Lecture 6 - The Cortex and Individual Differences Flashcards
How has brain size changed over human evolution?
Brain size increased from Australopithecus africanus to Homo sapiens, accompanied by increasingly sophisticated tools and cultural behaviours
Does brain size directly correlate with intelligence?
Not necessarily. Larger animals (such as elephants) have larger brains, but humans have a greater number of cortical neurons, which is more relevant to intelligence
Why might human brains be considered more intelligent despite being smaller than elephants’?
Human brains (3-4lbs) have more cortical neurons (16.3 billion) compared to elephants (5-6 billion), highlighting neuron density over brain size
What role does the brain-to-body ratio play?
Humans have the largest brain size relative to body weight, which is important for higher cognitive functions
What is unique about Einstein’s brain?
Though slightly smaller than average, his parietal lobe was 15% wider and had 80% more neuroglia, suggesting enhanced neuron communication
How do neuron density and orientation relate to IQ?
- High IQ: Larger cortical volume, lower neurite density and orientation density
- Low IQ: Smaller cortical volume, higher neurite density
Which brain region’s volume strongly correlates with IQ (Spearman’s g)?
Frontal cortex grey matter volume shows a significant correlation with IQ (p = 0.0044)
What cortical differences are seen in Down syndrome (DS)? Why is this?
DS brains show smaller cortical surface area but increased cortical thickness, due to reduced synaptic pruning
What do twin studies suggest about genetic influence on cortical structure?
Dizygotic (DZ) twins show a 30% typical variation in grey matter density, especially in language and spatial association areas
Which brain regions are linked to artistic creativity?
- Supplementary motor area (SMA): Improvisation, movement planning
- Anterior cingulate cortex: Cognitive flexibility, error monitoring
How is creativity associated with grey matter?
Greater creative potential is linked to higher grey matter volume in frontal, temporal and parietal regions (via voxel-based morphometry, VBM, studies)
What is the connectome and how is it studied?
The connectome is a map of brain connectivity, studied using fMRI, especially during tasks like divergent thinking (e.g., Alternative Uses Task)
How does creativity relate to brain connectivity?
Highly creative people show more frequent transitions between dynamic connectivity patterns (Beaty et al., 2018)
How is personality reflected in brain activity?
Personality traits (e.g., Neuroticism, Extraversion) predict Resting-State Functional Connectivity (RSFC) patterns
What structural brain differences are found psychopaths?
Psychopaths have reduced grey matter in areas involved in social and emotional processing, especially in the prefrontal cortex (Gregory et al., 2012)
Which brain regions are implicated in antisocial and psychopathic behaviour?
- Left/right front-insular cortex
- Left dorsomedial & lateral prefrontal cortex
- Right lateral prefrontal cortex
- Amygdala
How do grey matter levels differ among psychopathy groups?
Order from most to least grey matter:
Healthy individuals > ASPD-P > ASPD+P (especially in the LH)
ASPD-P = Antisocial Personality Disorder without Psychopathy
ASPD+P = Antisocial Personality Disorder with Psychopathy
What determines intelligence more than brain size?
Neural organisation and cortical neuron density
Which traits are linked to individual differences in cortical morphology?
- Intelligence
- Creativity
- Personality traits
What structural features are linked to antisocial behaviour?
- Altered frontal cortex networks
- Reduced grey matter in social/emotional brain areas, e.g., amydgala
