Approaches in Psychology AQA Practice Test 2026 - Free Psychology Practice Questions and Study Guide

Communication between the two halves of the brain hinges on a major bundle of nerve fibers called the corpus callosum. It sits beneath the cerebral cortex and forms a thick bridge across the brain’s midline, containing hundreds of millions of axons that carry information between the left and right hemispheres. This cross-hemisphere communication is what allows coordinated movement, integrated sensory processing, and unified cognitive functioning, so both sides can work together smoothly. The cerebral cortex is the outer processing layer, but it is not the bridge itself. The thalamus acts as a relay for signals inside the brain, not specifically as a connector between hemispheres. The pituitary gland is part of the hormonal system and isn’t involved in linking the two sides. Because of its role as the primary bridge that enables interhemispheric communication, the corpus callosum is the best fit.