How We Scan: Point to Point to Point

The mind's eye scans like a spotlight

You're meeting a friend in a crowded cafeteria. Do your eyes scan the room like a roving spotlight, moving from face to face, or do you take in the whole scene, hoping that your friend's face will pop out at you? And what, for that matter, determines how fast you can scan the room?

Researchers at MIT's Picower Institute for Learning and Memory say you are more likely to scan the room, jumping from face to face as you search for your friend. In addition, the timing of these jumps appears to be determined by waves of activity in the brain that act as a clock. The study, which appears in the Aug. 13 issue of the journal Neuron, sheds new light on a long-standing debate among neuroscientists over how the visual system picks out an object of interest in a complex scene.

In the study, monkeys were given the task of searching for one particular tilted, colored bar among a field of bars on a computer screen. By monitoring the activity of neurons in three of the animals' brain regions, researchers found that the monkeys spontaneously shifted their attention in a sequence, like a moving spotlight that jumped from location to location.

What's more, the study showed that brain waves act as a kind of built-in clock that provides a framework for shifting attention from one location to the next. The work could have implications for understanding or treating attention deficit disorder or even potentially speeding up the rate of cognition in the brain.

"For many years, neuroscientists have been debating competing theories on whether humans and animals spontaneously search elements of a visual scene in a serial or parallel manner," said lead author Earl K. Miller, the Picower Professor of Neuroscience. "Ours is the first study based on direct evidence of neurophysiological activity."

Technorati Tags: psychology, biology, neuroscience, perception

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Does This Include Dirty Dancing?--Getting Dirty Elevates Mood

Dr. Larry Dossey: "Is Dirt the New Prozac?"

"Cleanliness is almost as bad as godliness."

-- H. L. Mencken

Imagine: You're feeling so depressed that you visit your doctor and request a prescription for a mood elevator. Instead of writing you a prescription for Prozac or a similar antidepressant, she advises you to get dirty. While you consider changing doctors, she describes how getting dirty changes your brain chemistry. The microbes in dirt, she says, tweak the same neurons that are stimulated by Prozac. Your options, she explains, are an expensive drug plus its possible side effects, or gardening, yard work, or a romp in the park. Your doctor, it turns out, hasn't gone round the bend. She is actually up-to-date on the latest scientific findings about how the natural environment affects our brain function.

Technorati Tags: psychology, depression, dirt

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One Body, Two Heads: A Case Study, and an Allegory about the Body Politic (Heads Up, Iran!)

Vaughn Bell writes:

I've just been reminded of one of the most remarkable case studies in the psychiatric literature, of a patient who believed he had two heads and who seriously injured himself with a gunshot wound trying to remove the 'second' head.

He described a second head on his shoulder. He believed that the head belonged to his wife's gynaecologist, and described previously having felt that his wife was having an affair with this gynaecologist, prior to her death. He described being able to see the second head when he went to bed at night, and stated that it had been trying to dominate his normal head.

He also stated that he was hearing voices, including the voice of his wife's gynaecologist from the second head, as well as the voices of Jesus and Abraham around him, conversing with each other. All the voices were confirming that he had two heads; the voice from the second head had been telling him that it was the 'king pin', and would also say to him that it was going to take his wife away. He did not describe any other hallucinatory or delusional experiences.

"The other head kept trying to dominate my normal head, and I would not let it. It kept trying to say to me I would lose, and I said bull-shit." "I am the king pin here" it said and it kept going on like that for about three weeks and finally I got jack of it, and I decided to shoot my other head off."

He stated that he fired six shots, the first at the second head, which he then decided was hanging by a thread, and then another one through the roof of his mouth. He then fired four more shots, one of which appeared to have gone through the roof of his mouth and three of which missed. He said that he felt good at that stage, and that the other head was not felt any more. Then he passed out. Prior to shooting himself, he had considered using an axe to remove the phantom head.

link: Mind Hacks