2014年8月27日水曜日

Anterior Insula Activity Reflects the Effects of Intentionality on the Anticipation of Aversive Stimulation

Mimi Liljeholm, Simon Dunne, and John P. O'Doherty
The Journal of Neuroscience, 20 August 2014, 34(34):11339-11348


他人から「意図的」に「嫌がらせ」をされた場合に反応する脳部位は前島皮質。「嫌がらせ」は(お金を奪われるとかじゃなくて)「塩水を飲まされる」のがポイント。たぶん。 http://www.jneurosci.org/content/34/34/11339

If someone causes you harm, your affective reaction to that person might be profoundly influenced by your inferences about the intentionality of their actions. In the present study, we aimed to understand how affective responses to a biologically salient aversive outcome administered by others are modulated by the extent to which a given individual is judged to have deliberately or inadvertently delivered the outcome. Using fMRI, we examined how neural responses to anticipation and receipt of an aversive stimulus are modulated by this fundamental social judgment. We found that affective evaluations about an individual whose actions led to either noxious or neutral consequences for the subject did indeed depend on the perceived intentions of that individual. At the neural level, activity in the anterior insula correlated with the interaction between perceived intentionality and anticipated outcome valence, suggesting that this region reflects the influence of mental state attribution on aversive expectations.

2014年8月12日火曜日

The habenula encodes negative motivational value associated with primary punishment in humans

Rebecca P. Lawson, Ben Seymour, Eleanor Loh, Antoine Lutti, Raymond J. Dolan, Peter Dayan, Nikolaus Weiskopf, and Jonathan P. Roiser
PNAS vol. 111 no. 32, 11858–11863

高解像度fMRIでhabenulaを狙いました、という研究。

Learning what to approach, and what to avoid, involves assigning value to environmental cues that predict positive and negative events. Studies in animals indicate that the lateral habenula encodes the previously learned negative motivational value of stimuli. However, involvement of the habenula in dynamic trial-by-trial aversive learning has not been assessed, and the functional role of this structure in humans remains poorly characterized, in part, due to its small size. Using high-resolution functional neuroimaging and computational modeling of reinforcement learning, we demonstrate positive habenula responses to the dynamically changing values of cues signaling painful electric shocks, which predict behavioral suppression of responses to those cues across individuals. By contrast, negative habenula responses to monetary reward cue values predict behavioral invigoration. Our findings show that the habenula plays a key role in an online aversive learning system and in generating associated motivated behavior in humans.