Unit 3B: The Brain

I. The Tools of Discovery: Having Our Head Examined

Recording the Brain’s Electrical Activity

Electroencephalogram (EEG) Electrical waves of activity that sweep across the brain’s surface. Electrical waves of activity that sweep across the brain’s surface. Electrodes on the scalp. Electrodes on the scalp.

CT (Computed Tomography) scan  Series of X-ray photographs  Taken from different angles  CAT scan  dics/CAT-Scans.htm

PET (Positron Emission Tomography) scan  Visual display of brain activity  Detects glucose  While performing a task.

MRI (Magnetic Resonance Imaging)  Magnetic fields and radio waves  Computer-generated images of soft tissue.

The Brain

II. Older Brain Structures

Brainstem Brainstem  Oldest part of the brain Shared in common w/ other mammals Shared in common w/ other mammals Earliest parts to evolve Earliest parts to evolve  Spinal cord and brain meet  Automatic survival functions

Medulla  Base of brainstem  Controls life-supporting functions  Heartbeat, breathing  Damage = ??????

Reticular Formation  Nerve network up and down spinal cord to the thalamus.  Controls level of alertness; arousal  Damage = ?????

Thalamus Thalamus  Sits atop the brainstem  Brain’s sensory switchboard  Receives info from all senses except smell passes them to higher brain regions passes them to higher brain regions

Cerebellum Cerebellum  “Little brain”  Controls balance, muscle coordination and memories on how to use your body. Examples? Examples?  Damage = ??????  Alcohol…

Limbic System

Amygdala  Controls emotional responses such as fear, aggression, rage, anger.

Hippocampus  Processes new memories for permanent storage.  Damaged: ?????

Hypothalamus Regulates hunger, thirst, body temperature, sexual behavior and the fight or flight reaction to stress. Regulates hunger, thirst, body temperature, sexual behavior and the fight or flight reaction to stress.

Corpus Callosum  Band of neural fibers that connects the two brain hemispheres and carries messages between them  Is sometimes cut to prevent seizures

The Amazing Human Brain!!!  Film Time….  dex.cfm?guidAssetId=9BE0695B C8-A747E4E5FE8C

III. The Cerebral Cortex

Cerebral Cortex

 Control and information processing center  Contains 30 billion nerve cells  Divided into 4 lobes  85% of brains weight  Brain weighs lbs.

Longitudinal, Central, Lateral Fissures  Divides brain into hemispheres  Called lobes

Structure of the Cortex  Glial cells (“glue cells”) cells in the nervous system that support, nourish, and protect neurons. cells in the nervous system that support, nourish, and protect neurons.

Frontal Lobes  Making plans and judgments  Speaking and muscle movements

Parietal Lobes  Processing and mathematical reasoning  Receives sensory input for touch and body position

Occipital Lobe  Interprets visual information  Located in the back of the head

Temporal Lobes  Auditory areas  Receiving information primarily from the opposite ear.

Functions of the Cortex Motor Functions  Motor Cortex Rear of frontal lobes Rear of frontal lobes Controls voluntary movements Controls voluntary movements  Mapping the Motor Cortex

Functions of the Cortex Sensory Functions  Sensory Cortex front of the parietal lobes front of the parietal lobes registers and processes body touch and movement sensations. registers and processes body touch and movement sensations.

Functions of the Cortex

Functions of the Cortex Association Areas  Association areas- not involved in primary motor or sensory functions. Frontal: judgement, planning, memory Frontal: judgement, planning, memory Parietal: math/spatial Parietal: math/spatial Temporal-facial recog. Temporal-facial recog.

Phineas Gage  Film Time….  g/saf/1302/video/ watchonline.htm

Language  Aphasia Aphasia impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding). impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding).

Broca’s Area  Left frontal lobe  Expressive language; muscle movement  Damaged = form ideas but not express them as speech Ex. A stroke Ex. A stroke

Wernicke’s Area  Left temporal lobe  Controls receptive language; our ability to understand what someone else says

Language

Plasticity  The ability of the brain tissue to take on new functions  Greatest in childhood  Important if parts of the brain are damaged or destroyed

IV. Hemispheric Differences

Hemisphere Dominance Site  1/Unit1/Left%20Right%20Brain%20Test.p df

Right Hemisphere  Language functions  2 important parts of left brain: Broca’s area Broca’s area Wernicke’s area Wernicke’s area Left Hemisphere  Spatial abilities  Connections between words  Perceive, organize, distance

Splitting the Brain  Vogel and Bogen Corpus-callosum Corpus-callosum Corpus-callosum large band of neural fibers connecting the two brain hemispheres and carrying messages between themlarge band of neural fibers connecting the two brain hemispheres and carrying messages between them

 Split Brain a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers. a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers. Myers and Gazzaniga Myers and Gazzaniga

Right-Left Brain Differences

Half the Brain…  Film Time….  honline.htm honline.htm honline.htm  5. The Divided Brain

Left/Right Hemisphere Specialization  Analytic thought Step by step process Step by step process  Logic Conclusions based upon a logical or consecutive order Conclusions based upon a logical or consecutive order  Language Using words to name/describe/define Using words to name/describe/define  Math & Science Number use, awareness of time, symbols, facts & linear reasoning Number use, awareness of time, symbols, facts & linear reasoning  Facial recognition  Emotional processing  Holistic thought Seeing “big” picture before understanding details  Intuition Insight based upon “hunches”  Creativity Demonstrative with minimal word use, understanding relationships  Art & Music Putting pieces together to form “wholes” LEFTRIGHT

V. The Brain and Consciousness  Consciousness Consciousness our awareness of ourselves and our environment. our awareness of ourselves and our environment. Evolutionary Psychologists Evolutionary Psychologists Consider consequences Consider consequences

Cognitive Neuroscience  Cognitive neuroscience Cognitive neuroscience Cognitive neuroscience the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory and language). the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory and language). Relating brain states with conscious experiences. Relating brain states with conscious experiences.

Dual Processing The principle that information is often simultaneously processed on separate conscious and unconscious tracks. The principle that information is often simultaneously processed on separate conscious and unconscious tracks. Conscious left brain Conscious left brain Intuitive right brain Intuitive right brain Conscious Conscious Unconscious Unconscious

The End