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Protein synthesis and degradation are required for the incorporation of modified information into the pre-existing object-location memory.

Choi JH, Kim JE, Kaang BK - Mol Brain (2010)

Bottom Line: In this study, we utilized an object rearrangement task, in which partial information related to a pre-existing memory is changed, promoting memory modification.Inhibitors of both protein synthesis and protein degradation impaired adequate incorporation of the altered information, each in a distinctive way.These results indicate that protein synthesis and degradation play key roles in memory modification.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Creative Research Initiative Center for Memory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, 151-742 Seoul, Korea.

ABSTRACT
Although some reports indicate that protein synthesis dependent process may be induced by updating information, the role of protein synthesis and degradation in changing the content of pre-existing memory is yet unclear. In this study, we utilized an object rearrangement task, in which partial information related to a pre-existing memory is changed, promoting memory modification. Inhibitors of both protein synthesis and protein degradation impaired adequate incorporation of the altered information, each in a distinctive way. These results indicate that protein synthesis and degradation play key roles in memory modification.

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Protein synthesis and degradation is required to appropriately incorporate partially modified information. A, Schematic view of the task. The process is similar as in Figure 1A, except that the mice have received intrahippocampal injection right after day 2 exposure. B, Cannula location in the hippocampus, at two different rostro-caudal planes. Numbers indicate the posterior direction from the bregma. Grey, blue, red, and purple circles indicate the infusion site of vehicle, βlac, anisomycin, and βlac plus anisomycin double infusion group, respectively. C, Preference to unswitched and switched objects at the third day (Veh, vehicle, n = 10; Ani, anisomycin, n = 7; βlac, clasto-lactacystin-β-lactone, n = 7; Ani+ βlac, n = 4. F = 9.869, p = 0.0002; one-way ANOVA. *p < 0.05, **p < 0.01, ***p < 0.001; unpaired t test). D, Preference to unswitched and switched objects at the second day.
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Figure 2: Protein synthesis and degradation is required to appropriately incorporate partially modified information. A, Schematic view of the task. The process is similar as in Figure 1A, except that the mice have received intrahippocampal injection right after day 2 exposure. B, Cannula location in the hippocampus, at two different rostro-caudal planes. Numbers indicate the posterior direction from the bregma. Grey, blue, red, and purple circles indicate the infusion site of vehicle, βlac, anisomycin, and βlac plus anisomycin double infusion group, respectively. C, Preference to unswitched and switched objects at the third day (Veh, vehicle, n = 10; Ani, anisomycin, n = 7; βlac, clasto-lactacystin-β-lactone, n = 7; Ani+ βlac, n = 4. F = 9.869, p = 0.0002; one-way ANOVA. *p < 0.05, **p < 0.01, ***p < 0.001; unpaired t test). D, Preference to unswitched and switched objects at the second day.

Mentions: As our aim was to focus on the associative memory between the objects and their location, we targeted hippocampus which seems to be more specifically involved in object-location memory [13,14]. Hippocampus is known to be important for object-location memory [14-17]; although other regions such as mPFC and perirhinal cortex are also implicated in such tasks, they are probably more involved in novelty processing. Especially, it was recently reported that PKMzeta inhibitor destructed object location memory, but not object identity memory, when it was locally applied in hippocampus [18]. We implanted guide cannulae one week before the behavioral procedure and injected the protein synthesis inhibitor anisomycin (Ani; 200 μg/μl in aCSF, 0.3 μl) and/or the proteasome inhibitor clasto-lactacystin-β-lactone (βlac; 32 ng/μl in aCSF, 0.3 μl) or vehicle (Veh; aCSF, 0.3 μl) in the CA1 region of dorsal hippocampus, bilaterally, right after the exposure to the changed object location on day 2 (Figure 2A). Position of the cannulae tips are shown in Figure 2B.


Protein synthesis and degradation are required for the incorporation of modified information into the pre-existing object-location memory.

Choi JH, Kim JE, Kaang BK - Mol Brain (2010)

Protein synthesis and degradation is required to appropriately incorporate partially modified information. A, Schematic view of the task. The process is similar as in Figure 1A, except that the mice have received intrahippocampal injection right after day 2 exposure. B, Cannula location in the hippocampus, at two different rostro-caudal planes. Numbers indicate the posterior direction from the bregma. Grey, blue, red, and purple circles indicate the infusion site of vehicle, βlac, anisomycin, and βlac plus anisomycin double infusion group, respectively. C, Preference to unswitched and switched objects at the third day (Veh, vehicle, n = 10; Ani, anisomycin, n = 7; βlac, clasto-lactacystin-β-lactone, n = 7; Ani+ βlac, n = 4. F = 9.869, p = 0.0002; one-way ANOVA. *p < 0.05, **p < 0.01, ***p < 0.001; unpaired t test). D, Preference to unswitched and switched objects at the second day.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823727&req=5

Figure 2: Protein synthesis and degradation is required to appropriately incorporate partially modified information. A, Schematic view of the task. The process is similar as in Figure 1A, except that the mice have received intrahippocampal injection right after day 2 exposure. B, Cannula location in the hippocampus, at two different rostro-caudal planes. Numbers indicate the posterior direction from the bregma. Grey, blue, red, and purple circles indicate the infusion site of vehicle, βlac, anisomycin, and βlac plus anisomycin double infusion group, respectively. C, Preference to unswitched and switched objects at the third day (Veh, vehicle, n = 10; Ani, anisomycin, n = 7; βlac, clasto-lactacystin-β-lactone, n = 7; Ani+ βlac, n = 4. F = 9.869, p = 0.0002; one-way ANOVA. *p < 0.05, **p < 0.01, ***p < 0.001; unpaired t test). D, Preference to unswitched and switched objects at the second day.
Mentions: As our aim was to focus on the associative memory between the objects and their location, we targeted hippocampus which seems to be more specifically involved in object-location memory [13,14]. Hippocampus is known to be important for object-location memory [14-17]; although other regions such as mPFC and perirhinal cortex are also implicated in such tasks, they are probably more involved in novelty processing. Especially, it was recently reported that PKMzeta inhibitor destructed object location memory, but not object identity memory, when it was locally applied in hippocampus [18]. We implanted guide cannulae one week before the behavioral procedure and injected the protein synthesis inhibitor anisomycin (Ani; 200 μg/μl in aCSF, 0.3 μl) and/or the proteasome inhibitor clasto-lactacystin-β-lactone (βlac; 32 ng/μl in aCSF, 0.3 μl) or vehicle (Veh; aCSF, 0.3 μl) in the CA1 region of dorsal hippocampus, bilaterally, right after the exposure to the changed object location on day 2 (Figure 2A). Position of the cannulae tips are shown in Figure 2B.

Bottom Line: In this study, we utilized an object rearrangement task, in which partial information related to a pre-existing memory is changed, promoting memory modification.Inhibitors of both protein synthesis and protein degradation impaired adequate incorporation of the altered information, each in a distinctive way.These results indicate that protein synthesis and degradation play key roles in memory modification.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Creative Research Initiative Center for Memory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, 151-742 Seoul, Korea.

ABSTRACT
Although some reports indicate that protein synthesis dependent process may be induced by updating information, the role of protein synthesis and degradation in changing the content of pre-existing memory is yet unclear. In this study, we utilized an object rearrangement task, in which partial information related to a pre-existing memory is changed, promoting memory modification. Inhibitors of both protein synthesis and protein degradation impaired adequate incorporation of the altered information, each in a distinctive way. These results indicate that protein synthesis and degradation play key roles in memory modification.

Show MeSH
Related in: MedlinePlus