Phrenology

Ways we Study the Brain Accidents Lesions EEG CAT Scan PET Scan MRI Functional MRI

Accidents Phineas Gage Story Personality changed after the accident. What this this tell us? That different part of the brain control different aspects of who we are.

Lesions Removal or destruction of some part of the brain. Frontal Lobotomy

Electroencephalogram EEG Detects brain waves through their electrical output. Used mainly in sleep research.

Computerized Axial Tomography CAT Scan 3D X-Ray of the brain. Good for tumor locating, but tells us nothing about function.

Magnetic Resonance Imaging MRI More detailed picture of brain using magnetic field to knock electrons off axis. Takes many still pictures and turns images into a movie like production.

Positron Emission Tomography PET Scan Measures how much of a chemical the brain is using (usually glucose consumption).

Functional MRI Combination of PET and MRI

Different areas of the brain have different roles.

Major Brain Regions: Brainstem Medulla Breathing, muscle tone and regulating circulation T h a l m u s C o r p c H y t P n M e d S i b Pons Connects brainstem with cerebellum & involved in sleep and arousal C e r r Cerebellum Coordination of voluntary movement and sense of equilibrium

Major Brain Regions: Midbrain Part of the brainstem twixt the hindbrain and the forebrain T h a l m u s C o r p c H y t P n M e d S i b Concerned with certain sensory processes and dopamine production Midbrain Reticular Formation Modulates muscle reflexes, breathing & pain perception. Also regulates sleep, wakefulness & arousal

Major Brain Regions: Forebrain Thalamus Relay station for all sensory info (except smell) to the cortex T h a l m u s C o r p c H y t e b x P n M d S i Cerebrum/Cerebral Cortex Hypothalamus Regulates basic needs fighting, fleeing feeding, and mating e Limbic System Involved in regulation of emotion, memory & motivation

THALAMUS It relays to the cerebral cortex information received from diverse brain regions. Sort of a requisite 'last pit stop' for information going to cortex. Axons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortex

Emotion and Memory are closely connected. Amygdala A little almond shaped structure, connects with the hippocampus. Hippocampus Is particularly involved with memory phenomena, specially with the formation of long-term memory (the one that, sometimes, lasts forever).

The pituitary gland may be king, but the power behind the throne is clearly the hypothalamus.

Major Brain Regions: Cerebral Cortex Convoluted outer layer of cerebrum Responsible for learning, memory, thinking, sensation and consciousness

Structure of the Cortex 1/8th inch thick 30 billion nerve cells + 270 billion Glial cells Each nerve cell makes 10,000 contacts each Approximately 300 trillion connections

Lobes of Cerebral Hemispheres primary motor cortex primary somatosensory cortex primary auditory cortex primary visual cortex Temporal (“tones”) - Devoted to auditory processing Occipital (“objects”) - Devoted to visual processing Parietal (“pressure”) - Devoted to sense of touch Frontal (“??”) - Devoted to control of muscle movement and other behavioral functions (e.g., personality)

Lobes of the Cerebral Cortex

Motor and Sensory Cortexes

Cerebral Laterality Idea of Hemispheric Specialization Broca’s Area Important in the production of speech Wernicke’s Area Important in the comprehension of language Idea of Hemispheric Specialization (“Left/Language & Right/Visual-Spatial”) leads to Split Brain Research by Sperry & Gazzaniga

Speaking the Heard Word LANGUAGE CENTERS Disrupts Understanding Disrupts Speaking Speaking the Heard Word Speaking the Written Word Angular Gyrus Speak & Understand, Unable to Read

(Right side of the brain controls the Left side of the body) Cerebral Hemispheres Corpus Callosum 200 million nerve fibers that connect Left & Right hemispheres. Allows communication between two sides of the brain. Each hemisphere’s primary connections are to the opposite side of the body (Right side of the brain controls the Left side of the body)

HE ART Split Brain What effect does cutting the Corpus Callosum Left Visual Field Right Visual Field Split Brain What effect does cutting the Corpus Callosum have on behavior? HE ART l “Say what you saw vs Point at what you saw” Retina Optic Chiasm Thalamus Left Visual Cortex Right Visual Cortex Corpus Callosum

Central Nervous System Consists of the Brain and the Spinal Cord CNS is nourished and protected by the Cerebrospinal Fluid Blood-Brain Barrier Semi-permeable membrane-like mechanism that prevents some chemicals from passing between the bloodstream and the brain

Don’t You Believe It “Everybody knows that we only use 10% of our brains.” “Imagine what we’d be like if we could use the other 90%!”