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Specific Projects |
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1. Neuronal representation of abstract value Lead Investigator: Steve Kennerley Potential treatments: Addiction, obesity, eating disorders, obsessive-compulsive disorder A key question in the behavioral sciences is how we determine the best course of action among competing alternative. We often must make decisions that require a consideration of both our internal needs and desires as well as the potential costs of meeting those needs. For example, we might desire a house in the suburbs, but must consider the increased commute to our workplace. How do we make such choices? How do we ensure that we consistently select the course of action that will most efficiently realize our needs and goals? Two brain regions that are key to choice behavior are the orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC). Damage to these areas has been associated with dramatic changes in social behavior and impaired ability to make choices in everyday life. Moreover, OFC and ACC dysfunction have been associated with neuropsychiatric illnesses that disrupt choice behavior, particularly those that involve compulsive and impulsive choices. The aim of this project is to provide a clearer understanding of the neuronal and pharmacological mechanisms that underlie choice behavior to aid in the development of improved interventions and treatments for these disorders. We will test the hypothesis that OFC neurons encode all the parameters necessary to make a decision, by deriving an abstract value signal. We will simultaneously record the activity of single neurons in four different frontal areas in awake, behaving monkeys (ACC, OFC, ventrolateral prefrontal cortex and dorsolateral prefrontal cortex) while they choose between two pictures associated with different values varied along three physically different valuation scales. Specifically, monkeys will choose between one group of pictures that differ in their association with reward magnitude, one group in their association with the amount of effort required to earn a fixed reward, and a third group in the probability that a reward would be delivered. Additional experiments will manipulate the parameters underlying the choice, to determine precisely on what the value signal is based.
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2. Integration of spatial working memory and reward information Lead Investigator: Steve Kennerley Potential treatments: Attention deficit hyperactivity disorder
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3. Representation of reward in working memory Lead Investigator: Antonio Lara Potential treatments: Addiction, obesity, eating disorders In many laboratory studies, earning a reward is a simple process. The subject pushes a button or presses a lever and gets a reward. But in real life rewards are often not so easily earned. We often have to forego immediate rewards in order to obtain distant goals. For example, we sacrifice our favorite foods or devote time to exercise for the reward of better health and increased quality of life. Obtaining such distant rewards requires considerable planning of future actions, which in turn requires working memory, a temporary workspace in which to manipulate information and organize behavior. Most working memory studies have concentrated on keeping in mind sensory information. However, the workspace presumably also contains a representation of the goal towards which behavior is directed. This project will examine how neurons in the brain hold information about rewards and goals in working memory so we can begin to understand the mechanisms that underlie planning and organizing behavior to achieve distant goals. Knowing how the brain keeps reward information in mind during the process of planning whether to have a salad or a triple cheeseburger, will help us understand what happens when people, despite their best intentions, opt for the triple cheeseburger and forgo the salad. Such mechanisms may be a common feature of disorders involving a lack of control, including eating disorders, addiction and pathological gambling. |
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4. Goal-directed and habitual control of action Lead Investigator: Chung-Hay Luk Potential treatments: Addiction, stroke Most of our actions are motivated by goals: we drive to the store to pick up ice cream. But many of our actions are also habits, and are not directed towards a specific goal. On the way to the store we brake at a red light automatically with little thought to the consequences if we did not brake. This transistion, from a goal-directed behavior to a habit, makes sense for actions that we regularly perform. We do not want to devote precious cognitive resources to deciding whether we want to brake at every stop light, but instead want to spend our time thinking about more important things (which is why many of us experience driving as if on 'autopilot'). However, it might also play an important role in the process of addiction. Some investigators have argued that addiction initially involves administering a drug in a goal-directed manner (we administer the drug because it gives us pleasure) but over time the habit system takes over and we administer the drug as if on autopilot. Or as a Japanese proverb states, "First the man takes a drink. Then the drink takes a drink. Then the drink takes the man.". This project will examine the neuronal mechanisms that underlie how behavior transitions from goal-directed to habitual actions. Understanding those mechanisms may lead to treatments that can prevent people from becoming addicted to drugs of abuse. |
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