Psychology 2135A/B Chapter Notes - Chapter 2: Cerebral Cortex, Hindbrain, Fetus
27 May 2018
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Psych 2135
May 7-11, 2018
Chapter 2: The Neural Basis for Cognition
- Capgras syndrome – can result from various injuries to the brain and is sometimes one
of the accompaniments to Alzheier’s syndrome
o Someone with this syndrome is able to fully recognize the people in her world
but is utterly convinced that these people are not who they appear to be
o The person on the scene is not the genuine article
Explaining Capgras syndrome
- One line of evidence comes from neuroimaging techniques, that enable researchers to
take high quality three dimensional pictures of living brains
- The neural basis for Capgras syndrome
o Facts about structure of the brain are gained in older studies from PET scans and
current studies usually rely on MRI scans
▪ These scans suggest a link between the syndrome and abnormalities in
several areas of the brain
o One site of damage in patients is in the temporal lobe particularly on the right
side of the head
▪ This damage probably disrupts circuits involving the amygdala – an
almond shaped structure that serves as an emotional evaluator to detect
stimuli associated with threat or danger
▪ Also disrupts the indication of positive stimuli that indicate safety or
available rewards
▪ People with this damaged amygdala will not experience the warm sense
of feeling good
o People with Capgras syndrome also have brain abnormalities in the frontal lobe,
specifically in the right prefrontal cortex
▪ Prefrontal cortex is especially active when a person is engaged in tasks
that require planning or careful analysis and less active when someone is
dreaming
• Explains why dreams are illogical
• Frontal lobe activity is also diminished in schizophrenia patients
experiencing hallucinations
- What do we learn from Capgras syndrome?
o Some evidence from psychology labs confirm the suggestion that recognition of
all stimuli involves two separate mechanisms – one that hinges on factual
koledge ad oe that’s ore eotioal ad tied to the ar sese of
familiarity
o We can use Capgras syndrome to illuminate broader issues about the nature of
the brain and of the mind
▪ Suggests that the amygdala plays a crucial role in supporting the feeling
of familiarity and decision making for decisions
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o Also tells us that this emotional evaluator works in a fashion separate from the
evaluation of factual information, providing us a way to think about the
oasios i hih soeoe’s ealuatio of the fats poits toards oe
conclusion, while the emotional evaluation points to another
The study of the brain
- Brain weighs 3-4 pounds and the size of a small melon
- Estimated to contain a trillion nerve cells, each which is connected to 10000 more
- Also contains a huge number of glial cells (outnumber nerve cells 10 to 1)
- Phineas Gage suffered damage to the front most part of his brain which led to severe
personality and emotional problems
- Paul Broca noted that damage to a different location – eft side of the brain – led to a
disruption of language skills
Hindbrain, midbrain and forebrain
- The hindbrain
o Sits directly atop the spinal cord and includes the structures crucial for
controlling key life functions
o Rhythm of heartbeats and breathing are regulated here
o Also plays a essetial role i aitaiig the ody’s oerall toe, posture ad
balance and level of alertness
o Largest area of the hindbrain is the cerebellum
▪ Main role was in the coordination of bodily movements and balance
▪ Damage to this organ can cause problems in spatial reasoning,
discriminating sounds and integrating the input received from various
sensory systems
- The midbrain
o Important part in coordinating your movements, including the skilled, precise
movements of your eyes as you explore the visual world
o Also in the midbrain are circuits that relay auditory information from the ears to
areas in the forebrain where this info is processed and interpreted
- The forebrain
o The most interesting brain region and the most large
o This structure surrounds and hides from view the entire midbrain and most of
the hindbrain
o Only the outer surface of the forebrain, the cortex is only visible in such pictures
o Cortex is just a thin lining on the outer surface of the forebrain and is on average
a mere 3mm thick
o Cortex constitutes 80% of the human brain
o The crumpling of the cortex is what produces the brains most obvious visual
feature – the wrinkles or convolutions that cover the outer surface
o Some of these valleys between the wrinkles are actually deep grooves that
divide the brain into different sections
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Document Summary
One line of evidence comes from neuroimaging techniques, that enable researchers to take high quality three dimensional pictures of living brains. Brain weighs 3-4 pounds and the size of a small melon. Estimated to contain a trillion nerve cells, each which is connected to 10000 more. Also contains a huge number of glial cells (outnumber nerve cells 10 to 1) Phineas gage suffered damage to the front most part of his brain which led to severe personality and emotional problems. Paul broca noted that damage to a different location eft side of the brain led to a disruption of language skills. Surrounding the thalamus and hypothalamus is another set of interconnected structures which form the limbic system. Included here is the amygdala and hippocampus: these are crucial for learning and memory and emotional processing. The study of the brains structures and how they relate to brain function.
