Effects of rapid eye movement sleep deprivation on regional brain metabolism as measured by 2-[14C]deoxyglucose autoradiography

Regional brain metabolic activity of six male Sprague-Dawley rats was investigated with 2-[14C]deoxyglucose autoradiography. Regional brain metabolic activity was determined bilaterally for 60 brain structures, using laser densitometry. After 5 days of uninterrupted rapid eye movement sleep deprivation, increased metabolic activity was found in the lateral habenula, the caudal and middle parts of the limbic system, and in the corpus callosum.     

Linking adult psychopathy with childhood hyperactivity-impulsivity-attention problems and conduct problems through retrospective self-reports

The purpose of the present study was to test whether adult criminals with psychopathy diagnoses, more than those without, have histories of hyperactivity-impulsivity-attention problems (HIA) and conduct problems (CP). We compared psychopathic and nonpsychopathic violent criminal offenders on retrospective reports of conduct problems before the age of 15 and hyperactivity-impulsivity-attention problems before the age of 10. We used a sample of 186 adult men sentenced to prison in Sweden for 4 years or more for violent, nonsexual crimes. The mean age was 30.7( SD = 9.4). The results showed that a combination of childhood HIA problems and CP was typical for adult psychopathic offenders. They were four times more likely than chance to have had a combination of HIA problems and CP during childhood and only one-fifth as likely than chance to have had neither problem. Nonpsychopathic offenders, on the other hand, were five times more likely than chance to have had neither problem and only one-quarter as likely than chance to have had both problems.     

Psychopathy and intelligence: a second look

Empirical studies using the PCL-R (Hare, 2003) have shown no intelligence differences between psychopaths and nonpsychopaths. However, Cleckley (1976) argued that psychopaths often show superior intelligence. The purpose of the present study was to test the hypothesis that the correlation between intelligence and severity of criminal development is the opposite in psychopaths than in nonpsychopathic criminals using a sample of 370 men sentenced for violent (nonsexual) crimes. That pattern would provide a way of explaining the discrepancy between Cleckley's view and later empirical work. The results showed that for nonpsychopaths, higher total IQ and particularly verbal intelligence meant a later start in violent crime. For those diagnosed as psychopaths, however, this association was reversed.     

Number-word sequence skill and arithmetic performance

In two studies, the role of the number‐word sequence skill for arithmetic performance was investigated. In the first, children between 4 and 8 years of age were asked to count forward and backward on the number‐word sequence and to solve arithmetic problems followed by post‐solution interviews about solution procedures. The results demonstrated that the number‐word sequence skill predicted both number of problems solved and strategy to solve the problems. In Study 2 it was found that solving doubles (e.g., 2 + 2 = ?) problems served as a link between the number‐word sequence skill and the number of arithmetic problems solved. The findings suggest that counting on the number‐word sequence may be an early solution procedure and that, with increasing counting skill, the child may detect regularities in the number‐word sequence that can be used to form new and more accurate strategies for solving arithmetic problems.     

Age-related differences in familiarity and recollection: ERP evidence from a recognition memory study in children and young adults

Using event-related potentials (ERPs), we examined the relative contributions of familiarity and recollection to recognition memory for items and their study contexts in school-aged children and adults. Whereas adults were able to selectively accept target items and to reject familiar nontarget items in an exclusion task, this discrimination was more difficult for children, as was evident in the high false alarm rates to nontargets even when item memory was controlled for. The analysis of the adults’ ERPs revealed more flexible and task-appropriate retrieval mechanisms, as was evident in the correlates of familiarity, recollection, and nontarget retrieval, as well as in postretrieval evaluation. In contrast, children’s ERPs revealed a parietal old/new effect for targets taken as a putative correlate of recollection. These findings suggest that children rely predominantly on recollection during recognition judgments, even in the absence of efficient memory control processes. The latter processes enable adults to monitor and verify the retrieved information and to control nontarget retrieval in the service of adequate source memory performance.     

Hume's Surprise and the Logic of Belief Changes

If the logic of belief changes is extended to cover belief states which contain both factual and normative beliefs, it is easily shown that a change of a factual belief (an 'Is') in a mixed belief state can imply a change of a normative belief (an 'Ought') in the same state. With regard to Hume's so-called 'Is-Ought problem', this means that one has to distinguish its statics from its dynamics. When this is done, it becomes clear that changes of factual beliefs can, for rational reasons, have far-reaching normative consequences. Similarly, a change of a factual belief can imply a change of a value belief. This revised version was published online in June 2006 with corrections to the Cover Date.     

Electrocortical Responses to ecologically relevant visual stimuli among professional drivers with and without cardiovascular disease

Electrocortical responses were assessed using two simulated aspects of visual signals encountered in traffic: the Glare Pressor Test (GPT) and Event-Related Potential Avoidance Task (ERPAT) among four groups of male professional drivers: 12 with ischemic heart disease (IHD), 12 hypertensives, 10 borderline hypertensives, 34 who were apparently healthy and 23 nonprofessional driver healthy control subjects. The blood pressure (BP) responses immediately after the ERPAT were also measured. There was a significant between groups effect for the amplitude of the target N2 component in the ERPAT (p=0.02), with the lowest means among the drivers with IHD and the highest among those with hypertension. Drivers with IHD also showed the highest diastolic BP reactivity to the ERPAT. Significantly more than the expected number of drivers with IHD failed to recover alpha activity after the first glare impulse of the GPT. Professional drivers who failed to recover baseline levels of alpha activity after the GPT showed a significantly smaller N2 amplitude compared to those who recovered (p=0.01). There was a positive correlation between abundance of alpha activity at rest with P300 amplitude (p=0.02). An inverse relation was found between number of work hours behind the wheel and the amplitude of the target P300 (p=0.04). Results are interpreted in light of recent advances concerning integrative mechanisms of defence versus vigilance response patterns. The findings in this study justify further applications of these psychophysiologic methods to assess the relationship between simulated signals of the work environment and mechanisms of cardiac risk in this occupational group.     

Perceived angle of oscillatory motion

The general background of these experiments was the fact, known from e.g. trapezoidal window experiments, that rotary motion under certain conditions is perceived as oscillation. The aim was to identify the variables that determine the perceived angle of this oscillatory motion. Different shapes and different methods of generating the stimulation were used. No effect was obtained when varying the degree of trapezoidality of trapezoids, the location of the axis of rotation, the size of the stimulus pattern and the speed of the change. Both the occurrence and the perceived angle of oscillation was effected, however, by the width-height ratio of the stimulation, a decreasing ratio giving increasing occurrence of oscillation and decreasing perceived angle.     

Some relevant factors in the transfer of material from short-term to long-term memory

The relationship between short-term memory (STM) and long-term memory (LTM) for digits was investigated by means of a Hebb-type experiment, viz. a presentation of a series of nine-digit numbers, in which a certain number recurs at intervals. Improvement in performance, with regard to the critical, or recurring, number was found when the rehearsal grouping was three-three-and-three, but was absent when there were no opportunities for rehearsal or when the rehearsal strategy was grouping five-and-four or searching for systematic numbers.

However, if an overt recall response was given on each occasion the recurring number was presented, improved performance was found even with rehearsal stratgegy five-and-four.

The conclusion was drawn that rehearsal is the main transferring mechanism from STM to LTM, with the occurrence of an over recall response as a subsidiary factor.