Lecture 8: Bridging human and animal neuroscience Flashcards
Why do psychologists learn about animal neuroscience?
learning about functions from evolution
practical reasons
ethics
interesting
to understand human behavior via animal models
What are major similarities between humans and animals?
neurons and glia cells
What are major differences between humans and animals?
number of neurons and glia cells, structures
Why studying invertebrates is easier?
no ethical permission needed
genetic manipulations easier and faster
cheap
famous research: giant axon of squid
Why most labolatory animals are rats and mice?
there is already a lot of data; especially about mice genome; easy to keep and breed, pretty cheap, brain fairly similar to humans, genetic approaches possible
What are characteristics of human brain?
convoluted with bulges (gyri) and spaces (sulci)
neurons + glia cells
1300-1400 grams
mess in comparison to rodent brain
astrocytes
control the microenvironment around neurons, provide strutural integrity, important for maintaining blood-brain barrier
Why brains post-mortem are smaller?
because people who died are usually old and brain is affected by different diseases
major difference in rodent research: rodents are healthy!
Rodent brain
smooth, no gyrification
neurons and glia present
better organized than human brain
microglia
phagocytic -> they eat and clean staff, part of immune system
changes its shapes when deals with pathogens
oligodendrocytes
myelination of neurons in CNS
when myelination occurs in human CNS?
at 4 month of gestation (lasts until 2nd decade of life)
How can we study development of human brain?
studying children with EEG
sometimes, children may be placed in MRI scanner - due to disease
very rarely, studying children brains post-mortem
How does development of rodent brain relates to human brain?
humans are born after 9 months of pregnancy, rodents after 21 days of pregnancy - they look like half embryos
What happens when myelin sheeth fails?
multiple sclerosis (can be seen on the brain scan as white spots)
ependymal cells
line ventricular cavities and central canal of spinal cord
they sense what is going on in CSF via cilia
Schwann cells
responsible for myelination in PNS
What happens when your brain gets bigger evolutionary?
neuronal density gets smaller - fewer neurons per brain because they increase in size
however, glia density gets bigger - because they don’t grow over evolution as neurons
What happens if you damage primary motor cortex?
contralateral spastic paresis - weakening of voluntary movement contralateraly
What happens if you damage premotor cortex?
apraxias - inability to perform purposeful movement
prefrontal cortex
rostral to premotor area
1/4 of human cerebral cortex
organizing and planning of intellectual and emotional aspects of behavior
What happens if you lesion prefrontal cortex?
loss of concentration, distraction, lack of initiative, foresight and perspective, apathy, suckling and grasp reflexes evident; similar to what happens at the very end of Alzheimer’s disease
expressive aphasia
are in left or dominant hemisphere affected -> Broca’s area damage = difficulty in speech production
parietal lobe
place of sensory homunculus - postcentral gyrus
holds primary somatosensory cortex
What happens if you lesion posterior parietal association cortex?
lesions in dominant hemisphere result in apraxia (difficulty with motor planning to perform tasks or movements)
astereognosia may be present
no loss of tactile sensations
What is astereognosia?
inability to recognize objects by touch
receptive aphasia
inability to comprehend spoken language, possible inability to read (alexia), there may be fluent verbalization BUT lacking meaning