Tyrosine hydroxylase activities in the brains of wild Norway rats and silver foxes selected for reduced aggressiveness towards humans

Tyrosine hydroxylase (TH) activity was measured in brains from Norway rats and silver foxes showing wild type aggressiveness and from their counterparts selected over 20-25 generations for reduced aggressiveness towards humans (tameness). TH activity in the brain stem and cortex was increased in tame animals of both species compared with aggressive counterparts. Selection increased hypothalamic TH activity in foxes, but decreased it in rats. There was no difference in TH activity in corpus striatum between the tame and aggressive animals. Fetal TH activity in the posterior part of the brain was higher in tame than aggressive rats at day 20 of embryogensis. Increased TH activity in the brain stem and cortex of adult aggressive rats was observed after treatment of their mothers with hydrocortisone on the days 16 and 18 of pregnancy. This elevation in TH activity was associated with attenuation of the defense behavior of aggressive rats. The data suggested that alterations in neural TH activity in tame rats and foxes may be part of the neurochemical basis of their behavioral phenotype which is developed by selection. © 1994 Wiley-Liss, Inc.     

Reduced K+ Channel Inactivation, Spike Broadening, and After-Hyperpolarization in Kvβ1.1-Deficient Mice with Impaired Learning

A-type K⁺ channels are known to regulate neuronal firing, but their role in repetitive firing and learning in mammals is not well characterized. To determine the contribution of the auxiliary K⁺ channel subunit Kvβ1.1 to A-type K⁺ currents and to study the physiological role of A-type K⁺ channels in repetitive firing and learning, we deleted the Kvβ1.1 gene in mice. The loss of Kvβ1.1 resulted in a reduced K⁺ current inactivation in hippocampal CA1 pyramidal neurons. Furthermore, in the mutant neurons, frequency-dependent spike broadening and the slow afterhyperpolarization (sAHP) were reduced. This suggests that Kvβ1.1-dependent A-type K⁺ channels contribute to frequency-dependent spike broadening and may regulate the sAHP by controlling Ca²⁺ influx during action potentials. The Kvβ1.1-deficient mice showed normal synaptic plasticity but were impaired in the learning of a water maze test and in the social transmission of food preference task, indicating that the Kvβ1.1 subunit contributes to certain types of learning and memory.     

Passive-aggressive (negativistic) personality disorder: a population-based twin study

The objective of this study was to investigate the familial aggregation of passive aggressive personality disorder (PAPD), and explore issues regarding PAPD raised by the DSM-IV Personality Disorder Work Group. Two thousand seven hundred and ninety-four Norwegian twins from the population-based Norwegian Institute of Public Health Twin Panel were interviewed with the Structured Interview for DSM-IV Personality (SIDP-IV). Because of the rarity of the twins meeting full diagnostic criteria for PAPD a dimensional representation of the disorder was used for the analyses. Overlap with other axis II disorders was assessed by polychoric correlations, while familial aggregation was explored by structural equation twin models. Overlap was highest with paranoid (r = 0.52) and borderline personality disorder (r = 0.53), and lowest with schizoid (r = 0.26). Significant familial aggregation was found for PAPD. The twin correlations and parameter estimates in the full model indicated genetic and shared environmental effects for females, and only shared environmental effects for males, but the prevalence of endorsed PAPD criteria in this community sample was too low to permit us to conclude with confidence regarding the relative influence of genetic and shared environmental factors on the familial aggregation of PAPD.     

Impairment of Cognitive Function in Different Domains Early After Lung Transplantation

Journal of Clinical Psychology in Medical Settings - In this prospective observational pilot study patients with the diagnosis of end-stage lung disease and listed for lung transplantation...     

Defending Evidence‐Resistant Beliefs

There is a view in the literature around beliefs that evidence responsiveness is a necessary feature of beliefs. The reasoning is that because beliefs are governed by truth they must be evidence responsive. A mental state that fails to be evidence responsive, therefore, could not be a belief as it could not be governed by truth. The implication is that even those evidence‐resistant mental states that appear to be beliefs are in fact something else. I argue that evidence resistance is a feature of at least some beliefs, so evidence responsiveness cannot be a necessary feature of belief.