Effective connectivity during haptic perception: a study using Granger causality analysis of functional magnetic...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Sensory Processing

Background:

• Visual cortical areas are known to be involved in processing tactile information.
• The precise mechanisms, whether top-down visual imagery or bottom-up sensory processing, remain debated.

Purpose of the Study:

• To investigate the effective connectivity within human brain networks during haptic perception of shape and texture.
• To determine the roles of bottom-up somatosensory inputs versus top-down visual imagery in recruiting visual cortex during touch.

Main Methods:

• Functional magnetic resonance imaging (fMRI) data analyzed using multivariate Granger causality analysis.
• A network reduction procedure was applied to identify significant connections.
• Focus on shape- and texture-selective regions in the human brain.

Main Results:

• Haptic perception involves flexible interactions between somatosensory, multisensory, visual, and motor areas.
• Bottom-up somatosensory inputs from the postcentral sulcus and posterior insula project to visual areas (LOC, medial occipital cortex).
• Top-down inputs from the parietal cortex influence the lateral occipital complex (LOC).

Conclusions:

• Evidence supports visual cortical areas acting as multisensory processors receiving bottom-up somatosensory information.
• Suggestive evidence for top-down parietal inputs potentially mediating visual imagery exists.
• Brain networks exhibit flexible cooperation, integrating sensory inputs and cognitive processes.