The Brain

Ways of Studying the Brain

Electroencephalogram (EEG) Detects brain waves Used to detect states of consciousness

Magnetic Resonance Imaging (MRI) uses magnetic fields to measure density and location of brain material (tissue) used instead of CAT sometimes to prevent radiation detects structure, not function

Positron Emission Tomography (PET) lets researchers see what part of the brain is active during different tasks (glucose) measures brain chemicals like neurotransmitters, drugs, and oxygen

Functional MRI (fMRI) combines MRI and PET scan can show brain structure and function (what is actually going on while thinking)

Computerized Axial Tomography (CAT) a sophisticated X-ray used to see the structure of the brain, not the function used to see tumors or lesions

Brain Structures

Brainstem

Brainstem The oldest part and central core of the brain It begins where the spinal cord swells as it enters the skull Is responsible for automatic survival functions

Medulla

Medulla Located at the base of the brainstem Controls life-supporting functions like heartbeat and breathing Damage to this area can lead to death.

Pons

Pons Bridge between brain and spinal cord In charge of motor messages and sleep cycle

Reticular Formation

Reticular Formation A nerve network in the brainstem that plays an important role in controlling wakefulness and arousal Extending up and down the spinal cord into the brain Controls an organism’s level of alertness Damage to this area can cause a coma.

Thalamus

Thalamus Sits atop the brainstem The brain’s sensory switchboard Directs messages to the sensory receiving areas in the cortex

Cerebellum

Cerebellum Latin for the “little brain” Attached to the rear of the brain Helps coordinate voluntary movements and balance If damaged, the person could perform basic movements but would lose fine coordination skills.

Limbic System

Limbic System A ring of structures at the border of the brainstem and cerebral cortex Helps regulate memory, aggression, fear, hunger, and thirst Includes the hypothalamus, hippocampus, and amygdala

Hypothalamus A neural structure lying below the thalamus Regulates the body’s maintenance activities such as; hunger, thirst, body temperature, and sex drive Helps govern the endocrine system via pituitary gland Ventromedial & Lateral

https://www.youtube.com/watch?v=t72b4RKhH7U&app=desktop

Hippocampus A neural center located in the limbic system that wraps around the back of the thalamus Helps processing new memories for permanent storage “If you saw a hippo on campus, you would remember it.”

Amygdala Two almond shaped neural cluster in the limbic system Controls emotional responses such as fear and anger

New Part of Brain

Cerebral Cortex

Cerebral Cortex The intricate fabric of interconnected neurons that form the body’s ultimate control and information processing center All higher order thinking Covers the brain’s cerebral hemispheres

Structure of the Cortex

Frontal Lobes Acts as a filter to limbic system (amygdala) Controls functions such as Planning Personality Judgment Temperament Producing speech sounds Controlling emotions Movement (motor cortex)

Phineas Gage

Motor Cortex The strip of brain tissue at the rear of the frontal lobes Controls voluntary movement The motor cortex in the left hemisphere controls the right side of the body and visa versa.

Parietal Lobes Regions available for general processing, including mathematical reasoning Controls functions of body position Spatial positioning Touch Pressure temperature

Somatosensory Cortex Front of the parietal lobe Registers and processes body touch and movement sensations

Temporal Lobes Includes the auditory (hearing) areas of the brain Storing long term memory Where sound information is processed Located roughly above the ears

Occipital Lobes The portion of the cerebral cortex lying at the back of the head It includes the primary visual processing areas of the brain

Association Areas Uncommitted areas of the brain that are involved in higher mental thinking Associated Disorder: Aphasia

Broca’s Area The brain area of the left frontal lobe Directs the muscle movements involved in speech If damaged the person can form the ideas but cannot express them as speech

Wernicke’s Area A brain area of the left temporal lobe Involved in language comprehension and expression Our ability to understand what is said to us

Differences Between the Two Hemispheres

Corpus Callosum

Hemispheric Differences Brain is divided into two hemispheres but works as a single entity Both sides continually communicate via the corpus callosum, except in those with split brains Communicates in a criss cross function

https://www.youtube.com/watch?v=82tlVcq6E7A

The Brain’s Hemispheres Right Brain: spatial abilities Our spatial ability allows us to perceive or organize things in a given space, judge distance, etc. Left Brain: language functions Words, letters, math, reading, writing, arithmetic

Brain’s Plasticity Brain is sculpted by our genes but shaped by our experiences…the more it is used the more connections are made Plasticity refers to the brain’s ability to modify itself after some type of injury or illness

https://www.youtube.com/watch?v=VaDlLD97CLM&app=desktop