural information that can be divided among objects.

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