Biomedical subjects

Natacha Deroost

Publications and source records attributed to Natacha Deroost.

5 recordsLinked to original sources

PubMed2006

Learning sequence movements in a homogenous sample of patients with Parkinson's disease.

We investigated the acquisition of sequence movements in Parkinson's disease (PD) by means of the serial reaction time (SRT) task. To this end, we used a sample of PD patients that fell within the same stage of the disease. Sixteen PD patients and 16 age-, sex- and education-matched control subjects performed the SRT task with a first-order conditional (FOC) sequence and with a second-order conditional (SOC) sequence. The results showed that the group of PD patients could be divided into two distinct subgroups: a fast PD patient subgroup (n=11) and a slow PD patient subgroup (n=5). FOC and SOC sequence learning in faster PD patients proved to be highly comparable to the group of controls. In contrast, learning of FOC and SOC sequences was severely impaired in slower PD patients. Since slow PD patients also scored lower on measures of cognitive functioning than faster PD patients, we assume that the deficits in SRT learning of the former reflect some more general cognitive impairment. This indicates that SRT performance can provide additional information about the cognitive abilities of PD patients, and accordingly may contribute to disease screening.

Aged↗

PubMed2006

Spatial processing and perceptual sequence learning in SRT tasks.

We investigated the influence of processing relevant spatial information on learning a probabilistic sequence of irrelevant locations. Using the SRT design of Remillard (2003), we found that spatial perceptual learning occurs with paired but not with single targets. The pairs of targets consisted of the same stimuli, but in a different order, so that responses could have been based on the left-right location of an element, relative to the other element of the pair. The prerequisite of spatial pairs of targets suggests that spatial processing of relevant information plays a crucial role in perceptual location learning. In addition, spatial perceptual learning only took place when the target pair was presented together with other stimuli, but was absent when the target pair was presented in a blank field. Since in the latter case attention is automatically captured, this suggests that sequence learning requires endogenous attention.

Adult↗

PubMed2006

The role of response selection in sequence learning.

We investigated the role of response selection in sequence learning in the serial reaction time (SRT) task, by manipulating stimulus-response compatibility. Under conditions in which other types of learning, like perceptual, response-based, and response-effect learning, were unaffected, sequence learning was better with an incompatible than with a compatible stimulus-response mapping. Stimulus discriminability, on the other hand, had no influence on the amount of sequence learning. This indicates that the compatibility effects cannot be accounted for by a different level of task difficulty. Relating our results to the dimensional overlap model (Kornblum, Hasbroucq, & Osman, 1990), which assumes that incompatible stimulus-response mappings require more controlled response selection than do compatible stimulus-response mapping, we suggest that sequence learning in the SRT task is particularly effective when response selection occurs in a controlled way.

Adult↗

PubMed2005

Effector-dependent and response location learning of probabilistic sequences in serial reaction time tasks.

We investigated the contributions of the sequences of effectors and response locations to probabilistic sequence learning in the serial reaction time task by means of bimanual transfer. Participants, trained with the dominant hand, were either required to maintain responding with the dominant hand after transfer or to switch to the nondominant hand. For both groups, half of the participants were transferred to the originally trained sequence, whereas the other half was transferred to a mirror-ordered sequence. This way, the sequence of effectors varied independently of the sequence of response locations. Sequence learning was assessed with probabilistic sequences, composed of either first-order or second-order probabilities. Transfer of sequence knowledge to the nondominant hand was equally good for the originally trained sequence as for the mirrored sequence. This suggests that probabilistic sequence learning can be based on either the sequence of effectors or response locations. However, when participants responded with the dominant hand to a mirrored sequence, transfer performance was disturbed. This indicates that changing both the sequences of effectors and response locations has a disruptive effect on the learning performance.

Adult↗

PubMed2004

Perceptual or motor learning in SRT tasks with complex sequence structures.

We investigated under which conditions sequence learning in a serial reaction time task can be based on perceptual learning. A replication of the study of Mayr (1996) confirmed perceptual and motor learning when sequences were learned concurrently. However, between-participants manipulations of the motor and perceptual sequences only supported motor learning in cases of more complex deterministic and probabilistic sequence structures. Perceptual learning using a between-participants design could only be established with a simple deterministic sequence structure. The results seem to imply that perceptual learning can be facilitated by a concurrently learned motor sequence. Possibly, concurrent learning releases necessary attentional resources or induces a structured learning condition under which perceptual learning can take place. Alternatively, the underlying mechanism may rely on binding between the perceptual and motor sequences.

Adult↗