Predictive Mechanisms Are Not Involved the Same Way during Human-Human vs. Human-Machine Interactions: A Review <s> INDIVIDUAL ACTION Predictive Systems for Individual Action Generation <s> Much of the functioning of the motor system occurs without awareness. Nevertheless, we are aware of some aspects of the current state of the system and we can prepare and make movements in the imagination. These mental representations of the actual and possible states of the system are based on two sources: sensory signals from skin and muscles, and the stream of motor commands that have been issued to the system. Damage to the neural substrates of the motor system can lead to abnormalities in the awareness of action as well as defects in the control of action. We provide a framework for understanding how these various abnormalities of awareness can arise. Patients with phantom limbs or with anosognosia experience the illusion that they can move their limbs. We suggest that these representations of movement are based on streams of motor commands rather than sensory signals. Patients with utilization behaviour or with delusions of control can no longer properly link their intentions to their actions. In these cases the impairment lies in the representation of intended movements. The location of the neural damage associated with these disorders suggests that representations of the current and predicted state of the motor system are in parietal cortex, while representations of intended actions are found in prefrontal and premotor cortex. <s> BIB001 </s> Predictive Mechanisms Are Not Involved the Same Way during Human-Human vs. Human-Machine Interactions: A Review <s> INDIVIDUAL ACTION Predictive Systems for Individual Action Generation <s> 237 Opinion In this article we present a framework that can account for several disparate abnormalities in the awareness and control of action. Our framework is based on an established model of normal motor learning and control [1]. In the first section of the article we summarize this model of motor control and speculate on which of its components are available to awareness. In the second section we outline how this model can be used to understand specific signs and symptoms of various <s> BIB002 </s> Predictive Mechanisms Are Not Involved the Same Way during Human-Human vs. Human-Machine Interactions: A Review <s> INDIVIDUAL ACTION Predictive Systems for Individual Action Generation <s> Abstract There is an increasing amount of empirical work investigating the sense of agency, i.e. the registration that we are the initiators of our own actions. Many studies try to relate the sense of agency to an internal feed-forward mechanism, called the “comparator model”. In this paper, we draw a sharp distinction between a non-conceptual level of feeling of agency and a conceptual level of judgement of agency. By analyzing recent empirical studies, we show that the comparator model is not able to explain either. Rather, we argue for a two-step account: a multifactorial weighting process of different agency indicators accounts for the feeling of agency, which is, in a second step, further processed by conceptual modules to form an attribution judgement. This new framework is then applied to disruptions of agency in schizophrenia, for which the comparator model also fails. Two further extensions are discussed: We show that the comparator model can neither be extended to account for the sense of ownership (which also has to be differentiated into a feeling and a judgement of ownership) nor for the sense of agency for thoughts. Our framework, however, is able to provide a unified account for the sense of agency for both actions and thoughts. <s> BIB003
Before one performs a deliberate goal-directed action, many sensorimotor information needs to be processed. Action control models suggest predictive mechanisms come into play during motor planning (see Figure 1 ; BIB001 BIB002 BIB003 . It has been proposed that the sensory consequences of a given action as soon as the motor command has been computed, before the onset of the action . According to the Comparator Model (CM), when an agent wants to achieve a goal, he or she will first represent a desired state . To meet this desired state, the agent has to program a specific motor command using sensory information about its own current state and the current state of the environment (e.g., affordances). The motor command is thus computed by an inverse model or set of paired controllers, which specifies the spatio-temporal dynamic of the appropriate action. To do so, controllers encode the dynamic properties of a given action each time this latter is performed in a specific sensorimotor context so they can then compute a motor command designed to yield the desired state given the current internal and external contexts. Once execution has started and feedback becomes available, the actual system's state is estimated and compared to the desired state, allowing error signals to be used to correct motor commands and to improve the functioning of the controllers (comparison 1, Figure 1 ). Before the motor command triggers the action, a copy of the motor command, called an efference copy, is made and sent to a forward model or a set of predictors that will compute the predicted consequences of the action. Then, this up-coming predicted state is compared to the initial desired state and in case of mismatch, an error signal is produced in advance of any sensory reafference (comparison 2, Figure 1 ). Finally, the estimated actual state can be compared to the predicted state and this comparison allows the set of predictors functioning to be optimized (comparison 3, Figure 1 ) . Such mechanisms are essential to anticipate and adjust our motor performances on-line, especially when the environment is uncertain and fluctuating. Importantly, in addition to their important role in the control of one's actions, there are reasons to think that predictive mechanisms are also involved in the sense of self-agency construction.