Unveiling the neural correlates of habit in the dorsal striatum

We have recently reported sustained inhibition in the dorsomedial striatum (DMS) and sustained excitation in the dorsolateral striatum (DLS) during execution of a lever press sequence in a discrete-trials task promoting habit. This sustained dorsostriatal activity was present early on, and did not clearly change in step with improved performance over ten training sessions. Early onset of sequence-related neural activity could have resulted from rapid habitual learning promoted by presentation of lever cues, predicting reward availability and delivery. To test this hypothesis, we compared DLS and DMS spiking activity in the discrete trials habit-promoting task with two task variants that promote goal-directed behavior. Comparison of the three tasks revealed that mean neuronal spiking activity was generally sustained across the lever press sequence in the task promoting habit and characterized by overall excitation in DLS and inhibition in DMS relative to baseline. In contrast, mean activity differences in DLS and DMS were much less prominent, and most changes occurred transiently around individual lever presses, in the tasks promoting goal-directed behavior. These results indicate that sequence delineation cues, such as the lever cues in these studies, promote habitual behavior and that this habitual behavior is encoded in the striatum by cue-triggered sustained DLS excitation and DMS inhibition that likely reflects cue-elicited behavioral chunking.

A Comparison of Self-Selected Walking Speeds and Walking Speed Variability When Data Are Collected During Repeated Discrete Trials and During Continuous Walking

A typical gait analysis data collection consists of a series of discrete trials, where a participant initiates gait, walks through a motion capture volume, and then terminates gait. This is not a normal ‘everyday’ gait pattern, yet measurements are considered representative of normal walking. However, walking speed, a global descriptor of gait quality that can affect joint kinematics and kinetics, may be different during discrete trials, compared to continuous walking. Therefore, the purpose of this study was to investigate the effect of continuous walking versus discrete trials on walking speed and walking speed variability. Data were collected for 25 healthy young adults performing 2 walking tasks. The first task represented a typical gait data collection session, where subjects completed repeated trials, beginning from a standstill and walking along a 12-m walkway. The second task was continuous walking along a “figure-of-8” circuit, with 1 section containing the same 12-m walkway. Walking speed was significantly higher during the discrete trials compared to the continuous trials (p < .001), but there were no significant differences in walking speed variability between the conditions. The results suggest that choice of gait protocol may affect results where variables are sensitive to walking speed.

Investigating the Effectiveness of a Training Program based on Discrete Trials on Children with Autism in United Arab Emirates

The study aimed to investigate the false memory level, and the effectiveness of a metamemory training program in rejecting false memory events among preschool children. The sample of this study consisted of 30 children of preschool stage from Bane Obaid educational directorate, Jordan which was equally divided randomly into experimental and control groups.The Deese-Roediger- McDermott (DRM) was used to measure false memory level. A meta-memory training program was developed also and applied after establishing its validity and reliability over 8 weeks with 2 sessions per week. The results showed that the preschool children had a high level of false memory, and that a statically significant decrease (p. = 0.05) in the mean of false memory scores of the experimental group in comparison with the control group on the post and the follow up tests.

Investigating the Effectiveness of a Training Program based on Discrete Trials on Children with Autism in United Arab Emirates

This study aimed at investigating the effectiveness of a training program based on discrete trials on children with autism. The sample of this study consisted of eight children with autism. To achieve the purpose of this study, researchers implemented the Language Behavioral Evaluation Scale prior to and after the training program in order to assess participants’ improvement. Following hypotheses testing and data analyses using Wilcoxon test and Z score, the study revealed that there were significant differences in averages of ranks in chronological gaps with children prior to and after the implementation of the training program. These differences were found in areas of movement modeling, matching and receptive naming. However; there were no significant differences in areas of oral imitating and expressive naming.

Using Nonlinear Tools to Evaluate Movement of Fragile Objects

We investigated the movement strategies of young, healthy participants (7 men/7 women) during the movement of a fragile object using nonlinear analysis. The kinematic variables of position, velocity, and acceleration were quantified using largest Lyapunov exponent (LyE) and approximate entropy (ApEn) analysis to identify the structure of their movement variability and movement predictability, respectively. Subjects performed a total of 15 discrete trials of an upper extremity movement task without crushing the object at each fragility condition, using each hand (left/right). We tested four fragility conditions hypothesizing that an increase in fragility would result in higher movement predictability and decreased temporal variability. Comparisons between the structure of movement variability and movement predictability were based on fragility condition, handedness, and kinematic measures. In this specific population, object fragility and participant handedness did not significantly impact the structure of movement variability (LyE) in the primary direction of movement (Z direction), although some effects were observed in the anterior/posterior directions. ApEn values were minimized across conditions, showing increased movement predictability, and is suggested for the analysis of discrete kinematic movements. In healthy populations, the results of this study suggest minimal effects on task performance and movement predictability as a result of object fragility.