Altered interhemispheric functional homotopy and connectivity in temporal lobe epilepsy based on fMRI and...

Area of Science:

• Neuroscience
• Radiology
• Psychiatry

Background:

• Temporal lobe epilepsy (TLE) is a common neurological disorder characterized by recurrent seizures originating in the temporal lobe.
• Understanding the neurobiological underpinnings of TLE, particularly alterations in brain connectivity, is crucial for diagnosis and treatment.
• Functional magnetic resonance imaging (fMRI) offers a non-invasive method to investigate brain functional organization and connectivity.

Purpose of the Study:

• To investigate changes in whole-brain functional homotopy and functional connectivity (FC) in patients with TLE.
• To identify brain regions critical for classifying TLE using fMRI data.
• To explore the correlation between altered brain connectivity and neuropsychological status, including anxiety and depression.

Main Methods:

• fMRI data were acquired from patients with TLE and matched healthy controls.
• Voxel-mirrored homotopic connectivity (VMHC) and FC analyses were performed.
• Multivariate pattern analysis (MVPA) was used to determine the classification accuracy and the contribution of different brain regions based on VMHC.

Main Results:

• Patients with TLE showed decreased functional coordination in the bilateral inferior temporal gyrus (ITG) and increased functional homotopy in the bilateral lingual gyrus compared to controls.
• TLE patients exhibited lower cognitive function (Montreal Cognitive Assessment) and higher anxiety and depression scores (HAMA, Hamilton Depression Scales), with HAMA scores correlating with altered bilateral ITG.
• FC analysis revealed increased connections between the right lingual gyrus and the left superior temporal gyrus/left insula. MVPA achieved 68.49% classification accuracy, highlighting the temporal lobe, cerebellum, and parietal lobe as significant contributors.

Conclusions:

• Functional homotopy and connectivity are altered in TLE, and these changes are associated with anxiety levels.
• Abnormal VMHC patterns are a significant fMRI biomarker for TLE.
• fMRI, particularly VMHC analysis, can aid in classifying TLE, with specific brain regions playing a decisive role.