JoVE Science Education
Neuropsychology
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JoVE Science Education Neuropsychology
Decision-making and the Iowa Gambling Task
  • 00:00Overview
  • 01:11Experimental Design
  • 03:30Running the Experiment
  • 04:59Representative Results
  • 06:17Applications
  • 07:54Summary

意思決定とギャンブル課題アイオワ

English

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Overview

ソース: ジョナス ・ t. カプラン サラ I. ギンベル所-南カリフォルニア大学

意思決定は、行動や認知のコースについての選択肢が多くの可能性から行われる人間の執行機能の重要なコンポーネントです。前頭葉の粗悪な部品への損傷は、良い意思決定をする人の能力に影響を与えます。しかし、意思決定の赤字は、自分の人生に大きな影響を持つことができます中、これらの赤字は研究室で定量化することは困難することができます。1990 年代半ばにタスクは、実験室で実際の生活の意思決定を模倣するように設計されました。アイオワ州ギャンブル タスク (IGT) として知られている、このタスクは、意思決定能力の非常に敏感な測定として研究や臨床研究で広く用いられる認知的複雑なタスクです。1-3

IGT、参加者は 4 組のカードが表示され、各ターン 1 つのデッキのカードを明らかにすることを選択します。カードをめくって、参加者はいくつかのお金を受け取るが、時も違約金を支払う必要が。デッキの 2 つは高い給料支払いがように選択これらのデッキからリード純損失は長期的にも高いペナルティがあります。他の 2 つのデッキより低い給料支払いも小さい罰に存在、これらのデッキが純利益につながるのでから選択します。したがって、有利な選択をするためには、参加者は、時間をかけて利益と損失についてを統合しなければなりません。

このビデオでは、意思決定するには、この脳領域のユニークな貢献を明らかに一致した健常者のグループに腹内側前頭前野に損傷患者のパフォーマンスを比較する IGT を管理する方法を示します。

Procedure

1. 参加者募集 患者の募集 前頭皮質の腹内側のセクターに損傷を持つ 10 人の患者を募集します。 この地域への損傷は MRI と神経イメージング研究によって確認されます。腹内側前頭前野腹側表面の大脳皮質の最も前方の内側の壁に位置しています。損傷は、片側または、両側ですが腹内側前頭前野を超えて拡張する必要があります。このような患者の脳の例は?…

Results

In 100-card draws from four decks, normal controls made more selections from the good decks (C and D), and avoided the bad decks (A and B). In contrast, patients with ventromedial prefrontal cortex (VMPFC) damage made more selections from the bad decks (A and B), and avoided the good decks (C and D; Figure 3). The number of cards selected by controls from decks A and B were significantly less than the number of cards selected from those decks by the patients. In contrast, the number of cards selected by the control population from decks C and D were significantly more than the number selected by patients.

Figure 3
Figure 3: Control subject and patient performance on the Iowa Gambling Task. In one hundred card selections from four decks, normal controls made more selections from the good decks (C and D), and were more apt to avoid the bad decks (A and B). In contrast, patients with ventromedial prefrontal cortex damage made more selections from the bad decks (A and B), and avoided choosing from the good decks (C and D).

These results show that the patients perform differently in this task from healthy controls, in that they tend to draw from high reward/high punishment decks more frequently even though these decks result in long term losses. Examination of the pattern of responses shows that this deficit in performance is stable over time. While controls initially sample from the bad decks, they eventually learn to avoid them. Patients, on the other hand, continue to sample from the bad decks throughout the experiment. Since participants must rely on their ability to estimate which decks are risky and which are profitable over time, patients' performance mimics their real-life inability to made advantageous decisions. This task allows the detection of the impairment in these patients in a laboratory setting, and provides insight into the role of the VMPFC, which appears crucial for incorporating emotional knowledge about decision outcomes into behavior.

Applications and Summary

This task can serve to assess decision-making deficits in a variety of populations. For example, in addition to patients with damage to the VMPFC, patients with bilateral amygdala damage also show severe decision-making impairments that can be measured by the IGT. Additionally, disadvantageous decision-making characterizes various psychopathological conditions, including substance addiction, pathological gambling, schizophrenia, obsessive-compulsive disorder, anorexia nervosa, attention deficit/hyperactivity disorder, psychopathy, obesity, and many others.

One of the advantages of this task is its ability to distinguish among different cognitive contributions to the complex process of decision-making. For example, we can compare the performance of patients with VPMFC damage to patients with schizophrenia, both of whom show deficits on the task. The tendency of VPMFC patients to choose from the bad decks has been interpreted as a deficit in incorporating information about long-term future consequences into behavior; in these patients, choices are made only on the basis of potential short-term reward. Patients with schizophrenia also choose more frequently from the bad decks than normal controls. However, their distinctive pattern of choices, in which they tend to choose more often from the decks with low frequency, high magnitude losses (decks B and D), reveals a different underlying deficit.4 This pattern of choices suggests that schizophrenic patients are sensitive to the frequency of reward versus punishment, but fail to advantageously take into account the magnitude of the punishment. Thus, the IGT is able to reveal a range of cognitive contributions to decision-making that may be associated with dysfunction in different brain regions.

References

  1. Bechara, A., Damasio, A.R., Damasio, H. & Anderson, S.W. Insensitivity to future consequences following damage to human prefrontal cortex. Cognition 50, 7-15 (1994).
  2. Bechara, A., Damasio, H., Tranel, D. & Damasio, A.R. Deciding advantageously before knowing the advantageous strategy. Science 275, 1293-1295 (1997).
  3. Li, X., Lu, Z.L., D'Argembeau, A., Ng, M. & Bechara, A. The Iowa Gambling Task in fMRI images. Hum Brain Mapp 31, 410-423 (2010).
  4. Shurman, B., Horan, W.P. & Nuechterlein, K.H. Schizophrenia patients demonstrate a distinctive pattern of decision-making impairment on the Iowa Gambling Task. Schizophr Res 72, 215-224 (2005).

Transcript

Decision-making is an important component of human executive function, one in which a choice about a course of action is made from many possibilities.

For instance, a person’s ability to obtain a beverage could result from making good decisions, like choosing to go to the cash register and pay for it, or poor ones, such as running out the door without paying.

This latter example—the risky act of stealing—is considered an undesirable decision, one that occurs as a result of damage to the frontal lobes—and in particular, the ventromedial prefrontal cortex, VMPFC for short.

This video demonstrates how to design and execute the Iowa Gambling Task—a highly sensitive measure of complex decision-making ability—where individuals must integrate information about losses and gains over the course of a high-risk card game.

In this experiment, two groups of participants—patients with known damage to the VMPFC and controls, individuals without such damage—perform the Iowa Gambling Task, which examines decision-making ability dealing with reward and punishment.

All are shown four decks—labeled A through D—that contain identical-looking cards and given play money to use, as the overall goal is to maximize profit.

During each turn, participants choose one card from any of the four piles and subsequently receive a certain amount of predetermined money that only the researcher knows.

For instance, they might pick a card that results in not only winning money but also losing some. Or, they may even lose more than they win. The trick then is to understand the risk associated with every deck.

Although A and B yield greater rewards than C and D, they also result in higher penalties and thus, lead to losses in the long term. Decks A and B result in the same long term losses, but the punishment in A is more frequent and of lower magnitude than in B.

Overall, choosing from A and B will result in net losses, while choosing from C and D will result in net gains, which is why sets A and B are referred to as bad, and C and D as good.

Thus, to make advantageous choices, participants must integrate information about losses and gains over time and avoid the bad sets.

The dependent variable here is the number of card turns the participant makes from each of the four decks.

Based on previous work by Bechara, Damasio, and colleagues, patients with VMPFC damage are expected to make more selections from the bad ones—A and B—and avoid choosing from the good—C and D—mimicking their real-life inability to make valuable decisions.

For the purpose of this demonstration, test a patient with known cortical damage. Note that their data will be compared to those collected from controls without brain damage, who are also matched in age and intellect.

In preparation for the task, seat the patient at a table in front of four decks of identical-looking cards, and hand them $2000 in play money.

Instruct them that they must choose one card at a time from any of the four piles, and after flipping each card, they will receive a certain amount of money.

Further inform them that they are free to switch between decks at any time, as often as they want, and to take their time, in order to maximize their profit on the loan money.

Begin by having the patient make their first selection, and announce the amount of the reward or penalty according to the scorecard. Give them the amount of play money that they earn, and tell them to hand back any money they have lost before proceeding to the next turn.

Keep track of every card turn by marking the appropriate cell of the scorecard. In the event that a deck is completed before the experiment is over, notify the patient that they can now only choose from the three remaining decks. End the task when 100 cards have been turned.

To examine participants’ decisions over time, plot the deck selections across the course of the 100 trials—separately for controls versus patients with VMPFC damage.

While controls initially sampled from the bad decks, they eventually learned to avoid them. Patients, on the other hand, continued to sample from the bad ones throughout the experiment.

To make group comparisons, summarize these data into a bar graph, where the total number of card turns is plotted across decks.

Notice how normal controls made more selections from the good decks—C and D—and avoided the bad—A and B. On the other hand, patients with VMPFC damage made more selections from the bad sets, and largely avoided the good ones.

These results indicate that patients with frontal brain damage perform differently in this task compared to healthy controls, such that they more frequently draw from the high reward/high punishment decks, even though those decisions result in long-term losses.

Now that you are familiar with using the Iowa Gambling Task to quantify risky outcomes in patients with frontal lobe damage, let’s look at how the paradigm can be used to assess decision-making in a variety of populations, including individuals with amygdala damage and those diagnosed with schizophrenia.

While the role of the PFC in decision-making is well studied, other brain regions contribute to implementing advantageous versus disadvantageous choices.

Given the amygdala’s role in processing incentive stimuli, damage to this region would likely disrupt the integration of reward and punishment states vital to the gambling task.

Using a similar paradigm, researchers have shown that patients with bilateral amygdala damage also show severe decision-making impairments.

Just like patients with VMPFC damage, individuals with schizophrenia also choose from bad decks; however, they show a distinctive pattern of choices, making more selections from the low frequency but high magnitude losses—decks B and D.

These results indicate that schizophrenic patients are sensitive to reward versus punishment, but fail to advantageously take into account the magnitude of the punishment.

Thus, the Iowa Gambling task can be used to reveal a range of cognitive contributions to decision-making that may be associated with different underlying deficits.

You’ve just watched JoVE’s introduction to quantifying decision-making in the laboratory using the Iowa Gambling Task. Now you should have a good understanding of how to administer this paradigm by observing and responding to different card choices, as well as how to analyze and interpret the results.

Thanks for watching!

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JoVE Science Education Database. JoVE Science Education. Decision-making and the Iowa Gambling Task. JoVE, Cambridge, MA, (2023).