Lateralization of Functions Quiz

Lateralization of Functions

• Lateralization refers to the localization of brain functions in either the left or right hemisphere.

Myth vs Fact

• Hemisphere Dominance for personality traits is a myth; specific functions do exhibit lateralization.

Hemispherectomy

• Effective treatment for Rasmussen's syndrome, which involves seizures in one hemisphere of the brain.

The Split Brain

• Condition where neural pathways between the cerebral hemispheres are severed.
• Research by Bogen demonstrated no changes in personality, intelligence, or speech post-surgery.
• Reports of unusual behaviors, including the phenomenon known as "alien hand."
• Gazzaniga and Sperry also contributed to understanding this condition.

Left Visual Field

• Stimuli in the left visual field can prompt movement of the right arm and verbalization.

Right Visual Field

• Stimuli in the right visual field leads to movement of the left arm and the ability to draw or use objects.

Development of Lateralization

• Prenatal androgens influence lateralization; more males tend to be left-handed.
• Females with congenital adrenal hyperplasia (CAH) are more likely to be left-handed.
• Hemispheric asymmetry has implications for behavior, handedness, language, and musical abilities.
• Dichotic listening tasks provide evidence for lateralization, including prosody in language.

The Planum Temporale

• The left planum temporale is typically larger than the right in most individuals.
• In musicians with perfect pitch, this size difference is even more pronounced, suggesting a left-hemisphere mediation for perfect pitch.

Anecdotally

• Girls generally start speaking earlier, have larger vocabularies, perform better in reading, and receive fewer diagnoses for language disabilities.

Meta-Analysis

• Studies confirm a gender difference in handedness but find no significant discrepancies in lateralization of language or structural brain symmetry.

Right Hemisphere

• Responsible for motor control of the left side of the body and processing left visual field information.
• Exhibits a left-ear advantage in dichotic listening tasks.
• Involved in prosody, music, intuition, spatial relations, and artistic abilities.

Left Hemisphere

• Controls motor functions for the right side of the body and processes information from the right visual field.
• Shows a right-ear advantage in dichotic listening tasks.
• Plays a central role in language, mathematical tasks, and logical processing.

Why do we have a hand preference?

• About 90% of individuals are right-handed, while roughly 10% are left-handed.