Decisions, decisions

Throughout life, each person's future and ultimately their survival depends upon choices made each day, whether it be accepting that new job offer, continuing to pursue a particular relationship, or deciding what to eat for lunch. In order to choose the best option, it’s important to weigh the pros and cons of each possibility and predict whether the outcome might be worth the effort it will cost to obtain it.

As a concrete example, consider a person who is deciding what to eat for lunch. They need to think about the type of food they want to eat, how far away they will need to travel in order to obtain it (can they make it there and back during their lunchtime?), how much money the food will cost, and whether the food will adequately nourish their body. On paper, this type of calculation may require pen and paper, but the brain is able to handle this algorithm quite well. The ultimate reward is to eat a meal that will provide the maximum amount of nutrients and energy for the body but requires a minimal amount of energy to obtain it.

Scientists at the University of Washington in Seattle and the University of Oxford are studying the processes that underlie our brain's analysis of these situations. Each aspect must be taken into account to ensure that the net effect is beneficial for us. These researchers recently reported in Nature Neuroscience that dopamine released from the nucleus accumbens encodes information regarding the value of the reward itself but not the costs associated with obtaining that reward unless the cost is particularly low.

At the heart of reward processing is the mesolimbic dopamine pathway, which lies in the midbrain and contains neurons that release dopamine to the nucleus accumbens. This circuit analyzes how likely it is to receive the reward, how much of that reward is possible to obtain, and how long it will take to receive the reward.

In order to achieve these results, the group studied the quantitative amounts of dopamine released in rats at the nucleus accumbens when the value of a reward or the cost of a reward was changed. To begin, the rats were trained to choose between two options:

1. Pressing a lever 16 times, which is the cost, to receive 1 pellet of food, which is the reward.

-OR-

2. A similar protocol in which the cost was manipulated by increasing to 32 lever presses or decreasing to 2 lever presses OR a similar protocol in which the reward was manipulated by increasing to 4 food pellets or decreasing to no food pellets at all.

A significantly greater amount of dopamine was released when the rat chose 4 food pellets over 1 food pellet; likewise, more dopamine was released when the rat chose 1 food pellet over no food pellets. Thus, the higher levels of dopamine were released when the 'better' of the two possible rewards was chosen.

When the cost of the reward was manipulated, more dopamine was released when the rats chose to press the lever 2 times instead of 16 times. However, there was no difference in the amount of dopamine released when the rat chose 16 lever presses over having to press the lever 32 times. It was concluded, then, that the nucleus accumbens is important for determining the value of the reward but unless the cost is particularly low (if you're getting a real good deal!), evaluating the cost is processed elsewhere.

Focus on UAB neuroscience

Originally published in the UAB Kaleidoscope on April 28, 2008:

On Wednesday, April 23, the UAB School of Public Health presented the Glenwood Endowed Lecture Series, a joint effort between UAB and Glenwood to heighten awareness of the social concerns faced by people who have autism and also to shed light on recent research efforts being made to understand autism. In addition to the keynote speaker’s presentation on brain-based research of autism, workshops were presented by Birmingham-area clinicians. Glenwood, the Autism and Behavioral Health Center of Alabama, touches the lives of 4,500 children, teens, adults, and families affected by mental health disorders annually.

“The aim of the Glenwood Endowed Lecture is to foster a growing sense of unity among the public, service providers, and researchers around the societal impacts of behavioral health disorders such as autism,” said Dottie Mitchell, Director of Communications and Marketing at Glenwood. “We have received an enthusiastic response to this year’s Glenwood Endowed Lecture keynote speaker, Dr. Nancy Minshew. Response has poured in from educators, researchers, parents, advocates, and individuals who have loved ones affected by autism and others from across Alabama.”

Indeed, these efforts have resulted in a much larger knowledge base, as participation in the workshops has increased almost 5 fold in only three years!

“Our first lecture took place in 2005, and there were about 40 people registered; today, we have approximately 185 people registered,” said Mitchell.

Autism is a neurodevelopmental disorder that affects a person’s ability to communicate and interact with others. People who have autism are affected to varying degrees, thus the inclusive terminology “autism spectrum disorder” (ASD) has been coined. There are three main forms of ASD including autism, Asperger syndrome, and pervasive developmental disorder not otherwise specified. In many instances, people who have autism avoid eye contact, cannot perceive other’s feelings, and tend to display repetitive behaviors. An important social consideration is to educate the public about this disorder in an effort to help these individuals integrate into society.

“It is important to educate parents, teachers, and others about autism,” said Nancy Minshew, M.D., Director of the NIH Autism Center of Excellence, and professor of psychiatry and neurology at the University of Pittsburgh School of Medicine. “These are children who are never invited to birthday parties or called on the telephone. Others need to be taught that teasing and bullying are not acceptable.”

It is just this theme that permeated the workshops. Each was tailored to address the specific needs of people who have autism in successive stages of life. Additionally, the event included updates on scientific advancements and research in autism.

“The advent of functional MRI has helped to make tremendous advances in understanding autism,” said Minshew. “In the past, we could only determine that there was an increase in the brain size of young children who have autism because we were limited by the level of resolution afforded by the imaging technology at that time. Now, we have been able to determine that autism is actually a problem of higher-order neural circuitry; their higher-order circuitry is underdeveloped, but their simpler processing and abilities are intact.”

One UAB student believes that knowledge of the basic science underlying a disorder combined with the social considerations that evolve out of the disorder is important for medical researchers.

“I believe it is very important for a basic science researcher to understand not only the underpinnings of the biological component that causes autism but also the societal impact of the disorder,” said Chris Chapleau, a UAB graduate student. “How are these kids going to be in 5 to 10 years? What impact does this have on a family? I believe that understanding these things makes a more well-rounded researcher who is better able to address the questions and provide answers for various aspects of the disorder.”

Opportunities exist for UAB students to learn more about autism and become involved in raising awareness of the disorder by volunteering at Glenwood.

“There are several ways to get involved at Glenwood,” said Mitchell. “Students can help with one of Glenwood’s fundraisers; assist with the Annual Holiday Pecan Sale; or get a group together and participate in a project on Glenwood’s campus.”

For more information regarding volunteer opportunities, contact Rebecca Rhodes Sibley at 205-795-3267 or rsibley@glenwood.org.

We do what's necessary to survive

Ever known someone who consistently returned to an abusive partner or spouse regardless of their resolve to end the cycle? Attempting to understand why someone would willingly subject themselves to more violence can indeed be mind-boggling. Scientists at several institutions around the country are finding out, however, that there is a biological explanation for this type of behavior, and it originates from the early years spent with our mom.

Throughout the early stages of life, it’s important that offspring remain close to their mom at all times, since she provides their basic needs for survival - nourishment, shelter, and protection. Separation or withdrawal from her during this time would put their very lives in jeopardy. To ensure this doesn’t happen, infants are born with an inherent preference for their mom, an attraction so strong that even poor treatment from her doesn’t interfere with their desire to be near her.

In their Nature Neuroscience paper published November 2, Gordon A. Barr et al. gave rats an electrical shock while exposing them to a particular odor. This conditioning caused adult rats to avoid all subsequent encounters with the scent since they associated it with getting shocked. The opposite reaction was reported in young rats, however. These pups actually exhibited a preference for the very odor they had been conditioned to avoid. It’s believed that, although they don’t have the ability to identify and avoid potentially harmful stimuli, they reach a stage at some point in development where they learn this strategy.

Further experiments revealed that the steroid corticosterone, also known as the stress hormone, reverses the preference behavior exhibited in the young rats. When corticosterone was injected into young rats prior to the electrical shock and odor exposure, they learned to avoid that odor in the future, which is the same response demonstrated by the adult rats!

At the core of this phenomenon lies dopamine, which is one of the brain’s molecules responsible for transmitting signals between cells. There is less dopamine released from neurons in young pups demonstrating preference behavior than in the young pups who avoided the odor because they were injected with corticosterone beforehand. The quantitative measurements of dopamine were taken from the amygdala, an area of the brain that processes threats and fears. The greater the release of dopamine, the stronger the synapses will be in the amygdala; this solidifies our memory of those stimuli that we’ve learned to avoid.

To further demonstrate the role of dopamine in avoidance behavior, young rats were infused with dopamine prior to conditioning. Those rat pups that would normally exhibit a preference for the odor now demonstrated an aversion for the scent. If a dopamine receptor antagonist were infused, the young rats demonstrated preference behavior. Once again, the elevated levels of dopamine are associated with the ability to learn and remember which stimuli to fear and avoid.

The preference behavior exhibited by young rats described herein has been selected for throughout many years of evolution. Obviously, nature has decided that it is more advantageous for us to prefer our mom and form an attachment to her even in instances of poor treatment or abuse. Our chances of survival are higher if we remain alongside her. After all, at birth and throughout infancy, we are virtually helpless and have no way of setting out to find better conditions and sources of nourishment.

At such a young age, we don’t have the ability to identify and learn which stimuli to fear and avoid. As we grow older and stronger and are thus better able to take care of ourselves, the dependence upon and attachment to mom lessens and we are able to learn which things to fear and avoid. Without mom right by our side to keep corticosterone levels at bay, it’s possible for us to detect stressful situations and learn how to deal with them.

Psychologically speaking, who really benefits from an apology?

Each day, people around the world experience altercations with others, whether it be a spouse, family member, friend, or even a stranger. In the event of an apology between the parties involved, however, who is the actual benefactor?

Having been the “good” Catholic schoolgirl at one point in my life, it’s understandable that the first answer in my head is easily “the recipient of the apology.” After all, a common mantra drilled into our heads while growing up is that we must say we are sorry when we hurt someone. It’s supposed to make them feel better, right?

Is the act of apologizing, however, something that is really intended to make the wronged person feel better? Or, is it the one delivering the apology that actually benefits, considering that it is their conscious being cleansed through the very act?

It seems to me that, in some cases, a verbal apology could very well be considered a selfish act.

Yes. Selfish.

This concept may be illustrated through the following: a friend of mine who is divorced received an apology from her ex-husband after several years with no contact between the two of them.

Granted, in the conventional way of thinking, the man certainly owed her an apology. He had betrayed her, cheated on her, and abused her.

The question remains, though…did he really take her psychological well being into consideration when approaching her with an “I’m sorry”? Did he even think about the effect this apology may have on her and her life? Did he once again commit a selfish act against her when he failed to think about how the apology would affect her?

If this man truly had her best interest at heart, he would have chosen to stay away.

His apology had the opposite effect that our old childhood mantra would predict…instead of making her feel better, she was tossed right back into the throes of sadness.

When I think about it, my friend exerted so much energy and effort to get through the divorce and all the emotional mazes divorce brings with it. After years of counseling, heartache, and trauma, she made peace with the situation. She was forced to create her own closure on the event, as he had offered nothing in that area. Until the point at which her ex briefly re-entered her life, she was healthy and doing quite well.

Instead of taking the time to consider what stage my friend was at in her life, her ex placed more value upon lifting the burden of guilt off his shoulders.

Approaching someone so many years after an intense emotional altercation to say “I’m sorry” may not have the effect one would think. If the person wronged has moved on in their life, sometimes it may be more respectful to leave them alone instead of causing the other person to dredge up hurtful memories of the past and, once again, deal with them.

In the case of my friend, I believe her ex’s “I’m sorry” was actually beneficial for himself. I mean, his conscience is cleared. He can now move on without showing any regard for the wake left behind him.

Do scientists use social media?

Yesterday, the Postdoctoral Association at UAB hosted a seminar entitled, "Social Media for Scientists: How Facebook and LinkedIn can bolster your career". The talk, presented by Wade Kwon and David Sher - both experts in this area, was informative and convincingly made the point that social media is here to stay. We're at an advantage if we make use of these tools now.

What surprised me was the small percentage of those in attendance that actually use social media networks such as Facebook, Twitter, etc. Most of the audience have never used these networks and, if so, rarely update their accounts. It made me wonder why scientists might shy away from these simplistic forms of communication.

The stereotypical phenotype of a scientist is an anti-social individual wearing a white coat who prefers to work isolated in a laboratory, mixing flasks of bubbling solutions that are oh-so-beautifully colored. But does this image really hold up today?

Sciencey Movies

I admit it ... I love movies. This is one of the reasons I was so excited about Chicago's 45th International Film Festival taking place at the same time as the Society for Neuroscience (SfN) conference. Of course, SfN being SfN with all of it's bustling and busyness, I never had a chance to go :(

For me, it can't be just any movie. I'm not a big fan of special effects and everybody/everything blowing to pieces before the film is over. And they can keep the girl-gets-guy/guy-gets-girl 'romantic comedies' ... no matter how hard Hollywood tries to approach reality in this genre of film, the star *always* gets their love interest (or some other, better lover that they didn't notice until later) by the end ... not exactly reality.

Yesterday, however, I was reading a blog post by Sabbi Lall from Nature magazine, and learned about the Imagine Science Film Festival recently held in New York City. These are my kind of movies! I just wish this festival would travel south for the winter :)

Below are just a few of the films that grabbed my attention ...

One of the films screened at the festival, entitled "In Search of Memory", documents the life of Eric Kandel, who is one of the most influential people in the field of neuroscience. And as an added bonus, Kandel was present for a question and answer session following the screening.

Animated Minds offers a glimpse into the lives of people who suffer from mental illness. An example of four different disorders are portrayed: obsessive-compulsive disorder, manic depression, anxiety, and psychosis. A particularly interesting story is told through the person who has obsessive-compulsive disorder. This man believed that each time he thought about Saddam Hussein, he was contributing to the Gulf War. It reached a point where, if he thought about Hussein while partaking in daily activities such as talking, eating, and walking, he had to go back and repeat the task.

Dreams of a Scientist is one of a series of animated shorts about the dreams that scientists have at night. A quick Google search will bring up clips of the film.

PCR Rap, by The Science Rapper, tells the story of the polymerase chain reaction from both the scientific and historical point of view. It promises to make you feel like it's your first time to replicate DNA!

Gulf War Illness

One morning at SfN, a friend and I were looking over the day's schedule deciding which posters we were going to see. We glanced by one abstract containing the words 'Gulf War Syndrome' and 'mouse'. We were a bit amused at first, trying to figure out exactly how one goes about making a mouse line that has Gulf War Syndrome. Does Harlan raise them in a war zone?

Of course that's not the case. Instead, rats or mice are exposed to various chemicals that were potentially used in the Persian Gulf War in the early 1990s. These include pesticides and nerve gases, many of which are acetylcholinesterase inhibitors that prevent the break-down of excess acetylcholine at synapses in the CNS and PNS.

Gulf War Illness affects many soldiers who served in Operation Desert Storm and/or Desert Shield; some reports estimate this number to be as high as 25% to 30% of veterans! Symptoms of Gulf War Illness presented slowly and, in some cases, took almost two years. Another confounding factor is the seemingly random set of symptoms, which include depression, bronchitis, stomach upset, chronic fatigue, memory problems, and musculoskeletal issues.

Effort is now being put forth by the US Department of Veterans Affairs to study this illness, and several of these research studies were presented at SfN.

Many veterans report problems related to memory recall. Because the hippocampus plays a major role in learning and memory, one study conducted by HE Speed et al. from UT Southwestern investigates the effect of chlorpyrifos, a common insecticide used during the Gulf War, on this brain structure. They found that chlorpyrifos exerts a biphasic effect on synaptic transmission. Closely following initial exposure, mice actually showed an enhancement in synaptic transmission and a small increase in learning and memory. However, the later phase was characterized by a 50% decrease in synaptic transmission, which indicates a loss in synaptic efficacy, in the number of synapses, and/or in the number of neurons. It's interesting to note that this later effect was detected three months after exposure to chlorpyrifos, consistent with the delayed onset of symptoms associated with Gulf War Illness.

Another study by VK Parihar et al. once again looked at the hippocampus and the effect of chemicals and stress on neurogenesis within this brain structure. The group found that rats exposed to pesticides and stress experienced a significant reduction in hippocampal neurogenesis, which may underlie some of the memory and mood disruptions reported by veterans of the first Gulf War.

Finally, P Ferchimin et al. are investigating the possibility that a compound found in the leaves and flowers of tobacco plants (4R) can impart neuroprotection following exposure to insecticides or nerve toxins. Tested on acute hippocampal slices, the researchers found that treatment with 4R 30 minutes after exposure to a toxin prevented any loss of neurons. If 4R was applied 1 hour after exposure, only 30% of the neuronal population was lost. Neuron survival was determined via electrophysiological recordings of a 'pop spike', which is an extracellular measurement of neurotransmitter release from a population of neurons.

SfN ... coming soon to a location near you

Word on the street is that Chicago is going to be added to the rotation list of cities hosting SfN. Also, SfN will return to New Orleans in 2012. What are your thoughts? Which is your preferred SfN city?

Me? San Diego. But, then again, I'm very partial to San Diego!

Like Google, but for neuroscientists!

A new search tool has been designed by researchers at the University of California, San Diego that promises to revolutionize internet searches for neuroscientists! It's called the Neuroscience Information Framework and, if you're at SfN right now, you can get a demonstration of it at booth #2103. More info coming soon!

Are your feet hurting at SfN?

After walking around a large conference center like McCormick Place all day, many people end up with feet that decide they just can't go on. And when the feet hurt, it takes its toll on the whole body.

This year, however, was the first time I've seen a massage area at SfN. The group didn't set up in some obscure place, either. Instead, they strategically placed themselves in the heart of the poster sessions, around aisle E. Mi Bon Spa McCormick offers massage services and manicures for SfN attendees. Choose from the Windy City Foot Massage, Chicago Classic Neck and Back, Millennium Head and Shoulder, or the Michigan Avenue Hand and Arm massage.

Right now, you can go by their space and pick up a coupon for a free calf massage with the purchase of a foot massage, which is a $40 value. The group says they are very busy in the afternoons but their services are available all day.

I started wondering how foot massage or reflexology can affect the brain. It seems that a group in Hong Kong has studied the benefits of reflexology and found an advantage conferred on the visual system. I'd like to delve deeper into this research, so stay tuned for more information!