Gaze orientation and learning (PhD, 2014-2017)
- PhD supervisors
- Laurent Perrinet and Anna Montagnini,
- STATE OF THE ART AND OBJECTIVES
In the continuous flow of sensory evidence, cognitive systems must provide rapid behavioral choices across different time scales. For instance, seeing a moving object may result in various responses such as catching or avoiding collision depending on the trajectory and the nature of the object, but also depending on the recent experience and the expectations associated with that object and its motion properties. The principal goal of the larger scientific project in which this PhD thesis is inscribed (see ANR-REM project) is the analysis of reinforcement learning processes in the domain of voluntary eye movements (saccades and smooth pursuit eye movements) in humans. Within this PhD project we will use a dual approach, based on behavioural experiments on human subjects and on computational modelling of the experimental data, in order to address this important question, with a particular emphasis on the time course of learning effects and on the hypothesised role of probabilistic inference as underlying mechanism.
Visually driven eye movements provide an ideal experimental preparation to probe sensorimotor behavior across different time-scales, processing levels (from sensory encoding to the final categorical choice) and movement repertoire (e.g. smooth pursuit and saccades). In addition, a remarkable flexibility of oculomotor behaviors has been highlighted by manipulating the expectancy for sensory features or the outcome associated to particular motor responses.
List of publications
- Jean-Bernard Damasse, Laurent Perrinet, Jeremie Jozefowiez, Laurent Madelain, Anna Montagnini. Operant reinforcement versus reward expectancy: effects on anticipatory eye movements, URL URL2 . In Proceedings of VSS, pages 1356. The Association for Research in Vision and Ophthalmology, 2016 abstract
- Jean-Bernard Damasse, Anna Montagnini, Laurent U. Perrinet. Modeling the effect of dynamic contingencies on anticipatory eye movements, URL . In Proceedings of ECVP, pages 2P044. 2016 abstract
- Jean-Bernard Damasse, Laurent Madelain, Laurent Perrinet, Anna Montagnini. Anticipatory smooth eye movements and reinforcement, URL . In Proceedings of VSS, The Association for Research in Vision and Ophthalmology, 2015 abstractWhen an object is moving in the visual field, we are able to accurately track it with a combination of saccades and smooth eye movements. These movements allow us to align and stabilize the object on the fovea, thus enabling visual analysis with high acuity. Importantly, when predictive information is available about the target motion, anticipatory smooth pursuit eye movements (aSPEM) are efficiently generated before target appearance, which reduce the typical sensorimotor delay between target motion onset and foveation. By manipulating the probability for target motion direction we were able to bias the direction and mean velocity of aSPEM (baseline condition). This suggests that probabilistic information may be used to inform the internal representation of motion prediction for the initiation of anticipatory movements. To further understand the nature of this process, we investigate the effects of reinforcement on aSPEM with two distinct experiments. First, it has been previously shown that several properties of eye movements can be modulated by reinforcement paradigms based on monetary reward (Madelain et al. 2011). We adapted and extended this framework to prediction-based aSPEM, by associating a monetary reward to a criterion-matching anticipatory velocity, in the gap before the target onset. Second, it has also been reported that accurate perception per se can play the role of an efficient ecological reinforcer for visually guided saccades (Montagnini & Chelazzi, 2005). With a gaze-contingent procedure, we manipulated the discriminability of a perceptual target (appearing during the pursuit trial and followed by a discrimination task) The difficulty level of this task has been matched depending on the velocity of aSPEM. This experiment taps on the very reason to produce anticipatory tracking movement, that is to grant a quicker high-acuity vision of the moving target. We compare predictive anticipatory eye movements across these conditions..