Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation

摘要

Inhibition of MEC input to hippocampus immediately after learning impairs long-term contextual fear memory formation. a Schematic depiction of bilateral AAV injection and optic ferrule implant site (left). Representative confocal microscopic pictures showing EGFP and eNpHR3.0-EYFP expression in MEC (top) and in the hippocampus (bottom). Asterisk indicates approximate position of the optic fiber tip. b Behavior scheme. c Histogram showing freezing level during test. eNpHR3.0 group (35.89 ± 3.21%, n = 11) showed significantly less freezing level compared to EGFP control group (53.13 ± 2.65%, n = 12) in LTM test. ***p < 0.0005; Student’s t-test. d Behavior scheme. e Histogram showing freezing level during test. eNpHR3.0 (50.31 ± 2.90%, n = 11) and EGFP (48.31 ± 4.27%, n = 10) group showed similar freezing level in LTM test. p > 0.05; Student’s t-test. n.s, not significant. f CAV and AAV injection strategy for retrograde labeling of MEC neurons projecting to hippocampus (left). Schematic depiction of bilateral CAV injection, AAV injection, and optic ferrule implant site (right). g Behavior scheme. h Histogram showing freezing level during test. eNpHR3.0 group (33.71 ± 4.06%, n = 11) showed significantly less freezing level compared to EYFP control group (50.13 ± 3.18%, n = 12) in LTM test. **p < 0.005; Student’s t-test. Data are presented as mean ± SEM