1. THE BRAIN Chapter 27 & 28

2. WHAT YOU NEED TO KNOW!  The formation of the nervous system from germ layers.  One function for each major brain region

3. BRAIN DEVELOPMENT  Zygote  blastula  gastrula (endoderm, mesoderm, ectoderm)  Part of the ectoderm thickens into the neural plate  Ridges form on either end of the neural plate called neural folds  The neural folds migrate inward and form the neural tube  The neural tube will ultimately form the spinal cord and brain

4. BRAIN DEVELOPMENT

5.  The neural tube further develops into 3 regions which further specialize: 1.Forebrain – cerebrum & diencephalon 2.Midbrain - midbrain 3.Hindbrain – Pons, cerebellum, & medulla oblongata

6. INJURY  UNDERSTANDING  We understand how brain functions from injury  Phineas Gage was a railroad construction foreman (1848)  An accidental explosion sent a rail spike through his head  Gage survived but he was a changed man…

7. A piercing image of Phineas Gage Thomas H. Maugh II Massachusetts photographers have unearthed the only known image of legendary brain-injury patient Phineas Gage, a daguerreotype showing the former railroad worker sitting in repose and holding the nearly 4-foot-long iron rod that pierced his brain without killing him. Contemporary accounts suggest that Gage's personality was dramatically altered because he was disfigured in the accident, but the new image, to be published online next week in the Journal of the History of the Neurosciences, shows a relatively handsome man -- confirming the belief of most experts that damage to his brain accounted for the changed personality. Gage was the 25-year-old foreman of a construction gang on Sept. 13, 1848, preparing a railroad bed outside Cavendish, Vt. As usual, he was using a pointed iron rod -- 3 feet, 7 inches long and 13 1/4 pounds -- to tamp gunpowder and sand into a hole drilled in the rock. But on that day, the mixture exploded, sending the rod through his left cheek and out through the top of his head. It was successfully removed and, to the surprise of physicians, Gage lived 11 more years, dying after a series of increasingly violent convulsions. His story is a showpiece in neurology texts and folklore because of his survival and the abrupt changes in his personality.

8. BRAIN STRUCTURE  Brainstem consists of the medulla, pons and midbrain  Cerebellum is mini-brain that sits at the back bottom of the brain  The thalamus and hypothalamus sit right on top of the brainstem and are at the central region of the forebrain  The cerebrum is the top and most identifiable region of the brain

9. BRAIN STRUCTURE  The cerebrum is composed of two hemispheres: left and right  The hemispheres are connected by the corpus callosum (split brain)  The cerebrum is further divided into four lobes: frontal, parietal, occipital, and temporal

10. FUNCTION  Medulla: controls breathing, circulation, swallowing, digestion, …  Pons: controls breathing  Midbrain: receives and integrates auditory data, coordinates visual reflexes, sends sensory data to higher brain centers  Cerebellum: coordinates body movement, plays a role in learning and in remembering motor responses  Thalamus: serves as input center for sensory data going to the cerebrum, output center for motor responses  Hypothalamus: functions as homeostatic control center, controls the pituitary gland, and serves as a biological clock

11. FUNCTION  Cerebrum: performs sophisticated integration, plays major role in memory, learning, speech, emotions, formulates complex behavioral responses  Frontal Lobe: speech, motor cortex  Parietal lobe: somatosensory cortex, taste, reading, speech  Occipital Lobe: vision  Temporal lobe: Hearing, smell

12. SLEEP & AROUSAL  Arousal is awake  alert Alpha waves indicate a relaxed brain that is awake Beta waves indicate an active awake brain  Sleep is the opposite of arousal Delta waves are slow wave sleep patterns during deep sleep REM (rapid-eye-movement) sleep is deep sleep with high levels of brain activity

13. LIMBIC SYSTEM  Emotions, memory, and learning  Amygdala lays down emotional memories  Hippocampus forms and retrieves memories  Short-term memory lasts minutes, long-term memory lasts a lifetime

14. NEUROLOGICAL DISORDERS  Schizophrenia (1%): psychotic episodes where patients lose the ability to distinguish reality  Depression: Major depression (5%): extreme sadness, loss of energy, and suicidal thoughts Bipolar disorder (1%): consists of extreme mood swings  Alzheimer’s Disease (65 – 10%, 85 – 35%): confusion and memory loss, usually in old age  Parkinson’s Disease (65 – 1%, 85 – 5%): difficulty in initiating movements, slowness of movement, and rigidity