Altered functional connectivity in an aged rat model of postoperative cognitive dysfunction: a study using...

Area of Science:

• Neuroscience
• Gerontology
• Surgical Complications

Background:

• Postoperative cognitive impairment is a frequent complication in elderly patients undergoing surgery.
• The underlying causes and mechanisms of this impairment remain largely unknown.
• This study investigates cognitive changes and brain functional connectivity in aged rats.

Purpose of the Study:

• To explore changes in functional connectivity using resting-state functional magnetic resonance imaging (fMRI).
• To examine the synchronization of low-frequency fluctuations (LFF) in an animal model.
• To correlate these changes with cognitive function after surgery.

Main Methods:

• Aged rats (22 months) underwent splenectomy under fentanyl and droperidol anesthesia.
• Cognitive function was assessed using the Y-maze test preoperatively and on postoperative days 1, 3, and 9.
• Resting-state fMRI data were acquired to evaluate functional connectivity.

Main Results:

• Cognitive function was impaired on postoperative days 1 and 3 compared to preoperative levels.
• Preoperatively, significant LFF synchronization was observed bilaterally in the primary somatosensory cortex and hippocampus.
• Postoperatively, LFF synchronization was reduced in the right somatosensory cortex and hippocampus, with recovery by day 9.

Conclusions:

• Splenectomy under neuroleptic anesthesia induces cognitive decline in aged rats.
• This cognitive decline is associated with altered spontaneous neuronal activity in the cortex and hippocampus.
• The findings highlight the impact of surgical procedures and anesthesia on brain function and cognition.