Related Experiment Video
Updated: Jul 11, 2026
04:40
Tactile Semiautomatic Passive-Finger Angle Stimulator (TSPAS)
Published on: July 30, 2020
Posteromedial parietal cortical activity and inputs predict tactile spatial acuity
Randall Stilla1, Gopikrishna Deshpande, Stephen LaConte
1Department of Neurology, Emory University, Atlanta, Georgia 30322, USA.
Summary
This study reveals that the right posterior intraparietal sulcus (pIPS) is crucial for tactile spatial acuity. Higher activity and stronger input connectivity to the pIPS correlate with better fine touch discrimination.
Area of Science:
- Neuroscience
- Somatosensory research
- Human psychophysics
Background:
- Tactile spatial acuity is essential for interacting with the environment.
- The neural basis of fine touch spatial processing remains incompletely understood.
- Previous research suggests a role for parietal cortex in somatosensation.
Purpose of the Study:
- To investigate the neural circuitry supporting tactile spatial acuity at the human finger pad.
- To identify brain regions and connectivity patterns critical for precise touch discrimination.
- To elucidate the functional role of the posterior intraparietal sulcus (pIPS) in somatosensory processing.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was employed to measure brain activity.
- A custom MRI-compatible pneumatic stimulator delivered precise three-dot tactile arrays to the index finger.
- Granger causality analysis was used to assess functional connectivity patterns, with a focus on the right pIPS.
Main Results:
- A distributed frontoparietal network showed activity specific to spatial processing.
- Activity levels in the right posterior intraparietal sulcus (pIPS) and precuneus predicted individual tactile acuity thresholds.
- Stronger input connectivity to the right pIPS was observed in individuals with better spatial acuity.
Conclusions:
- The right pIPS plays a critical role in tactile spatial acuity.
- Optimal tactile spatial discrimination likely involves top-down attentional signals interacting with somatosensory inputs in the pIPS.
- This interaction may facilitate the visualization of tactile stimuli or engage modality-independent spatial processing circuits.
Related Concept Videos
01:33Somatosensation
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
01:23Somatosensory, Motor, and Association Cortex
The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at the...
01:14Motor and Sensory Areas of the Cortex
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
01:21Association Areas of the Cortex
Association areas are regions of the cerebral cortex that do not have a specific sensory or motor function. Instead, they integrate and interpret information from various sources to enable higher cognitive processes such as memory, learning, and decision-making. Some key association areas include the following:
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...
Prefrontal Association Area: This area is located in the frontal lobe and is involved in planning, decision-making, and moderating social behavior. It connects with primary motor areas,...