Neurosciences

The minimum frustration principle is a computational approach which states that, in the long timescales of evolution, proteins’ freeenergy decreases more than expected by thermodynamical contraints as their aminoacids assume conformations progressively closer to the lowest energetic state. Here we show that this general principle, borrowed from protein folding dynamics, can be fruitfully applied to nervous function too. Highligting the foremost role of energetic requirements, macromolecular dynamics, and, above all, intertwined timescales in brain activity, the minimum frustration principle elucidates a wide range of mental processes, from sensations to memory retrieval. Brain functions are compared to trajectories which, in long nervous timescales, are attracted towards the lowenergy bottom of funnel-like structures characterized both by robustness and plasticity. We discuss how the principle, as derived explicitly from evolution and selection of a funneling structure from microdyn...

Matrix coils are based on Gugliemi detachable coils (GDC) but are covered with polyglycolic/polylactic acid. We present our experience regarding the immediate posttreatment results of aneurysm embolization using the 2 coil systems. We embolized 219 aneurysms in 187 patients with the use of GDCs and 145 aneurysms in 120 patients with the use of Matrix coils. Age, sex distribution, unruptured aneurysm cases, and multiple aneurysm cases were similar in the 2 groups. The percentage of patients in severe clinical condition was significantly higher in the Matrix group. The mean aneurysm size was slightly larger in the GDC group but the mean neck size was larger in the Matrix group. Satisfactory occlusion (at least 90%) was achieved in 95.9% of GDC-treated aneurysms and in 98.6% of Matrix-treated aneurysms. Procedure-related complications occurred in 19.6% of GDC procedures and in 15.6% of the Matrix ones resulting in procedure-related mortality and morbidity of 3.7% and 2.7% for the GDC g...

In this fMRI study we investigated functional connectivity between components of the mentalising system during a social emotion task, using psychophysiological interaction (PPI) analysis. Ten adults (22–32 years) and 18 adolescents (11–18 years) were scanned while thinking about scenarios in which a social or a basic emotion would be experienced. Unlike basic emotions (such as disgust and fear), social emotions (such as embarrassment and guilt) require the representation of another’s mental states. In both adults and adolescents, an anterior rostral region of medial prefrontal cortex (arMPFC) involved in mentalising showed greater connectivity with the posterior superior temporal sulcus (pSTS) bordering on the temporo-parietal junction (TPJ) and with anterior temporal cortex (ATC) during social than during basic emotion. This result provides novel evidence that components of the mentalising system interact functionally during a social emotion task. Furthermore, functional connectivity differed between adolescence and adulthood. The adolescent group showed stronger connectivity between arMPFC and pSTS/TPJ during social relative to basic emotion than did the adult group, suggestive of developmental changes in functional integration within the mentalising system.

Much research in the last two decades has demonstrated that human responses deviate from the performance deemed normative according to various models of decision making and rational judgment (e.g., the basic axioms of utility theory). This gap between the normative and the descriptive can be interpreted as indicating systematic irrationalities in human cognition. However, four alternative interpretations preserve the assumption that human behavior and cognition is largely rational. These posit that the gap is due to (1) performance errors, (2) computational limitations, (3) the wrong norm being applied by the experimenter, and (4) a different construal of the task by the subject. In the debates about the viability of these alternative explanations, attention has been focused too narrowly on the modal response. In a series of experiments involving most of the classic tasks in the heuristics and biases literature, we have examined the implications of individual differences in performa...

This review will discuss the latest knowledge of how the endocannabinoid system might be involved in treating addiction to the most common illicit drugs. Experimental models are providing increasing evidence for the pharmacological management of endocannabinoid signaling not only to block the direct reinforcing effects of cannabis, opioids, nicotine and ethanol, but also for preventing relapse to the various drugs of abuse, including opioids, cocaine, nicotine, alcohol and metamphetamine. Preclinical and clinical studies suggest that the endocannabinoid system can be manipulated by the CB1 receptor antagonist SR141716A, that might constitute a new generation of compounds for treating addiction across different classes of abused drugs.

The two contrasting theoretical approaches to visual perception, the constructivist and the ecological, are briefly presented and illustrated through their analyses of space and size perception. Earlier calls for their reconciliation and unification are reviewed. Neurophysiological, neuropsychological, and psychophysical evidence for the existence of two quite distinct visual systems, the ventral and the dorsal, is presented. These two perceptual systems differ in their functions; the ventral system's central function is that of identification, while the dorsal system is mainly engaged in the visual control of motor behavior. The strong parallels between the ecological approach and the functioning of the dorsal system, and between the constructivist approach and the functioning of the ventral system are noted. It is also shown that the experimental paradigms used by the proponents of these two approaches match the functions of the respective visual systems. A dual-process approa...

This study was performed with the aim of determining the diagnostic profile of newborns with hypotonia and of analyzing the usefulness of different procedures in the diagnostic process. One hundred thirty-eight hypotonic newborns were identified through the search of hospital records in a 10-year period: 121 (88%) had central hypotonia and 13 (9%) had peripheral hypotonia, whereas 4 (3%) remained unclassified. Analysis of the contribution of clinical data and results of investigations led to the construction of an algorithm, by which all cases in the group were diagnosed. Step 1, which included clinical data and results of examinations, solved 50% of all diagnosed cases. Neuroimaging techniques made up step 2 and contributed to the diagnosis in 13%. Step 3 was accomplished by a search through Oxford Medical Databases, which yielded the final diagnosis in 9%, whereas karyotyping and fluorescent in situ hybridization for Prader-Willi syndrome comprised step 4 and contributed to the di...