Animals and Sample Size

All animals of the same batch were born within an interval of 2 weeks and were kept 5 females of mixed genotype to a cage, at standard laboratory conditions (12 hr dark/light cycle, constant room temperature and humidity, and standard lab chow and water ad libitum). All experimental measurements and behavioral studies were conducted with female mice only. All the tests described below were performed between 11 A.M. and 5 P.M. For each test, the mice were transported a short distance from the holding mouse facility to the testing room in their home cages or in the transport boxes filled with wooden bedding from their home cages.

All mice were maintained on a pure 129sv/ev genetic background except the inducible deletion Ocn model (Ocn osb ERT2) (Mix background: 25% C57/BL6 and 75% 129sv/ev). For inducible gene deletion, tamoxifen was prepared in corn oil, injected daily intraperitoneally (IP) (1 mg/20 g of body weight) for 7 days. Controls for the inducible inactivation of Ocn were α1Col1-Cre, Ocnflox/flox, and WT mice. Each group described is represented individually in each panel.

Longitudinal testing of the mice was performed on an extended battery of functional tests between 3 and 4 months of age, and mice weight was between 22 and 28 g. The TST, FST, EPM, DLT tests presented in this study were repeated on 4 different batches of mice (n > 12 for each groups of each batches), the MWMT and OFT were assessed on two independent batches of mice (n > 12 for each groups of each batches) and the CFC and NOR on one batch (n = 7–18 female mice per group). The tests were performed by an experimentalist blind to the genotypes of the mice under study and were approved by the Ethical Research Committee of Columbia University Medical Center.

Mayorga et al., 2001 Mayorga A.J.

Dalvi A.

Page M.E.

Zimov-Levinson S.

Hen R.

Lucki I. Antidepressant-like behavioral effects in 5-hydroxytryptamine(1A) and 5-hydroxytryptamine(1B) receptor mutant mice. Steru et al., 1985 Steru L.

Chermat R.

Thierry B.

Simon P. The tail suspension test: a new method for screening antidepressants in mice. TST (). Mice were transported a short distance from the holding facility to the testing room in their home cages and left there undisturbed for at least 1 hr. Each mouse was suspended by its tail 35 cm above the floor using adhesive tape (distance from tip of tail was 2 cm). Typically, mice demonstrated several escape-oriented behaviors interspersed with temporally increasing bouts of immobility. The parameter recorded was the number of seconds spent immobile. Mice were scored over a 5 min period, blind to the genotype of the mice.

David et al., 2009 David D.J.

Samuels B.A.

Rainer Q.

Wang J.W.

Marsteller D.

Mendez I.

Drew M.

Craig D.A.

Guiard B.P.

Guilloux J.P.

et al. Neurogenesis-dependent and -independent effects of fluoxetine in an animal model of anxiety/depression. OFT (). Mice were transported a short distance from the holding facility to the testing room in their home cages and left there undisturbed for at least 30 min. Each animal was placed in a 43 × 43 cm open field chamber, and tested for 30 min. Mice were monitored throughout each test session by video tracking and analyzed using Matlab software. Mice were placed individually into the center of the open-field arena and allowed to explore freely. The overall motor activity was quantified as the total distance traveled. Anxiety was quantified by measuring the number of rearings, and the percentage of the time and distance spent in the center versus periphery of the open-field chamber.

David et al., 2009 David D.J.

Samuels B.A.

Rainer Q.

Wang J.W.

Marsteller D.

Mendez I.

Drew M.

Craig D.A.

Guiard B.P.

Guilloux J.P.

et al. Neurogenesis-dependent and -independent effects of fluoxetine in an animal model of anxiety/depression. EPMT. Mice were transported a short distance from the holding facility to the testing room in their home cages and left there undisturbed for at least 1 hr. The EPMT was made of opaque plastic and consisted of four arms measuring each 7.6 cm in width and 35 cm in length, elevated 31cm above the floor. Two arms were enclosed by 15 cm high walls, the other two were open. Each mouse was placed in the center of the maze and allowed to explore the apparatus for 5 min. Global activity was assessed by the number of entries in the open arms () scored by an experimenter blind to the genotype of the mice. Anxiety was assessed by the time spent in the open arms.

David et al., 2009 David D.J.

Samuels B.A.

Rainer Q.

Wang J.W.

Marsteller D.

Mendez I.

Drew M.

Craig D.A.

Guiard B.P.

Guilloux J.P.

et al. Neurogenesis-dependent and -independent effects of fluoxetine in an animal model of anxiety/depression. Mouse FST (). Mice were transported a short distance from the holding facility to the testing room in their home cages and left there undisturbed for at least 30 min. Mice were placed individually into glass cylinders (height: 25 cm, diameter: 10 cm) containing 10 cm high water, maintained at 23°C–25°C. Briefly, mice were dropped individually into glass cylinders (height: 25 cm, diameter: 10 cm) containing 18 cm water height, maintained at 23°C–25°C. Animals were tested for a total of 6 min. The total duration of immobility time was recorded manually. Mice were considered immobile when they made no attempts to escape with the exception of the movements necessary to keep their heads above the water. The total duration of immobility was recorded.

Light and dark test (DLT) was performed in a quiet, darkened room. Mice were transported a short distance from the holding facility to the testing room in their home cages. Mice were next individually housed in cages containing a handful of bedding from their home cage and acclimated to the room at least 30 min before the test. The lit compartment was brightly illuminated with an 8 W fluorescent tube (400 lx). Naive mice were placed individually in the testing chamber in the middle of the dark area facing away from the doorway to the light compartment. The test lasted 5 min, the number of entries and the time spent in the lit compartment were recorded.

MWMT. The maze had a diameter of 150 cm and contained water (23°C) made opaque with non-toxic white paint. The pool was located in a brightly lit room with distal visual cues, including computer, tables and posters with geometric figures attached to the walls. Mice were transported to the testing room in their home cages filled with wooden bedding and left there undisturbed for at least 30 min. Spatial learning was assessed across repeated trials (4 trials/day for 10 days). During trials, a small platform (diameter 10 cm) was hidden beneath the surface at a fixed position. A 15 cm round platform was hidden 1 cm beneath the surface of the water at a fixed position. Each daily trial block consisted of four swimming trials (15 min, intertrial interval) starting randomly from each of four starting positions. Mice that failed to find the platform within 2 min were guided to the platform. They had to remain on the platform for 15 s before they were returned to their cages. Mice were placed in the water at the border of the maze and had to reach the platform after which they were transported back to their home cage. Mice that did not reach the platform within 2 min were gently guided toward the platform and were left on it for 10 s before being placed back in their cages. Four of such daily training trials (inter trial interval: 5 min) were given on 10 subsequent days. Starting positions in the pool varied between four fixed positions (0°, 90°, 180°, and 270°). Since a decrease in latency to find the platform was already present on the second acquisition day, the first acquisition day is also reported.

Ennaceur and Delacour (1988) Ennaceur A.

Delacour J. A new one-trial test for neurobiological studies of memory in rats. 1: Behavioral data. 2) and was divided into two equal halves so that two sessions could occur simultaneously. Mice could not contact or see one another during the exposures. The light intensity was equal in all parts of the arena (around 20 lx). We used three different objects; each object was available in triplicate. The objects were (1) a blue, ceramic shoe (diameter 9.5 cm, maximal height 6 cm); (2) a black, plastic (8 × 3 × 9.5cm3); and (3) a clear plastic funnel (diameter 8.5 cm, maximal height 8.5 cm). The objects elicited equal levels of exploration as determined in pilot experiments. NOR. We used a modified version of the NOR task described by. The testing room was lit with two 60-W light bulbs and behavior sessions were recorded with a camera above the testing arena. The testing arena was a white, plastic transport box (55 × 40 × 15cm) and was divided into two equal halves so that two sessions could occur simultaneously. Mice could not contact or see one another during the exposures. The light intensity was equal in all parts of the arena (around 20 lx). We used three different objects; each object was available in triplicate. The objects were (1) a blue, ceramic shoe (diameter 9.5 cm, maximal height 6 cm); (2) a black, plastic (8 × 3 × 9.5cm); and (3) a clear plastic funnel (diameter 8.5 cm, maximal height 8.5 cm). The objects elicited equal levels of exploration as determined in pilot experiments.

Denny et al., 2012 Denny C.A.

Burghardt N.S.

Schachter D.M.

Hen R.

Drew M.R. 4- to 6-week-old adult-born hippocampal neurons influence novelty-evoked exploration and contextual fear conditioning. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. Mice were transported to the testing room in the transport boxes filled with wooden bedding. The NOR paradigm was administered as previously described () with the exception that the NOR paradigm consisted of two 5 min exposures with a 3 min interexposure interval. Between exposures, mice were held individually in standard cages, the objects and arenas were cleaned using PDI sani-cloth HB germicidal Disposable Wipes (Orangeburg, NY, USA), and the bedding was replaced. In general, the effect of context was analyzed using an ANOVA, using repeated-measures where appropriate. Significant ANOVAs were follwed up with Fisher’s PLSD tests where appropriate. All main effects and interactions are noted in the text. All data were analyzed using StatView 5.0 software (SAS Institute, Cary, NC, USA). Alpha was set to 0.05 for all analyses. Data are expressed as means ± SEM.p < 0.05,p < 0.01,p < 0.001.

Denny et al. (2012) Denny C.A.

Burghardt N.S.

Schachter D.M.

Hen R.

Drew M.R. 4- to 6-week-old adult-born hippocampal neurons influence novelty-evoked exploration and contextual fear conditioning. Drew et al. (2010) Drew M.R.

Denny C.A.

Hen R. Arrest of adult hippocampal neurogenesis in mice impairs single- but not multiple-trial contextual fear conditioning. Wiltgen et al. (2006) Wiltgen B.J.

Sanders M.J.

Anagnostaras S.G.

Sage J.R.

Fanselow M.S. Context fear learning in the absence of the hippocampus. CFC. The three-shock CFC procedure was based on those of, and. For the three-shock CFC training procedure, mice were placed in the conditioning chamber, received 3 shocks at 180 s, 240 s, and 300 s later (2 s, 0.75 mA), and were removed 15 s following the last shock. For context exposure, mice were placed in to the chamber for 300 s. All data are shown as an average of the percentage of freezing across the 300 s exposures.

For context A exposures, the chambers had clear plastic front and back walls, stainless steel walls on each side, and stainless steel bars on the floor. A house light was mounted directly above the chamber. Each chamber was located inside a larger, insulated, plastic cabinet that provided protection from outside light and noise. Each cabinet contained a ventilation fan that was operated during the sessions. A paper towel dabbed with lemon solution was placed under the stainless steel bars. Between runs, the context was cleaned using PDI Sani-Cloth HB Germicidal Disposable Wipes (Orangeburg, NY, USA).

Context A′ was a modified context A. For context A′ exposures, the stainless steel bars were covered with a white plastic insert and there was no scent associated with the chamber.

Context B was also a modified context A. For context B exposures, the stainless steel bars were covered with a white plastic insert, the walls of the chambers were covered with colored plastic inserts so as to change the shape of the chamber, and the chamber was then filled with bedding. The chamber was scented with anise, and the mice were transported to the apparatus in a white bucket.

Significant ANOVAs were follwed up with Fisher’s PLSD tests where appropriate. All main effects and interactions are noted in the text. All data were analyzed using StatView 5.0 software (SAS Institute, Cary, NC, USA). Alpha was set to 0.05 for all analyses. Data are expressed as means ± SEM. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001.