Member-Initiated Symposia
Symposia Overview
2008 Symposia
Perceptual expectations and the neural processing of complex images
Cortical organization
and dynamics for visual perception and beyond
Crowding
Visual Memory and the Brain
Bayesian models applied to perceptual
behavior
Action for perception: functional
significance of eye movements for vision
The past,
present, and future of the written word
Surface material perception
Symposia from Past Meetings |
Visual Memory and the Brain
Friday, May 9, 2008, 1:00 - 3:00 pm
Orchid 1
Organizer:
Marian Berryhill (University of
Pennsylvania)
Presenters:
Lynn C. Robertson (University of CA,
Berkeley & VA), Yaoda Xu (Yale
University), Yuhong Jiang (University
of Minnesota), Vincent Walsh (University
College London), Marian Berryhill (University
of Pennsylvania)
Symposium Description
Focus:
Visual memory describes the
relationship between perceptual processing and the storage and retrieval of the
resulting neural representations. Visual memory occurs over a broad time range of scenes across eye
movements - to years - in order to
visually navigate to a previously visited location or to recognize an old
friend. How does the brain encode, store, and retrieve these representations? What neural
mechanism limits the capacity and resolution of visual memory? Do the same
neural areas participate in short-term and long-term visual memory? Do
particular neural regions, such as the intraparietal sulcus, participate only in
visual memory, or does it have a more generally role in attentionally demanding
tasks such as binding and multi-object tracking? Are different brain areas
critically involved in storing different visual materials, such as simple colors
or complex scenes? These topics have
only begun to be studied; the purpose of this symposium is to discuss the latest
research and current problems facing our understanding of visual memory. Investigators in
this area of research employ a variety of techniques such as the lesion method
(neuropsychology and TMS), neuroimaging (fMRI, ERP), and behavioral studies.
Timeliness:
The finding that the
intraparietal sulcus may limit the capacity of visual short-term memory is an
example of a topic that has been published in prominent journals, thereby
fueling new studies and generating broad interest.
Moreover, this general topic of the neural basis of visual memory relates to
several other timely topics in the visual cognition literature including: neural
areas involved in multi-object tracking,
attention, scene perception, navigation, and long-term memory.
Audience:
This symposium would be
accessible to a broad VSS Audience as it includes both perceptual and cognitive
processing. Furthermore, by including speakers who come from a variety of methodological backgrounds,
including neuropsychology and neuroimaging. Both students and seasoned
researchers will find it of interest. The audience will gain a better
understanding of visual cognition and of current
methodological techniques being used to understand brain-behavior relationships.
Abstracts
Forms of visual representation in unattended
space: neuropsychological evidence
Lynn C. Robertson, Thomas
Van Vleet, UC Berkeley, VA
Although there is a great
deal of evidence that undetected information can affect subsequent performance
(e.g., priming), the nature of the memory representation that produces this
effect is not well understood. In a
series of studies with patients who suffer from left sided neglect and/or
extinction from right hemisphere damage, we show that feature displays prime a
subsequent central target equally well whether the features were more or less
likely to be detected. Conversely,
conjunction displays prime more when they are more likely to be detected.
These results will be discussed as they relate to visual storage of
undetected stimuli and how memory representations differ with attention.
Dissociable parietal mechanisms supporting
visual short-term memory for objects
Yaoda Xu, Yale University
In this talk, I will show
that visual short-term memory (VSTM) storage is mediated by distinctive
posterior brain mechanisms, such that VSTM capacity is determined both by a
fixed number of objects and by object complexity. These findings not only
advance our understanding of the neural mechanisms underlying VSTM, but also
have interesting implications to theories on visual object perception.
Speaker 3
Yuhong Jiang, U. Minnesota
Dr. Jiang will discuss
behavioral and fMRI data on visual short-term memory, with an emphasis on
synthesis of findings.
Migrating Memories: Remembering what comes
next
Vincent Walsh, UCL
Memory, along with
attention, imagery, learning, getting grants and awareness is sometimes assumed
to be a high level function. There is, however, an increasing "migration" of
functions from higher to lower areas as we ask more diffiucult questions of the
sensory cortex. For example, what were once considered "cognitive" contours with
neural correlates in IT can be inferred from the responses of V1 or V2 neurons
and visual imagery and visual awareness require V1. It is becoming increasingly
clear that a similar migration of complexity is occuring in memory and we can
now rightly speak about sensory memory in visual cortex. I will discuss
experiments which explore the role of visual areas in short term memory and
visual priming. Specifically I will discuss the effects of interfering with
memory processes by applying TMS over visual area V5, the frontal eye fields and
the parietal cortex.
When was I Where?
Marian E. Berryhill & Ingrid
R. Olson, U. Pennsylvania, Temple University
The perceptual deficits
following dorsal stream damage are well-known, i.e. hemispatial neglect,
Balint's syndrome. However, accumulating evidence suggests that these same
cortical regions are involved in processing 'when' as well as 'where'.
In a series of studies examining unilateral and bilateral parietal
patients we have observed visual, spatial working memory as well as
autobiographical and constructive memory impairments. These data suggest that
these patients have cognitive deficits that parallel their perceptual deficits.
In this talk, we will discuss the effects of dorsal stream damage on visual
perception as well as the effects on stored representations in short-term and
long-term memory.
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