Mapping a network for tics in Tourette syndrome using causal lesions and structural alterations

Area of Science:

• Neuroscience
• Neurology
• Movement Disorders

Background:

• Tics are sudden, stereotyped movements or vocalizations.
• Lesion-induced tics provide insights into the causal links between brain structures and symptoms.
• Understanding the neural network for tics is crucial for Tourette syndrome (TS) treatment.

Purpose of the Study:

• To localize a causal network for tics from lesion-induced cases.
• To refine and validate this network in patients with Tourette syndrome (TS).
• To investigate the pathophysiology of tics in TS.

Main Methods:

• Lesion network mapping using a functional connectome (n=1000) with lesion data (n=19).
• Anatomical likelihood estimation and coordinate network mapping using structural coordinates (n=7).
• Conjunction analysis to refine the tic network and resting-state functional connectivity MRI in TS patients (n=21) and controls (n=25).

Main Results:

• Lesions causing tics showed predominant basal ganglia connectivity.
• The refined lesion network included the posterior putamen, caudate nucleus, globus pallidus externus, and precuneus.
• Abnormal functional connectivity from this network to frontal and cingulate regions was observed in TS patients.

Conclusions:

• A neural network for tics, refined for Tourette syndrome, was identified using lesion and functional data.
• Abnormal connectivity within this network in TS patients provides insight into tic pathophysiology.
• Connectivity to the precuneus presents potential for non-invasive brain stimulation therapies.