Figure 1.
Hippocampal asymmetry and right isomerism of the iv/iv mouse hippocampus.
Left and right CA3 pyramidal neurons and their axons are colored red and blue, respectively. A postsynaptic CA1 pyramidal neuron is at the center, colored black, and it represents postsynaptic neurons in both left and right hemispheres. Closed and open circles represent ε2-dominant andε2-nondominant synapses, respectively. Apical, apical dendrites; Basal, basal dendrites.
Figure 2.
Schematic illustration of apparatus and experimental procedure.
(A) The front and back panel of the operant conditioning chamber, and (B) the delayed nonmatching-to-position task sequence.
Figure 3.
(A) Latency to reach the food-baited hole. Here and elsewhere in the legends, error bar shows the standard error of the mean. (B) Distance traveled to reach the food-baited hole.
Figure 4.
Exploratory behavior during the probe trial of the dry maze.
(A) Time spent exploring in quadrants of the open field during the probe trial (NE: north east, NW: north west; SE: south east, SW: south west). NE was the target quadrant, which contained the food-baited hole. A dashed line indicates the prediction from chance. Both groups explored the target quadrant containing the food-baited hole longer than would be expected from chance. (B) The coarse spatial distribution of exploratory behaviors during the probe trial. The open field was fitted into a 10×10 square matrix, and the duration spent in each cell was averaged across subjects and then contour plotted using spline interpolation. Orange circles indicate the location of the food-baited hole during training. The exploratory behavior of the iv/+ mice was more focused around the baited hole, whereas it was less focused in iv/iv mice.
Figure 5.
Acquisition of the delayed nonmatching-to-position (DNMTP) in iv/iv and iv/+ mice.
During DNTP training with a 0-s programmed delay interval, both iv/iv and iv/+ mice acquired the task equally fast.
Figure 6.
Retention accuracy of the delayed nonmatching-to-position (DNMTP).
(A) The delayed nonmatching performance was evaluated using the proportion correct, calculated for 5-s bins of retention intervals (the length of time between sample and comparison responses) for iv/iv and iv/+ mice in the last 20 sessions. (B) Mean discriminability as a function of retention interval for iv/iv and iv/+ mice. Parameter values for the best-fitting exponentials (solid and dashed curves) are given for the two groups. The data are based on the performances in Test 3. Log d0 indicates the discriminability at 0-s delay and b indicates the rate of forgetting. Measures of variance in the data accounted for (VAC) by the best fitting functions by Equation 2 indicate the fitting was satisfactory.