Neural dynamics of two players when using nonverbal cues to gauge intentions to cooperate during the Prisoner's Dilemma Game

Jahng, Jaehwan,Kralik, Jerald D.,Hwang, Dong-Uk,Jeong, Jaeseung ACADEMIC PRESS 2017 NEUROIMAGE Vol.157 No.-

<P><B>Abstract</B></P> <P>Social interaction is a fundamental part of our daily lives; however, exactly how our brains use social cues to determine whether to cooperate without being exploited remains unclear. In this study, we used an electroencephalography (EEG) hyperscanning approach to investigate the effect of face-to-face contact on the brain mechanisms underlying the decision to cooperate or defect in an iterated version of the Prisoner's Dilemma Game. Participants played the game either in face-to-face or face-blocked conditions. The face-to-face interaction led players to cooperate more often, providing behavioral evidence for the use of these nonverbal cues in their social decision-making. In addition, the EEG hyperscanning identified temporal dynamics and inter-brain synchronization across the cortex, providing evidence for involvement of these regions in the processing of face-to-face cues to read each other's intent to cooperate. Most notably, the power of the alpha frequency band (8–13Hz) in the right temporoparietal region immediately after seeing a round outcome significantly differed between face-to-face and face-blocked conditions and predicted whether an individual would adopt a ‘cooperation’ or ‘defection’ strategy. Moreover, inter-brain synchronies within this time and frequency range reflected the use of these strategies. This study provides evidence for how the cortex uses nonverbal social cues to determine other's intentions, and highlights the significance of power in the alpha band and inter-brain phase synchronizations in high-level socio-cognitive processing.</P>

Bursts and Heavy Tails in Temporal and Sequential Dynamics of Foraging Decisions

Jung, Kanghoon,Jang, Hyeran,Kralik, Jerald D.,Jeong, Jaeseung Public Library of Science 2014 PLoS computational biology Vol.10 No.8

<▼1><P>A fundamental understanding of behavior requires predicting <I>when</I> and <I>what</I> an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. In the current study, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding <I>when</I> choices were made, we found bursts of rapidly occurring actions, separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding <I>what</I> was chosen, we found sequential dynamics in affective choices characterized by two key features: (a) a highly biased choice distribution; and (b) preferential attachment, in which the animals were more likely to choose what they had previously chosen. To capture the temporal dynamics, we propose a dual-state model consisting of active and inactive states. We also introduce a satiation-attainment process for bursty activity, and a non-homogeneous Poisson process for longer inactivity between bursts. For the sequential dynamics, we propose a dual-control model consisting of goal-directed and habit systems, based on outcome valuation and choice history, respectively. This study provides insights into how the bursty nature of behavior emerges from the interaction of different underlying systems, leading to heavy tails in the distribution of behavior over time and choices.</P></▼1><▼2><P><B>Author Summary</B></P><P>To understand spontaneous animal behavior, two key elements must be explained: <I>when</I> an action is made and <I>what</I> is chosen. Here, we conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. With respect to <I>when</I>, we found bursts of rapidly occurring responses separated by long inactive periods. With respect to <I>what</I>, we found biased choice behavior toward the favorite items as well as repetitive behavior, reflecting goal-directed and habitual responding, respectively. We account for the <I>when</I> and <I>what</I> components with two distinct computational mechanisms, each composed of two processes: (a) active and inactive states for the temporal dynamics, and (b) goal-directed and habitual control for the sequential dynamics. This study provides behavioral and computational insights into the dynamical properties of decision-making that determine both when an animal will act and what the animal will choose. Our findings provide an integrated framework for describing the temporal and sequential structure of everyday choices among, for example, food, music, books, brands, web-browsing and social interaction.</P></▼2>

Vulnerability-Based Critical Neurons, Synapses, and Pathways in the <i>Caenorhabditis elegans</i> Connectome

Kim, Seongkyun,Kim, Hyoungkyu,Kralik, Jerald D.,Jeong, Jaeseung Public Library of Science 2016 PLoS computational biology Vol.12 No.8

<▼1><P>Determining the fundamental architectural design of complex nervous systems will lead to significant medical and technological advances. Yet it remains unclear how nervous systems evolved highly efficient networks with near optimal sharing of pathways that yet produce multiple distinct behaviors to reach the organism’s goals. To determine this, the nematode roundworm <I>Caenorhabditis elegans</I> is an attractive model system. Progress has been made in delineating the behavioral circuits of the <I>C</I>. <I>elegans</I>, however, many details are unclear, including the specific functions of every neuron and synapse, as well as the extent the behavioral circuits are separate and parallel versus integrative and serial. Network analysis provides a normative approach to help specify the network design. We investigated the vulnerability of the <I>Caenorhabditis elegans</I> connectome by performing computational experiments that (a) “attacked” 279 individual neurons and 2,990 weighted synaptic connections (composed of 6,393 chemical synapses and 890 electrical junctions) and (b) quantified the effects of each removal on global network properties that influence information processing. The analysis identified 12 critical neurons and 29 critical synapses for establishing fundamental network properties. These critical constituents were found to be control elements—i.e., those with the most influence over multiple underlying pathways. Additionally, the critical synapses formed into circuit-level pathways. These emergent pathways provide evidence for (a) the importance of backward locomotion, avoidance behavior, and social feeding behavior to the organism; (b) the potential roles of specific neurons whose functions have been unclear; and (c) both parallel and serial design elements in the connectome—i.e., specific evidence for a mixed architectural design.</P></▼1><▼2><P><B>Author Summary</B></P><P>One of the most important scientific aims is to uncover the functional design principles of nervous systems. To reach this aim, it is useful to examine a complex nervous system that is both well specified and highly tractable, making the nematode roundworm <I>Caenorhabditis elegans</I> an attractive model system, especially since it is the only complete connectome currently available for analysis. In this computational study, we tested the effects of individual attacks on every neuron and synaptic connection in the <I>C</I>. <I>elegans</I> connectome to identify and characterize the most critical constituents of the network by quantifying the changes in key network properties of the connectome that influence information processing. Our analysis identified 12 neurons and 29 synapses critical to clustering, information integration and propagation. These critical constituents formed circuit-level structures that control network processing in the <I>C</I>. <I>elegans</I> connectome. We believe our study provides a significant advance in the understanding of the network topology of the <I>C</I>. <I>elegans</I> connectome, and provides insights into the fundamental architectural design of complex nervous systems.</P></▼2>

Tools to Prioritize Construction Phase Sustainability Actions (CPSAs) and to Measure CPSAs Implementation

O'Connor, James T.,Torres, Neftali,Kralik, Nancy,Woo, Jeyoung Korea Institute of Construction Engineering and Ma 2018 Journal of construction engineering and project ma Vol.8 No.1

Achieving sustainability targets on construction projects has increasingly become one of the prime strategies for construction organizations. To provide more detailed guidance on sustainability implementation on projects, Construction Industry Institute (CII) Research Team (RT) 304 developed a catalog of the Construction Phase Sustainability Actions (CPSAs). The primary objective of this paper was the development of two support tools, the CPSA Screening Tool and the CPSA Implementation Index, that could be used to enable efficient application of CPSAs, support sustainability-related decisions, and measure CPSA implementation and performance. The authors developed the tools in four stages: conceptual, detailed planning, tool programming, and testing. The tools were then demonstrated on a capital project to confirm their efficacy and applicability. This paper presents the background, inputs and outputs, and the algorithms of each tool. The CPSA Screening Tool can prioritize the CPSAs most relevant to a project; the CPSA Implementation Index enables continuous monitoring of implementation levels.

Nucleus accumbens shell moderates preference bias during voluntary choice behavior

Jang, Hyeran,Jung, Kanghoon,Jeong, Jaehoon,Park, Sang Ki,Kralik, Jerald D.,Jeong, Jaeseung Oxford University Press 2017 Social cognitive and affective neuroscience Vol.12 No.9

<P><B>Abstract</B></P><P>The nucleus accumbens (NAc) shell lies anatomically at a critical intersection within the brain’s reward system circuitry, however, its role in voluntary choice behavior remains unclear. Rats with electrolytic lesions in the NAc shell were tested in a novel foraging paradigm. Over a continuous two-week period they freely chose among four nutritionally identical but differently flavored food pellets by pressing corresponding levers. We examined the lesion’s effects on three behavioral dynamics components: motivation (when to eat), preference bias (what to choose) and persistence (how long to repeat the same choice). The lesion led to a marked increase in the preference bias: i.e., increased selection of the most-preferred choice option, and decreased selection of the others. We found no effects on any other behavioral measures, suggesting no effect on motivation or choice persistence. The results implicate the NAc shell in moderating the instrumental valuation process by inhibiting excessive bias toward preferred choice options.</P>

The absolute measurment of the neutron emission rate with Manganese Sulphate Bath system

Hyeonseo Park,Jong-Man Lee,Kil-Oung Choi,Kyung-Beom Lee,Miloslav Kralik,Myung Sup Hahn 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.4

Recently, an absolute measurements of the neutron emission rates of neutron sources were carried out for 241Am . Be and 252Cf over a wide range of emission rates (2 × 105 2 × 108 s.1). The measurements were done using a Manganese Sulphate Bath method, which is the principal method for the absolute determination of the neutron emission rates of radionuclide neutron sources. The efficiency of the system was determined by means of a 56Mn radioactive source of well-defined activity. Various corrections, including epithermal neutron capture, the (n, p) and the (n, ) reactions, the leakage of neutrons, etc., were replaced by a direct calculation of the neutron capture probability for manganese nuclei. The neutron capture probability of the manganese nuclei was determined by using a careful MCNP (Monte Carlo N-Particle Transport Code System) calculation and was 0.102 0.105 for the present status of the KRISS (Korea Research Institute of Standards and Science) Manganese Sulphate Bath system. The emission rates were determined with an uncertainty of < 0.8 % (k = 1)