How the brain handles surprise, good and bad

September 19, 2007

Whether it’s a mugger or a friend who jumps out of the bushes, you’re still surprised. But your response—to flee or to hug—must be very different. Now, researchers have begun to distinguish the circuitry in the brain’s emotion center that processes surprise from the circuitry that processes the aversive or reward “valence” of a stimulus.

C. Daniel Salzman and colleagues published their findings in the September 20, 2007 issue of the journal Neuron, published by Cell Press.

“Animals and humans learn to approach and acquire pleasant stimuli and to avoid or defend against aversive ones,” wrote the researchers. “However, both pleasant and aversive stimuli can elicit arousal and attention, and their salience or intensity increases when they occur by surprise. Thus, adaptive behavior may require that neural circuits compute both stimulus valence—or value—and intensity.”

The researchers concentrated their study on the amygdala, known to be the brain center that processes the emotional substance of sensory input and helps shape behavioral response to that input.

In their studies, which used monkeys, the researchers performed two types of experiments as they recorded the electrical activity of neurons in the animals’ amygdala. In one experiment, they taught the monkeys to associate a pattern on a TV monitor with either the rewarding experience of a sip of water or an unpleasant puff of air to the face. The researchers measured how well the monkeys learned the association by recording how frequently the animals anticipated the water sip or the air puff by, respectively, licking the water spout or blinking. This experiment was intended to establish whether there were specific amygdala neurons activated by rewarding or aversive stimuli.

In the other experiment, the researchers surprised the monkeys by randomly delivering either the water sip or the air puff—which aimed to establish whether the amygdala harbored specific surprise-processing circuitry.

The researchers’ analyses of the activity of the amygdala neurons did reveal different types of neurons. Some neurons responded to either the reward or the aversive stimulus, but not both. However, the activity of distinctly different sets of neurons was affected by expectation of either a reward or an aversive experience.

“These different neuronal populations may subserve two sorts of processes mediated by the amygdala: those activated by surprising reinforcements of both valences—such as enhanced arousal and attention—and those that are valence-specific, such as fear or reward-seeking behavior,” wrote the researchers.

They concluded that “These different types of response properties may underlie the role of the amygdala in multiple processes related to emotion, including reinforcement learning, attention, and arousal. Future work must develop experimental approaches for unraveling the complex anatomical circuitry and mechanisms by which amygdala neurons influence learning and the many emotional processes related to the valence and intensity of reinforcing stimuli.”

Source: Cell Press

Explore further: Military service members face unique and sustained threats to optimal brain health

Related Stories

Military service members face unique and sustained threats to optimal brain health

November 12, 2017
Military service exposes soldiers to a unique set of physical challenges, including toxic chemicals and traumatic brain injury, which can have profound effects on their health and well-being. New research examines the effects ...

Research revises our knowledge of how the brain learns to fear

October 23, 2017
Our brains wire themselves up during development according to a series of remarkable genetic programs that have evolved over millions of years. But so much of our behavior is the product of things we learn only after we emerge ...

Recording bad dreams in rats

September 12, 2017
A trio of researchers working at New York University Neuroscience Institute has recorded what appear to be bad dreams in the brains of rats as they sleep. In their paper published in the journal Nature Neuroscience, Gabrielle ...

Child abuse affects brain wiring

September 25, 2017
Researchers from the McGill Group for Suicide Studies, based at the Douglas Mental Health University Institute and McGill University's Department of Psychiatry, have just published research in the American Journal of Psychiatry ...

Neuroscientists pinpoint location of fear memory in amygdala

January 28, 2013
A rustle of undergrowth in the outback: it's a sound that might make an animal or person stop sharply and be still, in the anticipation of a predator. That "freezing" is part of the fear response, a reaction to a stimulus ...

How brains process facial expressions

April 25, 2017
Have you ever thought someone was angry at you, but it turned out you were just misreading their facial expression? Caltech researchers have now discovered that one specific region of the brain, called the amygdala, is involved ...

Recommended for you

Scientists find key to regenerating blood vessels

November 23, 2017
A new study led by researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) identifies a signaling pathway that is essential for angiogenesis, the growth of new blood vessels from pre-existing vessels. The ...

Surprising roles for muscle in tissue regeneration, study finds

November 22, 2017
A team of researchers at Whitehead has illuminated an important role for different subtypes of muscle cells in orchestrating the process of tissue regeneration. In a paper published in the November 22 issue of Nature, they ...

Study reveals new mechanisms of cell death in neurodegenerative disorders

November 22, 2017
Researchers at King's College London have discovered new mechanisms of cell death, which may be involved in debilitating neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease.

Cinnamon turns up the heat on fat cells

November 21, 2017
New research from the University of Michigan Life Sciences Institute has determined how a common holiday spice—cinnamon—might be enlisted in the fight against obesity.

How rogue immune cells cross the blood-brain barrier to cause multiple sclerosis

November 21, 2017
Drug designers working on therapeutics against multiple sclerosis should focus on blocking two distinct ways rogue immune cells attack healthy neurons, according to a new study in the journal Cell Reports.

New simple test could help cystic fibrosis patients find best treatment

November 21, 2017
Several cutting-edge treatments have become available in recent years to correct the debilitating chronic lung congestion associated with cystic fibrosis. While the new drugs are life-changing for some patients, they do not ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.