Inactivation of Dorsolateral Prefrontal Cortex During Auditory Working Memory

Area of Science:

• Neuroscience
• Cognitive Neuroscience

Background:

• The dorsolateral prefrontal cortex (DLPFC) is implicated in working memory (WM), particularly visuospatial WM.
• Evidence for its role in auditory WM is mixed, with some studies suggesting involvement and others pointing to the ventrolateral prefrontal cortex (VLPFC).

Purpose of the Study:

• To investigate the role of the DLPFC in auditory working memory.
• To compare the effects of DLPFC inactivation with known effects of VLPFC inactivation on auditory WM performance.

Main Methods:

• Transient inactivation of the DLPFC (areas 46v, 46d, and 9) in rhesus macaques using cortical cooling.
• Permanent ibotenic acid lesions of the DLPFC followed by behavioral assessment of auditory WM task performance.

Main Results:

• Cortical cooling inactivation of the DLPFC did not significantly impair auditory WM performance.
• Ibotenic acid lesions of the DLPFC also did not significantly alter auditory WM performance.
• Transient inactivation led to increased gaze aversion in one subject, possibly indicating attention or motivation deficits.

Conclusions:

• The DLPFC does not appear to play a critical role in auditory working memory performance.
• These findings suggest a functional dissociation between the DLPFC and VLPFC in auditory WM, with the VLPFC potentially having a more significant role.