Transcript The Brain
Welcome!! Warm-Up On the sheet provided, label the Neuron correctly… then explain the three types of Neurons on the bottom of the paper The Brain The Brain • The most important structure in our bodies • Controls most of human thought and emotion. • From pain to pleasure it all comes from the brain. The Brain Made up of millions of densely packed neurons and actually it feels no pain. Pain actually stops once something reaches the actual brain. It was once commonly believed that if you damage brain cells (through drinking, smoking, hitting your head, or just holding your breath for a REALLY long time) they would never grow back And you would be in big trouble... There is some research now that points to the contrary. • So, if you have some brain damage, do not worry... – Some of our brain functions are flexible and if one part goes out, others will try to compensate and continue to function. • This is called Brain Plasticity Brain Plasticity • The idea that the brain, when damaged, will attempt to fix itself • It does this by rerouting connections to avoid damaged areas • Think of it this way…you are on the way for a romantic date when you find the highway flooded… – Would you give up?? – No, you would use Mapquest to get new directions • This is essentially what our brains try to do when damaged. Brain Plasticity • Unfortunately, as we age the ability of brain plasticity working decreases. – Children’s brains are more plastic than adults. • The lesson here is…??? – if you are going to damage your brain, do it at a very young age. Before we talk about brain structures, lets quickly go over some of the ways scientists learn about the brain • • • • • • • Ways we Study the Brain Accidents Lesions EEG CAT Scan PET Scan MRI Functional MRI Accidents Every so often someone gets smacked in the head REALLY hard and from that injury we learn about the brain. The Phineas Gage Story • Personality and behavior changed after damage to his Frontal Cortex What did this tell us? – different parts of the brain control different aspects of who we are. Lesions/Ablations • Removal or destruction of some part of the damaged brain. – Sometimes done intentionally • Frontal Lobotomy – Often used for mentally unstable patients An ablation of a rat’s brain Ok, that was a piece of cake, now on to the heart of this unit: Brain Anatomy and Function Before we begin… • Realize, that for this class, EXACT areas of the brain are not all that important. • As long as you understand the general function and location you are going to do fine. • So here we go… Brain Structures The brain can be broken down into three areas: 1. Hindbrain 2. Midbrain 3. Forebrain Hindbrain • Lowest part of the brain, on top of our spinal cord • Controls most of our basic biological functions. • i.e. heartbeat, breathing, ect. The brain in purple makes up the hindbrain. Medulla Oblongata Located just above the spinal cord Involved in control of • blood pressure • heart rate • breathing. If you get hurt in the MO you should just pack it in Pons Located just above the medulla • Relays information to other parts of the brain from the hindbrain Cerebellum Located at the bottom rear of the brain • Looks like a mini version of the brain - “little brain” • Controls balance, coordination, and fine muscle movement Cerebellum Midbrain Located in the middle of our brain and is the pathway that connect the hb and fb If stimulated • Most important structure in Midbrain is the Reticular Formation – controls arousal (no not that type of arousal) If Destroyed coma Wide awake Forebrain Largest part of the brain – The most important part of the brain for this class – What makes us human. Made up of 3 parts – Thalamus – Limbic System – Cerebral Cortex. Thalamus • The operator / switchboard of the brain (relay station) • Any sensory information that comes into our bodies (sight, hearing, touch and taste) goes to the Thalamus first from the spinal cord – Every sense except smell • It then sends them to other parts of the brain to get processed The Limbic System Sometimes called the emotional control center of our brain Contains Four Parts Hypothalamus Maybe the most important and powerful structure in the brain – Only the size of a pea Controls and regulates vital body functions • Body temperature • Sexual Arousal • Hunger • Thirst Often referred to as the “pleasure • Endocrine System center” Rat with an Implanted Electrode in the pleasure center of Hypothalamus Hippocampus • Involved in the processing and storage of memories. – Not stored here, but it helps put them in the right places Amygdala • Handles emotional response to fear and aggression • Also involved in handling basic emotions like anger and jealousy Pituitary Gland • “Master Gland” • Responsible for the production and distribution of hormones The Cerebral Cortex • The most important part of the brain – “makes us human” • Made up of densely packed neurons often called “gray matter” • It is big and full of wrinkles called fissures. • If I took out your cerebral cortex and ironed it, it would be as big as a large pizza (but would not taste as good) The Cerebral Cortex is divided into two hemispheres Lateralization: •Division of functions between sides of the brain •right controls left and vice versa •Often one side is better at certain tasks than The other side In general = Left Hemisphere: language abilities –speaking, reading, writing logical analysis - math Right Hemisphere: understanding spatial relationships – puzzles, reading maps = recognizing faces and interpreting facial expressions and perceiving and expressing emotion = likes art and music Looking at the nose… Smiling or Frowning??? Between the two hemispheres is a band of nerve fibers called the Corpus Callosum Divides the 2 hemispheres. Corpus Callosum Helps the two sides communicate with each other Sometimes this has to be removed (usually seen in people with epilepsy) Sometimes a whole side of the brain has to be removed • hemispherectomy They are then called Split Brain Patients They actually have two separate brains in their heads, and one brain has no idea what the other is doing However, through plasticity most sbp will find ways to get their hemispheres to communicate Testing the Divided Brain Sperry and Gazzaniga – tested split brain patients For For Example most people the ability to see comes from the left hemisphere (which controls the right field of vision) So if a sbp sees an elephant in their left visual field they will not be able to say what they see, but they can write it with their right hand (but not the left hand) – get it?? Split Brain Patients Decreasing Left-handers Areas of the Cerebral Cortex The Brain’s Thinking, Calculating, Organizing, and Creative Center The Cerebral Cortex is made up of four Lobes. REMEMBER!! We actually have 8 lobes!! Frontal Lobe Top part of our brain behind our eyes • Higher mental functions – thinking, planning, problem solving, decision making, and accessing memories • Motor Cortex – sends signals to our body controlling voluntary muscle movements – Damage this area and you may not be able to move certain parts of your body Parietal Lobe • Located in back of the frontal lobes on the top of our head • Contains Sensory Cortex – Process information relating to sensations of touch, pressure, temp. and pain – Damage this area and it may result in an inability to integrate sensations Motor and Sensory Cortexes Homunculus Occipital Lobe • Located in the very back of our brain • Deals with vision. • Contains Visual Cortex – interprets messages from our eyes into images we can understand. • Get hit here and you may “see stars” Temporal Lobe • Located just above our ears on both sides of our head • Contains the Auditory Cortex • Process sound sensed by our ears • NOT LATERALIZED – What?? Brain Activity when Hearing, Seeing, and Speaking Words Two Other Areas To Know Broca’s Area Responsible for transferring thoughts into audible spoken words • Damage to Broca’s Area is called Broca’s Aphasia: unable to make movements to talk. Wernike's Area: – Responsible for transforming spoken words into thoughts • Wernike's Aphasia: unable to understand speech Association Areas • Any area NOT associated with receiving sensory information or coordinating muscle movements. – But has some higher level purpose • We are not so concerned with association areas – But it does make up most of the cerebral cortex Specialization and Integration in Language How do we read and recite?? Parts of the brain! • Pinky and the Brain