The functional role of conscious sensation of movement.

This paper proposes a new framework for investigating neural signals sufficient for a conscious sensation of movement and their role in motor control. We focus on signals sufficient for proprioceptive awareness, particularly from muscle spindle activation and from primary motor cortex (M1). Our review of muscle vibration studies reveals that afferent signals alone can induce conscious sensations of movement. Similarly, studies employing peripheral nerve blocks suggest that efferent signals from M1 are sufficient for sensations of movement. On this basis, we show that competing theories of motor control assign different roles to sensation of movement. According to motor command theories, sensation of movement corresponds to an estimation of the current state based on afferent signals, efferent signals, and predictions. In contrast, within active inference architectures, sensations correspond to proprioceptive predictions driven by efferent signals from M1. The focus on sensation of movement provides a way to critically compare and evaluate the two theories. Our analysis offers new insights into the functional roles of movement sensations in motor control and consciousness.

Testing biased competition between attention shifts: The new multiple cue paradigm.

While the classic Posner cuing paradigm has been used to study cuing of a single endogenous shift of attention, we present a new multiple cue paradigm to study the competition between multiple endogenous shifts of attention. The new paradigm enables us to manipulate the number of competing attention shifts and their relative importance. In three experiments, we demonstrate that the process of selecting one among other relevant attention shifts is governed by limited capacity and biased competition. We show that the probability of performing the most optimal attention shift is influenced by the total number of attention shifts competing for execution and that reward is a determining factor for the selection between attention shifts. We explain our results with a recent mathematical model of biased selection of response sets (the model of intention selection [MIS]). Our new paradigm offers a critical test of MIS and is an important new tool for investigating the mechanisms underlying the retrieval of response sets from long-term memory (LTM). The model (MIS) and the new multiple cue paradigm can provide a new perspective on LTM representations of response sets for instrumental action and on habitual and goal-directed processing in action control. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A new cognitive model of long-term memory for intentions.

In this paper, we propose a new mathematical model of retrieval of intentions from long-term memory. We model retrieval as a stochastic race between a plurality of potentially relevant intentions stored in long-term memory. Psychological theories are dominated by two opposing conceptions of the role of memory in temporally extended agency - as when a person has to remember to make a phone call in the afternoon because, in the morning, she promised she would do so. According to the Working Memory conception, remembering to make the phone call is explained in terms of the construction and maintenance of intentions in working-memory. According to the Long-Term Memory conception, we should explain the episode in terms of an ability to store intentions in long-term memory. The two conceptions predict different processing profiles. The aim of this paper is to present a new mathematical model of the type of memory mechanism that could realise the long-term memory representations of intentions necessary for the Long-Term Memory conception. We present and illustrate the formal model and propose a new type of experimental paradigm that could allow us to test which of the two conceptions provides the best explanation of the role of memory in temporally extended agency.

Measures of agency.

The sense of agency is typically defined as the experience of controlling one's own actions, and through them, changes in the external environment. It is often assumed that this experience is a single, unified construct that can be experimentally manipulated and measured in a variety of ways. In this article, we challenge this assumption. We argue that we should acknowledge four possible agency-related psychological constructs. Having a clear grasp of the possible constructs is important since experimental procedures are only able to target some but not all the possible constructs. The unacknowledged misalignment of the possible constructs of a sense of agency and the experimental procedures is a major theoretical and methodological obstacle to studying the sense of agency. Only if we recognize the nature of this obstacle will we be able to design the experimental paradigms that would enable us to study the responsible computational mechanisms.

Sense of agency for movements.

In this paper, we argue that the comparator model is not a satisfactory model of sense of agency (SoA). We present a theoretical argument and experimental studies. We show (1) most studies of SoA neglect a distinction between SoA associated with movements (narrow SoA) and SoA associated with environmental events (broad SoA); (2) the comparator model emerges from experimental studies of sensory consequences narrowly associated with movements; (3) narrow SoA can be explained by a comparator model, but a motor signal model is simpler and explain narrow SoA equally well; and (4) standard experimental paradigms study only broad SoA. Finally, we present results from two experiments, where we have failed to induce illusory narrow SoA in healthy participants. We believe our experimental approaches should have led to illusory SoA, if the comparator model of SoA was correct. The results challenge proponents of the comparator model of narrow SoA.

A common representation of spatial features drives action and perception: grasping and judging object features within trials.

Spatial features of an object can be specified using two different response types: either by use of symbols or motorically by directly acting upon the object. Is this response dichotomy reflected in a dual representation of the visual world: one for perception and one for action? Previously, symbolic and motoric responses, specifying location, has been shown to rely on a common representation. What about more elaborate features such as length and orientation? Here we show that when motoric and symbolic responses are made within the same trial, the probability of making the same symbolic and motoric response is well above chance for both length and orientation. This suggests that motoric and symbolic responses to length and orientation are driven by a common representation. We also show that, for both response types, the spatial features of an object are processed independently. This finding of matching object-processing characteristics is also in agreement with the idea of a common representation driving both response types.

Consciousness and modality: on the possible preserved visual consciousness in blindsight subjects.

In a recent paper, Brogaard (2011) presents counter-arguments to the conclusions of an experiment with blindsight subject GR. She argues that contrary to the apparent findings that GR's preserved visual abilities relate to degraded visual experiences, she is in fact fully unconscious of the stimuli she correctly identifies. In this paper, we present arguments and evidence why Brogaard's argument does not succeed in its purpose. We suggest that not only is relevant empirical evidence in opposition to Brogaard's argument, her argument misconstrues necessary criteria to decide whether a conscious experience is visual or not visual.