Persistent ERK activation maintains learning-induced long-lasting modulation of synaptic connectivity

Pyramidal neurons in the piriform cortex from olfactory-discrimination (OD) trained rats undergo synaptic modifications that last for days after learning. A particularly intriguing modification is reduced paired-pulse facilitation (PPF) in the synapses interconnecting these cells; a phenomenon thought to reflect enhanced synaptic release. The molecular machinery underlying this prolonged physiological modulation of synaptic connectivity is yet to be described. We have recently shown that extracellular regulated kinase (ERK) pathway and protein kinase C (PKC) are also required for learning-induced enhancement of intrinsic neuronal excitability. Here we examine whether these signal-transduction cascades are instrumental for the learning-induced, long-lasting PPF reduction. Days after learning completion, PD98059, a selective inhibitor of MEK, the upstream kinase of ERK, increased PPF in neurons from trained, but not in neurons from na?ve and pseudo-trained rats. Consequently, the differences in PPF between neurons from trained rats and controls were abolished. The level of activated ERK in synaptoneurosomes was significantly higher in piriform cortex samples prepared from trained rats. Notably, ERK activation revealed that PPF reduction lags behind ERK activation by 2 d. Similarly, the PKC blocker, GF-109203X, enhanced PPF in neurons from trained rats only, thus abolishing the differences between groups. Interestingly, the PKC activator, OAG, had no effect, indicating that PKC activation is required, but not sufficient for long-lasting PPF reduction. Our data show that persistent ERK activation has a key role in maintaining learning-induced PPF reduction for days. This time frame of compartmental ERK-dependent synaptic modulation suggests a novel role for ERK in cortical function.     

Attention-Deficit/Hyperactivity Disorder: A Neuropsychological Perspective Towards DSM-V

Neuropsychological methods and techniques have much to offer in the evaluation of the individual suspected as having Attention-Deficit/Hyperactivity Disorder (ADHD). After a review of the historical evolution of the ADHD concept, incidence and prevalence, and DSM-IV criteria for diagnosis, especially as regards omission related to gender differences, and other associated cultural, familial, socioenvironmental, and subject influences, this paper describes a number of dilemmas and obstacles encountered in clinical practice. Included are the confounds associated with the wide range of possible comorbidities, the insufficiency of current DSM-IV criteria, the emergence of subtype differentiation and its impact on diagnosis and treatment. The complex relationship between neuropsychological constructs and ADHD, and obstacles to valid assessment are also addressed. The complexities associated with a thorough ADHD evaluation are viewed within an impressive and expansive existing scientific framework and recommendations are made for future directions.     

DNA Testing for Family Reunification in Canada: Points to Consider

Countries have adopted different laws, policies, and practices that allow immigration officers to request in certain cases DNA tests to confirm biological relationships in the context of family reunification. In Canada, Citizenship and Immigration Canada has adopted a policy of suggesting DNA testing only as a last resort in cases where no documentary evidence has been submitted or where the evidence provided is deemed unsatisfactory. However, in practice, there have been concerns on the increasing use of DNA tests in family reunification processes of nationals from certain regions including Africa, Asia, and Latin America. Moreover, the Immigration and Refugee Protection Regulations (IRPR) presents a biological definition of family as a determinant of parenthood in the context of family reunification that is inconsistent with the psychosocial definition used in provincial family laws. Although there are cases that can justify the request for DNA tests, there are also significant social, legal, and ethical issues, including discrimination and unfair practices, raised by this increasing use of genetic information in immigration. This policy brief identifies points to consider for policymakers regarding the use of DNA testing in Canadian family reunification procedures. These include (1) the need to refine the policy of “using DNA testing as a last resort” and its implementation, (2) the need to modify the definition of “dependent child” under the IRPR to reflect the intrinsic reality of psychosocial family ties, and (3) the importance of conducting more research on the use of DNA testing in other immigration contexts.     

To imitate or not to imitate? How the brain can do it, that is the question!

In this paper the authors discuss the most prominent views addressing the issue of how we imitate actions. It is argued that the existing theories lay along a continuum, with the direct mapping approach at one end (Butterworth, 1990; Gray, Neisser, Shapiro, & Kouns, 1991) the Active Intermodal Matching approach (Melzoff & Moore, 1997) in the middle, and the goal-directed theory (Bekkering, Wohlsh?ger, & Gattis, 2000) and the dual route theory (Rumiati & Tessari, 2002) at the opposite end. Interestingly the latter views can account for behaviors that cannot be explained by invoking the direct mapping or the Active Intermodal Matching approach.     

Über die Empfindlichkeit für Schnelligkeitsunterschiede

Ohne Zusammenfassung     

Psychometric properties of the Insomnia Catastrophizing Scale (ICS) in a large community sample

ABSTRACT

The purpose was to investigate the psychometric properties of the Insomnia Catastrophizing Scale (ICS) including factorial validity and internal consistency as well as discriminative and convergent validity. Associations with sleep parameters and daytime impairment are also examined. Drawn from a randomly selected sample of the general population, 1615 participants completed a survey on insomnia-related nighttime and daytime symptoms, health outcomes and psychological processes, including the ICS. A one-factor solution was supported for both the nighttime catastrophizing (11 items) and daytime catastrophizing (6 items) subscales. Both subscales displayed high internal consistencies (α > 0.90) and accounted for 59.1–70.1% of the variance. The insomnia disorder group had significantly higher scores than participants without insomnia on the two subscales and on the individual items. Cutoffs were established for both subscales with acceptable sensitivity and specificity. Both subscales displayed adequate convergent validity with measures indexing worry, cognitive pre-sleep arousal and anxiety. The two subscales were also significantly associated with nighttime and daytime insomnia symptoms. The ICS is a reliable and valid scale for the assessment of insomnia-related catastrophizing. Future research is needed to examine the test-retest reliability and treatment sensitivity of the ICS.     

A Systematic Review and Meta-analysis of Narrative Language Abilities in Children with Attention-Deficit/Hyperactivity Disorder

Research on Child and Adolescent Psychopathology - While children with ADHD are reported to have language problems, it is less clear if their ability to use language to tell a story (i.e., form a...     

Multidimensional locus of control and Machiavellianism in Italian and West German students: similarities and differences

In recent decades, the relationship between Machiavellianism and locus of control has received increasing attention in psychological literature. Presented below are the results of various studies conducted to determine correlations between these variables, complete with statistical information concerning gender-specific differences.