第16回 冬のワークショップ

意思決定のダイナミクス " Dynamics of Decision Making"


ノースウイング コンベンションホール 18番ホール 


意思決定のダイナミクス "Dynamics of Decision Making"
6日 スペシャルセッション
18:10-19:00 William T. Newsome (Stanford University)
19:10-20:00 Bahador Bahrami (University College London)
20:10-21:00 Matthew Rushworth (Oxford University)
21:00-23:00 ポスターセッション
7日 トピックセッション
15:30-16:20 本吉勇 (東京大学大学院総合文化研究科)
16:30-17:20 明和政子 (京都大学大学院教育学研究科)
17:30-18:20 天野薫 (情報通信研究機構 脳情報通信融合研究センター)
20:00-23:00 ポスターセッション
8日 トピックセッション
 9:00-9:50 柳下 祥 (東京大学大学院医学系研究科疾患生命工学センター構造生理学部門)
 10:00-10:50 堀川友慈 (ATR 脳情報研究所)
 11:00-11:50 宮崎勝彦 (沖縄科学技術大学院大学 神経計算ユニット)

Abstracts and References:

William T. Newsome 
Stanford University

Neural population dynamics in prefrontal cortex indicate changes-of-mind on single behavioral trials

The neural mechanisms underlying decision-making are typically examined by statistical analysis of large numbers of trials from sequentially recorded single neurons. Averaging across sequential recordings, however, obscures important aspects of decision-making such as 'changes of mind' (CoM) that occur at variable times on different trials. I will show that the covert decision variables (DV) can be tracked dynamically on single behavioral trials via simultaneous recording of large neural populations in prefrontal cortex. Vacillations of the neural DV, in turn, identify candidate CoM in monkeys, and show that they closely match the known properties of human CoM. Thus simultaneous population recordings can provide insight into transient, internal cognitive states that are otherwise undetectable.

References :
Dynamics of Neural Population Responses in Prefrontal Cortex Indicate Changes of Mind on Single Trials

Bahador Bahrami  
University College London

In the mind of the adviser

Influencing others is not easy. What should one do to minimize the chances that her advice falls on deaf ears? What should the adviser think about? Unsurprisingly, the question is not just interesting for psychologists/neuroscientists. Even better, some general principles have already been drawn out in other fields such as Statistics and Economics. I will explain what our lab has done in the past couple of years to bring these pre-existing ideas into social cognitive sciences.
References :
web site

Matthew Rushworth 
Oxford University

Using information over multiple time frames in anterior cingulate cortex to guide changes in behaviour

Decisions are guided by expectations about the values of future choices and these expectations are, in turn, based on past experience. The anterior cingulate cortex contains information about recent reward history based on information acquired over multiple time scales. Expectations of the value of future choices are calculated simultaneously on the basis of these timescales and used to guide decisions in different ways depending on the nature of the current environment. This has an advantage in that it allows flexible decision making based on estimates of what future decision values might be.

References :
1. Multiple neural mechanisms of decision making and their competition under changing risk pressure.
2. Neural mechanisms of foraging.
3. Contrasting Roles for Orbitofrontal Cortex and Amygdala in Credit Assignment and Learning in Macaques.

Isamu Motoyoshi
東京大学大学院総合文化研究科 Department of Life Sciences, The University of Tokyo

Spatiotemporal continuity of visual perception

Our perception is stable and continuous in time. Despite repeated disruptions of retinal inputs by blinks and eye movements, we rarely notice the discontinuities of a visual scene. Whereas the sensory attributes of a single stimulus are represented at disparate timings in the brain, we steadily perceive an integrated object and its smooth changes and movements. In this talk, I discuss neural computations underlying the temporal continuity of visual perception, by introducing illusions wherein smooth changes and motions are perceived discretely in time.

Masako Myowa-Yamakoshi
Graduate School of Education, Kyoto University

How does sensorimotor experience from the perinatal period affect later cognitive development?

Traditionally,developmental disorders including autism spectrum disorder (ASD) have been regarded as innate, genetic-defined brain dysfunction. However, recent cohort studies from the prenatal period have shown that different extrauterine experiences in the perinatal period would be closely related to later difficulties in cognitive, language, and emotional development.These suggest that sensorimotor experience in perinatal period might directly affect the later stage of emotional and cognitive development. There is a clear continuity in human sensorimotor development from prenatal to postnatal life. We have found that human fetuses have some knowledge of their own bodies; they manifest a sense of knowing that their bodies are entities different from the other entities in the external environment (ref.3). However, few studies have investigated the effects of preterm birth on neural activities at very early developmental stages. In addition, little is known about when or how these possible problems arise in the course of development. In this talk, I will present our recent findings suggesting that preterm infants at term-equivalent age and full-term newborns actually follow different trajectories in neural information processing (ref.2,3). Furthermore, we will discuss the possibility that such early neural alternations in the development might be related to later difficulties with higher social-cognitive development in preterm children.

References :
1. Shinya, Y., Kawai, M., Niwa, F., & Myowa-Yamakoshi, M. (2014) Preterm birth is associated with an increased fundamental frequency of spontaneous crying in human infants at term-equivalent age. Biology Letters, vol. 10, no. 8, doi: 10.1098/rsbl.2014.0350.
2.Naoi, N., Fuchino, Y., Shibata, M., Niwa, F., Kawai, M., Konishi, Y., Okanoya, K., & Myowa-Yamakoshi, M. (2013) Decreased right temporal activation and increased interhemispheric connectivity in response to speech in preterm infants at term-equivalent age. Frontiers in Psychology, 4: 94, doi: 10.3389/fpsyg.2013.00094.
3.Myowa-Yamakoshi, M. & Takeshita, H. (2006) Do human fetuses anticipate self-directed actions? A study by four-dimensional (4D) ultrasonography. Infancy, 10:3, 289-301.

Kaoru Amano
情報通信研究機構 脳情報通信融合研究センター
Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technologies(NICT)

Toward the neural cause of human visual perception

We have been trying to unravel the neural cause of human visual perception and behavior. One of the promising techniques for this purpose is the fMRI decoded neurofeedback (DecNef), which can non-invasively induce neural activities corresponding to specific information (e.g. color and motion). In the first study, subjects implicitly learned to induce the neural activity pattern in V1/V2 corresponding to red color during the presentation of an achromatic vertical grating via DecNef training. After the training, an achromatic vertical grating was perceived to be reddish, indicating the creation of orientation-specific color perception by manipulating V1/V2 activities. In the second part, we present an MEG experiment showing a functional role of alpha oscillation in visual processing. When borders defined by iso-luminant color change and those defined by luminance change are placed in close proximity, the color-defined boundary is perceived to be jittering at around 10 Hz (Amano et al., 2008). We have recently found that the individual alpha frequency during the resting state was highly correlated with the perceived jitter frequency. Perceived jitter frequency was also correlated with a small fluctuation of alpha frequency within individuals. MEG data during the illusory jitter perception showed an enhancement of alpha coherence between dorsal and ventral areas. These results suggest a possibility that an alpha oscillation might work as a clock for the interaction between visual areas, and a spatial delay of iso-luminant boarder is compensated at the alpha rhythm.

Amano, K., Arnold, D., Takeda, T. & Johnston, A. (2008): Alpha band amplification during illusory jitter perception, Journal of Vision 8(10): article 3, 1-8.

柳下 祥 
Sho Yagishita
Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo

Synaptic basis of reinforcement learning

The dopamine signal has been thought to represent the reward prediction error that teaches animal to modify their behavior to adopt unexpected events. Specifically, the phasic release of dopamine reinforces the preceding sensorimotor events while the transient drop in the dopamine causes the opposite effect. In contrast to strong evidences for the role of dopamine in behavioral learning, the cellular and synaptic mechanisms processing the dopamine signals remains elusive. Using optical techniques to manipulate dopamine and glutamate signals, we found that phasic dopamine had a critical time window for the enhancement of spine structural plasticity of D1R-MSNs in the nucleus accumbens. FRET imaging with spine resolution showed that this time window was shaped by rapid regulation of cAMP in thin distal dendrites, where PKA was activated by dopamine only within the time window because of a high phosphodiesterase activity. We now study how D2R-MSNs detect the decrease in the dopamine activity for the plasticity. Collectively, these studies may clarify the synaptic mechanisms underlying reinforcement learning.

A critical time window for dopamine actions on the structural plasticity of dendritic spines

Tomoyasu Horikawa
ATR 脳情報研究所
ATR computational neuroscience laboratory

Brain decoding of visual dream contents

Dreaming is a subjective experience during sleep, often accompanied by visual contents, whose neural basis remains unknown. Previous dream research attempted to link physiological states with dreaming, but did not demonstrate how the specific contents of visual experiences during dreaming are represented in the brain activity patterns. Brain decoding through neuroimaging analysis of functional magnetic resonance imaging (fMRI) signals has enabled the interpretation of mental contents represented in the brain activity patterns. The technique can thus be used to examine the neural representation of dreams by testing whether neural decoders can predict dream contents from brain activity patterns. In my talk, I introduce our study demonstrating decoding of visual dream contents from fMRI activity patterns during sleep. Our analysis showed that decoding models trained on stimulus-induced brain activity in visual cortical areas showed accurate classification, detection, and identification of dream contents, suggesting shared neural representations between perception and dreaming. Furthermore, additional analyses with imagery-task-induced brain activity reveal that dreaming shares neural representations with both perception and imagery in multiple brain areas with greater similarity to perception and imagery in lower and higher areas, respectively. Thus, our findings uncover unique properties of the neural representations of dreaming, characterizing the brain state of dreaming as a mixture of perception-like and imagery-like brain states. For further exploration into neural representations of our mental world, I would like to introduce several advanced techniques, which enable us to decode richer information on our mental contents.

Katsuhiko Miyazaki
沖縄科学技術大学院大学 神経計算ユニット
Neural Computation Unit, Okinawa Institute of Science and Technology

The role of serotonin in the regulation of waiting behavior for future rewards

Serotonin is a neuromodulator that is extensively involved in behavioral, affective, and cognitive functions of the brain. A large number of studies have shown that reduced levels of serotonin in the central nervous system promote impulsive behaviors. In my talk, I will introduce our recent studies that showed a causal relationship between serotonin neural activation and the promotion of patience to wait for future rewards. First, the activity of the serotonin neurons in the dorsal raphe nucleus (DRN) increases when rats perform tasks that require them to wait for delayed rewards. Second, Local pharmacological inhibition of the DRN serotonin neural activity impairs the rats’ patience for waiting for delayed rewards. Third, Optogenetic activation of serotonin neurons in the DRN enhances the patience of mice in waiting for both the conditioned reinforcer tone and food reward. Finally, serotonin’s effect on promoting patience depends on a high probability, but not expected value, of future reward.

References :
1. Miyazaki KW, Miyazaki K, Tanaka KF, Yamanaka A, Takahashi A, Tabuchi S, Doya K (2014) Optogenetic activation of dorsal raphe serotonin neurons enhances patience for future rewards. Current Biology 24:2033-2040.
2. Miyazaki KW, Miyazaki K, Doya K (2012) Activation of dorsal raphe serotonin neurons is necessary for waiting for delayed rewards. Journal of Neuroscience 32:10451-10457.
3. Miyazaki K, Miyazaki KW, Doya K (2011) Activation of dorsal raphe serotonin neurons underlies waiting for delayed rewards. Journal of Neuroscience 31:469-479.

©2012 Mechanism of Brain and Mind