1. PowerPoint® Presentation by Jim Foley The Biology of Behavior © 2013 Worth Publishers

2. Module 4: The Brain

3. The Brain What we’ll discuss:  how we learn about the brain  the life-sustaining inner parts of the brain: the brainstem and limbic system  the outer, wrinkled “bark”: the cortex  left, right, and split brains Questions about parts of the brain:  Do you think that the brain is the sum of its parts, or is the brain actually about the way they are connected?  What do you think might happen if a particular area of the brain was stimulated?  What do you think might happen if a particular area of the brain was damaged or not working well? Is it possible to ‘understand’ the brain? “If the human brain were so simple that we could understand it, we would be so simple that we couldn’t.” –Emerson M. Pugh …but we can try.

4. Exploring the Older Brain, Cerebral Cortex, and Divided Brain How we learn about the brain:  Scans and more The primitive, life- sustaining, inner parts of the brain:  The brainstem and limbic system  Cerebral Cortex Structure: The Lobes  Motor and sensory strips  Association areas  Brain Plasticity  Functioning of the right and left hemispheres from cases of the divided and intact brains

5. Monitoring activity in the brain Tools to read electrical, metabolic, and magnetic activity in the brain: EEG: electroencephalogram MRI: magnetic resonance imaging fMRI: functional MRI PET: positron emission tomography

6. 6 An EEG (electroencephalogram) is a recording of the electrical waves sweeping across the brain’s surface. An EEG is useful in studying seizures and sleep. EEG: electroencephalogram

7. The PET scan allows us to see what part of the brain is active by tracing where a radioactive form of glucose goes while the brain performs a given task. PET: positron emission tomography

8. 8 MRI (magnetic resonance imaging) makes images from signals produced by brain tissue after magnets align the spin of atoms. The arrows below show ventricular enlargement in a schizophrenic patient (right). MRI: magnetic resonance imaging Functional MRI reveals brain activity and function rather than structures. Functional MRI compares successive MRI images taken a split second apart, and shows changes in the level of oxygen in bloodflow in the brain. fMRI: functional MRI

9. The Brain: Less Complex Brain Structures Our tour of the brain begins with parts of the human brain found also in simpler animals; these parts generally deal with less complex functions: Brainstem (Pons and Medulla) Thalamus Reticular Formation Cerebellum Limbic System

10. The Brainstem: Pons and Medulla

11. The Base of the Brainstem: The Medulla  The medulla controls the most basic functions such as heartbeat and breathing.  Someone with total brain damage above the medulla could still breathe independently, but someone with damage in this area could not.

12. The Thalamus  The thalamus is the “sensory switchboard” or “router”: All sensory messages, except smell, are routed through the thalamus on the way to the cortex (outer brain).  These messages cross over from one side of the body to the opposite side of the brain. The crossover

13. Reticular (“net-like”) Formation  The reticular formation is a nerve network in the brainstem.  It enables alertness (arousal); stimulating this makes us wide awake.  It also filters incoming sensory information and relays it to other brain areas.

14. The cerebellum helps coordinate voluntary movement such as playing a sport. Cerebellum (“little brain”) The cerebellum has many other functions, including enabling nonverbal learning and memory.

15.  emotions such as fear and aggression.  basic drives such as hunger and sex.  the formation of episodic memories. The hippocampus (“seahorse”)  processes conscious, episodic memories.  works with the amygdala to form emotionally charged memories. The Amygdala (“almond”)  consists of two lima bean- sized neural clusters.  helps process emotions, especially fear and aggression. The Limbic (“Border”) System The limbic system coordinates:

16. The Amygdala: Enabling two different responses to threat  Electrical stimulation of one area of a cat’s amygdala provokes aggressive reactions.  If you stimulate a different part of the amygdala and put the cat in a cage with a mouse, the cat will cower in terror.

17.  lies below (“hypo”) the thalamus.  regulates body temperature and ensures adequate food and water intake (homeostasis), and is involved in sex drive.  directs the endocrine system via messages to the pituitary gland. The Hypothalamus: Thalamus Riddle: Why did the rat cross the grid? Why did the rat want to get to the other side? The Hypothalamus as a Reward Center Pushing the pedal that stimulated the electrode placed in the hypothalamus was much more rewarding than food pellets.

18. Review of Brain Structures

19. Higher Brain, Split Brain Topics for your cortex to process:  Cerebral Cortex Structure: The Lobes  The motor and sensory strips and association areas  Brain Plasticity  Functioning of he right and left hemispheres from cases of the divided and intact brains

20. The Cerebral Cortex : 300 billion synaptic connections The brain has left and right hemispheres  The outer grey “bark” structure that is wrinkled in order to create more surface area for 20+ billion neurons.  Organized into 4 lobes in each of two hemispheres.

21. 21 The Lobes of the Cerebral Cortex: Preview Frontal Lobes Parietal Lobes Occipital Lobes Temporal Lobes involved in speaking and muscle movements and in making plans and judgments include the sensory cortex include the visual areas; they receive visual information from the opposite visual field include the auditory processing areas

22. Input: Sensory cortex (Left hemisphere section receives input from the body’s right side) Output: Motor cortex (Left hemisphere section controls the body’s right side) Functions of the Brain: T he Motor and Sensory Strips  Axons receiving motor signals FROM the cortex  Axons sending sensory information TO the cortex

23. Sensory Functions of the Cortex  The sensory strip deals with information from touch stimuli.  The occipital lobe deals with visual information.  Auditory information is sent to the temporal lobe.

24. The Visual Cortex This fMRI scan shows increased activity in the visual cortex when a person looks at a photograph.

25. Association function of the cortex More complex animals have more cortical space devoted to integrating/associating information

26. Case study: Phineas Gage In a work accident, a metal rod shot up through Phineas Gage’s skull, destroying his eye and part of his frontal lobes. After healing, he was rude, odd, irritable, and unpredictable. Possible explanation for the change in personality: Damage to his frontal lobes hurt his ability to inhibit emotions and impulses.

27. Whole-brain Association Activity Whole-brain association activity involves complex activities which require communication among association areas across the brain such as:  memory  language  attention  meditation and spirituality  consciousness

28. This 6-year-old had a hemispherectomy to end life- threatening seizures; her remaining hemisphere compensated for the damage. Plasticity: The Brain is Adaptable If the brain is damaged, especially in the general association areas of the cortex:  the brain does not repair damaged neurons, BUT it can restore some functions  it can form new connections, reorganize, reassign brain areas to new functions.  Some neurogenesis, production of new brain cells, helps rebuild

29. Brain Studies Researchers have studied the impact of this surgery on patients’ functioning. Split- To end severe whole-brain seizures, some people have had surgery to cut the corpus callosum, a band of axons connecting the hemispheres.

30. Separating the Hemispheres: Factors to Keep in Mind  Each hemisphere controls the opposite side of the body AND is aware of the visual field on that opposite side.  Without the corpus callosum, the halves of the body and the halves of the visual field do not work together.  Only the left half of the brain has enough verbal ability to express its thoughts out loud.

31. Split visual field Each hemisphere perceives the half of the view in front of you that goes with the half of the body that is controlled by that hemisphere.

32. 32 Divided Awareness in the Split Brain Try to explain the following result:

33. The divided brain in action  Talent: people are able to follow two instructions and draw two different shapes simultaneously  Drawback: people can be frustrated that the right and left sides do different things

34. Our Two Hemispheres Lateralization (“going to one side”) The two hemispheres serve some different functions. How do we know about these differences?  Brain damage studies revealed many functions of the left hemisphere.  Brain scans and split brain studies show more about the functions of the two hemispheres, and how they coordinate with each other.

35.  Thoughts and logic  Language: words and definitions  Pieces and details  Feelings and intuition  Language: tone, inflection, context  Wholes, including the self The intact but lateralized brain Right-Left Hemisphere Differences Left Hemisphere Right Hemisphere