Fast track to the neocortex: A memory engram in the posterior parietal cortex

Area of Science:

• Neuroscience
• Cognitive Psychology
• Memory Research

Background:

• Systems memory consolidation models propose rapid hippocampal and slow neocortical learning.
• Neocortical memory contributions are traditionally viewed as hippocampus-dependent.
• The speed and location of neocortical memory trace formation remain debated.

Purpose of the Study:

• To investigate the rapid formation of memory engrams in the human neocortex.
• To challenge the traditional view of slow neocortical learning.
• To identify the neural mechanisms underlying rapid memory encoding in the parietal cortex.

Main Methods:

• Diffusion-weighted magnetic resonance imaging (dMRI) to assess microstructural plasticity.
• Functional brain activity measurements during an object-location learning task.
• Analysis of learning-specific changes in the posterior parietal cortex.

Main Results:

• Rapid microstructural plasticity detected in the posterior parietal cortex within 1 hour of learning.
• Neocortical plasticity was learning-specific and correlated with memory recall.
• Observed microstructural changes persisted for over 12 hours.
• Functional activity overlapped with the areas exhibiting plasticity.

Conclusions:

• The human posterior parietal cortex can rapidly form enduring memory engrams.
• This challenges the established models of slow neocortical memory consolidation.
• Suggests a faster neocortical contribution to memory formation than previously thought.