Induction- and conditioning-protocol dependent involvement of NR2B-containing NMDA receptors in synaptic potentiation and contextual fear memory in the hippocampal CA1 region of rats

Table 1 Contextual fear memory induced by the one and five CS-US pairing protocols

Protocol	Pre-shock	48-h Retention Test
Protocol 1: 1 CS-US (US: 1.0 mA, 2.0 s)	11.27 ± 4.65	72.86 ± 3.20
Protocol 2: 5 CS-US (US: 1.0 mA, 0.5 s)	9.53 ± 2.05	90.00 ± 1.77 **

Data is expressed as the percentage of freezing (mean ± SEM). Protocol-1: n = 7; Protocol-2: n = 6. **p < 0.01 vs. Protocol 1, t-test.

ISSN: 1756-6606