Functionally distinct contributions of parietal cortex to a numerical landmark task: An fMRI study

Area of Science:

• Neuroscience
• Cognitive Psychology
• Cognitive Neuroscience

Background:

• Understanding the neural mechanisms of numerical cognition is crucial for cognitive neuroscience.
• Working memory plays a vital role in complex cognitive tasks, including number processing.
• Previous research suggests distinct parietal lobe regions are involved in number processing, but their specific roles require further clarification.

Purpose of the Study:

• To elucidate the neural basis of magnitude processing for multiple numbers held in working memory.
• To functionally differentiate the roles of anterior and posterior parietal regions in number encoding and comparison.
• To investigate the involvement of working memory and spatial attention in numerical magnitude judgments.

Main Methods:

• A numerical landmark task was employed within a fragmented trial event-related fMRI design.
• Functional magnetic resonance imaging (fMRI) was used to measure brain activity during number processing.
• An attentional localizer task, not involving numbers, was utilized for further functional region specification.

Main Results:

• The right anterior intraparietal sulcus was identified as a key region for number encoding.
• Posterior parietal regions, including the bilateral superior parietal lobule and right inferior parietal lobule, supported working memory representation construction.
• These posterior regions also showed involvement in orienting spatial attention within the mental representation during number comparison.

Conclusions:

• The findings support a functional distinction between anterior and posterior parietal contributions to number processing.
• The right anterior intraparietal sulcus is specifically involved in the encoding of numerical information into working memory.
• Posterior parietal areas provide domain-general support for constructing and manipulating representations within working memory during numerical tasks.