2017/12/13 榎本

Optogenetic Inhibition Reveals Distinct Roles for Basolateral Amygdala Activity at Discrete Time Points during Risky Decision Making
Orsini CA, Hernandez CM, Singhal S, Kelly KB, Frazier CJ, Bizon JL, Setlow B
J Neurosci. 2017 Nov 29;37(48):11537-11548. doi: 10.1523/JNEUROSCI.2344-17.2017. Epub 2017 Oct 27

ラットにSmall & Safe rawardかLarge & Risky rewardかを選ばせる課題を用い、扁桃体BLAを光刺激で抑制したときに、光刺激のタイミングによって真逆の効果が見られることを報告しています。

Abstract

Decision making is a multifaceted process, consisting of several distinct phases that likely require different cognitive operations. Previous work showed that the basolateral amygdala (BLA) is a critical substrate for decision making involving risk of punishment; however, it is unclear how the BLA is recruited at different stages of the decision process. To this end, the current study used optogenetics to inhibit the BLA during specific task phases in a model of risky decision making (risky decision-making task) in which rats choose between a small, “safe” reward and a large reward accompanied by varying probabilities of footshock punishment. Male Long–Evans rats received intra-BLA microinjections of viral vectors carrying either halorhodopsin (eNpHR3.0-mCherry) or mCherry alone (control) followed by optic fiber implants and were trained in the risky decision-making task. Laser delivery during the task occurred during intertrial interval, deliberation, or reward outcome phases, the latter of which was further divided into the three possible outcomes (small, safe; large, unpunished; large, punished). Inhibition of the BLA selectively during the deliberation phase decreased choice of the large, risky outcome (decreased risky choice). In contrast, BLA inhibition selectively during delivery of the large, punished outcome increased risky choice. Inhibition had no effect during the other phases, nor did laser delivery affect performance in control rats. Collectively, these data indicate that the BLA can either inhibit or promote choice of risky options, depending on the phase of the decision process in which it is active.

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参考に、ここ数年の扁桃体関連論文リストです。

2015/11/11 神代

Monkeys head-gaze following is fast, precise and not fully suppressible.

Marciniak K, Dicke PW, Thier P.

Proc Biol Sci. 2015 Oct 7;282(1816).

Abstract

Human eye-gaze is a powerful stimulus, drawing the observer's attention to places and objects of interest to someone else ('eye-gaze following'). The largely homogeneous eyes of monkeys, compromising the assessment of eye-gaze by conspecifics from larger distances, explain the absence of comparable eye-gaze following in these animals. Yet, monkeys are able to use peer head orientation to shift attention ('head-gaze following'). How similar are monkeys' head-gaze and human eye-gaze following? To address this question, we trained rhesus monkeys to make saccades to targets, either identified by the head-gaze of demonstrator monkeys or, alternatively, identified by learned associations between the demonstrators' facial identities and the targets (gaze versus identity following). In a variant of this task that occurred at random, the instruction to follow head-gaze or identity was replaced in the course of a trial by the new rule to detect a change of luminance of one of the saccade targets. Although this change-of-rule rendered the demonstrator portraits irrelevant, they nevertheless influenced performance, reflecting a precise redistribution of spatial attention. The specific features depended on whether the initial rule was head-gaze or identity following: head-gaze caused an insuppressible shift of attention to the target gazed at by the demonstrator, whereas identity matching prompted much later shifts of attention, however, only if the initial rule had been identity following. Furthermore, shifts of attention prompted by head-gaze were spatially precise. Automaticity and swiftness, spatial precision and limited executive control characterizing monkeys' head-gaze following are key features of human eye-gaze following. This similarity supports the notion that both may rely on the same conserved neural circuitry.

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2015/10/28 菊池

明日の私の発表は、論文紹介は省略し、データについてお話したいと思います。

神経科学学会発表と重なりますが、いくつか載せることのできなかったデータやその後集めた文献などについてお話したいと思いますので、よろしくお願いいたします。

2015/10/14 鮫島

Signatures of Value Comparison in Ventral Striatum Neurons

Caleb E. Strait, Brianna J. Sleezer, Benjamin Y. Hayden
PLoS Biol. 2015 Jun; 13(6): e1002173.

明日は、ちょっと古いですけどHaydenのPlos biologyの論文を中心に、 「価値に基づく意思決定がどこでどのようにおきるか？」について、 またそれを検証する方法について考えたいと思います。

 よろしくお願いします。

Abstract
The ventral striatum (VS), like its cortical afferents, is closely associated with processing of rewards, but the relative contributions of striatal and cortical reward systems remains unclear. Most theories posit distinct roles for these structures, despite their similarities. We compared responses of VS neurons to those of ventromedial prefrontal cortex (vmPFC) Area 14 neurons, recorded in a risky choice task. Five major response patterns observed in vmPFC were also observed in VS: (1) offer value encoding, (2) value difference encoding, (3) preferential encoding of chosen relative to unchosen value, (4) a correlation between residual variance in responses and choices, and (5) prominent encoding of outcomes. We did observe some differences as well; in particular, preferential encoding of the chosen option was stronger and started earlier in VS than in vmPFC. Nonetheless, the close match between vmPFC and VS suggests that cortex and its striatal targets make overlapping contributions to economic choice.

じっさいの実験データも公開されています。

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2015/09/30 木村

明日は、「扁桃体システムの機能に関する考察」として、以下の論文を中心に紹介しながら、機能について視点を提案します。

The Framing of Decisions and the Psychology of Choice

Amos Tversky and Daniel Kahneman
SCIENCE, VOL. 211, 30 JANUARY 1981

A Genetically Mediated Bias in Decision Making Driven by Failure of Amygdala Control

Jonathan P. Roiser, Benedetto de Martino, Geoffrey C. Y. Tan, Dharshan Kumaran, Ben Seymour, Nicholas W. Wood, and Raymond J. Dolan
The Journal of Neuroscience, May 6, 2009 • 29(18):5985–5991 • 5985

The Good, the Bad, and the Irrelevant: Neural Mechanisms of Learning Real and Hypothetical Rewards and Effort

Jacqueline Scholl, Nils Kolling, Natalie Nelissen, Marco K. Wittmann, Catherine J. Harmer,
and Matthew F. S. Rushworth
The Journal of Neuroscience, August 12, 2015 • 35(32):11233–11251 • 11233

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2015/07/15 野々村

A Corticostriatal Path Targeting Striosomes Controls Decision-Making under Conflict
Friedman A, Homma D, Gibb LG, Amemori K, Rubin SJ, Hood AS, Riad MH, Graybiel AM.
Cell. 2015 Jun 4;161(6):1320-33. doi: 10.1016/j.cell.2015.04.049. Epub 2015 May 28.

Rat のPLから背内側線条体のマトリックスに投射しているニューロンが，Rewardと Aversive baseの意思決定におけるconflictに特異的に関わっていることを，光遺伝学と電気生理の技術を使用して証明した論文です．

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2015/07/01 榎本

Neuronal prediction of opponent's behavior during cooperative social interchange in primates
Keren Haroush, Ziv M. Williams
Cell. 2015 Mar 12;160(6):1233-45. doi: 10.1016/j.cell.2015.01.045.

Highlights

• Cingulate neurons predict another agent’s unknown decisions during social interaction 
• Other-predictive neurons are sensitive to social context, but not to expected reward 
• Distinct cingulate neurons encode the individual’s own decisions to cooperate or defect 
• Disrupting cingulate activity selectively inhibits mutually beneficial interactions

繰り返し囚人のジレンマゲームをおこなう横に並んだ二頭のアカゲザルの帯状皮質背側部（dACC）の細胞活動は相手の行動を予測する（デコードできる）。自分自身の戦略依存的な応答を示す細胞や報酬の期待値を表現するような細胞とは別の集団らしい。相手がコンピュータだったり、相手のサルが別室にいるばあいは協力戦略が減り、相手の行動予測応答を示す細胞の割合も減る。電気刺激で細胞活動を攪乱すると相手の協力行動に対して協力する割合が減るが、パレート最適なゼロサムゲームでは影響なし。社会的状況が重要ってことらしいけど、でもそのSocial contextっていったい何なんでしょうね。相手の表情を見たりすることはできないようにしてあるとしても、ジュース飲んでるところは見たり聞いたりできるはずなので、視線データでもいいからなにか行動指標がほしいところ。あとヒストロジーとまではいわんけど活動記録した場所の写真いっこでも載せて欲しいです。ていうかなんでCell誌？

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Shared decision-making drives collective movement in wild baboons
Ariana Strandburg-Peshkin, Damien R. Farine, Iain D. Couzin, Margaret C. Crofoot
Science 19 June 2015: Vol. 348 no. 6241 pp. 1358-1361. DOI: 10.1126/science.aaa5099

おまけです。オリーブヒヒの群移動におけるデモクラシー……というか多数決。選択肢が似てるばあいは折衷案を採るところなんかおもしろいです。

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