Question

What are the lobes of the cerebrum? Give the location and function of the following areas: primary motor area, primary somatosensory area, primary visual area, primary auditory area, primary taste area, and primary olfactory area. (pages \(285-86\) )

Short answer

The cerebrum comprises four main lobes: frontal, parietal, temporal, and occipital. The primary motor area is located in the frontal lobe's precentral gyrus and controls voluntary movement. The primary somatosensory area, located in the parietal lobe's postcentral gyrus, processes touch, pain, pressure, and temperature information. The primary visual area, in the occipital lobe, processes visual information. The primary auditory area, located in the temporal lobe's superior temporal gyrus, processes auditory stimuli. The primary taste area, located in the insular cortex, processes taste information. Finally, the primary olfactory area, located in the temporal lobe's uncus, processes information about smell.

Step-by-step solution

Overview of the Cerebrum

The cerebrum is the largest part of the brain and is responsible for higher brain functions, such as thinking, perceiving, and remembering. It is divided into two hemispheres, each of which has four main lobes: the frontal lobe, the parietal lobe, the temporal lobe, and the occipital lobe. Now let's look at each primary area and discuss its location and function.

Primary Motor Area

The primary motor area (also known as the motor cortex) is located in the frontal lobe, specifically in the precentral gyrus. This area is responsible for voluntary movement and sending motor commands to the muscles through the spinal cord. It gives us the ability to control our body movements effectively.

Primary Somatosensory Area

The primary somatosensory area (also known as the somatosensory cortex) is located in the parietal lobe, specifically in the postcentral gyrus. This area receives and processes information about touch, pain, pressure, and temperature from sensory receptors in the skin, muscles, and joints. It enables us to perceive sensations and interact with our environment.

Primary Visual Area

The primary visual area (also known as the visual cortex) is located in the occipital lobe at the back of the brain. It receives and processes visual information from the eyes, giving us the ability to see and interpret the world around us.

Primary Auditory Area

The primary auditory area (also known as the auditory cortex) is located in the temporal lobe, specifically on the superior temporal gyrus. It is responsible for receiving and processing auditory stimuli from our ears and allowing us to perceive and understand sounds.

Primary Taste Area

The primary taste area (also known as the gustatory cortex) is located in the insular cortex, a part of the cerebral cortex deep within the lateral sulcus. This area is responsible for processing information about taste, enabling us to experience and differentiate between different flavors.

Primary Olfactory Area

The primary olfactory area (also known as the olfactory cortex) is located in the medial part of the temporal lobe, specifically in the uncus. This area processes information about smell coming from the olfactory receptors in our nose. It enables us to detect and identify different odors in our environment.

Key concepts

Motor Cortex

The motor cortex, a key player in how we interact with the world, holds the reins of voluntary muscle movement. Situated in the frontal lobe along the precentral gyrus, it is the maestro coordinating our daily concert of actions, from waving hello to taking a stroll.

Picture neurons here as individual musicians, each with a specific role, playing their part in controlling different muscle groups across the body. The nerve impulses they conduct are the music commanding your muscles to move with precision and grace.

Somatosensory Cortex

Envision the somatosensory cortex as a hub of sensation, its home in the parietal lobe's postcentral gyrus. It's where the tactile symphony of touch, pressure, pain, and temperature is composed.

The myriad of sensations picked up from our skin and deeper within travels to this area, translating external stimuli into perceptual experiences. Through its sophisticated processing, we're equipped with the essential ability to perceive the warmth of a hug or the coolness of a breeze.

Visual Cortex

At the very back of the brain, in the occipital lobe, lies the visual cortex, our personal cinema screen where the world outside is projected.

The eyes gather visual stories, but it's at this silver screen where light and color come to life, decoded into the moving images we comprehend. It's not just about shapes and shadows; it's where patterns and faces, landscapes and letters become meaningful scenes in our daily lives.

Auditory Cortex

Tucked away in the temporal lobe, particularly the superior temporal gyrus, the auditory cortex is our private sound studio. It doesn't only receive the audio stream from our ears but edits and mixes it, refining noise into recognizable sounds and language.

It’s responsible for distinguishing a friend's laugh in a noisy room or identifying the subtle notes in our favorite song. This intricate process grants us the joy of auditory harmony and communication.

Gustatory Cortex

The gustatory cortex, nestled deep within the folds of the insular cortex, is our flavor judge, discerning sweet from savory and bitter from salty.

This taste central processes signals from our taste buds, allowing us to savor a chocolate's sweetness or cringe at a lemon's tartness. Its judgments influence our dietary choices, a crucial role in the pursuit of both nutrition and gastronomic pleasure.

Olfactory Cortex

Perched within the medial temporal lobe, in a region known as the uncus, the olfactory cortex is the curator of scents. It analyses the aromatic notes carried by olfactory receptors, be they the freshness of rain or the fragrance of a rose garden.

This sense of smell can evoke memories and emotions, intertwining with taste to enrich the experience of a meal or define a moment. Our olfactory cortex helps chart a map of the world not just seen or heard, but deeply and complexly smelled.