Understanding the Central Nervous System: Brain Functions and Regions

1. The Central Nervous System (CNS) As you view the rest of the lecture, label your brains workbook AND write the MAIN function(s) of that part of the brain next to the name Video snip: The brain’s regions full brain story A: Spinal cord, brainstem, and thalamus B: Brain • Cerebellum • Lobes and cortices (Funky Moms Smoke Pot On Tuesdays) • frontal Funky • motor Moms and somatosensory Smoke cortices • parietal Pot • occipital On • temporal Tuesdays • Corpus callosum C: Limbic system • hypothalamus • pituitary gland • amygdala • hippocampus

2. Female vs. Male Brain:the differences finally revealedWARNING: These images will reveal stereotypes, some of which you may find offensive!!

4. Human brain—interior view of left hemisphere

5. The Brain 1. 2 hemispheres (left and right) • The brain’s 2 hemispheres aresymmetrical in form but not in function • Brain’s symmetry: • Anatomically, the 2 hemispheres are almost symmetrical (left hemisphere tends to be slightly larger than right) • All lobes and glands in brain have a left and right version • Lateralization: The brain’s 2 hemispheres have regions that serve different, yet complementary functions • e.g. Language is usually associated with left hemisphere BUT grasping sarcasm, metaphors, subtleties of language occurs in right hemisphere. For purposes of studying form and function, scientists break the brain down in many ways: hemispheres, regions, lobes, areas... Video snippet: brain hemispherectomy

6. 2. Regions: Hindbrain, midbrain & forebrain

7. Exterior view of left brain (person looking to left of screen) angular gyrus Broca’s area Wernicke’s area Visual cortex Olfactory cortex auditory cortex angular gyrus: connects Wernicke’s to other sensory areas Damage results in inability to read, write, comprehend written word, read music....

8. Parts of the Central Nervous System (CNS) A. Spinal cord & brainstem Spinal cord transmits messages (motor & sensory) between brain and rest of body and reflex messages between nerves and spine Q. What kind of neurons are found in the spinal cord? A: interneurons! Brainstem—part of spinal cord that enters brain

9. Midbrain: involved in muscle movement and integration of sensory input • Reticular formation (AKA RAS) (found throughout midbrain, pons, and medulla): function is arousal, attention • cut=coma • electric stimulation=awake • (mnemonic: tickle arouses you!! give that baby raspberries!) • Pons: coordinates movement and facial expression; integral to REM stage of sleep (time when dreaming occurs) • mnemonic: pom pon girls are coordinated in movements and facial expressions and people dream about them! the Fonz makes good facial expressions and was a “dream boat” • Medulla: controls heart rate, breathing • mnemonic: (sung to tune of akuna mattata from Lion King) "medulla oblangata, what a wonderful thing! keeps me breathing and my heart beating!” ORMedusa: if you look at her, you turn to stone and stop breathing!

10. Damage to the spinal cord or brainstem can lead to: • DEATH (if medulla is severed, heart and breathing stop) • CNS information highway is cut in ½ (brain and rest of body cannot communicate) • Paralysis and lack of feeling below area injured—YET not all messages must go to brain!! Reflex response can remain after spinal injury, including bladder control, sexual function, knee jerk

11. The thalamus • Location: Center of brain, above midbrain • Function: The main processing station for all incoming sensory information EXCEPT for smell (that goes directly to olfactory lobe from nose!) • Thalamus directs traffic of incoming stimuli to appropriate areas in cerebral cortex for further processing Mnemonic: Is that a mouse? It looks like one, feels like one, sounds like one, tastes like one, but I can’t SMELL it!!

12. Cerebellum—the most primitive part of the brain • LOCATION: Base of brainstem in rear of head • SIZE: Baseball (1 in each hemisphere) • FUNCTIONS: • Coordinates voluntary movement, balance • Stores implicit memories! • If damaged: • loss of coordination of motor movement/inability to reach out and grab things • loss of ability to make motor skill memory • seems like you are drunk • Video clip: Medical mystery boy without cerebellum and pons

13. Cerebrum (80% of brain) is divided up into lobes and cortices Mnemonic: Funky Moms Smoke Pot On Tuesdays Cerebral cortex is layer of tissue approx. .5 cm thick that is folded onto itself creating the folds (gyrus) and fissures (sulcus) visible on the surface

14. Frontal Lobes • LOCATION: Top front of head, above temporal lobes • SIZE: Grapefruit (1 in each hemisphere) • FUNCTION? • Emotional control center • “Home” of personality • problem solving; “centralexecutive” • long-term memories stored here • language home to Broca’s Area (speech production) • impulse control • social and sexual behavior • LAST PART OF BRAIN TO DEVELOP IN ADOLESCENCE!!! Phineas Gage video clip 7:40 min.

15. Damage to the frontal lobes can lead to: Do we even want to go there? • Loss of spontaneity in interacting with others • Loss of flexibility in thinking • Persistence of a single thought (Perseveration) • Inability to focus on task • Mood changes • Broca’s aphasia –inability to speak fluently (clip) In sum: personality and attention changes!

16. Somatosensory and Motorsensory Cortexes • Somatosensory cortex and motorsensory cortex lie on either side of fissure of Rolando (division between parietal and frontal lobes) • Somatosensory cortex (on parietal lobe): neurons receive TOUCH sensory information • phantom limb video clip (start at 1.5) • Motorsensory cortex (on frontal lobe): neurons send messages to control bodymovement/muscles

19. Parietal Lobes • LOCATION: Top rear of head, above occipital and temporal lobes • SIZE: Grapefruit (1 in each hemisphere) • FUNCTION? Home of the somatosensory cortex! • Sensory perception (integrating all sensory information into 1 cognition/thought) • perception of stimuli related to touch, pressure, temperature and pain. • Spatial relations Mnemonic: P for perception and parietal

20. Damage to the parietal lobes can lead to: Any predictions before I show you? Damage to the left parietal lobe can result in • inability to perceive objects normally (agnosia) (clip) Damage to the right parietal lobe can result in: • neglecting part of the body or space (contralateral neglect), which can impair many self-care skills such as dressing and washing visual neglect video clip (3 min) • difficulty in making things and drawing

21. Occipital Lobes • LOCATION: Rear of head, above cerebellum • SIZE: Baseball (1 in each hemisphere) • FUNCTION? • Visual perception—all information taken in from eyes is processed in this lobe Mnemonic: optometrist, occ (see see?), optic all about eyes

22. Damage to the occipital lobe can lead to: Any predictions before I show you? • Defects in vision • Difficulty with locating objects in environment. • Difficulty with identifying colors (Color Agnosia). • Production of hallucinations • Word blindness - inability to recognize words. • Difficulty in recognizing drawn objects. • Inability to recognize the movement of an object (Movement Agnosia). • Difficulties with reading and writing.

23. Temporal Lobes • LOCATION: Right and left side of head above ears • SIZE: Grapefruit (1 in each hemisphere) • FUNCTION? • Hearing • olfactory lobe –sniffing scents • speech processing • Home to Wernicke’s Area

24. Damage to Temporal Lobes can lead to… • disturbance of language comprehension • altered sexual behavior (increase or decrease sex drive) • Difficulty in recognizing faces (Prosopagnosia video clip) (Clip 2) • Difficulty in understanding spoken words (Wernicke's Aphasia clip) • Short-term memory loss • Interference with long-term memory • Right lobe damage can cause persistent talking • Increased aggressive behavior

25. Corpus callosum axonal fibers that connect the 2 hemispheres to allow neurons to share information Video snippet severed corpus callosum (5 min) Video snippet #2: Scientific American (11 min)