Associations and Dissociations between Oculomotor Readiness and Covert Attention

The idea that covert mental processes such as spatial attention are fundamentally dependent on systems that control overt movements of the eyes has had a profound influence on theoretical models of spatial attention. However, theories such as Klein’s Oculomotor Readiness Hypothesis (OMRH) and Rizzolatti’s Premotor Theory have not gone unchallenged. We previously argued that although OMRH/Premotor theory is inadequate to explain pre-saccadic attention and endogenous covert orienting, it may still be tenable as a theory of exogenous covert orienting. In this article we briefly reiterate the key lines of argument for and against OMRH/Premotor theory, then evaluate the Oculomotor Readiness account of Exogenous Orienting (OREO) with respect to more recent empirical data. These studies broadly confirm the importance of oculomotor preparation for covert, exogenous attention. We explain this relationship in terms of reciprocal links between parietal ‘priority maps’ and the midbrain oculomotor centres that translate priority-related activation into potential saccade endpoints. We conclude that the OMRH/Premotor theory hypothesis is false for covert, endogenous orienting but remains tenable as an explanation for covert, exogenous orienting.

Is the premotor theory of attention essentially about pre-reflective intentionality?

The Premotor Theory of Attention (PToA) is a prominent, albeit controversial, modern experimental account of attentional processes. According to the PToA, motor preparation is both necessary and sufficient for spatial attention. Explaining the cognitive process of attention in terms of sensori-motor machinery can be considered as embedded in the idea of embodied cognition. The vocabulary adopted by the PToA seems to bear a particular resemblance to Merleau-Ponty’s phenomenological notion of pre-reflective intentionality. He articulates it by means of directness towards the lived world, which is constituted in the spatial motility of the body-subject. In this epistemological state of affairs, we come up with two leading questions: (a) can the main tenets of PToA be essentially reconstructed in terms of the notion of pre-reflective intentionality and since the bodily motility is meant by the French phenomenologist to be at the root of all forms of intentionality, (b) can the PToA be expanded to account for all kinds of attention? In conclusion, we advocate a positive answer for the former question and point to serious doubts as to why it can rather not be retained regarding the latter.

Paying Attention through Eye Movements: A Computational Investigation of the Premotor Theory of Spatial Attention

Growing evidence indicates that planning eye movements and orienting visuospatial attention share overlapping brain mechanisms. A tight link between endogenous attention and eye movements is maintained by the premotor theory, in contrast to other accounts that postulate the existence of specific attention mechanisms that modulate the activity of information processing systems. The strong assumption of equivalence between attention and eye movements, however, is challenged by demonstrations that human observers are able to keep attention on a specific location while moving the eyes elsewhere. Here we investigate whether a recurrent model of saccadic planning can account for attentional effects without requiring additional or specific mechanisms separate from the circuits that perform sensorimotor transformations for eye movements. The model builds on the basis function approach and includes a circuit that performs spatial remapping using an “internal forward model” of how visual inputs are modified as a result of saccadic movements. Simulations show that the latter circuit is crucial to account for dissociations between attention and eye movements that may be invoked to disprove the premotor theory. The model provides new insights into how spatial remapping may be implemented in parietal cortex and offers a computational framework for recent proposals that link visual stability with remapping of attention pointers.