A Neural Decision Signal during Internal Sampling from Working Memory in Humans

Area of Science:

• Cognitive Neuroscience
• Psychology
• Electrophysiology

Background:

• Decision-making research traditionally focuses on external sensory information processing.
• The gradual evidence accumulation model of decision-making has been theorized for internal working memory, but lacks neural support.

Purpose of the Study:

• To investigate the neural mechanisms underlying decision-making from working memory.
• To determine if internal information sampling follows a gradual evidence accumulation process.

Main Methods:

• Scalp electroencephalography (EEG) was used in human volunteers.
• Participants made decisions based on internally maintained visual information in working memory.

Main Results:

• A central parietal positivity, indicative of gradual evidence accumulation, was observed during internal working memory sampling.
• This EEG signal correlated with decision time and increased when participants decided among multiple memory items.

Conclusions:

• Neural evidence supports the gradual evidence accumulation framework for decisions based on working memory.
• Variability in memory-guided behavior may stem from internal mental content sampling processes.