The impact of yohimbine-induced arousal on facets of behavioural impulsivity

Rationale State-dependent changes in physiological arousal may influence impulsive behaviours. Objectives To examine the relationship between arousal and impulsivity, we assessed the effects of yohimbine (an α2-adrenergic receptor antagonist, which increases physiological arousal via noradrenaline release) on performance on established laboratory-based impulsivity measures in healthy volunteers. Methods Forty-three participants received a single dose of either yohimbine hydrochloride or placebo before completing a battery of impulsivity measures. Blood pressure and heart rate were monitored throughout the study. Results Participants in the yohimbine group showed higher blood pressure and better response inhibition in the Stop Signal Task, relative to the placebo group. Additionally, individual changes in blood pressure were associated with performance on Delay Discounting and Information Sampling tasks: raised blood pressure following drug ingestion was associated with more far-sighted decisions in the Delay Discounting Task (lower temporal impulsivity) yet reduced information gathering in the Information Sampling Task (increased reflection impulsivity). Conclusions These results support the notion that impulsive behaviour is dependent upon state physiological arousal; however, distinct facets of impulsivity are differentially affected by physiological changes

Binge drinking is associated with attenuated frontal and parietal activation during successful response inhibition in fearful context

Binge drinking is associated with increased impulsivity and altered emotional processing. The current study investigated, in a group of university students who differed in their level of binge drinking, whether the ability to inhibit a pre-potent response and to delay gratification is disrupted in the presence of emotional context. We further tested whether functional connectivity within intrinsic resting-state networks was associated with alcohol use. Higher incidence of binge drinking was associated with enhanced activation of the lateral occipital cortex, angular gyrus, the left frontal pole during successful response inhibition irrespective of emotional context. This observation suggests a compensatory mechanism. However, higher binge drinking attenuated frontal and parietal activation during successful response inhibition within a fearful context, indicating the selective emotional facilitation of inhibitory control. Similarly, higher binge drinking was associated with attenuated frontopolar activation when choosing a delayed reward over an immediate reward within the fearful, relative to the neutral, context. Resting-state functional data analysis revealed that binge drinking decreased coupling between right supramarginal gyrus and Ventral Attention Network, indicating alcohol-associated disruption of functional connectivity within brain substrates directing attention. Together, our results suggest that binge drinking makes response inhibition more effortful, yet emotional (more arousing) contexts may mitigate this; disrupted functional connectivity between regions underlying adaptive attentional control, is a likely mechanism underlying these response inhibition effects associated with binge drinking

Neural divergence and convergence for attention to and detection of interoceptive and somatosensory stimuli

Body awareness is constructed by signals originating from within and outside the body. How do these apparently divergent signals converge? We developed a signal detection task to study the neural convergence and divergence of interoceptive and somatosensory signals. Participants focused on either cardiac or tactile events and reported their presence or absence. Beyond some evidence of divergence, we observed a robust overlap in the pattern of activation evoked across both conditions in frontal areas including the insular cortex, as well as parietal and occipital areas, and for both attention and detection of these signals. Psycho-physiological interaction analysis revealed that right insular cortex connectivity was modulated by the conscious detection of cardiac compared to somatosensory sensations, with greater connectivity to occipito-parietal regions when attending to cardiac signals. Our findings speak in favour of the inherent convergence of bodily-related signals and move beyond the apparent antagonism between exteroception and interoception

A role for accessory genes rI.-1 and rI.1 in the regulation of lysis inhibition by bacteriophage T4

Lysis inhibition (LIN) is a known feature of the T-even family of bacteriophages. Despite its historical role in the development of modern molecular genetics, many aspects of this phenomenon remain mostly unexplained. The key element of LIN is an interaction between two phage-encoded proteins, the T holin and the RI antiholin. This interaction is stabilized by RIII. In this report, we demonstrate the results of genetic experiments which suggest a synergistic action of two accessory proteins of bacteriophage T4, RI.-1, and RI.1 with RIII in the regulation of LIN

Analysis of cancer metabolism with high-throughput technologies

<p>Abstract</p> <p>Background</p> <p>Recent advances in genomics and proteomics have allowed us to study the nuances of the Warburg effect – a long-standing puzzle in cancer energy metabolism – at an unprecedented level of detail. While modern next-generation sequencing technologies are extremely powerful, the lack of appropriate data analysis tools makes this study difficult. To meet this challenge, we developed a novel application for comparative analysis of gene expression and visualization of RNA-Seq data.</p> <p>Results</p> <p>We analyzed two biological samples (normal human brain tissue and human cancer cell lines) with high-energy, metabolic requirements. We calculated digital topology and the copy number of every expressed transcript. We observed subtle but remarkable qualitative and quantitative differences between the citric acid (TCA) cycle and glycolysis pathways. We found that in the first three steps of the TCA cycle, digital expression of aconitase 2 (<it>ACO2</it>) in the brain exceeded both citrate synthase (<it>CS</it>) and isocitrate dehydrogenase 2 (<it>IDH2</it>), while in cancer cells this trend was quite the opposite. In the glycolysis pathway, all genes showed higher expression levels in cancer cell lines; and most notably, digital gene expression of glyceraldehyde-3-phosphate dehydrogenase (<it>GAPDH</it>) and enolase (<it>ENO</it>) were considerably increased when compared to the brain sample.</p> <p>Conclusions</p> <p>The variations we observed should affect the rates and quantities of ATP production. We expect that the developed tool will provide insights into the subtleties related to the causality between the Warburg effect and neoplastic transformation. Even though we focused on well-known and extensively studied metabolic pathways, the data analysis and visualization pipeline that we developed is particularly valuable as it is global and pathway-independent.</p

Otępienie czołowo-skroniowe : ujęcie interdyscyplinarne

Publikacja recenzowana / Peer-reviewed publicationZe wstępu: Oddajemy do rąk Czytelników monografię Otępienie czołowo-skroniowe: ujęcie interdyscyplinarne, która stanowi oryginalny zbiór odpowiednio dobranych rozdziałów, opracowanych przez autorów z różnych specjalności medycznych i paramedycznych zajmujących się diagnozą i rehabilitacją osób z otępieniem. Otępienie czołowo-skroniowe stanowi nadzwyczaj ważki i trudny temat dla współczesnej neuronauki. Temat jest ważki przede wszystkim dlatego, że problemy związane z otępieniem w starszych latach dotyczą wciąż wzrastającej liczby osób, co stanowi nieunikniony, choć dość paradoksalny skutek przedłużenia się życia przeciętnego człowieka, bez proporcjonalnej poprawy jego kondycji fizycznej i psychicznej. Oznacza to m.in., że najprawdopodobniej mało kto z nas (tj. sami autorzy wraz z Czytelnikami) uniknie tego problemu w przyszłości, a ten dość przykry fakt czasami utrudnia proces utrzymywania należytego dystansu naukowego do tematu. Wiele rozdziałów publikowanych w tej książce jest owocem 13. Międzynarodowego Kongresu Polskiego Towarzystwa Neuropsychologicznego, zorganizowanego przez Krakowską Akademię im. Andrzeja Frycza Modrzewskiego w dniach 22 do 24 lutego 2010 roku. Uczestnicy kongresu podjęli panelową dyskusję, mającą na celu syntezę przyczyn i objawów otępienia czołowo-skroniowego. Główne tezy z tej dyskusji wykorzystano również w przygotowywaniu rozdziałów tej monografii