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Present study has been carried out to assess whether early alterations of the behavioural structure may be detected in mice affected by Duchenne muscular dystrophy (DMD). To this purpose, both quantitative and T-pattern analysis (TPA) were used to analyse the behaviour of two groups of male, two months old mice, 18 MDX and 18 normal as control, tested in an open-field apparatus. T-pattern analysis is a multivariate technique able to reveal hidden structural features of behaviour and, in particular, its temporal characteristics. As to quantitative analyses, mean durations evidenced a significant increase of Walking, Modified Climbing and Rearing and a significant reduction of Immobile-Sniffing, Paw Licking and Immobility in MDX animals. A similar outcome was present in mean occurrences where the only difference was a significant result in Climbing rather than Immobile Sniffing. In addition, mean occurrences, evaluated for all the behavioural components, showed a significant increase for MDX mice. As to TPA, control mice performed 78 different T-patterns occurring 9500 times, whereas in MDX group 47 different T-patterns occurring 7082 times. Overall, MDX mice showed T-patterns of significantly shorter length. Finally, percent distribution of T-patterns encompassing each component of the behavioural repertoire showed significant differences between Control and MDX groups in all the behavioural components, except Climbing. Results suggest that the combined use of quantitative and temporal pattern analyses offers a useful approach to deeply investigate from a behavioural point of view pre-symptomatic stages of DMD in humans and related animal models as well., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The basal ganglia circuitry plays a crucial role in the sequential organization of behavior. Here we studied the behavioral structure of the animals after 21 days of 6-OHDA-induced lesion of the dopaminergic nigrostriatal system. Frequencies and durations of individual components of the behavioral repertoire were calculated; moreover, whether a temporal organization of the activity was present, it was investigated by using T-pattern analysis, a multivariate approach able to detect the real-time sequential organization of behavior. Six sham-depleted and six rats with unilateral 6-OHDA-lesion of the Substantia Nigra pars compacta were used. As to quantitative evaluations, the comparison between lesioned and unlesioned rats revealed significant differences only for the mean occurrences of Walking, Immobile Sniffing and Stretched Sniffing, reduced in lesioned subjects. All the remaining components of the behavior did not show significant changes. On the other hand, results from T-pattern analysis showed a reduction of the number of different T-patterns, of their mean length and of their occurrences in 6-OHDA-lesioned rats. Overall, these results suggest that the main deficit in 6-OHDA-lesioned subjects, rather than in the production of individual behavioral components, lies in deficiencies of their sequential organization., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of the present research was to study the effects of different basal levels of anxiety on the behavioral shift studied in the central platform of the elevated plus maze. To this purpose, quantitative and multivariate analyses, the latter based on transition matrix elaboration, were carried out on Wistar and on DA/Han rats the latter belonging to a strain characterized by different reactivity to anxiogenic stimuli. Wistar rats spent 74.11±5.11 s in the central platform, whereas DA/Han significantly more: 127.08±9.87. Per cent distributions evidenced a clear-cut difference in walking activities (46.25% in Wistar, 28.4% in DA/Han rats) and in the sniffing activities (45.82% in Wistar, 62.54% in DA/Han). Mean frequencies of each behavioral element showed in DA/Han strain a value significantly lower than in Wistar for central-platform entry, open arm-entry and closed-arm entry and a significant higher value for central- platform sniffing, open-arm sniffing and corner-rearing. Moreover, the ratio open-arm entry/open-arm sniffing and closed-arm entry/closed-arm-sniffing showed significant higher values in the Wistar strain. Finally, by means of hierarchical clustering analysis, strong differences between the two strains were observed in the behavioral architecture: a cascade-shaped dendrogram, branching from Walking activities, indicates that Wistar rat behavior is oriented to cross the central platform so to rapidly reach an arm; on the contrary, the dendrogram of DA/Han rats displays a behavior heavily oriented toward the permanence in the central platform. The results show that different basal levels of anxiety provoke significant differences in the behavioral shift studied in the central platform of the elevated plus maze. Such differences, evidenced by means of transition matrices elaboration, might represent the behavioral expression of anxiety-induced modifications of decision making process underlying behavioral shift activities., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Aim of the research was to study, by means of descriptive and multivariate analyses, whether, and how, learning influences the behavioral structure of rat response to pain. To this purpose, a hot-plate test daily repetition procedure was carried out on male Wistar rats for five days. A 6-day interval without stimulation elapsed before last test was carried out on day 12. After composition of an ethogram, descriptive (number, latency, per cent distribution) and multivariate analyses (cluster, stochastic) were carried out for each scheduled test day. One-way ANOVA and Newman-Keuls post-hoc test for multiple comparisons revealed significant changes for climbing, jumping, front-paw licking and stamping mean latencies. Student's t-test, carried out between days 1 and 12, showed that significant modifications persisted over time only for climbing and jumping. Cluster analysis evidenced three different clusters: exploratory (sniffing, walking), primary noxious evoked elements (front-paw licking, hind-paw licking, stamping), and escape (climbing and jumping), each showing modifications during test repetition. Comparison between days 1 and 12 revealed substantial differences in similarity values of escape patterns whereas, for the response to pain ones, a conservative structure of dendrograms was maintained. Stochastic analysis revealed a progressive increase of transitions toward jumping and a significant reduction of the ones between sniffing and walking. Such modifications persisted also after 6 days without any stimulation. Present study shows that learning provokes a complex and fine temporal evolution of the innermost behavioral structure of rat response to pain aiming at a more efficient escape strategy., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The aim of present research was to analyze the temporal structure of rodent's anxiety-related behavior in hole-board apparatus (HB). Fifteen male Wistar rats were tested for 10 min. Video files, collected for each subject, were coded by means of a software coder and event log files generated for each subject. To assess temporal relationships among behavioral events, log files were processed by means of a t-pattern analysis. 14 two-element t-patterns, four t-patterns encompassing 3 events and 2 t-patterns encompassing 4 and 5 events respectively were revealed. It was demonstrated that rat behavior in HB was mainly structured on the basis of the temporal patterning among exploratory events; these ones were the most structured t-patterns detected and appeared mainly during the first 5 min of exploration, while grooming t-patterns were present prevalently after the fifth minute. Specific t-pattern parameters, such as overall occurrences and mean duration of each given t-pattern in each subject, were also studied. Present research: (a) reports for the first time that some behavioral events occur sequentially and with significant constraints on the interval lengths separating them; (b) presents the temporal flows of some behavioral elements through multimodal behavioral vectors; (c) could also be used to improve HB test reliability and its ability to detect even small induced behavioral changes., (Copyright 2009 Elsevier B.V. All rights reserved.)

The influence of the mesolimbic-mesocortical dopaminergic (DA) system on the motor pattern evoked by substantia nigra pars compacta (SNpc) stimulation was studied. Electrical stimulation of the A10 group of neurons caused an inhibitory effect preferentially directed towards the orientation movement. Sulpiride administration at low dosages (50 mg/kg i.p.) did not modify this movement at the basal condition, but abolished the increase of its duration induced by ventral tegmental area (VTA) co-stimulation. Mesolimbic activation opposes the effects of SNpc stimulation, restraining the animal in its antero-posterior axis by means of orientation movement inhibition. The results suggest a role of the DA mesolimbic-mesocortical system in the maintenance of focused attention.

Head-turning and circling movements evoked by substantia nigra (pars compacta) (SNpc) stimulation have been ethologically analyzed in order to attribute a functional meaning to these lateralization processes. It has been shown that these motor acts, separated by a constant interval, may be considered a fixed action pattern. The duration of the single acts depends on the SNpc stimulation parameters: the increase in the stimulus strength produces an increase in the number of turns but does not induce the disappearance of the orientation movement. The body movement is always preceded by the head-movement. Haloperidol administration induces a dose-related increase of the orientation component of the motor pattern. These data together with others in the literature suggest the participation of the SNpc in the mechanism of shift in the focus of attention from one point to another in the contralateral surrounding environment.