Short-term memory errors are strongly associated with a drift in neural activity in the posterior parietal cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Systems Neuroscience

Background:

• Understanding short-term memory (STM) errors is vital for cognitive research and treating neuropsychiatric disorders.
• Previous hypotheses suggested STM errors stem from initial sensory misrepresentation or decay.

Purpose of the Study:

• To investigate the neural basis of short-term memory errors.
• To differentiate between misrepresentation and decay as causes of STM errors in the posterior parietal cortex (PPC).

Main Methods:

• Utilized 2-photon calcium imaging in mice performing a delayed match-to-sample task.
• Recorded neural activity in the posterior parietal cortex (PPC).
• Analyzed neural selectivity for directional and temporal information.

Main Results:

• Identified PPC neurons with directional and temporal selectivity.
• Found that STM errors correlate more strongly with neural activity drift during the delay period than with initial encoding.
• Observed a gradual divergence from correct neural representations leading to behavioral errors.

Conclusions:

• STM errors are primarily driven by the instability of neural representations in the PPC during the delay phase.
• Maintaining stable neural activity in the PPC is crucial for accurate short-term memory.
• Targeting PPC activity stabilization could be a therapeutic strategy for cognitive deficits in disorders like schizophrenia.