The Brain Unit 3 B

The Brain

Phineas Gage Video http://www.youtube.com/watch?v=oPAqTP7058Q

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 does this tell us? That different part of the brain control different aspects of who we are.

Lesions Purposeful 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.

CT example

Magnetic Resonance Imaging MRI More detailed picture of brain using magnetic field to knock electrons off axis. Shows the structure of the brain Takes many still pictures and turns images into a movie like production. Does not study function!

MRI example Notice the tumor…

Positron Emission Tomography PET Scan: depicts brain activity by showing each brain areas’ use of its chemical fuel Measures how much of a chemical the brain is using (usually glucose consumption). Also shows activity of the brain Good for studying function.

PET scan Depression

Functional MRI Combination of PET and MRI: shows functioning and activity fMRI is good for function, hence the f.

f MRI example Amygdala activation Primary Visual Cortex activation

Dr. Jones, a brain researcher, is investigating the connection between certain environmental stimuli and brain processes. Which types of brain scans is she most likely to use? A. MRI and CAT B. CAT and EKG C. PET and fMRI D. EKG and CAT E. lesioning and MRI

The answer was C. The CAT and the MRI give insight into brain structure, not function.

Brain Structures Hindbrain/brain stem Midbrain/limbic system Forebrain/cerebral cortex Cerebral cortex is part of forebrain

The brain was built like a house, bottom to top. The hindbrain controls basic functions like breathing. Shared with animals The forebrain is the most complex

Hindbrain Structures on top of our spinal cord. Controls basic biological structures. All animals have hindbrains! 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. (basic stuff!)

Pons Located just above the medulla. Connects hindbrain with midbrain and forebrain. Helps coordinate movements Involved in facial expressions. Bladder control, eye movement, posture, hearing and more

Cerebellum Bottom rear of the brain. Means “little brain” Coordinates fine muscle movements and balance. Kicking a goal in soccer

What is reticular formation? Part of brain – affects consciousness. Sleep meds affect this part of the brain. Damage leads to a coma. Controls arousal and ability to focus attention

Midbrain Consists of the thalamus Cerebellum and the Limbic system

Cerebellum

The Limbic System deals with memory and emotions

Thalamus Switchboard “relay station” of the brain. Receives sensory signals from the spinal cord and sends them to other parts of the forebrain. Every sense except smell.

Hypothalamus Maybe most important structure in the brain. Controls and regulates the temperature, hunger, thirst Controls the endocrine system. All the glands The most powerful structure in the brain.

Rat with an Implanted Electrode in pleasure center of Hypothalamus

Ventromedial Hypothalamus Lateral Hypothalamus Ventromedial Hypothalamus When stimulated it makes you hungry. When lesioned (destroyed) you will never be hungry again. Larger Hunger When stimulated you feel fufull. When lesioned you will never feel fullulagain. Very Minute Hunger

Hippocampus Involved in the processing and storage of memories. Its proximity to your emotional centers explains why memories and emotions are so linked!

http://www. youtube. com/watch http://www.youtube.com/watch?v=WmzU47i2xgw&list=PL2920A92123EAF834&index=76

Amygdala Brain part involved in telling your body to produce norepinephrine (adrenaline) More involved in volatile emotions like anger. The emotion of anger has not changed much throughout evolution.

What is the cerebral cortex?

The Cerebral Cortex Made up of densely packed neurons we call “gray matter” Wrinkles are called fissures. If you lay brain out it would be as big as a large pizza. It’s divided into 2 hemispheres and 4 lobes! Left and right hemispheres

Cerebral Cortex What makes us human, animals without a large cortex act on instinct Cc contains 20-23 billion nerve cells 300 trillion synaptic connections Glial cells support these nerve cells. Neurons are like queen bees they cannot feed or protect themselves glial cells worker bees they provide nutrients, and insulating myelin, mop up neurotransmitters , chat with neurons

The Cerebral Cortex is made up of four Lobes. Label your brain outline!

What are Frontal Lobes? Abstract thought and emotional control and planning. Contains Motor Cortex, Broca’s area. Lobotomies damage this. Suppresses the Amygdala.

What is the motor cortex? Part of the brain in the frontal lobe that tells my body how to move (like typing this).

What is the sensory cortex? It’s the part that deals with touch sensations. It’s In the parietal lobe.

What are Motor and Sensory Cortexes? The wires are switched! Right controls left! The motor cortex is in which lobe?

Sensory homunculus A visual representation of how much space your brain needs to operate parts of your body. Notice how big the face and hands are. How small everything else is!

Motor strip and homunculus

Parietal Lobes Contain Sensory Cortex: receives incoming touch sensations from rest of the body. Most of the Parietal Lobes are made up of Association Areas. Where would this girl feel the most pain from her sunburn?

Occipital Lobes Think “optical”. Contains Visual Cortex: interprets messages from our eyes into images we can understand.

Notice how close the auditory cortex is to the ears.

Association areas About ¾ of the brain which is not involved in the sensory or motor activity Association areas integrate information These areas link sensory inputs with stored memories –Very important Found in all 4 lobes In frontal lob association areas allow us to learn, judge and process new memories but damage would not allow you to plan ahead

Association Areas continued In parietal lobes assoc. areas allow us to use math and spatial reasoning, recognize faces

Figure 3B.16 Areas of the cortex in four mammals More intelligent animals have increased “uncommitted” or association areas of the cortex. These vast areas of the brain are responsible for integrating and acting on information received and processed by sensory areas. © 2011 by Worth Publishers

Temporal Lobes Process sound sensed by our ears. Interpreted in Auditory Cortex. NOT LATERALIZED. Sound goes to both temporal lobes

Aphasia- impaired use of language Broca’s area – production of speech think (boca) (left side of the frontal lobe).Struggle to speak but can sing and comprehend Angular gyrus- speak and understand cannot read aloud Wernicke’s area deals with comprehension of language. Speak meaningless words also disrupts comprehension Which side of brain are we seeing?

Aphasia Videos http://www.youtube.com/watch?v=1aplTvEQ6ew http://www.youtube.com/watch?v=aVhYN7NTIKU

Figure 3B.18 A simplified model of brain areas involved in language processing © 2011 by Worth Publishers

Figure 3B.19 Brain activity when hearing, seeing, and speaking words PET scans such as these detect the activity of different areas of the brain. © 2011 by Worth Publishers

Specialization and Integration in Language

Brain Activity when Hearing, Seeing, and Speaking Words Which side of the brain are we seeing?

Brain Plasticity The idea that the brain, when damaged, will attempt to find news ways to reroute messages. Children’s brains are more plastic than adults. Neurogenesis- the ability of the brain to make new neurons

Video Brain Plasticity http://www.youtube.com/watch?v=rDTiZpPyqRk http://www.youtube.com/watch?v=D0njlDSFie4

Neurons’ ability to re-route their messaging in case of injury. Brain plasticity Neurons’ ability to re-route their messaging in case of injury.

When brain researchers refer to brain plasticity, they are talking about A. the brain’s ability to quickly regrow damaged neurons B. the surface texture and appearance caused by the layer known as the cerebral cortex C. the brain’s versatility caused by the millions of neural connections D. our adaptability to different problems ranging from survival needs to abstract reasoning E. new connections forming in the brain to take over for damaged sections

Demonstration: Any volunteers? What is Split Brain? Demonstration: Any volunteers?

The Corpus Callosum Divides the 2 hemispheres. Divides the left from right sides. The corpus callosum is cut to prevent seizures from spreading to the other side of the brain.

A Tour Through The Brain: Lateralization The left and right hemispheres of the brain each specialize in particular operations.

Figure 3B.22 The information highway from eye to brain Information from the left half of your field of vision goes to your right hemisphere, and information from the right half of your visual field goes to your left hemisphere, which usually controls speech. (Note, however, that each eye receives sensory information from both the right and left visual fields.) Data received by either hemisphere are quickly transmitted to the other across the corpus callosum. In a person with a severed corpus callosum, this information sharing does not take place. © 2011 by Worth Publishers

Split Brain Patients Those who, due to epilepsy, have their corpus callosum cut or removed.

Visual Information Visual information directed to each side of the brain comes from visual fields not from the eyes. The left eye does not send information to the right hemisphere and vice versa. The RIGHT HALVES of each eye send information to the right hemisphere and vice versa

Figure 3B.23 Testing the divided brain When an experimenter flashes the word HEART across the visual field, a woman with a split brain reports seeing the portion of the word transmitted to her left hemisphere. However, if asked to indicate with her left hand what she saw, she points to the portion of the word transmitted to her right hemisphere. From Gazzaniga, 1983 © 2011 by Worth Publishers

A Tour Through The Brain: Split-Brain Research (Continued)

Split Brain Video http://www.youtube.com/watch?v=aCv4K5aStdU http://www.youtube.com/watch?v=8C8qu8FnuAo

Experiment #1 Split-brain patients Experimenter shows fork to left hemisphere (presents to the right side) Participant is asked what he saw… He states “fork” Experimenter shows spoon to right hemisphere Participant is asked what he saw Response: “I don’t know” Participant is asked to reach in a bag with left hand (right hemisphere) to retrieve what he saw He pulls out a spoon…explain?

Other weird issues with split-brain A split-brain patient was asked what he wanted to do with his life… Left hemisphere wrote: architect Right hemisphere wrote: race car driver Suicide case study Left hand (right hemisphere) kept trying to strangle herself Left hemisphere was unaware of why this was happening and had to defend herself Tumor was discovered on her corpus collosum

On the next slide, say the COLOR of the word without reading the word.

Right-Left Brain Differences for the rest of us with intact brains Right Brain: Perceptual tasks Making inferences Sense of self Problem seeing other people in relation to themselves Cannot recognize themselves in a mirror Left Brain Speaks Calculates Literal interpretation in language Sign language included

Brain and Consciousness What is consciousness? Evolutionary psychologist believe it must be involved with reproduction or survival But how do brain cells talk to one another? No clue how the brain creates consciousness Cognitive neuroscience- science of brain activities connected to mental processes

Studies show if you imagine doing something an fMRI of your brain indicates activity We have dual processing- 2 minds operate at the same time conscious mind (explicit) mind and your unconscious mind (implicit) Much of our thinking operate outside of our awareness