PSYC14H3 Lecture Notes - Lecture 9: Uptodate, Fusiform Face Area, Haemodynamic Response
● This is an idea I spoke about in the second
lecture – with cultural evolution. But it seems
pertinent to revisit the concept here because
we’re talking about cultural as existing at the
biological level, at the level of brain and
genes.
● We are in a unique position because our
species is currently driving our own
evolution… we are so successful as a
species (and we’ve done all that we’ve done
in terms of innovation, invention, technology,
etc. etc.) not because of our raw cognitive
skills or brain power, but because we are
hungry for cultural learning. We evolved
genetic traits that prepared us to take in
information from conspecifics, particularly
those like us and from those whom we trust.
● One on one, and we’re not that impressive
compared to other ape species. In fact, in
many economic strategy games, we are far
worse on individual performance, with
chimps out performing us and finding the
rational equilibrium point.
Got Milk, gene culture coevolution
● Much of what underlies difference in genetic
expression and brain structure/processing is
that we are who we are because of two
strong forces of evolution working together:
Cultural evolution and Genetic evolution
● I’m going to go over some of these principles
before diving into the empirical work on
differences in genes/brain processing
between cultures.
Epigenetic influences
● Methylation of FKBP5 “stress gene” in
Holocaust survivors → predisposed to mood
disorders and PTSD
● Examined same patterning in children
● Epigenetic changes coded in sequence
● Found a reduced level of methylation on this
particular point of the gene … suggesting
that parents exposed to trauma see changes
in inheritance by leading their future
generation offspring to either be more
vulnerable or develop a resistance. This
particular study suggests multiple
generations down, Holocaust survivors
grandchildren are more likely to develop
resistance in the way of this altered genetic
patterning
● 5-HTTLPR – Serotonin transporter gene;
and anxiolytic drugs take their effects – like
Prozac for instance. Past work has shown
that people with the short allele of this
serotonin transporter gene are more
susceptible to anxiety and depression and
various social stress life experiences.
● BUT that’s only part of the story. Those with
the short version of the allele are also more
likely to experience positive social
experiences. In fact when the right social
interactions are present in their life, the short
allele people are the LEAST likely to develop
anxiety and/or depression… indicating that
this gene is responsible for moderating
social interaction, be it positive OR negative.
● The G Allele is a similar, related
polymorphism to the gene above. EXCEPT
it’s a single base change, a C to a G. It is
also implicated in social sensitivity. People
who have greater social sensitivity are better
equipped to navigate the social world; to
know if they are fulfilling the relational duties
and obligations …
● Someone who is socially sensitive will more
prone to depression IF their social needs
aren’t being met. But someone who is
socially sensitive will be protected against
depression if their social needs are being
met, and even be more likely to be protected
from negative emotionality
● If you remember back to our lecture a few
weeks ago on Identity and Motivation,
individualistic people are more likely to be
consistent and see themselves the same
regardless of the social situation. In contrast,
collectivistic folks are more likely to see
themselves differently depending on who
they’re interacting with.
● Area of the brain where we represent our
sense of self …
● First, let’s talk about fMRI. fMRI measures
changes in the BOLD signal
(blood-oxygen-level dependent) – an active
neuron will immediately receive blood (called
the hemodynamic response). This change in
oxygenated blood (vs. deoxygenated blood)
has differences in magnetic properties,
which is detected by the MRI scanner. You
can assess which areas are active by
relative changes in the BOLD signal. Spatial
resolution is fantastic; temporal resolution is
not because it takes a while for the blood to
supply those activated neurons.
● Our results show that self-relevant
processing within MPFC varies as a function
of SCS. People who endorse individualistic
cultural values showed greater MPFC
activation to general self-descriptions,
whereas people who endorse collectivistic
cultural values showed greater MPFC
activation to contextual self-descriptions.
● The scatterplot deltaMPFC is contextual –
general identities
● We know from the emotions lecture that east
Asians and others from typical collectivistic
cultures are prone to suppress emotional
expressions. The question is, Does this carry
out in the early affective processing in the
brain?
● EEG technology? Superior temporal
resolution so you can examine cognitive and
affective processes that unfold rapidly in
time, often preconscious, which makes it a
wonderful tool for understanding questions
about emotion and attentional processing
(i.e., happening rapidly)
● This is a difference wave score --
(SUPPRESS LPP - ATTEND LPP)
● While we’re in the realm of emotions, let’s
look at another study that examined how we
process emotions in others.
● One hypothesis is that given the automatic,
prepotent nature of amygdala response to
fear faces and the adaptive importance of
responding to any signal of imminent danger
in the environment, cultural affiliation will not
affect the amygdala response to fear faces.
An alternative hypothesis is that amygdala
response may be enhanced for own-culture
fear faces, given the greater similarity
between self and other members of the
same cultural group. A threat to another
member of the same cultural group, as
inferred by that member’s fear facial
expression, may be a more salient signal of
impending threat to oneself.
● Instructions: Told to categorize the emotion
they’re seeing and respond as quickly as
possible. Couching faces in a task like this is
a perfect way to measure the neural
reactivity to stimuli while engaging in some
other task.
● RESULTS: Caucasians were more accurate
at categorizing fear for own targets, relative
to Japanese for their own targets; however,
Japanese were faster at categorizing fear in
own targets, relative to Americans for own
targets.
Document Summary
I"m going to go over some of these principles before diving into the empirical work on differences in genes/brain processing between cultures. Holocaust survivors predisposed to mood disorders and ptsd. Found a reduced level of methylation on this particular point of the gene suggesting that parents exposed to trauma see changes in inheritance by leading their future generation offspring to either be more vulnerable or develop a resistance. This particular study suggests multiple generations down, holocaust survivors grandchildren are more likely to develop resistance in the way of this altered genetic patterning. 5-httlpr serotonin transporter gene; and anxiolytic drugs take their effects like. Past work has shown that people with the short allele of this serotonin transporter gene are more susceptible to anxiety and depression and various social stress life experiences. Those with the short version of the allele are also more likely to experience positive social experiences.
