Figure 1.
The performance of wildtype and NK1R-/- mice during training in the 5-CSRTT.
% Omissions, perseveration and latency to collect the reward are all greater in NK1R-/- mice than wildtypes, regardless of time of day (A–C). There was no difference in accuracy (D) or latency to correct response (E), but premature responses (F) were greater in wildtypes, especially during Stage 3 of training. Points show mean ± s.e.m. * P<0.05, ** P<0.01, *** P<0.001. N = 23–24 per group.
Figure 2.
The performance of wildtype and NK1R-/- mice tested with a long ITI (‘LITI’) in the 5-CSRTT.
% Omissions (A), perseveration score (B) and latency to collect the reward (C) are all greater in NK1R-/- mice than wildtypes, regardless of time of day, when tested with a long inter-trial interval (LITI). Bars show mean ± s.e.m score for each behavior. N = 23–24 per group. * P<0.05, ** P<0.01, *** P<0.001.
Table 1.
Behavior of the two cohorts of untreated mice in the VITI test.
Figure 3.
The performance of wildtype and NK1R-/- mice tested with a variable ITI (‘VITI’) in the 5-CSRTT.
NK1R-/- mice show greater % omissions (A), perseveration score (B) latency to correct response (C), % premature responses (D) but lower % accuracy (E) than wildtypes and no difference in latency to collect the reward (F), regardless of time of day, when tested with a variable inter-trial interval (VITI). Bars show mean ± s.e.m for each behavioral score. * P<0.05, ** P<0.01, *** P<0.001 for differences between group means. N = 23–24 per group.
Figure 4.
Effects of d-amphetamine on the behavior of wildtype and NK1R-/- mice tested with the LITI in the 5-CSRTT.
The perseveration score of NK1R-/- mice is exacerbated by saline injection but ameliorated by d-amphetamine: the latter has no effect in the wildtypes (A). d-Amphetamine has no effect on % omissions in either genotype (B) but increases latency to reward in wildtypes (C) and latency to correct response (D) in both genotypes. Bars show mean ± s.e.m for the behavior of either untreated mice, tested for the second time with the LITI (NI-2), or mice given an i.p. injection of saline (Sal) or d-amphetamine (0.3 mg/kg, ‘A(0.3)’ or 1 mg/kg, ‘A(1)’). The mice experienced each treatment, once only, at weekly intervals. The sequence of treatments (including NI-2) was pseudo-randomised (latin-square) across the subjects. The black line linking adjacent bars indicates a genotype difference, regardless of time of day, of P<0.05, at least. N = 12 per group. * P<0.05, ** P<0.01, *** P<0.001 for comparisons of group means indicated above the bars.
Figure 5.
Effects of d-amphetamine on the behavior of wildtype and NK1R-/- mice tested with the VITI in the 5-CSRTT.
d-Amphetamine did not affect % omissions (A) or perseveration score (B) but increased latency to collect the reward in both genotypes (C) and % premature responses in NK1R-/- mice (D). d-Amphetamine slightly reduced the % accuracy of wildtypes, only (E). Bars show mean ± s.e.m for the behavior of either untreated mice, tested for the second time with the VITI (NI-2), or mice given an i.p. injection of saline (Sal) or d-amphetamine (0.3 mg/kg, ‘A(0.3)’ or 1 mg/kg, ‘A(1)’). The mice experienced each treatment once only, at weekly intervals. The sequence of treatments (including NI-2) was pseudo-randomised (Latin-square) across the subjects. The black line linking adjacent bars indicates a genotype difference of P<0.05, at least, regardless of time of day. N = 11-12 per group. * P<0.05, ** P<0.01, *** P<0.001 of comparisons of groups means indicated above the bars.
Figure 6.
Behaviors of NK1R-/- and wildtype mice in the 5-CSRTT that depend on time of day.
(A) the number of sessions needed to train mice to baseline criteria for testing; (B) % premature responses during stage 3 of training; (C) % premature responses in the LITI test; (D) % omissions in the VITI test. Bars show mean ± s.e.m. * P<0.05, ** P<0.01 for comparisons indicated. N = 23–24 per group.
Table 2.
Schedule for stimulus parameters during Stages 1 to 6 (training) and testing in the 5-CSRTT.