References of "Lejeune, Helga"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailAbout Skinner and time: behavior-analytic contributions to research on animal timing
Lejeune, Helga ULg; Richelle, Marc ULg; Wearden, J. H.

in Journal of the Experimental Analysis of Behavior (2006), 85(1), 125-142

The article discusses two important influences of B. F. Skinner, and later workers in the behavior-analytic tradition, on the study of animal timing. The first influence is methodological, and is traced ... [more ▼]

The article discusses two important influences of B. F. Skinner, and later workers in the behavior-analytic tradition, on the study of animal timing. The first influence is methodological, and is traced from the invention of schedules imposing temporal constraints or periodicities on animals in The Behavior of Organisms, through the rate differentiation procedures of Schedules of Reinforcement, to modern temporal psychophysics in animals. The second influence has been the development of accounts of animal timing that have tried to avoid reference to internal processes of a cognitive sort, in particular internal clock mechanisms. Skinner's early discussion of temporal control is first reviewed, and then three recent theories-Killeen & Fetterman's (1988) Behavioral Theory of Timing; Machado's (1997) Learning to Time; and Dragoi, Staddon, Palmer, [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailActivation of the supplementary motor area and of attentional networks during temporal processing
Macar, F.; Lejeune, Helga ULg; Kirsch, Murielle ULg et al

in Experimental Brain Research (2002), 142(4), 475-485

This paper first provides a survey of the expanding brain imaging literature in the field of time processing. showing that particular task features (discrete vs rhythmic, perceptual vs motor) do not ... [more ▼]

This paper first provides a survey of the expanding brain imaging literature in the field of time processing. showing that particular task features (discrete vs rhythmic, perceptual vs motor) do not significantly affect the basic pattern of activation observed. Next, positron emission tomography (PET) data obtained in a timing task (temporal reproduction) with two distinct duration ranges (2.2-3.2 and 9-13 s) are reported. The stimuli consisted of vibrations applied to the subject's right middle finger. When the vibration ended, the subject estimated an interval identical to its length before pressing a response button. The control task used cued responses with comparable intervals and stimuli, The pattern of activation obtained in the timing task as compared to control mainly included areas having attentional functions (the right dorsolateral prefrontal, inferior parietal, and anterior cingulate cortices), and the supplementary motor area (SMA). No significant difference was seen as a function of the duration range. It is argued, firstly. that involvement of the attentional areas derives from specific relations between attention and the temporal accumulator, as described by dominant timing models. and, secondly, that the SMA, or more probably one of its subregions, subserves time processing [less ▲]

Detailed reference viewed: 29 (1 ULg)
Peer Reviewed
See detailTemporal differentiation in two strains of small rodents: a wood mouse (Apodemus sylvaticus) and an albino mouse (Mus musculus OF1)
Lejeune, Helga ULg; Huynen, Marie-Claude ULg; Ferrara, André ULg

in Behavioural Processes (2000), 52(2-3), 155-169

Wood mice (Apodemus sylvaticus) and OF1 albino mice (Mus musculus) were compared over durations ranging from 0.5 to 7 s, using the differential reinforcement of response duration schedule (DRRD) and a ... [more ▼]

Wood mice (Apodemus sylvaticus) and OF1 albino mice (Mus musculus) were compared over durations ranging from 0.5 to 7 s, using the differential reinforcement of response duration schedule (DRRD) and a 'platform' response, i.e. staying on a small platform for a specified criterion duration to be reinforced. Species-related differences were found for mean response durations, efficiency and the number of trials needed to reach a preset performance criterion. Coefficients of variation of response durations did not differ. Overall, OF1 mice needed more trials than wood mice to reach a temporal criterion. However, over 3-7 s, data from both strains almost fitted the behavioral assumptions of Scalar Timing theory. Performance of mongolian gerbils (Meriones unguiculatus) trained in a similar setting was shown for visual comparison. [less ▲]

Detailed reference viewed: 36 (8 ULg)
See detailEl análisis de las conductas temporales
Richelle, Marc ULg; Lejeune, Helga ULg

in Ardila, Rubén (Ed.) Manual de análisis experimental del comportamiento (1998)

Detailed reference viewed: 15 (0 ULg)
Full Text
See detailAre we close to decyphering the timer's enigma ?
Richelle, Marc ULg; Lejeune, Helga ULg

in Current Psychology of Cognition [=CPC] = Cahiers de Psychologie Cognitive [=CPC] (1998), 17(4-5), 867-879

Among the theoretical models, Gibbon and Chruch's temporal information processing model is by far the most popular explanatory device in the domain of animal timing, and timing recorded using the peak ... [more ▼]

Among the theoretical models, Gibbon and Chruch's temporal information processing model is by far the most popular explanatory device in the domain of animal timing, and timing recorded using the peak procedure is considered to reflect pure cognitive time. Neuropharmacological breakthroughs suggest that diferent neurotransmitter systems subserve different functions or stages, as specified by the temporal information proccessing model. Cerebral activations correlated to timing performance have been described in humans. however, several questions remain unanswered, particularly those regarding the specificity of the neutral and biochemical correlates of timing performance. At the behavioral level, the dynamic aspects of timing, as well as timing patterns which cannot be explained within the framework of existing models, deserve a renewal of interest. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailThe basic pattern of activation in motor and sensory temporal tasks: positron emission tomography data
Lejeune, Helga ULg; Maquet, Pierre ULg; Bonnet, Michel et al

in Neuroscience Letters (1997), 235(1-2), 21-24

Positron emission tomography (PET) data were obtained from subjects performing a synchronization task (target duration 2700 ms). A conjunction analysis was run to identify areas prominently activated both ... [more ▼]

Positron emission tomography (PET) data were obtained from subjects performing a synchronization task (target duration 2700 ms). A conjunction analysis was run to identify areas prominently activated both in this task and in a temporal generalization task (target duration 700 ms) used previously. The common pattern of activation included the right prefrontal, inferior parietal and anterior cingulate cortex, the left putamen and the left cerebellar hemisphere. These areas are assumed to play a major role in time processing, in relation to attention and memory mechanisms. [less ▲]

Detailed reference viewed: 7 (1 ULg)
Peer Reviewed
See detailChanging sensitivity to duration in human scalar timing: An experiment, a review, and some possible explanations
Ferrara, André ULg; Lejeune, Helga ULg; Wearden, J. H.

in Quarterly Journal of Experimental Psychology. B, Comparative & Physiological Psychology (1997), 50B

Detailed reference viewed: 20 (4 ULg)
Peer Reviewed
See detailTransprocedural invariance of the neural networks involved in the estimation of duration : contribution of PET studies (poster abstract)
Lejeune, Helga ULg; Maquet, Pierre ULg; Kirsch, Murielle ULg et al

in Besson, M. (Ed.) Neural substrates of cognitive functions : conference in homage to Jean Requin (1938-1996), Marseille, May 15-16, 1997 (1997)

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailBrain activation induced by estimation of duration : A PET study
Maquet, Pierre ULg; Lejeune, Helga ULg; Pouthas, V. et al

in Neuroimage (1996), 3(2), 119-126

Duration information about a visual stimulus requires processing as do other visual features such as size or intensity. Using positron emission tomography, iterative (H2O)-O-15 infusions, and statistical ... [more ▼]

Duration information about a visual stimulus requires processing as do other visual features such as size or intensity. Using positron emission tomography, iterative (H2O)-O-15 infusions, and statistical parametric mapping, we investigated the neural correlates of time processing. Nine normal subjects underwent six serial rCBF. Three tasks were studied: (a) Atemporal generalization task (D task) in which the subjects had to judge (by pressing one of two keys) whether the duration of the illumination of a green LED was equal to or different from that of a previously presented standard; (b) An intensity generalization task. (I task) in which the judgment concerned the intensity of the LED; and (c) A control task (C task) in which the subjects had to press one of the two keys at random in response to LED illumination. A significant increase in rCBF during the D task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, anterior cingulate cortex, vermis, and a region corresponding to the left fusiform gyrus. A significant increase in rCBF during the I task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, right extrastriate cortex, anterior cingulate cortex, left inferior parietal lobule, vermis, and two symmetrical regions corresponding to the fusiform gyri. No significant activation was observed in the D task when compared to that in the I task. We propose that these cortical maps are best explained by the recruitment of visual attention and memory structures, which play a major role in prospective time judgements as indicated by behavioral studies. The data also suggest that the temporal dimension of a visual stimulus is processed in attributes. the same areas as other visual attributes. [less ▲]

Detailed reference viewed: 33 (4 ULg)
Full Text
See detailAmineptine, response timing and time discrimination in the albino rat
Lejeune, Helga ULg; Hermans, Isabelle ULg; Mocaer, E. et al

in Pharmacology, Biochemistry and Behavior (1995), 51(2-3, Jun-Jul), 165-173

Experiment 1 recorded the effects of single (doses of 1, 5, 10, and 20 mg/kg) and repeated intraperitoneal injections (10 mg/kg) of amineptine (a tricyclic antidepressant drug) on the performance of ... [more ▼]

Experiment 1 recorded the effects of single (doses of 1, 5, 10, and 20 mg/kg) and repeated intraperitoneal injections (10 mg/kg) of amineptine (a tricyclic antidepressant drug) on the performance of albino rats in differential reinforcement of low rate (DRL) of 30 s, fixed-interval (FI) of 60 s, and signalled continuous reinforcement (CRF-SD) schedules. In the second experiment, the effects of repeated (10 mg/kg) and single injections (20 mg/kg) were assessed on the discrimination of the duration of auditory stimuli (2 and 8 s). A dose-related increase in response rates was observed in FI and DRL, correlating with a dose-related impairment in the temporal regulation of performance. However, the drug remained without effect on duration discrimination. In other respects, decreases in response latency in CRF-SD or duration discrimination tended to indicate that the drug improved vigilance and reactivity to extraneous significant stimuli. Interpretations in terms of sensitization, tolerance, or dependency could be discarded. Our data support the hypothesis that drug effects on temporal regulation in FI and DRL are secondary to a nonspecific activation of motor activity. They question the plausibility of an antidepressant effect of the drug in humans via modulation of a timing mechanism. [less ▲]

Detailed reference viewed: 16 (0 ULg)
See detailFrontal activation observed with PET in visual discrimination involving duration or intensity parameters
Maquet, Pierre ULg; Lejeune, Helga ULg; Pouthas, V. et al

in Proceedings of the sixth meeting of the European Neurological Society, Tutzing (Munich), RFA, June 17-21 (1995)

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailAmineptine and response timing in the rat
Lejeune, Helga ULg; Hermans, Isabelle ULg; Mocaer, E. et al

in Behavioural Processes (1993), 29

Detailed reference viewed: 1 (0 ULg)
Full Text
See detailAmineptine and response timing in the rat
Lejeune, Helga ULg; Hermans, Isabelle ULg; Mocaer, E. et al

in Soffié, M. (Ed.) Proceedings of the 13th Low Countries Meeting, May 22, University of Louvain-la-Neuve, Belgium (1992)

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailTiming behavior and development : comments on some animal and human data
Lejeune, Helga ULg; Richelle, Marc ULg

in International Journal of Comparative Psychology (1990), 4

This paper discusses timing behavior as measured by Fixed Interval (FI), Differential Reinforcement of Low rate (DLR) or Differential Reinforcement of Response Duration (DRRD) performances, in humans and ... [more ▼]

This paper discusses timing behavior as measured by Fixed Interval (FI), Differential Reinforcement of Low rate (DLR) or Differential Reinforcement of Response Duration (DRRD) performances, in humans and animals at different developmental stages. Infants and rats display similar behavior patterns in FI and DRL. From childhood on, humans develop species-specific behavior patterns in FI, which differ from those of animal species. However, DRL patterns do follow similar developmental trends in animals and humans. These discrepancies and similarities may be explained by the availability of cognitive and luinguistic tools in humans, and the degree of schedule constraint on behavior. Motivation and reinforcer variables as well as indices favorable to a cross-specific timing mechanism (such as scalar timing)are briefly comented upon. Available data tend to show that human shift from contingency-shaped or "animal-like" behavior, in infancy, to rule-governed behavior. This transition is progressive and does not seem to erase forms of adaptation to temporal contraints that humans share with other species. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Full Text
See detailLes temps de la psychologie
Richelle, Marc ULg; Lejeune, Helga ULg

in Grotard, P. (Ed.) Le temps : actes du colloque de philosophie des sciences tenu à l'ULB, 29-30 janvier 1988 (1989)

Detailed reference viewed: 4 (0 ULg)
See detailLe temps en psychologie
Richelle, Marc ULg; Lejeune, Helga ULg

in Nysenholc, Adolphe; Boon, Jean-Pierre (Eds.) Redécouvrir le temps (1988)

Detailed reference viewed: 10 (0 ULg)
Full Text
See detailLa perception du temps chez l'animal
Richelle, Marc ULg; Lejeune, Helga ULg

in La recherche (1986), 182

Detailed reference viewed: 113 (0 ULg)
Full Text
Peer Reviewed
See detailLes conduites temporelles chez le jeune enfant: Lacunes et perspectives de recherche
Pouthas, V.; Macar, F.; Lejeune, Helga ULg et al

in Année Psychologique (L') (1986), 86

The main purpose of this critical overview of current knowledge in the field of the development of timing behavior in young children is to pave the way of future research. Traditional psycho-physiological ... [more ▼]

The main purpose of this critical overview of current knowledge in the field of the development of timing behavior in young children is to pave the way of future research. Traditional psycho-physiological methods have supplied coherent data on the estimation and perception of duration in children over age six. Only a few unsystematic studies have dealt with early temporal conditioning. To determine whether complex temporal regulations in the adult human are the result of a continuous process, deriving from elementary forms of temportal organization of activity, much more data are needed on infant adaptation to time, as well as on the role of language and capacities for inhibition in the evolution of temporal behavior. Furthermore, studies on the physiological bases of internal timing mechanisms and the ontogenesis of temporal regulation in young animals should help to assess the relative weight of early experience, maturation and cognitive development in the child. [less ▲]

Detailed reference viewed: 38 (9 ULg)
Full Text
See detailThe temporal regulation of behavior: A comparative approach
Lejeune, Helga ULg; Richelle, Marc ULg

in Behavioral Processes (1985), 10

Detailed reference viewed: 1 (0 ULg)