Habituation and migraine

The most reproducible and ubiquitous interictal abnormality of the migraineurs’ brain is lack of habituation in neuronal information processing. The underlying mechanisms are uncertain. Increased neuronal excitability, decreased inhibition or decreased pre-activation levels have all been proposed as possible culprits.The present review summarizes the available data on habituation in migraine patients obtained with different methodological approaches. We will discuss the change of habituation level over the migraine cycle and we will show that these data congruently indicate that the sensory cortices of migraineurs react excessively to repetitive, but not to a small series of stimuli.Although the precise cellular and molecular mechanisms of this hyper-responsivity must still be determined, we will describe experimental data suggesting that a dysrhythmic thalamo-cortical activity due to inadequate monoaminergic control might be a plausible explanation.     

Electrophysiology in neuropsychiatric research: a network perspective

A growing number of anatomic and physiologic studies have shown that parallel sensory and motor information processing occurs in multiple cortical areas. These findings challenge the traditional model of brain processing, which states that the brain is a collection of physically discrete processing modules that pass information to each other by neuronal impulses in a stepwise manner. New concepts based on neural network models suggest that the brain is a dynamically shifting collection of interpenetrating, distributed, and transient neural networks. Neither of these models is necessarily mutually exclusive, but each gives different perspectives on the brain that might be complementary. Each model has its own research methodology, with functional magnetic resonance imaging supporting notions of modular processing, and electrophysiology (eg, electroencephalography) emphasizing the network model. These two technologies might be combined fruitfully in the near future to provide us with a better understanding of the brain. However, this common enterprise can succeed only when the inherent limitations and advantages of both models and technologies are known. After a general introduction about electrophysiology as a research tool and its relation to the network model, several practical examples are given on the generation of pathophysiologic models and disease classification, intermediate phenotyping for genetic investigations, and pharmacodynamic modeling. Finally, proposals are made about how to integrate electrophysiology and neuroimaging methods.     

Does the use of dolls facilitate children's memory of visits to the doctor?

Age differences in children's recall of salient experiences have frequently been documented, but these findings have routinely been based on studies in which verbal interviews have been employed. Because verbal interview protocols may underestimate the memory of young children, the purpose of this research was to compare the effectiveness of such an interview with two alternative protocols that involved the use of a doll. Using these contrasting protocols, 3-and 5-year-old children were asked to remember the details of a routine physical examination. Neither doll protocol facilitated 3-year-olds' recall of the features of the check-up. In contrast, 5-year-olds who were asked to demonstrate with a doll what happened in their examination showed enhanced recall. The inclusion of a doll had no effect on older or younger children's provision of elaborative detail about their visits to the doctor. Various measures of individual differences (e. g. temperament, language skill) predicted some aspects of the children's recall and elaboration. The findings are discussed in terms of the cognitive skills necessary for effective use of dolls in the assessment process, and are related to problems associated with interviewing young children who are involved in legal proceedings.     

Parallel acquisition of awareness and differential delay eyeblink conditioning

There is considerable debate about whether differential delay eyeblink conditioning can be acquired without awareness of the stimulus contingencies. Previous investigations of the relationship between differential-delay eyeblink conditioning and awareness of the stimulus contingencies have assessed awareness after the conditioning session was finished using a post-experimental questionnaire. In two experiments, the point at which contingency awareness developed during the conditioning session was estimated from a button-press measure of expectancy of the unconditioned stimulus (US). In both experiments, knowledge of the stimulus contingencies and acquisition of differential delay eyeblink conditioning developed approximately in parallel. In Experiment 1 it was shown that predicting the US facilitated eyeblink conditioning compared with predicting the eyeblink response. In Experiment 2, a masking task was used that slowed down the emergence of awareness, and it was shown that differential conditioning only occurred in participants who were able to predict the US. The current findings challenge the hypothesis that differential delay eyeblink conditioning is entirely mediated by a functionally and neurally distinct nondeclarative learning system.     

Long-term transfer of learning from books and video during toddlerhood

Television viewing and picture book reading are prevalent activities during toddlerhood, and research has shown that toddlers can imitate from both books and videos after short delays. This is the first study to directly compare toddlers' long-term retention rates for target actions learned from a video or book. Toddlers (N=158) at 18- and 24-months of age saw an experimenter demonstrating how to make a novel three-step toy rattle via a prerecorded video or a picture book. The toddlers' imitation of the target actions was tested after a specific delay (e.g., 2, 4 weeks), and their performance was compared with that of age-matched controls who did not see a demonstration. The 18-month-olds retained the target actions for 2 weeks, exhibiting forgetting at 4 weeks, whereas the 24-month-olds retained the information for up to 4 weeks, exhibiting forgetting at 8 weeks. Retention rates for books and videos did not differ at either age. These findings demonstrate very impressive retention from a brief two-dimensional media demonstration, and they contribute to our overall understanding of long-term memory processes during infancy.     

Effects of Fluency Versus Accuracy Training on Endurance and Retention of Assembly Tasks by Four Adolescents with Developmental Disabilities

Schools are increasingly being encouraged to teach vocational skills to middle and high school students. Although extensive research exists demonstrating the benefits of fluency instruction when teaching academic skills to this population of students, few studies have examined the importance of fluency training when teaching vocational skills. Using an alternating treatments design, the present study examined the effects of fluency versus accuracy training on 4 students’ fluency in completing 2 vocational tasks. Following the training phase, students completed each task during 20- and 40-min work sessions to assess endurance and retention of the trained skills. Overall, results suggest that the fluency condition produced greater work productivity.