Ketamine-Induced Alteration of Working Memory Utility during Oculomotor Foraging Task in Monkeys

Area of Science:

• Neuroscience
• Cognitive Psychology
• Behavioral Science

Background:

• Working memory (WM) impairments are common in neurodegenerative disorders but difficult to quantify clinically.
• Low-dose ketamine disrupts WM in animal models, mimicking schizophrenia pathophysiology.

Purpose of the Study:

• To develop a novel behavioral paradigm for assessing multiple WM components.
• To quantitatively evaluate WM deficits induced by ketamine in non-human primates.

Main Methods:

• An oculomotor foraging task with 15 objects and a liquid reward was designed.
• A foraging model incorporating memory capacity, decay, and utility rate was constructed.
• Monkeys performed the task with and without ketamine administration.

Main Results:

• The foraging model explained over 92% of behavioral variations.
• Ketamine significantly reduced memory capacity (15%) and utility rate (57%).
• Memory decay remained largely unchanged after ketamine administration.

Conclusions:

• Ketamine-induced behavioral deficits are primarily due to decreased short-term memory usage.
• The developed oculomotor paradigm and foraging model can quantify WM components.
• This approach shows potential for clinical application in assessing WM dysfunction.