Computer controlled system

The light-dark box test was performed based on the procedure reported by Chocyk et al. [41 (link)]. To this purpose, we used an apparatus consisting of four cages with the computer-controlled system (TSE Systems, Bad Homburg, Germany). Each experimental box had two compartments: light (covering ¾ of the cage, brightly lit, 100 lx) and dark (covered with a lid), made of clear and black acrylic, respectively. Both sections were permeable to infrared light and were connected by a central gate (10.6 × 10.4 cm). Therefore, the two parts of the cage were freely accessible for the animals to explore. The experimental boxes were located in soundproof, ventilated cabinets, on bases containing integrated infrared sensors along the horizontal and the vertical axes. One hour before the test, the male rats at PND90 from the control and MIA groups were kept in total darkness. The entire experiment was also conducted in a dark room. At the beginning of each testing session, which lasted 10 min, an animal was placed in the one corner of the light compartment, facing away from the gate. The behavioural response during the trials was recorded by Fear Conditioning Software (TSE, Bad Homburg, Germany). Specifically, time spent in each compartment, distance travelled, and average speed were calculated for each animal.

The light dark-box test was performed according to the procedure described by Chocyk et al. [132 (link)]. An apparatus consisting of four cages with a computer-controlled system (TSE Systems, Bad Homburg, Germany) was used for the test. Each experimental box had two compartments: light (covering ¾ of the cage, brightly lit—100 lx) and dark (covered with a lid), made of transparent and black acrylic, respectively. Both chambers were permeable to infrared light and were connected by a central gate (10.6 cm × 10.4 cm). These two parts of the cage were freely available to animals for exploration. The experimental boxes were placed in soundproof, ventilated cabinets on the basis of integrated infrared sensors along the horizontal and vertical axes. The male rats at PND90 from the control and MIA groups were kept in darkness for an hour before the test. The whole experiment was carried out in a dark room. At the beginning of each 10-min test session, the animal was placed in one corner of the light compartment, facing away from the gate. The behavioural response of rats during the trials was recorded by Fear Conditioning Software (TSE, Bad Homburg, Germany). In particular, the time spent in each compartment, the distance travelled, and the average speed were calculated for each animal.

The light-dark box test was performed using an apparatus consisting of four cages with a computer-controlled system (TSE Systems, Bad Homburg, Germany) based on the procedure reported by Chocyk et al. [42 (link)]. Each experimental box had two compartments: light (covering ¾ of the cage, brightly lit – 100 lx) and dark (covered with a lid), which were made of clear and black acrylic, respectively. Both sections were permeable to infrared light and were connected by a central gate (10.6 cm × 10.4 cm). Therefore, the two parts of the cage were freely accessible for the animals to explore. The experimental boxes were located in soundproof, ventilated cabinets on base constructions that contained integrated infrared sensors along the horizontal and vertical axes. One hour before the test, male rats (PND88) were kept in total darkness. The entire experiment was also conducted in a dark room. At the beginning of each testing session, which lasted 10 min, an animal was placed in one corner of the light compartment, facing away from the gate. The behavioural response during the trials was recorded by Fear Conditioning Software (TSE, Bad Homburg, Germany). Specifically, the time spent in each compartment, the distance travelled and the average speed were calculated for each animal (n = 8–9 in the kLPS and LPS groups, n = 19–21 in the kPoly and Poly I:C groups).