Chapter 3 - The Brain and Cognitive Neuroscience

Question 1

*Insert questions about the brain based on textbook

Question 2

Explain Phrenology.

Answer 2

Brain functional specialization: Phrenology
* Gall and Spurzheim (late 1700s)
* Parts of the brain correspond to mental functions and
personality
-Well-used mental functions: related brain area grows (bump)
-Under-used mental functions: related brain area shrinks (dent)
* False assumption that the highly developed functions
have larger brain areas (only size matters) , the large the
region
* Used speculation for localizing functions

Question 3

Explain functional specialization.

Answer 3

Functional specialization
* Modern cognitive neuroscience identifies brain area or networks
that supports a particular cognitive function
* Established via Neuropsychological cases and Neuroimaging tools
(examples to come in a few slides)
* E.g., Fusiform face area responds selectively to the perception of
faces
* But some evidence it just discriminates exemplars
of any category someone has expertise
Greebles study in the textbook

Question 4

Name the neuroimaging techniques used in cognitive neuroscience research.

Answer 4

• Measures neural communication, which is a chemical and
  electrical as well as a metabolic event (i.e., uses energy)
  1. Electroencephalography (EEG) – electrical activity
  2. Functional Magnetic Resonance Imaging (fMRI) - energy
  3. Brain stimulation techniques - change

Question 5

Explain Electroencephalography (EEG).

Answer 5

• An active brain produces electrical activity
  -Event-related potentials (ERP)
• EEG measures activity in a large group of
  neurons at certain times
• Provides estimate of WHEN the brain is active
• EEG provides information about activity in the brain at certain time periods
  -Example: Present learned words and look at ERPs as view a learned word that
  they remember vs have forgotten
• Good timing information (temporal resolution); millisecond level
• Not good location information (spatial resolution)
• Lots of things can affect ERP signals, which means a researcher needs to
  collect a lot experimental trials and this limits the studies you can run

Question 6

Explain Magnetic Resonance Imaging (MRI) and fMRI.

Answer 6

• Structural MRI:
• Anatomy of the brain
  -E.g., volume, location of grey matter
• Used to detect structural anomalies
• Functional (f)MRI:
• Information about activity in the brain
• An indirect measure as it measures blood flow and not
  neural activity
  How?
• Active brain areas need oxygen (metabolic energy)
• A magnet detects changes in oxygenated blood
• Measure ratio of oxygenated and de- oxygenated blood flow in regions of the
  brain during a task
• Use measurements to create a spatial
  image of brain activity

An example fMRI finding:
* Participants viewed images of body parts or inanimate objects
* Consistent activity in the right lateral occipitotemporal cortex when viewing body parts compared to viewing objects
* This is evidence of a cortical selective region for processing body parts:
functional specialization

Strengths of fMRI:
* Provides good spatial resolution
* About a 1000 papers published per month ( lots of replication,
validation)

Weaknesses of fMRI:
* Does not provide good temporal resolution to determine timing of
brain activity
* It is an indirect measure of neural activity: correlational
* Assumption that increase in blood flow means more activity
* It is very noisy …

Question 7

Explain Brain Stimulation.

Answer 7

• Noninvasive method of
  changing brain activity that
  can inhibit or increase
  activity
• A main form is Transcranial
  Magnetic Stimulation (TMS)
  in a focal magnetic field
  induces temporary change in
  brain activity

TMS may improve memory: Participants in the TMS group had improved scores (up to 25%) on the posttraining compared to pre-training memory test

Strenghts:
* Good to test causality (testing effect of
temporary lesion or stimulation)
* fMRI and EEG are correlational (associate
brain activity to task)

Weaknesses:
* But the way it works is not entirely clear
* Stimulation techniques have broad effects
on the brain, so it is hard to localize effects

Question 8

Some notes?

Answer 8

Note: Advances in analysis
* Linking single brain areas to functions might be too simplistic
* Remember these questions about functional specialization
* Can a single brain region participate in more than one function?
* Functions might emerge from a collection of brain regions
* Many neuroimaging analysis go beyond studying brain areas in
isolation and study the brain as interconnected networks
* Functional connectivity
* Multi—voxel pattern analysis