03/05/2010 by admin.

ScienceDaily has an item (here) reporting on a paper, “Out of Mind, Out of Sight: Eye Blinking as Indicator and Embodiment of Mind Wandering” by D. Smilek and group in Psychological Science.

When your mind wanders, you’re not paying attention to what’s going in front of you. A new study suggests that it’s not just the mind, it’s the body, too; when subjects’ minds wandered, they blinked more, setting up a tiny physical barrier between themselves and the outside world….

… participants blinked more when their minds were wandering than when they were on task. …”What we suggest is that when you start to mind-wander, you start to gate the information even at the sensory endings — you basically close your eyelid so there’s less information coming into the brain,” says Smilek.

This is part of a shift in how scientists are thinking about the mind, he says. Psychologists are realizing that “you can’t think about these mental processes, like attention, separately from the fact that the individual’s brain is in a body, and the body’s acting in the world.” The mind doesn’t ignore the world all by itself; the eyelids help.

I suspect that the process that turns down the volume of auditory signals (for instance when we ourselves are speaking) may also be at work in this situation. As attention focus is the result of both a top-down and a bottom-up control, in order for the top-down to have more control, it may have to interfere with normal perception and bottom-up signals.

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30/04/2010 by admin.

A good post in Frontal Cortex (here) talked about enculturation and how that inhibits new ideas, how we just don’t notice what it would be uncomfortable to notice because it would break our rules.

….There was a squirt of blood to the anterior cingulate cortex, a collar of tissue located in the center of the brain. The ACC is typically associated with the perception of errors and contradictions — neuroscientists often refer to it as part of the “Oh shit!” circuit — so it makes sense that it would be turned on when we watch a video of something that seems wrong….But there’s another region of the brain that can be activated as we go about editing reality. It’s called the dorsolateral prefrontal cortex, or DLPFC. It’s located just behind the forehead and is one of the last brain areas to develop in young adults. It plays a crucial role in suppressing so-called unwanted representations, getting rid of those thoughts that don’t square with our preconceptions.

When physics students saw the Aristotelian video with the aberrant balls, their DLPFCs kicked into gear and they quickly deleted the image from their consciousness. In most contexts, this act of editing is an essential cognitive skill. (When the DLPFC is damaged, people often struggle to pay attention, since they can’t filter out irrelevant stimuli.) However, when it comes to noticing anomalies, an efficient prefrontal cortex can actually be a serious liability. The DLPFC is constantly censoring the world, erasing facts from our experience. If the ACC is the “Oh shit!” circuit, the DLPFC is the Delete key. When the ACC and DLPFC “turn on together, people aren’t just noticing that something doesn’t look right,” Dunbar says. “They’re also inhibiting that information.”

This is a top-down erasing of sensory data. We have to process the image to understand what it is, then conclude that it is ‘impossible’, then eliminate the offending part from the image, all before the image is rendered conscious and we are aware of it. No spam in the conscious in-box – it makes life easier.

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03/04/2010 by admin.

Science Daily reports (here) on a paper in Nature Neuroscience, A central role for the lateral prefrontal cortex in goal-directed and stimulus-driven attention, by C. Asplund and group. They investigated being made temporarily blind by surprises.

“The simple example of having your reading interrupted by a fire alarm illustrates a fundamental aspect of attention: what ultimately reaches our awareness and guides our behavior depends on the interaction between goal-directed and stimulus-driven attention. For coherent behavior to emerge, you need these two forms of attention to be coordinated… We found a brain area, the inferior frontal junction, that may play a primary role in coordinating these two forms of attention.”

… the research team asked individuals to detect the letter “X” in a stream of letters appearing on a screen while their brain activity was being monitored using functional magnetic resonance imaging, or fMRI. Occasionally, an image of a face would unexpectedly interrupt the stream. The surprise caused the subject to completely miss the “X” the first couple of times, despite the fact they were staring directly at the part of the screen on which it appeared. They were eventually able to identify it as successfully as when there was no surprise. …the inferior frontal junction, a region of the lateral prefrontal cortex, was involved in both the original task and in the reaction to the surprise.

“What we think might be happening is that this brain area is coordinating different attention systems — it has a response both when you are controlling your attention and when you feel as though your attention is jerked away.”

“What we show is the dark side or negative impact of the orienting response. We found it blinds you to other events that can occur soon after the presentation of the surprise stimulus.,” The researchers hypothesize that we may be temporarily blinded by surprise because the surprise stimulus and subsequent response occupies so much of our processing ability. “The idea is that we can’t attend to everything at once. It seems that the inferior frontal junction is involved in this limitation in attention.”

The new research supports previous work by Marois’ laboratory that found the interior frontal junction plays the role of an attentional bottleneck — limiting our ability to multitask and attend to many things at once.

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31/03/2010 by admin.

When we are looking at consciousness, we are also looking at altered states of consciousness. One of the most common altered state is the result of consuming alcohol. Psyblog has an interesting look at the effects of alcohol (here) especially its effect on attention. Here is part of the posting.

According to a growing body of evidence collected over the last three or more decades, people’s Jekyll and Hyde behaviour while drinking can be understood by a simple idea which has some intriguing ramifications.

The alcohol myopia model says that drink makes our attentional system short-sighted and the more we drink, the more short-sighted it becomes. With more alcohol our brains become less and less able to process peripheral cues and more focused on what is right in front of us. It’s this balance between what is right in front of us and what we don’t notice around the edges that determines how alcohol affects us in different situations.

Here are a few effects which imbibers will recognise immediately:

• An ego boost: when people drink, they often feel better about themselves. This may be because the attentional short-sightedness induced by alcohol makes all our shortcomings float away and so we feel closer to our ideal selves. This is probably one of the reasons it is so potentially addictive, it is self-actualisation in bottle form.

• Real worries can get worse: if we’ve had a bad day and we sit quietly with a drink, alcohol can make it worse because all the peripheral cues which are potential distractors are cut out and all we see are our problems.

• Pleasure in the moment: the flip-side of this attentional focus is that if, while drinking, we are doing something enjoyable, we find it easier to ignore any nagging doubts or stray worries wandering through our minds. We can be totally in the moment listening to music, watching sports or talking with a good friend.

• In the zone: it’s even possible that for some types of task it may increase performance as we let go of our insecurities. Perhaps that’s why so many writers wrote with a glass of whisky at their side.

Tentatively, I think consciousness is essentially no more than a model of reality, a focus of attention and a working memory operating together. Of course, this may sound simple, but it isn’t – there are many processes that each could be and many ways they could interact.

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06/01/2010 by admin.

ScienceDaily has an item on a paper in Dec Nature Neuroscience by reseachers at the Salk Institute. (here)

The work connects part of the brain stem that controls eye movements with control of mental attention. Mental attention is closely linked with consciousness.

Like a spotlight that illuminates an otherwise dark scene, attention brings to mind specific details of our environment while shutting others out. …

“Our ability to survive in the world depends critically on our ability to respond to relevant pieces of information and ignore others,” explains graduate student and first author Lee Lovejoy, who conducted the study together with Richard Krauzlis, Ph.D., an associate professor in the Salk’s Systems Neurobiology Laboratory. “Our work shows that the superior colliculus is involved in the selection of things we will respond to, either by looking at them or by thinking about them.”

As we focus on specific details in our environment, we usually shift our gaze along with our attention. “We often look directly at attended objects and the superior colliculus is a major component of the motor circuits that control how we orient our eyes and head toward something seen or heard,” says Krauzlis.

But humans and other primates are particularly adept at looking at one thing while paying attention to another. As social beings, they very often have to process visual information without looking directly at each other, which could be interpreted as a threat. This requires the ability to attend covertly.

It had been known that the superior colliculus plays a role in deciding how to orient the eyes and head to interesting objects in the environment. But it was not clear whether it also had a say in covert attention.

In their current study, the Salk researchers specifically asked whether the superior colliculus is necessary for covert attention. To tease out the superior colliculus’ role in covert attention, they designed a motion discrimination task that distinguished between control of gaze and control of attention.

The superior colliculus contains a topographic map of the visual space around us, just as conventional maps mirror geographical areas. Lovejoy and Krauzlis exploited this property to temporarily inactivate the part of the superior colliculus corresponding to the location of the cued stimulus on the computer screen. No longer aware of the relevant information right in front of them the subjects instead based all of their decision about the stimulus’ movement on irrelevant information found elsewhere on the screen.

“The result is very similar to what happens in patients with neglect syndrome,” explains Lovejoy, “Up to a half of acute right-hemisphere stroke patients demonstrate signs of spatial neglect, failing to be aware of objects or people to their left in extra-personal space.”

“Our results show that deciding what to attend to and what to ignore is not just accomplished with the neocortex and thalamus, but also depends on phylogenetically older structures in the brainstem,” says Krauzlis. “Understanding how these newer and older parts of the circuit interact may be crucial for understanding what goes wrong in disorders of attention.”

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16/06/2009 by admin.

An item in ScienceDaily (here) reports on research by R Desimone’s group at MIT into gamma waves associated with attention. The report uses an interesting analogy to describe the waves.

Just as our world buzzes with distractions — from phone calls to e-mails to tweets — the neurons in our brain are bombarded with messages. Research has shown that when we pay attention, some of these neurons begin firing in unison, like a chorus rising above the noise. Now, a study in the May 29 issue of Science reveals the likely brain center that serves as the conductor of this neural chorus. … neurons in the prefrontal cortex — the brain’s planning center — fire in unison and send signals to the visual cortex to do the same, generating high-frequency waves that oscillate between these distant brain regions like a vibrating spring. These waves, also known as gamma oscillations, have long been associated with cognitive states like attention, learning, and consciousness. …

To explain neural synchrony, Desimone uses the analogy of a crowded party with people talking in different rooms. If individuals raise their voices at random, the noise just becomes louder. But if a group of individuals in one room chant together in unison, the next room is more likely to hear the message. And if people in the next room chant in response, the two rooms can communicate. …

Desimone looked for patterns of neural synchrony in two “rooms” of the brain associated with attention — the frontal eye field (FEF) within the prefrontal cortex and the V4 region of the visual cortex. …

When the monkeys first paid attention to the appropriate object, neurons in both areas showed strong increases in activity. Then, as if connected by a spring, the oscillations in each area began to synchronize with one another. Desimone’s team analyzed the timing of the neural activity and found that the prefrontal cortex became engaged by attention first, followed by the visual cortex — as if the prefrontal cortex commanded the visual region to snap to attention. The delay between neural activity in these areas during each wave cycle reflected the speed at which signals travel from one region to the other — indicating that the two brain regions were talking to one another.

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17/04/2009 by admin.

Here is more from Psyblog (here) on attention. This time on the independence of eye direction and attention.

“Eye direction normally coincides with where attention is directed but it is such an important social signal that disguise is sometimes necessary. Take these for instance:
People in close proximity like rail commuters who can watch each other by adopting a fixed gaze and letting their attention wander around the visual field.
Parents keeping tabs on their children out of the corner of their eye while looking at their conversational partner.
Skilled sports people hiding their intended passes or moves by using their peripheral vision rather than looking directly…
Posner and others argued that it is our attention moving around the visual field, often remarkably independent of our actual gaze direction. Indeed even if we’re looking directly at something, and when we don’t expect to see it, we’re no more likely to notice it than if it appears on the edge of our vision…
It appears that attention can be likened to a spotlight roving across our vision like a virtual eye, just picking out the things in which it is interested; it’s not as attached to where we point our eyes as we might imagine. ”

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14/04/2009 by admin.

It is easy to confuse attention and consciousness. Attention seems even part of consciousness. Some articles in the blog Psyblog (here) make an interesting take on attention. In fact, what I found at this blog was so engaging that I intend to visit it regularly.
An article by M. Miller from Nature 2003 is cited by the blogger. It shows that visual attention can be divided between two things. Here is the abstract:

“By voluntarily directing attention to a specific region of a visual scene, we can improve our perception of stimuli at that location. This ability to focus attention upon specific zones of the visual field has been described metaphorically as a moveable spotlight or zoom lens that facilitates the processing of stimuli within its ‘beam. A long-standing controversy has centred on the question of whether the spotlight of spatial attention has a unitary beam or whether it can be divided flexibly to disparate locations. Evidence supporting the unitary spotlight view has come from numerous behavioural and electrophysiological studies. Recent experiments, however, indicate that the spotlight of spatial attention may be divided between non-contiguous zones of the visual field for very brief stimulus exposures (<100 ms). Here we use an electrophysiological measure of attentional allocation (the steady-state visual evoked potential) to show that the spotlight may be divided between spatially separated locations (excluding interposed locations) over more extended time periods. This spotlight division appears to be accomplished at an early stage of visual-cortical processing.”

This does seem to indicate that attention is a complex concept and not just another word for consciousness. If each sense mode has zero, one or more focuses of attention at any time, plus perhaps other things (non-sensory) being attended to, then attention may be a busy little area.

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