Gaining control: training executive function and far transfer of the ability to resolve interference

Functional brain-imaging data document overlapping sites of activation in prefrontal cortex across memory tasks, suggesting that these tasks may share common executive components. We leveraged this evidence to develop a training regimen and a set of transfer tasks to examine the trainability of a putative executive-control process: interference resolution. Eight days of training on high-interference versions of three different working memory tasks increased the efficiency with which proactive interference was resolved on those particular tasks. Moreover, an improved ability to resolve interference was also transferred to different working memory, semantic memory, and episodic memory tasks, a demonstration of far-transfer effects from process-specific training. Participants trained with noninterference versions of the tasks did not exhibit transfer. We infer that the transfer we demonstrated resulted from increased efficiency of the interference-resolution process. Therefore, this aspect of executive control is plastic and adaptive, and can be improved by training.     

Insight without cortex: lessons from the avian brain

Insight is a cognitive feature that is usually regarded as being generated by the neocortex and being present only in humans and possibly some closely related primates. In this essay we show that especially corvids display behavioral skills within the domains of object permanence, episodic memory, theory of mind, and tool use/causal reasoning that are insightful. These similarities between humans and corvids at the behavioral level are probably the result of a convergent evolution. Similarly, the telencephalic structures involved in higher cognitive functions in both species show a high degree of similarity, although the forebrain of birds has no cortex-like lamination. The neural substrate for insight-related cognitive functions in mammals and birds is thus not necessarily based on a laminated cortical structure but can be generated by differently organized forebrains. Hence, neither is insight restricted to mammals, as predicted from a “scala naturae”, nor is the laminated cortex a prerequisite for the highest cognitive functions.     

Inflammation, glutamate, and glia in depression: a literature review

Multiple lines of evidence suggest that inflammation and glutamate dysfunction contribute to the pathophysiology of depression. In this review we provide an overview of how these two systems may interact. Excess levels of inflammatory mediators occur in a subgroup of depressed patients. Studies of acute experimental activation of the immune system with endotoxin and of chronic activation during interferon-alpha treatment show that inflammation can cause depression. Peripheral inflammation leads to microglial activation which could interfere with excitatory amino acid metabolism leading to inappropriate glutamate receptor activation. Loss of astroglia, a feature of depression, upsets the balance of anti- and pro-inflammatory mediators and further impairs the removal of excitatory amino acids. Microglia activated by excess inflammation, astroglial loss, and inappropriate glutamate receptor activation ultimately disrupt the delicate balance of neuroprotective versus neurotoxic effects in the brain, potentially leading to depression.     

Culture, self, and the emergence of reactance: Is there a “universal” freedom?

In this article we suggest that independent vs. interdependent aspects of the self yield different manifestations of psychological reactance and that this is especially relevant in a cross-cultural context. In Studies 1, 2, and 4 we showed that people from collectivistic cultural backgrounds (individuals holding more interdependent attitudes and values) were less sensitive to a threat to their individual freedom than people from individualistic cultural backgrounds (individuals holding more independent attitudes and values), but more sensitive if their collective freedom was threatened. In Study 3 we activated independent vs. interdependent attitudes and values utilizing a cognitive priming method and yielded similar results as the other studies hinting at the important causal role of self-related aspects in understanding reactance in a cross-cultural context.     

Mortality salience and the desire for offspring

Research on terror management theory (TMT) illustrates that following mortality salience (MS) people defend their cultural worldviews and bolster self-esteem to transcend death. Recently, research additionally showed that MS increased self-reports of the number of children desired in Dutch men but not in Dutch women. We conducted three studies to further investigate the role of desire for offspring in terror management. In Study 1, we conceptually replicated previous findings for Germany and found increased desire for offspring following MS in both men and women. Extending prior research Study 2 revealed that following MS not only was the accessibility of death-related thoughts increased, but also the accessibility of thoughts related to offspring. Finally, Study 3 suggested that the MS effect on ingroup bias was eliminated under conditions of offspring salience. Relating these findings to TMT, anticipated or actual offspring is discussed as a buffer against existential anxiety.     

Multimodal action representation in human left ventral premotor cortex

We used functional magnetic resonance imaging (fMRI) to investigate the neural systems responding to the sight and to the sound of an action. Subjects saw a video of paper tearing in silence (V), heard the sound of paper tearing (A), and saw and heard the action simultaneously (A + V). Compared to a non-action control stimulus, we found that hearing action sounds (A) activated the anterior inferior frontal gyrus and middle frontal gyrus in addition to primary auditory cortex. The anterior inferior frontal gyrus, which is known to be activated by environmental sounds, also seems to be involved in recognizing actions by sound. Consistent with previous research, seeing an action video (V) compared with seeing a non-action video activated the premotor cortex, intraparietal cortex, and the pars opercularis of the inferior frontal gyrus. An A + V facilitation effect was found in the ventral premotor cortex on the border of areas 44, 6, 3a, and 3b for the action stimuli but not for the control stimuli. This region may be involved in integrating multimodal information about actions. These data provide evidence that the ventral premotor cortex may provide an action representation that abstracts across both agency (self and other) and sensory modality (hearing and seeing). This function may be an important precursor of language functions.     

Cognitive behavior therapy vs exposure in vivo in the treatment of panic disorder with agoraphobia (corrected from agrophobia)

Seventy-three psychiatric outpatients with DSM-IV diagnosis of panic disorder with agoraphobia were assessed with a battery of independent assessor, self-observation, self-report and behavioral measures before and after therapy, and at a 1-yr follow-up. They were randomly assigned to Exposure in vivo (E; n = 25), Cognitive Behavior Therapy (CBT; n = 26), or a Wait-list control (WLC; n = 22) and received 12-16 individual therapy sessions, once weekly. The treatments yielded significant improvements, both on panic/agoraphobia measures and on measures of general anxiety, depression, social adjustment and quality of life, which were maintained at follow-up. However, there were no significant differences between E and CBT. The three criteria of clinically significant improvement were achieved by 67% of the E-patients and 79% of the CBT-patients at post-treatment, and 74% and 76%, respectively, at follow-up. The conclusion that can be drawn is that adding cognitive therapy to exposure did not yield significantly better results than for exposure alone.     

Connecting terror management and dissonance theory: Evidence that mortality salience increases the preference for supporting information after decisions

From the perspective of terror management theory, reminders of mortality should intensify the desire to pursue cognitive consistency. The authors investigated this notion with regard to dissonance theory starting from the finding of research on "selective exposure to information" that after having made a decision, people prefer consonant over dissonant information. The authors found that following mortality salience, people indeed showed an increased preference for information that supported their decision compared to information conflicting with it. However, this only occurred with regard to a worldview-relevant decision case. For a fictitious decision scenario, mortality salience did not affect information seeking. Practical and theoretical implications are discussed.     

Amnesic effect of GMP depends on its conversion to guanosine

Extracellular guanine-based purines, namely the nucleotides GTP, GDP, GMP and the nucleoside guanosine, exert important neuroprotective and neuromodulator roles in the central nervous system, which may be related to inhibition of the glutamatergic neurotransmission activity. In this study, we investigated GMP effects on mice inhibitory avoidance performance and the dependence on its conversion to guanosine for such effect, by using the ecto-5'-nucleotidase specific inhibitor AOPCP. We also investigated if this conversion occurs in the central nervous system or peripherally, and if guanosine and GMP affect nociception by the tail-flick test. I.p. GMP or guanosine (7.5 mg/kg) or i.c.v. GMP (480 nmol) pretraining administration was amnesic for the inhibitory avoidance task. I.c.v. AOPCP (1 nmol) administration completely reversed the amnesic effect of i.c.v. GMP, but not of i.p. GMP, indicating that peripheral conversion of GMP to guanosine is probably relevant to this effect. AOPCP alone did not interfere with the performance. Furthermore, tail-flick measurement was unaffected by i.p. GMP and guanosine, suggesting that the amnesic effect of both purines was not due to some antinociceptive effect against the footshock used in the task. All these data together, in accordance to those previously observed in studies involving glutamate uptake and seizures reinforce the idea that guanosine is the specific extracellular guanine-based purines effector and indicate that its conversion occurs not only in the central nervous system but also peripherally.     

rCBF/SPECT in the evaluation of inner-city minority patients with a history of impaired memory: a pilot blind read pre- and poststudy

Eight patients (seven women), mean +/- SD T1 age 68.57 +/- 12.43 years, average educational level 5.83 +/- 3.70 years, had two Tc-99m ECD SPECT examinations separated by an average 8.49 +/- 5.59 months. Patients were imaged using standard Harlem Hospital acquisition and processing protocols with approximately 30 mCi of ECD on a Prism 3000 triple head gamma camera. Images were interpreted by an independent reader blinded to the patients' clinical history and imaging date. T1 psychiatric diagnosis was seven Alzheimer's dementia (AD) and one depression. Eight T1 images were interpreted as abnormal, six indicative of AD. Binomial 95% two-tail confidence interval for T1 agreement between diagnosis and interpretation was 0.25 0.63 0.92. T2 diagnosis was seven AD and one none. Seven T2 images were abnormal and indicative of AD, and one was normal. T2 confidence interval was 0.34 0.75 0.97. These findings suggest SPECT's value in assessing AD in uneducated socioeconomically disadvantaged geriatric patients.