From: Walter Watts (wlwatts@cox.net)
Date: Sat Jul 20 2002 - 17:47:33 MDT
joedees@bellsouth.net wrote:
> On 19 Jul 2002 at 10:44, Wade Smith wrote:
>
> > http://news.bmn.com/news/story?day=020719&story=2&printerready=yes
> >
> > A cold-eyed analysis of hot objects
> > 18 July 2002 20:30 GMT
> >
> > by Bea Perks, BioMedNet News
> >
> > Our brains do not allow us to observe an entire scene in one
> > fell swoop; the visual system can only process a finite number
> > of images at a time. So objects in our field of view must
> > compete for attention either by being in sharp contrast (via
> > so-called "bottom-up" processes, whereby lower brain regions
> > inform higher regions); or by having "emotional valence" -
> > eliciting an emotional response - that allows higher brain
> > regions to inform lower regions of the image's emotional content.
> >
> > One question that has puzzled cognitive scientists is whether
> > objects with emotional valence will always divert our attention
> > from "neutral" objects.
The test below is not a fair test. It is a well known fact that there are
"integrative" sub-nets in the brain that are responsible for nothing BUT
facial recognition. That takes that "neutral" emotional valence away,
doesn't it Joe?
Walter
>
> >
> > Now, Leslie Ungerleider, chief of the National Institute of
> > Mental Health's Laboratory of Brain and Cognition in Bethesda,
> > Maryland, has preliminary data to suggest that images with
> > emotional valence still have to compete with neutral images for
> > a share of the visual system's attentional resources. She
> > presented her findings yesterday at the third biennial forum of
> > the Federation of European Neuroscience Societies in Paris.
> >
> > Ungerleider set up a study in which subjects were shown an image
> > of a face (either happy, fearful, or neutral), together with an
> > image of two short bars in varying orientation.
> >
> > The study comprised two trials. In the first, the "attended"
> > trial, subjects were asked to concentrate on ("attend" to) the
> > image of the face and perform a gender discrimination test (is
> > this face female or male?). In the second, or "unattended,"
> > trial, subjects were asked to switch their attention to the bars
> > and to perform an orientation test (are they oriented in the
> > same way or not?).
> >
> > During the trials, the activity in different regions of the
> > subjects' brains was monitored with fMRI.
> >
> > When Ungerleider analyzed the fMRI data for the amygdala, a
> > brain region involved in processing information with emotional
> > valence, she found, as expected, that there was greater activity
> > in that region when subjects attended to the emotional images of
> > faces compared with when they attended to the neutral images of
> > bars.
> >
> > However, when subjects attended to the bars, the simultaneous
> > appearance of a face image elicited a reduced activity in the
> > amygdala. In other words, the neutral bars successfully competed
> > for attention with the relatively emotional face. This result
> > was the same regardless of the face's expression.
> >
> > "The valence effect was only impressive during attended trials,"
> > said Ungerleider. "During the unattended trials, the valence
> > effect is completely eliminated."
> >
> > She found a similar pattern for other brain regions, including
> > the occipital (or visual) cortex and the superior temporal
> > sulcus (another higher-order visual region.)
> >
> > "Stimuli that have emotional valence, like all neutral stimuli,
> > must compete for these processing resources," said Ungerleider.
> >
> > "That's not to say that stimuli with emotional valence cannot
> > bias competition in their own right," she added. "We think, for
> > example, that fearful faces compared with neutral faces ... bias
> > competition in [the former's] favor. However, if resources are
> > depleted by a very difficult competing task, even the processing
> > of emotional stimuli will not take place."
> >
> > The data were warmly received by delegates attending last
> > night’s plenary session on Mechanisms of visual attention in the
> > human brain. Ungerleider's work has made visual attention "the
> > hottest topic in cognitive science," said session chair Jean
> > Bullier, director of the CNRS Brain and Cognition Unit in
> > Toulouse, France.
> >
> >
> >
> > This was distributed via the memetics list associated with the
> > Journal of Memetics - Evolutionary Models of Information Transmission
> > For information about the journal and the list (e.g. unsubscribing)
> > see: http://www.cpm.mmu.ac.uk/jom-emit
> >
-- Walter Watts Tulsa Network Solutions, Inc. "No one gets to see the Wizard! Not nobody! Not no how!"
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