Er two hours of anesthesia, the animals were replaced in the induction chamber, which was then flushed with oxygen. After recovery, the mice were returned to their home cages.on the board were changed randomly. Mice should learn that only marked cylinders are baited with food. According to previous studies [26?8], several cognitive functions were evaluated. A hole was counted as visited if the animal poked its nose over the rim of the cylinder. Omission errors were defined as the number of marked and baited holes, which were not visited at all during one trial. Wrong choices represents the number of non-marked holes, which were visited. The time each animal required for performing the trial (i.e. visiting all three baited holes; max. 5 min; time trial) indicates cognitive performance as well as the motivation to perform the test. Additionally to the assessment of the described cognitive parameters, the MHBT also allows an investigation of a variety of behavioral parameters that can be assigned to ethologically given and previously validated behavioral categories [26?8]. The number of times the mouse enters the board (board entries) served as an indicator for anxiety. The number of times the mice crossed the marked lines per minute (line crossings) was counted and assessed as an indicator for locomotor activity. In the experimental set-up, all mice were placed one after the other on the starting position in the experimental box and were allowed to explore the box freely for a maximum of five minutes or until they found and ate all three food Title Loaded From File rewards. Three days before anesthesia, each mouse was habituated to the food reward by receiving pieces of almond in their home cage. The test was performed on eight consecutive days (D1 to D8). The first examination took place 24 h (D1) after anesthesia or sham treatment. Four trials were carried out per day, with one trial lasting for a maximum of 300 s followed by a minimum of ten minutes inter-trial interval. Compared to other cognitive tests, e.g. the Morris water maze or the radial arm maze, the MHBT provides several advantages [29]. First, by supplying a highly attractive Title Loaded From File food-reward, the mice do not have to be deprived of food or water, which potentially could induce stress. Furthermore, they are motivated to perform the test voluntarily, and this also has been shown to avoid test inherent stress. Second, a variety of behavioral parameters can be evaluated in addition to cognitive parameters in one session, allowing for the assessment of altered motivational systems, which could potentially have an impact on cognitive performance. A recently published direct comparison showed that the MHBT is at least not inferior compared to the Morris water maze in assessing the functional outcome of rats in a model of cerebral ischemia [30].Cognitive testingThe modified hole board test (MHBT), which enables the investigation of cognitive, exploratory, and motivational parameters in rodents [26], was used to assess the cognitive performance of mice after sevoflurane anesthesia or sham treatment. The MHBT consists of an opaque grey polyvinyl chloride board on which ten cylinders (36363 cm) are placed in two lines. The board (3561861 cm) is placed in the middle of a polyvinyl chloride box (50650650 cm), thus representing the unprotected central area 1676428 of an open field. The outer protected area is divided into eight quadrants (16616 cm) by white lines. Each cylinder contains a small piece of almond (0.05 g), whi.Er two hours of anesthesia, the animals were replaced in the induction chamber, which was then flushed with oxygen. After recovery, the mice were returned to their home cages.on the board were changed randomly. Mice should learn that only marked cylinders are baited with food. According to previous studies [26?8], several cognitive functions were evaluated. A hole was counted as visited if the animal poked its nose over the rim of the cylinder. Omission errors were defined as the number of marked and baited holes, which were not visited at all during one trial. Wrong choices represents the number of non-marked holes, which were visited. The time each animal required for performing the trial (i.e. visiting all three baited holes; max. 5 min; time trial) indicates cognitive performance as well as the motivation to perform the test. Additionally to the assessment of the described cognitive parameters, the MHBT also allows an investigation of a variety of behavioral parameters that can be assigned to ethologically given and previously validated behavioral categories [26?8]. The number of times the mouse enters the board (board entries) served as an indicator for anxiety. The number of times the mice crossed the marked lines per minute (line crossings) was counted and assessed as an indicator for locomotor activity. In the experimental set-up, all mice were placed one after the other on the starting position in the experimental box and were allowed to explore the box freely for a maximum of five minutes or until they found and ate all three food rewards. Three days before anesthesia, each mouse was habituated to the food reward by receiving pieces of almond in their home cage. The test was performed on eight consecutive days (D1 to D8). The first examination took place 24 h (D1) after anesthesia or sham treatment. Four trials were carried out per day, with one trial lasting for a maximum of 300 s followed by a minimum of ten minutes inter-trial interval. Compared to other cognitive tests, e.g. the Morris water maze or the radial arm maze, the MHBT provides several advantages [29]. First, by supplying a highly attractive food-reward, the mice do not have to be deprived of food or water, which potentially could induce stress. Furthermore, they are motivated to perform the test voluntarily, and this also has been shown to avoid test inherent stress. Second, a variety of behavioral parameters can be evaluated in addition to cognitive parameters in one session, allowing for the assessment of altered motivational systems, which could potentially have an impact on cognitive performance. A recently published direct comparison showed that the MHBT is at least not inferior compared to the Morris water maze in assessing the functional outcome of rats in a model of cerebral ischemia [30].Cognitive testingThe modified hole board test (MHBT), which enables the investigation of cognitive, exploratory, and motivational parameters in rodents [26], was used to assess the cognitive performance of mice after sevoflurane anesthesia or sham treatment. The MHBT consists of an opaque grey polyvinyl chloride board on which ten cylinders (36363 cm) are placed in two lines. The board (3561861 cm) is placed in the middle of a polyvinyl chloride box (50650650 cm), thus representing the unprotected central area 1676428 of an open field. The outer protected area is divided into eight quadrants (16616 cm) by white lines. Each cylinder contains a small piece of almond (0.05 g), whi.
