Brain Structure and Function Terminology

Key Concepts in Brain Anatomy and Imaging Techniques

Definition of Terms

• Lesion:

  • Pronunciation: [LEE-zhuhn]

  • Definition: Tissue destruction. A brain lesion refers to a naturally or experimentally caused destruction of brain tissue.

Brain Imaging Techniques

• EEG (Electroencephalogram):

  • Description: An amplified recording of the waves of electrical activity that sweep across the brain's surface.

  • Measurement: These waves are measured by electrodes placed on the scalp.

• MEG (Magnetoencephalography):

  • Description: A brain imaging technique that measures magnetic fields produced by the brain's natural electrical activity.

• CT (Computed Tomography) Scan:

  • Description: A series of X-ray photographs taken from different angles.

  • Processing: These are combined by a computer to produce a composite representation of a slice of the brain's structure.

  • Also referred to as: CAT scan.

• PET (Positron Emission Tomography) Scan:

  • Description: A visual display of brain activity that detects the location of a radioactive form of glucose in the brain as it performs a given task.

• MRI (Magnetic Resonance Imaging):

  • Description: A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue.

  • Function: MRI scans are particularly useful for showing brain anatomy.

• fMRI (Functional MRI):

  • Description: A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans.

  • Function: fMRI scans indicate both brain function and structure.

Major Components of the Brain

• Brainstem:

  • Definition: The oldest part and central core of the brain that begins where the spinal cord swells as it enters the skull.

  • Function: Responsible for automatic survival functions.

  • Medulla:

    • Pronunciation: [muh-DUL-uh]

    • Location: Base of the brainstem.

    • Control Functions: Regulates heartbeat and breathing.

  • Thalamus:

    • Pronunciation: [THAL-uh-muss]

    • Location: Positioned on top of the brainstem.

    • Function: Acts as the brain's sensory control center by directing messages to the sensory receiving areas in the cortex and transmitting replies to the cerebellum and medulla.

  • Reticular Formation:

    • Definition: A nerve network that travels through the brainstem into the thalamus.

    • Role: Plays a crucial role in controlling arousal.

• Cerebellum:

  • Pronunciation: [sehr-uh-BELL-um]

  • Location: At the rear of the brainstem.

  • Functions:

  • Processes sensory input.

  • Coordinates movement output and balance.

  • Enables nonverbal learning and memory.

• Limbic System:

  • Description: A neural system that includes the amygdala, hypothalamus, and hippocampus, located below the cerebral hemispheres.

  • Association: Closely associated with emotions and drives.

  • Amygdala:

    • Pronunciation: [uh-MIG-duh-la]

    • Description: Comprises two lima-bean-sized neural clusters in the limbic system.

    • Function: Linked to emotion.

  • Hypothalamus:

    • Pronunciation: [hi-po-THAL-uh-muss]

    • Location: Lies below the thalamus.

    • Functions:

    • Directs several maintenance activities such as eating, drinking, and regulating body temperature.

    • Governs the endocrine system via the pituitary gland.

    • Linked to emotion and reward.

  • Hippocampus:

    • Definition: A neural center located in the limbic system.

    • Function: Assists in processing for storage explicit (conscious) memories of facts and events.