Chapter 2: Cognitive Neuroscience

Simple, yet so complex; The Neuron

Either or operation

At rest: Average 100ms between firing

Excitation: Much faster

Inhibition: A bit slower

Neural Speed

• 10 volunteers

• Hold hands, squeeze when your neighbor does: Timed

• Hold shoulders, squeeze when your neighbor does: Timed

Written by Nancy Jo Melucci, Santa Monica College

•100 billion neurons• A typical neuron has about 1,000 to 10,000

synapses (that is, it communicates with 1,000 –10,000 other neurons, muscle cells, glands, etc.).

•100 trillion synapses• Weight 46 - 50 ounces (≈ 3 pounds)

Brain Facts

value  1¢, (one cent)

width  0.75 inches, (3/4 of an inch)

height  0.75 inches, (3/4 of an inch)

thickness  0.0625 inches, (1/16 of an inch)

weight  0.1 ounces, (1/10 of an ounce)

100 Million, Billion, Trillion… What’s the diff? *Shrug*

 

value  16¢, (sixteen cents)

width (side-by-side)  12 inches, (one foot)

height (stacked)  1 inch

thickness  0.0625 inches, (1/16 of an inch)

weight  1.6 ounces

value  $10.00, (Ten dollars and no cents)

width  3.75 inches

height  3.75 inches

thickness  2.5 inches

weight  100 ounces, (6.25 pounds)

height stacked  62.4 inches, (5.2 feet)

area (laid flat)  562.5 square inches (3.9 square feet)

1,000 pennies

value  $983.04(Nine hundred eighty-three dollars and four cents)

width  24 inches, (two feet)

height  12 inches, (one foot)

thickness  12 inches, (one foot)

weight  614.4 pounds

height stacked  512 feet

area (laid flat) 384 square feet

100,000 pennies

 

value  $10,037.76(Ten thousand, thirty-seven dollarsand seventy-six cents)

width  Four feet

height  Five feet

thickness  12 inches, (one foot)

weight  6273.6 pounds (3.14 tons)

height stacked  5,228 feet ( 0.99 Miles )

area (laid flat) 3,921 square feet

1,000,000 pennies

value $10,000,181.76(Ten million, one hundred eighty-onedollars and seventy-six cents)

width  45 feet

height  11 feet

thickness  41 feet

weight  3,125 tons

height stacked  987 Miles

area (laid flat)  3,906,321 square feet (89.7 acres)

1,000,000,000 pennies

 

value  $100,000,235.52(One hundred million, two hundred thirty-fivedollars and fifty-two cents)

width  90 feet

height  11 feet

thickness  205 feet

total weight  31,250 tons

height stacked  9,864 Miles

area (laid flat)  897 acres

100,000,000,000 Neurons in the brain!

value  $10,000,000,166.40(Ten billion, one hundred andsixty-six dollars and forty cents)

width  273 feet

height  273 feet

thickness  273 feet

total weight  3,125,000 tons

height stacked  986,426 Miles

area (laid flat)  89,675.2 acres

1,000,000,000,000 pennies

•Sears Tower

•Empire State Building

•Washington Monument

•Lincoln Memorial

2,623,684,608,000 pennies.

value  $26,236,846,080.00(Twenty-six billion, two hundred thirty-six million,eight hundred forty-six thousand andeighty dollars)

total weight  8,199,014 tons

height stacked  2,588,073 Miles

area (laid flat)  235,279.3 acres

100,000,000,000,000 synapses in the brain!

A stack of pennies 98,642,600 Miles long!

Long enough to wrap 4,000 times around the earth.

Methodology

• Postmortem studies

• Animal Studies

• Electrical Recordings

• Static Imaging Techniques

• Metabolic Imaging

Methodology

Postmortem Studies

• Identify disorder and then examine after death– Young, Holcomb, Yazdani, Hicks & German

(2004)• Found that depression is associated with a greater

number of nerve cells in the Thalamus being devoted to emotional regulation

• Supported idea that structural abnormality may lead to depression

Methodology

Animal Studies: In Vivo

• Monitor activity of a single neuron

Methodology Animal Studies: Single Neuron Monitoring

• Gross, Bender & Rocha-Miranda, 1969– Increased firing in the inferotemporal region in

response to more hand-like objects

Inferotemporal region

Methodology

EEG-Human Studies

Electroencephalograph Research Example

Methodology

Positron Emission Tomography (PET)

• Radioactive material is injected or inhaled

• Participant is then scanned to produce an image of the brain’s activity

Methodology

Magnetic Resonance Imaging

• Strong magnetic field passed through the skull• Uses the detection of radio frequency signals produced

by displaced radio waves in a magnetic field • Creates a detailed anatomical image of the brain

Methodology

Functional magnetic resonance imaging (fMRI)

• fMRI quick series of images analyzed for differences

• Brain areas with more blood flow have been shown to have better visibility on MRI images

Where am I?

Common sense, though all very will for everyday purposes, is easily confused, even by such simple questions as… When you feel a pain in the leg that has been amputated, where is the pain? If you say it is in your head, would it be in your head if your leg had not been amputated? If you say yes, then what reason have you for ever thinking you have a leg?

– (Bertrand Russell)

Anatomy of the Brain

• Forebrain

• Midbrain

• Hindbrain

Anatomy of the Brain

Forebrain

• Cerebral cortex• Basal ganglia• Limbic system

– Amygdala– Hippocampus– Thalamus– Hypothalamus

Anatomy of the Brain Forebrain

Cerebral Cortex• Frontal• Parietal• Temporal• Occipital

Anatomy of the Brain Forebrain Cerebral Cortex

Frontal Lobe

• Impulse control, judgment, language, memory, problem solving, sexual behavior, socialization and spontaneity.

"It seems possible that with additional experience and a minute study of the pathologic changes seen in the brain, the knife may be the means of restoring to reason many cases now considered incurable"

--Emory Lamphear (1895)

Walter Freeman

Anatomy of the Brain Forebrain Cerebral Cortex

Parietal Lobe

• Somatosensory cortex

• Sensory integration

• Two point discrimination test

Anatomy of the Brain Forebrain Cerebral Cortex

Temporal Lobe

• Auditory & Perceptual processing

• Wernicke’s area– Wernicke’s aphasia– Fluent nonsense

Anatomy of the Brain Forebrain Cerebral Cortex

Occipital Lobe

• Visual processing– Movement discrimination– Color discrimination

• Black-out• Damage can cause visual

illusions– Large or small appearance– Odd coloring

• Without it there is no concept of color

Anatomy of the Brain Forebrain

Basal Ganglia• Ganglion is a collection of

cell bodies outside the central nervous system

• Controll voluntary movements

• Establish postures

• Damages causes unwanted movements, such as involuntary jerking movements of an arm or leg or spasmodic movement of facial muscles.

Anatomy of the Brain Forebrain

Limbic System

• Controls Mood and attitude

• Stores highly charged emotional memories

• Controls appetite and sleep cycles

Anatomy of the Brain Forebrain

Limbic System

• Amygdala– Involved in anger, & fear

• Hippocampus– Is important in the

formation of memories– Korsakoff’s syndrome

Anatomy of the Brain Forebrain

Limbic System

• Thalamus– Relay sensory

information to the cerebral cortex

• Hypothalamus– Important to metabolic

behaviors, eating, drinking, sexual behaviors, and regulating emotions

Anatomy of the Brain

Midbrain• Location

– The midbrain extends from the pons to the lower portion of thalamus

• Reticular activating system– Controls respiration, cardiovascular function,

digestion, alertness, and sleep

• Brain Stem– Vital in basic attention, arousal, and consciousness

Anatomy of the Brain

Hindbrain

• Medulla Oblongata• Pons• Cerebellum

Anatomy of the Brain Hindbrain

Medulla Oblongata

• Nerve crossover

• Cardiac functioning

• Respiration

• Digestion

• Swallowing

Anatomy of the Brain Hindbrain

Pons

• Relay station

• Bridge in Latin

Anatomy of the Brain Hindbrain

Cerebellum

• Latin for “little brain”• Coordination• Balance• Muscle tone• Sensory integration in

perception• Motor output• Spatial updating

Cerebral Cortex Principles

• Contralaterality

• Corpus Callosum

• Localization of Function

• Hemispheric Specialization

Click, Hum and Recite

• Hold the counter in right hand• Press it as fast as you can for 30 seconds• Reset the counter and repeat for the left hand• Repeat with right and left hands while reciting the pledge of

allegiance. These two bits of data are your right and left “oral data.” • Repeat with right and left hand while humming a song (Forget about

the words). These two bits of data are your left and right “music data.”

• The hypothesis in this experiment is that talking will interfere more with right-hand pressing, whereas humming will interfere more with left-hand pressing, due to the hemispheric specializations involved in these tasks.

Written by Nancy Jo Melucci, Santa Monica College

Cerebral Cortex Principles

Contralaterality

• Right side of brain controls left side of body

• Left side of brain controls right side of body

Cerebral Cortex Principles

Corpus Callosum

• Neural fibers connecting left and right lobes

• Allows communication between right and left sides of the brain

Cerebral Cortex Principles

Localization of function

• Specific mental processes are correlated with discrete regions of the brain

Body in the Brain

Cerebral Cortex Principles

Hemispheric Specialization

Each lobe of the brain has specialized functions

Left side processes:• Speech• Analysis• Time• Sequence It Recognizes:• Letters • Numbers • Words

Right side processes:• Creativity • Patterns • Spatial Awareness • Context It Recognizes:• Faces • Places • Objects

Activity

• Get a blank sheet of lined paper. Every time you read a description or characteristic that applies to you, write down its number on the blank sheet of paper. There is no certain number of characteristics you must choose.

1. I constantly look at a clock or wear a watch 2. I keep a journal or diary of my thoughts 3. I believe there is a either right and wrong way to do everything 4. I find it hard to follow directions precisely 5. The expression "Life is just a bowl of cherries" makes no sense to me 6. I frequently change my plans and find that sticking to a schedule is

boring 7. I think it's easier to draw a map than tell someone how to get

somewhere 8. To find a lost item, I try to picture it in my head where I last saw it 9. I frequently let my emotions guide me 10. I learn math with ease 11. I'd read the directions before assembling something 12.People tell me I am always late getting places 13.People have told me that I'm psychic 14. I need to set goals for myself to keep me on track 15.When somebody asks me a question, I turn my head to the left 16. If I have a tough decision to make, I write down the pros and the cons17. I'd probably make a good detective

18. I learn music with ease 19. To solve a problem, I think of similar problems I have solved in the

past 20. I use a lot of gestures 21. If someone asks me a question, I turn my head to the right 22. I believe there are two ways to look at almost everything 23. I have the ability to tell if people are lying or guilty of something, just

by looking at them 24. I keep a "to do" list 25. I am able to thoroughly explain my opinions in words 26. In a debate, I am objective and look at he facts before forming an

opinion 27. I've considered becoming a poet, a politician, an architect, or a

dancer 28. I always lose track of time 29. When trying to remember a name I forgot, I'd recite the alphabet

until I remembered it 30. I like to draw 31. When I'm confused, I usually go with my gut instinct 32. I have considered becoming a lawyer, journalist, or doctor

1. L 2. L 3. L 4. R 5. L 6. R 7. R 8. L 9. R 10. L 11. L 12. R 13. R 14. L 15. R 16. L

17. L 18. R 19. R 20. R 21. L 22. R 23. R 24. L 25. L 26. L 27. R 28. R 29. L 30. R 31. R 32. L

Evidence for Specialization of Left lobe

• Wernicke’s area– Speaks fluently but

nonsensically– Not coherent,

contains lexical and grammatical errors

• Broca’s area– Can understand

everything said – Patient can only

respond in monosyllabic words

Split Brain Methodology

• Corpus callosum severed

• Techniques used test each half-brain

Split Brain Demonstration

What would a split brain patient say they saw? What would a split brain patient point to with their left hand?

Where am I?-Daniel C. Dennett

• Supersonic Tunneling Underground Device (STUD)

• Dennett– Yorick (Original Brain)– Hamlet (Original Body)– Fortinbras (New Body)– Hubert (New Brain)

Where am I?

– “The experiments I’ve discussed so far have helped us understand what is going on the brain of patients with phantoms and given us hints as to how we might help alleviate their pain. But there is a deeper message here’ your own body is a phantom, one your brain has temporarily constructed”. (Ramachandran & Blakeslee, 1998)