Structural analyses in the study of anxiety and anxiety-related behaviour

According to the latest Diagnostic and Statistical Manual of Mental Disorders, 5th edition, anxiety encompasses various conditions sharing an excessive sense of fear and/or apprehension for no evident reason and related behavioural disturbances (Association, 2013). The association of such a gloomy symptomatology, with the great diffusion in the general population, explains the critical impact of anxiety disorders on inter-personal relationships and job-related activities (Greenberg et al.,1999; Wittchen & Hoyer, 2001; Keeley & Storch, 2009). Hence, anxiety disorders represent an important and consistent topic of discussion, not only in terms of underlying neuro-psychological processes but, importantly, also in terms of behavioral dynamics. In such a context, behavioral neurosciences play a central role in understanding anxiety. Different assays are available to study the characteristics of anxiety-related behavior, such as the open- field (OF), the hole-board (HB) and the Elevated Plus Maze (EPM).peer-reviewe

Lateral habenula regulates temporal pattern organization of rat exploratory behavior and acute nicotine-induced anxiety in hole board

Nicotine is one of the most addictive drugs of abuse. Tobacco smoking is a major cause of many health problems worldwide, and is the first preventable cause of death. Several findings show that nicotine exerts significant aversive as well as the well-known rewarding motivational effects. Less certain is the anatomical substrate that mediates or enables nicotine aversion. Here we have focused on nicotine-induced anxiety-like behavior in unlesioned and lesioned lateral habenula (LHb) rats. Firstly, we showed that acute nicotine induces anxiogenic effects in rats at the doses investigated (0.1, 0.5, and 1.0 mg/kg, i.p.) as measured by the hole-board apparatus, and manifested in behaviors such as decreased rearing and head-dipping and increased grooming. No changes in locomotor behavior were observed at any of the nicotine doses given. T-pattern analysis of the behavioral outcomes revealed a drastic reduction and disruption of complex behavioral patterns induced by all three nicotine doses, with the maximum effect for 1 mg/kg. Lesion of the LHb induced a significant anxiogenic effect, reduced the mean occurrences of T-patterns detected, and strikingly reverted the nicotine-induced anxiety to an anxiolytic effect. We suggest that LHb is critically involved in emotional behavior states and in nicotine-induced anxiety, most likely through modulating serotonergic/dopaminergic nuclei.peer-reviewe

Prior test experience produces changes of t-patterns spatial distribution in the elevated plus maze test

Aim of present research was to investigate in male Wistar rats whether a prior elevated plus maze experience modifies the temporal structure of the behavioral response following a retest applied after 24h. Video files were coded by means of a software coder and event log files generated for each subject were analyzed by means of a specific software for temporal pattern analysis (Theme). Present research shows a clear reduction of the number of t-patterns from trial one to trial two. This reduction is provoked by the disappearance of t-patterns consisting of behavioral elements occurring in the unprotected zones of the maze. The results suggest that the previous experience in the maze causes learning-dependent behavioral changes inducing a more clear-cut response to environmental anxiogenic conditions

Structural analyses in the study of behavior: From rodents to non-human primates

The term "structure" indicates a set of components that, in relation to each other, shape an organic complex. Such a complex takes on essential connotations of functionally unitary entity resulting from the mutual relationships of its constituent elements. In a broader sense, we can use the word "structure" to define the set of relationships among the elements of an emergent system that is not determined by the mere algebraic sum of these elements, but by the interdependence relationships of these components from which the function of the entire structure itself derives. The behavior of an integrated living being can be described in structural terms via an ethogram, defined as an itemized list of behavioral units. Akin to an architectural structure, a behavioral structure arises from the reciprocal relationships that the individual units of behavior establish. Like an architectural structure, the function of the resulting behaving complex emerges from the relationships of the parts. Hence, studying behavior in its wholeness necessitates not only the identification of its constitutive units in their autarchic individuality, but also, and importantly, some understanding of their relationships. This paper aimed to critically review different methods to study behavior in structural terms. First, we emphasized the utilization of T-pattern analysis, i.e., one of the most effective and reliable tools to provide structural information on behavior. Second, we discussed the application of other methodological approaches that are based on the analysis of transition matrices, such as hierarchical clustering, stochastic analyses, and adjusted residuals. Unlike T-pattern analysis, these methods allow researchers to explore behavioral structure beyond its temporal characteristics and through other relational constraints. After an overview of how these methods are used in the study of animal behavior, from rodents to non-human primates, we discussed the specificities, advantages and challenges of each approach. This paper could represent a useful background for all scientists who intend to study behavior both quantitatively and structurally, that is in terms of the reciprocal relationships that the various units of a given behavioral repertoire normally weave together

Alcohol, Cannabinoids and Nicotine in liver pathophysiology

The liver can be affected by a wide range of therapeutic and environmental chemicals and here we want to provide a summary of the complex effects of alcohol, cannabinoids and nicotine on liver function. Alcohol is the most important agent that produces liver injury, manifesting as alcoholic fatty liver disease. In addition, it is one of the main etiologic agents for hepatocellular carcinoma development. Studies reviewed in this article regarding cannabinoids, show that Δ9-THC does not produce any harmful effects on the liver, while cannabidiol has hepatoprotective effects in ischemia/reperfusion and alcohol-induced liver injuries. The liver is negatively affected by nicotine exposure, but surprisingly nicotine was shown to have a positive effect on the liver in the diet-induced obese animal model, which should be confirmed by future research.peer-reviewe