Biology 345: Neurobiology
Lecture 6: Neuroanatomy
Imaging and the Cortex

Question 1:
If all the cranial nerves except CN IV exit the brain or brainstem on the ventral surface, why are their nuclei primarily located dorsally in the brainstem?

A. Protection
B. Integration
C. Accident
D. Reticular Formation gets in the way

Best way to stay awake while driving is chewing, because of the feedback from the reticular formation. Seems the nuclei got pushed there over evolution because of the development of the reticular formation.

Question 2:
Traumatic injury to the head causes the blood vessels passing thru the dura mater to rupture. This results in the condition known as:

A. Hydrocephalus
B. Anencephaly
C. Subdural hematoma
D. Spina bifida

Meninges
3 membranes that surround the brain

• dura mater
• arachnoid membrane
• pia mater

Between arachnoid and pia are spiderlike connections, probably to keep the blood vessels in place. Brain floats in cerebrospinal fluid around in the skull, and it needs protection. Subarachnoid space filled with salty clear liquid.

Ventricular system:

• CSF filled caverns and canals inside the brain
• choroid plexus - specialized tissue in ventricles that secretes CSF
• Path: Cerebrum > brain stem core > subarachnoid space > structures called arachnoid villi fill up the space

DaVinci was the first one to see the ventricular system. Fluid in ventricular system is constantly moving

Computed Tomography (CT)

• Hounsfield and Cormack (1979 Nobel Prize)
• Generates an image of a brain slice
• x-ray beams are used to generate data that generates a digitally reconstructed image

Magnetic Resonance Imaging (MRI)

• Advantages over CT
• More detail
• Doesn't require x-irradiation
• brain slice image in any angle
• uses info on how hydrogen atoms respond in the brain to perturbations of a strong magnetic field - signals mapped by computer

Functional Brain Imaging

• Positron emission tomography (PET)
• Functional MRI (fMRI)
• Basic principles
• detect changes in regional blood flow and metabolism within the brain
• active neurons demand more glucose and oxygen, more blood to active regions, techniques detect changes in blood flow

Cerebral Cortex

• Common features
• cell bodies in layers or sheets
• surface layer separated from pia mater, layer 1

Neocortex

• Areas of Neocortex
• Brodmann
• Evolution and structure function relationships
• cortex amount has changed, not structure
• Leah Krubitzer

Question 3:
Which cortical area isn't working when a kid sticks his tongue on a flagpole on a cold day?

1. Precentral Gyrus (motor responses)
   
2. Postcentral Gyrus (motor responses)
   
3. Occipital Lobe (controls vision)
   
4. Hippocampus (forms new memories)
   
5. Hypothalamus (controls sensations like heat and cold)
   
6. Amygdala (emotion)
   

Development

1. Philosophical Orientations
1. John Locke: tabula rasa
2. Jean Jacques Rousseau: acorn theory
3. Nature-Nurture controversy
1. sensitive periods
2. cloning
4. Phases vs Stages
1. Phases is like a ramp--gradual development
2. Stages: steps of development
3. Characteristics of stage theories
1. stages must be qualitatively different from each other
2. stages progress in an invariable sequence
3. stages are never repeated
4. changes are integrated into next stage
5. Changes effect several changes simultaneously
2. Piaget's Theory of Cognitive Development
1. Basics
1. stage theory
2. schemas: cognitive development is constituted of changes in schemas
3. 2 processes
1. organization
2. adaptation: refers to the modification of a schema in order to deal with new experiences
1. assimilation:add new info to a schema you already have
2. accommodation: either create a new schema for the new experience or alter the schema to accommodate the new situation. Through accommodation that we move from one stage to the next
2. Sensorimotor stage: Birth to 2yrs
1. coordinate movements with senses: turn head to sound, look at things when reaching for them, etc.
2. operate on the world
1. primary circular reactions: learning the body by kicking feet, waving arms, sucking on toes, etc.
2. secondary circular reactions: start to involve external objects. bang on pots, dropsies (often accidental)
   
3. tertiary circular reactions: intentional, experimental. splashing peas onto high chair, etc.
3. Object permanence: realizing an object or an individual continues to exist even though you can't sense it
1. happens around 6 months
2. used his own kids in his research. Hides toys and before 6 months, out of sight, out of existence. After 6 months, kids would uncover the blanket and find the toy. Eventually, kids will continue looking even if they don't find it where they last saw it being hidden.
4. Other research suggests that where Piaget may be wrong is when Object permanence attaches
1. Criticism of Piaget: physical search of the environment is pretty demanding of an infant under 6 months, for example
2. newer research: if we take the physical requirement away, find evidence for Object Permanence sooner.
   
3. Teddy bear on the conveyor belt trick. Kids are surprised when bear doesn't show up after being hidden. By 4 months, kids show surprise if teddy bear doesn't show up.
5. End of sensorimotor stage
1. experiment mentally
2. alter/refine behavior until it gets the effect they want. Example: getting head stuck between the rails of the stairs
3. imitate others' behavior from memory: eg. putting stuff in the DVD player
   
6. Form mental images. Can't yet reason with the schemas, which is a dramatic change into the next stage.
3. Preoperational stage (2yrs-7yrs.) Child is reasoning but not rational or logical
1. egocentrism (not in selfish terms, more like "I am the center of the universe"). Can't take the perspective of others. Everyone sees things from my perspective. Assumes that people think and feel the way they do. If I close my eyes, they can't see me.
1. Research: kids watch film of a boy at a table asking for a cookie from someone off screen. Watch it by themselves, then they watch the film for a second time with their mothers, but with the sound turned off. Kids are asked "does mommy know the kid is sitting at the table?" All the kids say yes. Does the mommy know the kid wants a cookie? 2-4 yr olds say yes, the 4-6 yr olds say no.
   
2. verbalizing perspectives is particularly difficult for kids in egocentric mode. Ask them what they see vs. what you see, and they have a hard time verbalizing it. Although they will be able to point to what they think you can see.
2. transductive reasoning. interpret correlation as causation. when the road is sticky they ice cream man comes around.
3. animism: kids in this stage believe inanimate objects are alive
4. Immanent justice. Idea that we live in a just world (largely because they don't have the deceptive skills older people do, so they get caught when they try to deceive
4. Concrete Operational Stage (7-11yrs) - child is fully decentered and can think about more than one thing at a time. Thinking is bound by physical reality. Not able to think in abstracts
1. Conservation: involves recognizing that important properties of an object (quantity or amount) stays the same despite changes in shape or appearance. Juice in 2 tall glasses and one poured into a shorter squatter glass example. Younger kids say there's more in the taller glass even after confirming they're the same in the first instance. See experiment here and see another one here