Research in both humans and monkeys has shown that even simple hand movements require cortical control beyond primary sensorimotor areas. An extensive functional neuroimaging literature demonstrates the key role that cortical fronto-parietal regions play for movements such as reaching and reach-to-grasp. However, no study so far has examined the specific white matter connections linking the fronto-parietal regions, namely the 3 parallel pathways of the superior longitudinal fasciculus (SLF). The aim of the current study was to explore how selective fronto-parietal connections are for different kinds of hand movement in 30 right-handed subjects by correlating diffusion imaging tractography and kinematic data. We showed that a common network, consisting of bilateral SLF II and SLF III, was involved in both reaching and reach-to-grasp movements. Larger SLF II and SLF III in the right hemisphere were associated with faster speed of visuomotor processing, while the left SLF II and SLF III played a role in the initial movement trajectory control. Furthermore, the right SLF II was involved in the closing grip phase necessary for efficient grasping of the object. We demonstrated for the first time that individual differences in asymmetry and structure of the fronto-parietal networks were associated with visuomotor processing in humans.

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Societies rely on trustworthy communication in order to function, and the need for trust clearly extends to human-machine communication. Therefore, it is essential to design machines to elicit trust, so as to make interactions with them acceptable and successful. However, while there is a substantial literature on first impressions of trustworthiness based on various characteristics, including voice, not much is known about the trust development process. Are first impressions maintained over time? Or are they influenced by the experience of an agent's behaviour? We addressed these questions in three experiments using the "iterated investment game", a methodology derived from game theory that allows implicit measures of trust to be collected over time. Participants played the game with various agents having different voices: in the first experiment, participants played with a computer agent that had either a Standard Southern British English accent or a Liverpool accent; in the second experiment, they played with a computer agent that had either an SSBE or a Birmingham accent; in the third experiment, they played with a robot that had either a natural or a synthetic voice. All these agents behaved either trustworthily or untrustworthily. In all three experiments, participants trusted the agent with one voice more when it was trustworthy, and the agent with the other voice more when it was untrustworthy. This suggests that participants might change their trusting behaviour based on the congruency of the agent's behaviour with the participant's first impression. Implications for human-machine interaction design are discussed.