What is the Difference Between Primary and Association Cortex

The key difference between primary and association cortex is that the primary cortex is a part of the cerebral cortex that generates signals to direct body movement and processes all sensory information received throughout the day, while the association cortex is a part of the cerebral cortex that performs complex cognitive functions. 

The cerebral cortex is the outer layer that normally lies on top of the cerebrum. It is the largest area of the brain, which is about 2 to 4 mm in thickness. It contains an aggregation of nerve cell bodies. It has many folds and groves, giving it a wrinkled appearance. The cerebral cortex plays important roles in memory, thinking, learning, reasoning, problem-solving, emotions, consciousness, and functions related to the senses. The primary and association cortex are two important parts of the cerebral cortex.

CONTENTS

1. Overview and Key Difference
2. What is the Primary Cortex
3. What is the Association Cortex
4. Similarities – Primary and Association Cortex
5. Primary vs. Association Cortex in Tabular Form
6. FAQ – Primary and Association Cortex
7. Summary – Primary vs. Association Cortex

What is the Primary Cortex?

The primary cortex contains two major parts: the primary motor and sensory cortex. The primary motor cortex is located in the dorsal portion of the frontal lobe, and it is involved in planning and executing voluntary movements.

In fact, many parts of the brain typically make up the primary sensory cortex. The primary sensory cortex is in charge of processing and interpreting sensory stimuli. Some parts of the primary sensory cortex are responsible for primary sensory interpretation, while other parts are responsible for the more complex secondary interpretation. Moreover, parts of the primary sensory cortex are involved in processing visual, olfactory, gustatory, auditory, and somatosensory information.

What is the Association Cortex?

The association cortex is a part of the cerebral cortex that plays important cognitive functions. The association cortex integrates information from various sources to help the higher-order cognitive processes, which allows performing complex functions such as perception, language, and thought. For example, an individual who possesses large amounts of association cortex tends to show more advanced reasoning skills.

The association cortex is mainly divided into parts: the unimodal association cortex and the heteromodal association cortex. The unimodal association cortex primarily deals with information from one sense modality, while the heteromodal association cortex primarily receives input from multiple sensory or multimodal areas. Furthermore, the association cortex is composed of contributions from various parts of the cerebral cortex, including the prefrontal cortex, the junction of the occipital, temporal, and parietal lobes, and the anterior-ventral portion of the temporal lobe.

What are the Similarities Between Primary and Association Cortex?

• The primary and association cortex are two parts of the cerebral cortex of the brain.
• Both parts play important functions.
• The vital roles of both parts are extremely important for the survival of individuals.
• Both parts can be affected by different diseases.

What is the Difference Between Primary and Association Cortex?

The primary cortex is a part of the cerebral cortex that generates signals to direct body movement and processes all the sensory information people receive throughout the day, while the association cortex is a part of the cerebral cortex that performs complex cognitive functions. Thus, this is the key difference between primary and association cortex. Furthermore, the primary cortex is composed of the primary motor cortex and primary sensory cortex, while the association cortex is composed of the unimodal association cortex and heteromodal association cortex.

The infographic below presents the differences between primary and association cortex in tabular form for side-by-side comparison.

FAQ: Primary and Association Cortex

What are the association areas of the cortex?

Association cortices include cortical areas that are located between visual, auditory, and somatosensory cortices, which integrate generated auditory, visual, gustatory, and general sensory impulses.

What are the association areas responsible for?

Association areas regulate intersensory association, communication, and memory.

Where is the primary cortex located?

The primary motor cortex lies in the posterior part of the frontal lobe.

Summary – Primary vs. Association Cortex

The cerebral cortex is the outermost layer of nerve cell tissue known as gray matter. The primary cortex refers to a part of the cerebral cortex that processes specific sensory inputs or motor outputs, while the association cortex is a part of the cerebral cortex that is involved in planning and executing voluntary movements. So, this summarizes the difference between primary and association cortex.

Reference:

1. “11.8C: Association Areas.” Medicine LibreTexts, Libretexts.
2. “Physiology, Cerebral Cortex Functions.” Statpearls – NCBI Bookshelf.

Image Courtesy:

1. “Motor Cortex Image” By SeanPatrickConnolly – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Córtex associative” By Ana Karolina Rodrigues da Silva – Own work (CC BY-SA 4.0) via Commons Wikimedia