Knockout mice exhibit impaired locomotor learning.

<p>(<i>A</i>). Rotarod performance by control (n = 12) and knockout (n = 11) animals across days; two-way, repeated-measures ANOVA: genotype effect <i>F</i>(1, 21) = 70.5, <i>P</i><0.001; day effect <i>F</i>(8, 168) = 1.63, <i>P</i> = 0.12; genotype x day effect <i>F</i>(8, 168) = 2.37, <i>P</i> = 0.02 (#<i>P</i><0.05); *<i>P</i><0.05, **<i>P</i><0.01, **<i>P</i><0.001 compared to trial 1 within genotype. (<i>B</i>) Latency to fall during a wire-grip test in control (n = 12) and knockout (n = 11) animals; <i>P</i> = 0.08 by unpaired t test.</p

Knockout mice are smaller than normal but have normal spontaneous locomotion, and intact exploratory behavior.

<p><i>(A)</i> Spontaneous locomotion by control (n = 10) and knockout (n = 11) animals; light cycle, <i>P</i> = 0.85; dark cycle, <i>P</i> = 0.93; total, <i>P</i> = 0.98 by unpaired t tests. (<i>B</i>). Body weight of 8-week-old animals; control (n = 15) and knockout (n = 12) males, <i>P</i><0.0001; control (n = 11) and knockout (n = 10) females, <i>P</i> = 0.002 by unpaired t tests; **<i>P</i><0.01; ***<i>P</i><0.0001. (<i>C</i>) Locomotor activity of control (n = 10) and knockout (n = 5) animals in an open field; <i>P</i> = 0.17 by unpaired t test. (<i>D</i>) Fraction of time spent in the center and periphery of the open field by control (n = 10) and knockout (n = 5) animals; <i>P</i> = 0.08 by unpaired t tests. (<i>E</i>) Number of open-field center crossings by control (n = 10) and knockout (n = 5) animals; <i>P</i> = 0.28 by unpaired t test.</p

Knockout mice fail to learn a simple (FR1) operant task.

<p>(<i>A</i>) Lever presses during operant conditioning sessions by control (n = 10) and knockout (n = 5) animals across days; two-way, repeated-measures ANOVA: genotype effect <i>F</i>(1, 13) = 15.72, <i>P</i> = 0.002; day effect <i>F</i>(6, 78) = 10.90, <i>P</i><0.001; genotype x day effect <i>F</i>(6,78) = 12.96, <i>P</i><0.001 (###<i>P</i><0.001); **<i>P</i><0.01, ***<i>P</i><0.001 compared to session 1 within genotype. (<i>B</i>) Latency to first lever press during operant conditioning sessions by control (n = 10) and knockout (n = 5) animals across days; two-way repeated measures ANOVA: genotype effect <i>F</i>(1, 13) = 38.75, <i>P</i><0.001; day effect <i>F</i>(6, 78) = 2.26, <i>P</i> = 0.04; genotype x day effect <i>F</i>(6,78) = 8.04, <i>P</i><0.001 (###<i>P</i><0.001); **<i>P</i><0.01, ***<i>P</i><0.001 compared to session 1 within genotype. (<i>C</i>) Total number of head entries during operant conditioning sessions by control (n = 10) and knockout (n = 5) animals across days; two-way repeated measures ANOVA: genotype effect <i>F</i>(1, 13) = 10.14, <i>P</i> = 0.007; day effect <i>F</i>(6, 78) = 1.93, <i>P</i> = 0.08; genotype x day effect <i>F</i>(6,78) = 2.25, <i>P</i> = 0.04 (#<i>P</i><0.05); *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 compared to session 1 within genotype.</p

Knockout mice that selectively lack NMDAR in striatal MSNs have abnormal MSN morphology.

<p><i>(A</i>) GPR88-CreGFP is expressed selectively in the striatum of knockout animals. A DAPI counterstain was performed. (<i>B</i>) NR1 Western blot of striatal (str) and cortical (cx) homogenates from control and knockout animals. (<i>C)</i> Representative micrographs and tracings of MSNs from control and knockout animals (20 µm scale bar). (<i>D)</i> Cell body size of MSNs in control and knockout mice (n = 18 neurons per genotype); <i>P</i> = 0.009 by unpaired t test; **<i>P</i><0.01. (<i>E)</i> Total MSN dendrite length in control and knockout mice (n = 18 neurons per genotype); <i>P</i> = 0.002 by unpaired t test; **<i>P</i><0.01. (<i>F)</i> Number of dendrites by dendrite order in control and knockout mice (n = 18 neurons per genotype); *<i>P</i><0.05 by unpaired t test. Diagram in (<i>F</i>) depicts the definition of dendrite order.</p