Cytosolic hippocampal PKC and aging: correlation with discrimination performance

Area of Science:

• Neuroscience
• Cognitive Aging
• Molecular Biology

Background:

• Aging is associated with cognitive decline, particularly in tasks requiring complex memory formation.
• Protein Kinase C (PKC) is implicated in synaptic plasticity and memory processes.
• Specific PKC isoforms and their roles in age-related memory deficits require further elucidation.

Purpose of the Study:

• To investigate age-related differences in relational memory formation using a radial maze task.
• To examine the correlation between hippocampal PKC activity and the ability to form relational representations in aged mice.
• To determine the specific role of calcium-dependent and -independent PKC in cognitive performance during aging.

Main Methods:

• Adult and aged mice performed regular and probe trials in a radial maze.
• Behavioral testing was conducted at baseline and after a 3-week interval.
• Hippocampal cytosolic calcium-dependent and -independent PKC activities were measured post-testing.

Main Results:

• Aged mice exhibited impaired performance on probe trials, which require relational representations, but not on regular trials.
• Aged mice displayed significantly lower hippocampal cytosolic calcium-dependent and -independent PKC activities compared to adult mice.
• Performance on probe trials strongly correlated with hippocampal calcium-dependent PKC activity.

Conclusions:

• Impaired relational memory formation in aged mice is linked to reduced hippocampal PKC activity.
• Calcium-dependent PKC activity is specifically associated with the ability to form relational representations.
• These findings highlight a critical role for hippocampal calcium-dependent PKC in maintaining cognitive flexibility during aging.