Nondominant hemisphere

The nondominant hemisphere of the brain refers to the hemisphere that is not primarily responsible for language and speech functions. In most individuals, the left hemisphere is the dominant one (associated with language and analytical tasks), making the right hemisphere the nondominant side. For left-handed individuals, the dominance may vary, but the right hemisphere is still often considered nondominant.

Functions:

Spatial and visual perception: Processes spatial relationships and three-dimensional orientation. Attention and awareness: Plays a significant role in attention, especially to the contralateral side of the body. Emotion and creativity: Involved in emotional processing, artistic abilities, and intuitive thinking. Nonverbal communication: Interprets facial expressions, gestures, and tone of voice. Clinical Relevance:

Lesions in the nondominant hemisphere can lead to specific syndromes and deficits, such as: Hemispatial neglect: Often occurs with damage to the parietal lobe, where the patient ignores stimuli on the contralateral side of the lesion. Apraxia: Difficulty with motor planning for movements or tasks despite normal strength and coordination. Emotional dysregulation: Changes in emotional expression and interpretation. Visual-spatial deficits: Trouble with depth perception, judging distances, or navigating through spaces. Insular Gliomas in the Nondominant Hemisphere:

Patients may tolerate larger resections in the nondominant hemisphere compared to the dominant side due to reduced risk of disrupting critical language networks. However, care is still needed to avoid injury to areas responsible for motor, sensory, and autonomic functions. Surgical Considerations:

Although the absence of language centers in the nondominant hemisphere reduces some risks, surgery must still respect critical white matter tracts (e.g., corticospinal tract, superior longitudinal fasciculus) and cortical areas (e.g., motor and sensory cortices). Mapping techniques such as functional MRI (fMRI), diffusion tensor imaging (DTI), and intraoperative monitoring are used to optimize outcomes. Post-Surgical Outcomes:

Deficits related to the nondominant hemisphere are often more subtle and might include impaired attention or emotional processing. Rehabilitation may focus on addressing spatial and perceptual challenges if present.