Page 21-25 Flashcards
What is the primary assertion of the Concerted Brain Hypothesis regarding brain evolution?
It suggests that brains evolve primarily through global modifications to neurogenesis duration, affecting all components simultaneously, leading to major covariations in brain structures due to developmental events.
What contradicts the Concerted Brain Hypothesis regarding brain evolution?
The Allometry concept disputes the idea of all brain regions evolving at the same rate, highlighting differences in the relative size of brain regions due to adaptive divergence in brain function, indicating variations in development and growth across different brain areas.
According to the Mosaic Brain Hypothesis, how does the evolutionary model of brain structure operate?
This hypothesis proposes that selective forces act on specific brain areas or networks independently, causing adaptive changes in those areas without necessarily impacting other brain regions, despite being heavily interconnected.
In the context of brain evolution, what does the Mosaic Brain Hypothesis suggest about heavily interconnected brain structures?
Despite selective forces acting on only specific brain regions, heavily interconnected brain structures tend to change together due to functional constraints, even if only one of the regions undergoes selective changes.
What is suggested by the lack of correlation between brain volume and the proportion of neocortical GM in terms of evolution?
It suggests that brain evolution involves more than just the increase in the number of neurons, indicating that factors like activity patterns (diurnal vs nocturnal), diet quality, and social complexity exert pressure on brain evolution.
What is proposed as the likely alternative for brain evolution, considering both concerted and mosaic brain evolution hypotheses?
The text suggests that the most likely alternative for brain evolution involves a combination of both the concerted and mosaic evolution hypotheses. For instance, songbird brains may have evolved as coordinated wholes but also underwent significant independent modifications due to specific selection pressures on dedicated systems.
Based on the allometric view, what emphasis is placed on the evolution of the frontal lobes in primates?
The emphasis lies in the role of the frontal lobes in carrying out functions that are distinctive to humans, suggesting that the size of the frontal cortex might explain the complexity of human cognition.
Despite not differing significantly in frontal cortex size, what aspect might contribute to the higher cognitive abilities observed in humans compared to great apes?
The higher cognitive abilities in humans might stem from differences in individual brain areas and richer connectivity rather than changes in size. This suggests evolutionary rewiring rather than solely a change in brain size.
How does the computation of the WM/GM ratio in the prefrontal cortex differ between humans and other primates?
Humans exhibit a shift towards more white matter (WM) compared to other primates, indicating stronger hierarchical interaction between areas, potentially explaining higher cognitive abilities.
What techniques are utilized to identify different and similar tracts in a whole-brain perspective for monkeys and humans?
For monkeys, axonal tracing methods such as antero- and retrograde tracing using radiotracers are used. In humans, Diffusion Weighted Images are employed to reconstruct white matter tracts based on water movement constraints within specific brain areas.
What can interspecies (interindividual) variability in the brain be attributed to?
Interspecies variability in the brain, shared between humans and monkeys, may result from genetic or epigenetic factors, potentially exploited by natural selection for the species’ survival.
According to the dual origin theory of the brain, what characterizes regions with low variability?
More ancient brain regions, such as the olfactory system and hippocampus, exhibit low variability. The theory suggests that the brain evolved from these archicortical regions, with increased variability in newer brain areas indicating a new level of complexity.
How does brain variability differ between newer and older brain structures within humans and between humans and macaques?
In humans, areas with the most differences in gray matter variability, compared to macaques, are newer brain regions. These differences define what makes a human distinct, reflecting increased variability in newer brain structures.
What determines the timeline for myelination in different brain regions during development?
Myelination progresses in specific sequences during brain development, with projection bundles (motor and sensory areas) being the first to myelinate, followed by limbic and commissural bundles, and lastly, association bundles.
How do regressive mechanisms influence brain development during childhood and adolescence?
Regressive mechanisms such as synaptic pruning and apoptosis contribute to refining the brain’s neural connections. Synaptic pruning eliminates unnecessary synapses, while apoptosis involves the programmed death of neurons, both processes optimizing brain networking capacity.
What is proposed by the Concerted Brain Hypothesis regarding brain evolution?
A) Brains evolve solely through global modifications to neurogenesis duration.
B) Brain structures covary primarily due to developmental events.
C) All brain regions evolve at different rates.
D) Evolution concerns only the number of neurons.
B) Brain structures covary primarily due to developmental events.
According to the Mosaic Brain Hypothesis, what is a key concept in brain evolution?
A) Selective forces act on specific brain areas independently.
B) All brain regions change together due to functional constraints.
C) Selective forces affect all brain networks simultaneously.
D) Brain evolution is solely influenced by global modifications in neurogenesis
A) Selective forces act on specific brain areas independently.
What does the Allometry concept suggest regarding brain evolution?
A) All brain regions evolve at the same rate.
B) Brain regions show variations in growth and development.
C) Evolution concerns only the number of neurons.
D) Brain evolution is solely influenced by social complexity.
B) Brain regions show variations in growth and development.
In the context of brain variability, what determines variability between humans and macaques?
A) Areas with the most differences are older brain regions.
B) Variability in humans is primarily in older brain structures.
C) Areas with the most differences define what makes a human distinct.
D) Variability in monkeys indicates new levels of complexity.
C) Areas with the most differences define what makes a human distinct.
How does brain myelination progress during development?
A) Limbic bundles are myelinated first, followed by association bundles.
B) Projection bundles are myelinated last during brain development.
C) Myelination follows a sequence from motor and sensory areas to association bundles.
D) Myelination occurs simultaneously across all brain regions.
C) Myelination follows a sequence from motor and sensory areas to association bundles.
