Differences in Spontaneously Avoiding or Approaching Mice Reflect Differences in CB1-Mediated Signaling of Dorsal Striatal Transmission

Approach or avoidance behaviors are accompanied by perceptual vigilance for, affective reactivity to and behavioral predisposition towards rewarding or punitive stimuli, respectively. We detected three subpopulations of C57BL/6J mice that responded with avoiding, balancing or approaching behaviors not induced by any experimental manipulation but spontaneously displayed in an approach/avoidance conflict task. Although the detailed neuronal mechanisms underlying the balancing between approach and avoidance are not fully clarified, there is growing evidence that endocannabinoid system (ECS) plays a critical role in the control of these balancing actions. The sensitivity of dorsal striatal synapses to the activation of cannabinoid CB1 receptors was investigated in the subpopulations of spontaneously avoiding, balancing or approaching mice. Avoiding animals displayed decreased control of CB1 receptors on GABAergic striatal transmission and in parallel increase of behavioral inhibition. Conversely, approaching animals exhibited increased control of CB1 receptors and in parallel increase of explorative behavior. Balancing animals reacted with balanced responses between approach and avoidance patterns. Treating avoiding animals with URB597 (fatty acid amide hydrolase inhibitor) or approaching animals with AM251 (CB1 receptor inverse agonist) reverted their respective behavioral and electrophysiological patterns. Therefore, enhanced or reduced CB1-mediated control on dorsal striatal transmission represents the synaptic hallmark of the approach or avoidance behavior, respectively. Thus, the opposite spontaneous responses to conflicting stimuli are modulated by a different involvement of endocannabinoid signaling of dorsal striatal neurons in the range of temperamental traits related to individual differences

Effectiveness of professionally-guided physical education on fitness outcomes of primary school children

Physical education (PE) at school is an important starting point for long-term interventions improving quality of life in elderly. To evaluate the effectiveness of professionally led PE on motor and health-related abilities of Italian primary schoolchildren (3rd–5th graders), three schools were assigned to the experimental groups “A” (38 pupils, 17 M, 21 F) and “B” (37 pupils, 16 M, 21 F), and to control group “C” (26 pupils, 18 M, 8 F). All groups underwent a six-month, twice-a-week (60 min each session) PE intervention. The PE program of the EGs was age-tailored, included strength training and was administered by specialised teachers. Group A and B programs differed in the strength training devices used, while they were identical in terms of training load. The control group program was not structured and administered by generalist teachers. At baseline and follow-up, children underwent a motor and health-related abilities test battery. At follow-up, children in group C gained significantly more weight than children in the EGs and scored significantly less than the children in the EGs in the following assessments: counter movement jump (C:+0.15% vs. A:+4.1% and B:+6.99%), plate tapping (C:+13.56% vs. A:+19.37% and B:+36.12%), sit-and-reach (C:−311.15% vs. B:+409.57%), pinch strength (C:+2.39% vs. B:+10.83, on average) and sit-up (C:+29.69% vs. A:+72.61%). In conclusion, specialist-led pupils demonstrated greater increases in some motor and health-related abilities tests compared to generalist-led peers, while different strength training devices produced comparable increases of strength in both EGs

Strength training in pre-pubertal children: a school based physical education approach

In the last decades, muscular fitness in European children has been decreasing (1-3). Strength training, if handled by qualified physical educators, is a safe and effective method to improve muscular fitness (4). Nevertheless, strength training has only a marginal role in Italian elementary school physical education curriculum. In this study, 101 pre-pubertal school children (50 M, 51 F; 7 to 10 year old) have been assigned to 2 experimental groups (EGs: ‘Kids’, ‘KLess’) and 1 control group (CG: ‘None’). KLess underwent a 6 month (2 times per week) physical education protocol concerning both basic motor abilities and health-related physical abilities, taught by qualified physical educators. Kids underwent the same protocol, except the use of a specific fitness equipment (Kid’s System; Panatta Sport). Lessons of None were completely taught by non specifically qualified teachers. Strength were assessed (pre- and post-study) in: hands and forearms (pinch-strength; hand-grip); abdomen (sit-up); lower limbs (Standing Long Jump [SLJ] and Counter Movement Jump [CMJ and CMJ-arms-free]). A two-way analysis of variance (group and gender) was performed to compare the means and the Bonferroni test was applied for multiple comparisons. Results show a general strength increase in all groups, except for pinch-strength and CMJ-arms-free tests in the CG. Statistical analysis shows a greater increase of strength in the EGs: significant (p<.05) for the CMJ-arms-free test and highly significant (p<.01) for both the pinch-strength and the sit-up tests. No children had muscular injury while strength increased. Most tests showed a significantly higher strength increase in the EGs who’s physical education protocol was handled by qualified physical educators. In conclusion, pre-pubertal strength training should be included in the elementary school physical education curriculum as a safe and effective method to improve strength in children provided its handling by qualified physical education teachers. Bibliography 1) Heeboll-Nielsen, K. Muscle strength of boys and girls, 1981 compared to 1956. Scandinavian journal of sports sciences 4: 37-43, 1982. 2) Ekblom O, Oddsson K, and Ekblom B. Health-related fitness in Swedish adolescents between 1987 and 2001. Acta Paediatr 93: 681-686, 2004. 3) Przeweda R and Dobosz J. Growth and physical fitness of Polish youths in two successive decades. J Sports Med Phys Fitness 43: 465-474, 2003. 4) Bernhardt DT et al. Strength training by children and adolescents. Pediatrics 107: 1470-1472, 2001

Behavioral responses of avoiding (AV), balancing (BA), and approaching (AP) mice in the EPM.

<p>All animals regardless the category they belonged to spent more time in the close arms, exhibiting thus the normal open arm avoidance.</p