Related Experiment Video
Updated: Jul 3, 2026

Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation
Published on: February 23, 2020
Connectivity between posterior parietal cortex and ipsilateral motor cortex is altered in schizophrenia
Giacomo Koch1, Michele Ribolsi, Francesco Mori
1Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Rome, Italy. giakoch@libero.it
Schizophrenia patients show impaired parieto-motor connectivity, unlike healthy individuals. This disconnection may be a core feature of schizophrenia, impacting global functioning and negative symptoms.
Area of Science:
- Neuroscience
- Psychiatry
- Cognitive Science
Background:
- Schizophrenia is increasingly hypothesized as a disorder of defective cortical connectivity.
- Neurophysiological evidence for this hypothesis remains limited.
Purpose of the Study:
- To investigate parieto-motor connectivity in schizophrenia using a novel twin-coil transcranial magnetic stimulation (tcTMS) approach.
- To explore the relationship between connectivity, clinical symptoms, and illness duration in schizophrenia patients.
Main Methods:
- Utilized twin-coil transcranial magnetic stimulation (tcTMS) to assess ipsilateral parieto-motor connectivity.
- Studied 20 schizophrenic patients (medicated and unmedicated) and 15 healthy controls.
- Applied conditioning TMS pulses over the posterior parietal cortex (PPC) and measured motor cortex excitability.
Main Results:
- Healthy subjects exhibited significant parieto-motor facilitation at specific interstimulus intervals (ISIs).
- Schizophrenia patients, both medicated and unmedicated, showed a lack of this facilitatory parieto-motor interaction.
- Impaired connectivity correlated with lower global functioning, higher negative symptoms, and longer illness duration.
Conclusions:
- Parieto-motor connectivity is demonstrably impaired in individuals with schizophrenia.
- Cortico-cortical disconnection is proposed as a potential core feature of schizophrenia.
Related Concept Videos
Somatosensation
Somatosensory, Motor, and Association Cortex
Motor and Sensory Areas of the 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.
Association Areas of the Cortex
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,...
Positive Symptoms of Schizophrenia: Hallucinations and Delusions
Thought Disorders
Disorganized and unusual thought processes mark thought disorders in schizophrenia. One key feature is disorganized speech, where an individual's conversation includes loosely...
Psychosis: Pathophysiology of Schizophrenia and Other Psychotic Disorders
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within the...

