Differential Cortical c-Fos and Zif-268 Expression after Object and Spatial Memory Processing in a Standard or...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Molecular Biology

Background:

• Episodic memory involves recalling event details (what, where, when).
• Medial temporal lobe and medial prefrontal cortex are implicated in episodic-like memory (ELM).

Purpose of the Study:

• To investigate differential expression of immediate early genes c-Fos and Zif-268.
• To compare gene expression patterns in medial temporal lobe and medial prefrontal cortex.
• To link gene expression to cognitive demands in object recognition (OR) and ELM tasks.

Main Methods:

• Rats performed object recognition (OR) and episodic-like memory (ELM) tasks.
• Gene expression of c-Fos and Zif-268 was measured 1 hour post-task.
• Expression levels were analyzed in the medial temporal lobe (dentate gyrus, CA1, perirhinal cortex) and medial prefrontal cortex.

Main Results:

• Both OR and ELM tasks increased c-Fos in the perirhinal cortex (PRh) and dorsal dentate gyrus (DG).
• The OR task uniquely increased c-Fos in the medial prefrontal cortex (mPFC).
• Both OR and ELM tasks increased Zif-268 in the mPFC; ELM uniquely increased Zif-268 in dorsal CA1 and PRh.
• Perirhinal-DG co-activation correlated with spatial and temporal memory retrieval in the ELM task.

Conclusions:

• Distinct cognitive demands of memory tasks elicit different neural activation patterns.
• Specific gene expression profiles (c-Fos, Zif-268) differentiate task demands.
• Findings highlight the role of perirhinal cortex and dentate gyrus in integrating 'what-where-when' information.