Distortions and fluctuations in topographic memory

Two experiments dealing with, the learning of a space by map or by navigation approached the questions of equivalency of the cognitive processes involved in spatial information and of response fluctuation. In the first experiment, 11 subjects were asked to situate, six times, 18 lo-cations on a blank map. In the second experiment, the subjects were first given 3 min to learn a map with 12 locations marked, and then asked to reproduce it. The task was repeated six times, using three different maps. This gave us several trials per subject, so that distortion could be distinguished from response fluctuation. In Experiment 1, the range of values was the same for response inaccuracy and response, fluctuation; in Experiment 2, the range was greater for response inaccuracy than for response fluctuation. The results showed that space learning by navigation and space learning by map involve different cognitive processes.     

Language and syntactic impairment following stroke in late bilingual aphasics

Purpose

Bilingual aphasia generally affects both languages. However, the age of acquisition of the second language (L2) seems to play a role in the anatomo-functional correlation of the syntactical/grammatical processes, thus potentially influencing the L2 syntactic impairment following a stroke. The present study aims to analyze the influence of late age of acquisition of the L2 on syntactic impairment in bilingual aphasic patients.

Methods

Twelve late bilingual participants (speaking French as L2 and either English, German, Italian or Spanish as L1) with stroke-induced aphasia participated in the study. The MAST or BAT aphasia batteries were used to evaluate overall aphasia score. An auditory syntactic judgement task was developed and used to test participants syntactic performance.

Results

The overall aphasia scores did not differ between L1 and L2. In a multiple case analysis, only one patient had lower scores in L2. However, four patients presented significantly lower performances in syntactic processing in the late L2 than in their native language (L1). In these four patients the infarct was localized, either exclusively or at least partially, in the pre-rolandic region.

Conclusion

This pilot study suggests that, in late bilingual aphasics, syntactic judgment abilities may be more severely impaired in L2, and that this syntactic deficit is most likely to occur following anterior lesions.     

Tau and Kappa Effects: The Case of Space-Like-Extent Frequencies

The organization of tonal-temporal information in a memory task was studied in two experiments. The stimuli consisted of four different configurations of eight beeps, presented sequentially. In two configurations, the stimuli were tonal-time congruent, with (constant or variable) inter-stimulus tonal distances corresponding to (constant or variable) inter-stimulus time intervals. In the two other configurations, the stimuli were tonal-time incongruent, with (constant or variable) inter-stimulus tonal distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants reproduced the spatial (Experiment 1) or temporal (Experiment 2) characteristics of the target 60 times in succession without ever re-examining the target configuration. Classically, in incongruent space-time conditions, the effects of variable inter-stimulus time intervals or inter-stimulus space intervals on the reproduction of constant distances (Tau effect) and constant durations (Kappa effect), respectively, are observed. However, our results showed that this was not the case when the spatial dimension was substituted for the tonal dimension (i.e., the distances between consecutive tones). The results are discussed in the light of the properties of the physical versus frequential space, that is, of a tonal dimension in which the different frequencies were considered as the spatial dimension.     

Experiences and Decisions that Motivate Women at Increased Risk of Breast Cancer to Participate in an Experimental Screening Program

Although the discovery of mutations on BRCA1 and BRCA2 genes associated with high breast cancer risk has given rise to screening and surveillance initiatives, there is little documentation on why high-risk women choose to enter screening programs. The objective of this qualitative study was to develop a detailed understanding of the experiences and decisions that motivate women with increased risk of hereditary breast cancer to participate in the multicentered Quebec experimental breast screening program. Our study involved 21 participants who were either BRCA carriers or at risk and untested. These women were interviewed while participating in the screening program. Our study demonstrates that intensive screening programs may provide valuable reassurance for women with increased familial risk of hereditary breast cancer, who count on early detection and rapid response from professionals if and when a problem arises. Health professionals must take these and others concerns into account to ensure their interventions are most consistent with women’s needs.     

Tau and Kappa effects in physical space: the case of audition

The organization of spatio-temporal information in an auditory memory task was studied in two experiments. Stimuli consisted of four different configurations of eight sequentially presented beeps. In two configurations, the stimuli were space-time congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were space-time incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants reproduced the spatial (Experiment 1) or temporal (Experiment 2) characteristics of the target 60 times in succession without re-examining the target configuration. Accuracy (with respect to the target) and variability (between responses) were found to evolve independently. In the incongruent space-time conditions, effects of variable inter-stimulus time intervals or distances on the reproduction of, respectively, constant distances (Tau effect) or constant time intervals (Kappa effect) were observed, while the reverse was not the case. Thus, dimensional interference occurred when the dimension to be ignored was variable. The results are discussed in the light of the distinction between properties of the stabilized mental image and the process of stabilization.     

Dynamics of balancing space and time in memory: tau and kappa effects revisited

In 3 experiments, the authors studied the organization of spatiotemporal information in memory. Stimuli consisted of configurations of dots, presented sequentially. The stimuli were either proportional, with interdot distances corresponding to interdot durations, or not proportional, with interdol distances not corresponding to interdot durations. After a learning phase, participants reproduced the spatial (Experiment 1), temporal (Experiment 2), or spatial and temporal (Experiment 3) characteristics of the target 60 times in succession. In the nonproportional conditions, effects of variable interdot durations or distances on the reproduction of, respectively, constant distances (tau effect) or durations (kappa effect) were observed, whereas no such effects were observed when variable distances or durations were to be produced. Tau and kappa effects influenced the accuracy but not the variability of responses. The results are discussed in light of the distinction between properties of the stabilized mental image and the process of stabilization.     

Priming complex words: evidence for supralexical representation of morphology

Effects of morphologically related primes were examined in two masked prime experiments. Responses to both free root and derived suffixed word targets were facilitated when primes were derived suffixed words containing the target’s root, and this facilitation effect showed a time course similar to that for the facilitation effect of repetition primes (though systematically smaller in magnitude). In a control experiment only the longest prime duration of Experiment 1 was used; responses to derived suffixed word targets were facilitated by both free root primes and derived suffixed word primes sharing the target’s root (relative to unrelated and form-related control primes). The free root and derived suffixed word prime conditions did not differ significantly. In Experiment 2, only true derived word primes produced facilitation, whereas morphologically simple primes containing a pseudoroot did not influence performance relative to the unrelated prime condition. We argue that this supports a supralexical account of morphological representation.     

Dynamic instability of visuospatial images

Five experiments using a visuospatial task were conducted to study memory accuracy and variability and to identify the origin of variations in steady states. This research was conducted from a dynamical perspective, that is, by analyzing the temporal course of discrepancies between the perceptual configuration and its memory (accuracy) and the temporal course of discrepancies between 2 successive memories (variability). In Experiment 1 the stimulus (12 black dots randomly disposed) was presented repeatedly to assess the general evolution of accuracy and variability. In Experiments 2 and 3 memory accuracy and memory variability were separated to identify their relationship. In Experiments 4 and 5 memory variability was studied to determinate the origin of steady state variations. Results show that memory accuracy and memory variability evolved independently and that memory variability reached a threshold that was subject-dependent. The dynamic properties of image construction and stability are discussed.     

Coupling kinematics of memory and kinematics of movement: the conditions for a psychological relativity

The organization of spatial and temporal information relative to memory-movement interactions was studied in a recall task. Stimuli consisted of four different configurations of eight dots, presented sequentially. In two configurations, the stimuli were spatiotemporal congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were spatiotemporal incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants performed a series of pointing movements to reproduce both spatial and temporal characteristics of the stimulus 60 times in succession without ever re-examining the target configuration. Classically, in incongruent spatiotemporal conditions, the reproduction of, respectively, constant distances or constant time intervals are strongly disturbed by the simultaneous perception of variable inter-stimulus time intervals (Tau effect) or variable distances (Kappa effect). We assume that these spatiotemporal dependencies, which occur when the response relates to one dimension only, crucially depend on the non-integration of motoric aspects in memory.     

Dynamics of visuo-spatial remembering: a study of information structuring in memory

We studied the process by which learning a pattern of motor activity reaches a steady-state characterized by a reduction in fluctuations. The stimuli consisted of eight visually presented dots that appeared sequentially. In a 20-trial learning phase, participants reproduced the positions of the eight dots after each presentation. Next, they reproduced the pattern 40 times without renewed presentation. In one condition, spatial distances between the dots were proportional to the intervals between their appearances; in the other they were not proportional. We analyzed how the reproduction stabilized at the configuration and dot levels. In proportional as well as non-proportional conditions, stabilization occurs at different time scales for the configuration and dot levels. The stabilization rate differed between proportional and non-proportional conditions. These results are discussed in the framework of dynamical systems.