Evolution of Cognition III Flashcards
Das Volumen des menschlichen Gehirns ist im Laufe der Evolution …
… (scheinbar exponentiel) gestiegen.
Korreliert die größe von bestimmten Gehirnarealen mit kognitiven Fähigkeiten? + Beispiel
ja -
Singvögel: größe des Gesangareals korreliert mit der Größe des Gesangrepertoirs
Welche Gehirnstruktur wird in Zusammenhang mit räumlichem Gedächtnis gebracht?
Hippocampus
Hippocampus in food-caching Birds?
ist größer!
London Taxi Driver Example;
2 points:
- Posterior Hippocampus is larger in London Taxi-Drivers than in non-Taxi-Drivers
- Correlation of volume change with time as taxi driver. -> neural plasticity
What does Neuroplasticity actually mean?
Brain is continually changing!
Traditional view on neuro-plasticity:
no new neurons in adult brain, except in the olfactory system
(despite clear evidence in 60s and 70s, this was believed up until recently)
What is neurogenesis?
Neurogenesis (birth of neurons) is the process by which neurons are generated from neural stem and progenitor cells.
Is it known now that there is neurogenesis in adult brains? Who?
Yes!
Elizabeth Gould leads the way
rat gymnastics lead to …
… more synapses and dendrites
Was kann zu schrumpfen des Hippocampus führen?
sozialer Stress
New sensory maps can develop over weeks, this was shown by …
… sewing together to digits of a monkey hand. Clear border between digit 3 and digit 4 on the somatosensory cortex vanished within month.
Who are leading figures in neurogenesis research?
Pasko Rakic
Fernando Nottebohm
Liz Gould
enriched environment leads to …
… more neurogenesis.
String players have …
… larger left hand representation in motor cortex.
relative regional size of brain ____ matter
DOES
Does absolute brain size matter?
complex question!
Welche Tiere haben große Gehirne?
Delphin, Elefant, Mensch
What’s the case of large brains within species?
- variance is huge
- brain size accounts only for 4 - 16 % of IQ variance
Brain-to-body size ratio, a small ranklist:
Maulwurf kleine Vögel Mensch Maus Frosch Elefant
The Chihuahua Fallacy?
Encephalization is the degree to which an animal’s brain size is larger than would be predicted for an animal of its size. Encephalization is, therefore, the relationship between the brain and the body, and can be affected by changes in either one.
This is most easily demonstrated in domestic breeds of dogs. Small dogs have a large ratio between brain and body size, and large dogs have a small ratio between brain and body size. Does this fact, then, mean that small dogs with a larger ratio are intelligent and large dogs with a smaller ratio are relatively stupid? There is, of course, no pattern like this for dog intelligence.
What is the encephalization quotient?
the ratio between actual brain weight and (from body-weight) predicted brain weight by a regression equation e.g.: Cat 1/1 Mouse 1/2 Dolphin 4/1 Human 7/1
Who developed the encephalization quotient?
Harry Jerison
What says the Expensive Tissue Hypothesis?
Tradeoff between brain and digestive tract:
Bad food -> big gut, small brain
