Split-Brain & Hemispheric Specialization

Vocabulary flashcards covering key terms from the lecture on split-brain surgery, hemispheric functions, visual processing, language areas, and related disorders.

Split-Brain Operation

Surgical procedure that severs the corpus callosum to control severe epilepsy and isolate the two cerebral hemispheres.

Corpus Callosum

A thick band of hundreds of millions of axons connecting the left and right hemispheres; cut in split-brain surgery.

Epileptic Seizure

Uncontrolled, spreading electro-chemical brain activity; can be limited to one hemisphere by cutting the corpus callosum.

Hemispheric Specialization

The idea that the two brain hemispheres perform different functions (e.g., language in left, spatial in right).

Visual Field

The area visible to each eye; left visual field projects to right hemisphere and right visual field to left hemisphere.

Contralateral Processing

Neural rule in which each hemisphere processes information from the opposite side of the body or visual field.

Bilateral Eye Projection

Each eye sends information to both hemispheres, making eye input itself bilateral even though visual fields are contralateral.

Optic Chiasm

Subcortical crossing point where optic nerves switch sides; still functions after corpus-callosum sectioning.

Right Hemisphere

Brain side that receives left-field visuals, controls left hand, and handles many non-verbal, non-conscious processes.

Left Hemisphere

Brain side that receives right-field visuals, controls right hand, and houses language and most conscious analytic thought.

Split-Brain Patient

Individual whose corpus callosum has been cut; hemispheres act independently in tests.

Left-Hand Response

Motor output controlled by right hemisphere; used to reveal right-hemisphere knowledge in split-brain experiments.

Right-Hand Response

Motor output controlled by left hemisphere; reveals left-hemisphere processing in split-brain tests.

Nonconscious Processing

Influential mental activity that occurs without awareness, often linked to right hemisphere and subcortical areas.

Language Processing

Functions of producing and comprehending speech, primarily managed by the left hemisphere’s Broca’s and Wernicke’s areas.

Broca’s Area

Region in the left frontal lobe (motor cortex) responsible for speech production.

Wernicke’s Area

Region at the left temporal-parietal junction responsible for language comprehension.

Broca’s Aphasia

Impairment in speech production; comprehension preserved, writing often possible with non-paralyzed hand.

Wernicke’s Aphasia

Fluent but meaningless speech with poor comprehension; patient produces “word salad.”

Alien Hand Syndrome

Condition in which the left hand (right hemisphere) acts without conscious control, often after callosal damage.

Hemispherectomy

Surgical removal of an entire cerebral hemisphere; patients, especially young, can adapt remarkably.

Contralateral Motor Control

Each hemisphere controls muscles on the opposite side of the body (e.g., left hemisphere → right hand).

Contralateral Sensation

Sensory input from one side of the body is processed by the opposite cerebral hemisphere.

Implicit Processes

Skills, habits, conditioning, and priming that operate without conscious awareness, often subcortical.

Explicit (Conscious) Processes

Deliberate, aware mental activities like reasoning and language, largely managed by the left hemisphere.