Stereotyped, automatized and habitual behaviours: are they similar constructs under the control of the same cerebral areas?

Comprehensive knowledge about higher executive functions of motor control has been covered in the last decades. Critical goals have been targeted through many different technological approaches. An abundant flow of new results greatly progressed our ability to respond at better-posited answers to look more than ever at the challenging neural system functioning. Behaviour is the observable result of the invisible, as complex cerebral functioning. Many pathological states are approached after symptomatology categorisation of behavioural impairments is achieved. Motor, non-motor and psychiatric signs are greatly shared by many neurological/psychiatric disorders. Together with the cerebral cortex, the basal ganglia contribute to the expression of behaviour promoting the correct action schemas and the selection of appropriate sub-goals based on the evaluation of action outcomes. The present review focus on the basic classification of higher motor control functioning, taking into account the recent advances in basal ganglia structural knowledge and the computational model of basal ganglia functioning. We discuss about the basal ganglia capability in executing ordered motor patterns in which any single movement is linked to each other into an action, and many actions are ordered into each other, giving them a syntactic value to the final behaviour. The stereotypic, automatized and habitual behaviour's constructs and controls are the expression of successive stages of rule internalization and categorisation aimed in producing the perfect spatial-temporal control of motor command.

Targeted therapy of human glioblastoma via delivery of a toxin through a peptide directed to cell surface nucleolin

Targeted anticancer therapies demand discovery of new cellular targets to be exploited for the delivery of toxic molecules and drugs. In this perspective, in the last few years, nucleolin has been identified as an interesting surface marker to be used for the therapy of glioblastoma. In this study, we investigated whether a synthetic antagonist of cell-surface nucleolin known as N6L, previously reported to decrease both tumor growth and tumor angiogenesis in several cancer cell lines, including glioblastoma cells, as well as endothelial cells proliferation, could be exploited to deliver a protein toxin (saporin) to glioblastoma cells. The pseudopeptide N6L cross-linked to saporin-S6 induced internalization of the toxin inside glioblastoma cancer cells. Our results in vitro demonstrated the effectiveness of this conjugate in inducing cell death, with an ID50 four orders of magnitude lower than that observed for free N6L. Furthermore, the preliminary in vivo study demonstrated efficiency in reducing the tumor mass in an orthotopic mouse model of glioblastoma.

Neural network subtyping of depression

OBJECTIVE

To examine the applicability of a neural network classification strategy to examine the independent contribution of psychomotor disturbance (PMD) and endogeneity symptoms to the DSM-III-R definition of melancholia.

METHOD

We studied 407 depressed patients with the clinical dataset comprising 17 endogeneity symptoms and the 18-item CORE measure of behaviourally rated PMD. A multilayer perception neural network was used to fit non-linear models of varying complexity. A linear discriminant function analysis was also used to generate a model for comparison with the non-linear models.

RESULTS

Models (linear and non-linear) using PMD items only and endogeneity symptoms only had similar rates of successful classification, while non-linear models combining both PMD and symptoms scores achieved the best classifications.

CONCLUSIONS

Our current non-linear model was superior to a linear analysis, a finding which may have wider application to psychiatric classification. Our non-linear analysis of depressive subtypes supports the binary view that melancholic and non-melancholic depression are separate clinical disorders rather than different forms of the same entity. This study illustrates how non-linear modelling with neural networks is a potentially fruitful approach to the study of the diagnostic taxonomy of psychiatric disorders and to clinical decision-making.

Suicide among young Australians, 1964-1993: an interstate comparison of metropolitan and rural trends

OBJECTIVES

(i) To compare suicide rates in 15-24 year old men and women; and (ii) for 15-24 year old men, to investigate differences in suicide rates between metropolitan and rural area, and changes in method-specific suicide rates and, in particular, firearm and hanging suicide rates in rural and metropolitan areas.

DESIGN

Retrospective analysis of Australian Bureau of Statistics (ABS) suicide data (1964-1993).

SETTING

All Australian States.

SUBJECTS

Young women and men aged 15-24 years who died by suicide.

RESULTS

Male youth suicide rates rose substantially over the 30 years in all Australian States, whereas female rates did not increase. Increases in suicide rates in young men in small rural towns consistently exceeded those in metropolitan areas in all Australian States. Metropolitan rates in 1964 were higher than those in small rural towns, but by 1993 the position was reversed. Medium-sized cities were the only areas where there was no consistent interstate trend. Differences were noted in suicide base rates in different States. High car exhaust suicide rates were noted in Western Australia, and high firearm suicide rates in Tasmania and Queensland. The ratio of firearm suicide rates in small rural areas to those in metropolitan areas rose in all mainland States, but the same ratio for hanging suicide rates changed little.

CONCLUSIONS

All Australian States reflect national suicide trend in relation to sex and residential area. In some States, particular suicide methods predominate. A decreasing trend in overall firearm suicide rates in young men in all States from 1984 to 1993 conceals substantial increases in firearm suicide rates in small rural areas in all mainland States over the 30-year period. This, together with the marked rate ratio difference in firearm suicides between metropolitan and small rural areas, suggests that particular risk factors for suicide are operating in small rural areas. The fact that hanging rate ratios changed little suggests that more general factors in male youth suicide are also operating in all areas. A better understanding of similarities and differences in health risks faced by metropolitan and rural youth is required.