Chapter 2 (Cognitive neuroscience) Flashcards
The brain is __% of our body mass and consumes __% of our blood supply
2% - 20%
4 views on the mind brain problem
- Interactionism
- Epiphenomenalism
- Parallelism
- Isomorphism
- Interactionism view of the mind-brain problem
“The mind and brain are separate but interact”
Descartes, pineal gland is where they interact
Mind is the Most important thing / Body like machine driven by mind
*2. Epiphonomenalism view of mind-brain problem
“The mind is irrelevant”
Huxley & similar to Skinner
Mind = Consciousness / It is a byproduct of what the body is doing
- Parallelism view of mind-brain problem (no causation)
“the mind and brain are two aspects of same reality (2 levels of abstraction)”
G.T Fechner - All operates in parallel mental event = physical event in brain
mind-brain at the same time
(similar to isomorphism but causation?!)
*4. Isomorphism view of the mind-body problem (causation what we see what brain does)
From Gestalt
Wolfgang Kohler
Direct causal link mind-brain symmetry
Actions of mind-brain = same structure
Literal connection mind-brain you see something, same visual image created in the mind
Similar parallelism but isomorphism = causation
Who was opposed to epiphenomenalism
William James
Sais mental events don’t affect brain activity that produce them any more than shadow on the steps of a traveler
Argument - epiphenomenalism
Consciousness can be slower than actions so it can’t be the drive of all behaviours
But Tibet et al (1982) found out brain prepares for action before we are consciously aware of it (cause before effect) - Argument for epiphenomenalism
What did Libet et al (1982) try to do?
Map the speed of consciousness vs initiation of conscious action
For epiphenomenalism
The brain prepares for action .3-.2ms before we are consciously aware of it
What did Libet et al (1982) find ?
The brain starts to prepare an action before we are consciously aware of having made the decision to act
How long does the brain change occur before we are conscious we want to make an action
Preparation -550ms
Awarness -.200ms
Movement o ms
So difference = .200- .300 milliseconds
Cause must precede effect
The problem for consciousness?
The problem with parallelism
Makes no claim about the nature of the relationship between mental and physical
2 Relms in parallelism
if you talk to yourself ( __ relm)
if someone else talk to you ( ___ Relm)
Mental relm
Physical relm
What is the difference between isomorphism and parallelism
Isomorphism = cube neuron
Parallelism the synchrony of many cues together create whole
Injury to the left side of the brain
Language, right side of the body control
A neuron is
A primary functional unit of the brain
Neurons are connected in clusters called
Modules
Neurons in Modules are connected forming
Networks
Neurons communicate via
Electrical signals
The Hebb Rule (1949)
Neurons get connected when often excited close to the other “neurons that fire together wire togeather”
Unilateral neglect
Ex left hemispheric neglect - clock drawing they don’t have conscious awareness of cues on the left side
Damage to Wernicke’s area affects language
Comprehension issues
Damage to Broca’s area causes language
production issues of language
Imagining movement trajectory / Perception of rhythmic motion / processing musical syntax / natural language syntactic processing
4 methods to measure brain activity
- Positron emission Tomography (PET)
- Functional Magnetic Resonance Imaging (FMRI)
- Electroencephalography (EEG)
- Magnetoencephalography (MEG)
PET tells us about
Blood flow / an idea of where oxygen went / most used parts
After the action occurs
Difference scores (brain at rest brain in action)
Radioactive substance injected
Hard to interpret the cause of brain activation
What does fMRI tell us
Changes in the flow of oxygenated blood can then be picked up
as alterations in the magnetic field, and this information can be used to construct an image of cortical activity.
Gives spatial resolution
Like PET but safer / also slow but not as much / loud
Big magnets
What does EEG tell us
Safe / like fMRI but a lot faster
ms accuracy
Detects electrical neural communication
Only outer layers of cortex
Temporal resulution
What does MEG imaging tell us
Like blend of EEG and fMRI (but detects current activity)
Detects magnetic fields produced by electrical activity in the brain
Still the outer layers of cortex
What does eye tracking allow
Use behaviour to infer brain processes
Isomorphism vs Necker cube
A demonstration of Gestalt psy and isomorphism
Neurons get breaks so we get a ‘switching’ effect in our conscious experience
The neuron “cube” is firing and then a different one will fire
2 kinds of brain injury
- Epidural hematoma (outside)
- Subdural Hematoma (inside)
Grey matter is
Outside
White matter is
Inside
Injury to the right side of the brain can cause
Spatial issues
Injury to the left side of the brain can cause
Language issues
the important lobes
Frontal - Executive functions
Parietal -
Occipital - vision at the back
Temporal -
Learning occurs when
neurons becomes connected
What is the somatosensory cortex responsible for
Processing sensory information
Where is the somatosensory cortex
Across from the central sulus and primary motor cortex
With the homunculus we see that for humans … are important in the brain
Hands and mouth
Cognitive ethology takes into account
Eat role of the body and affordances in interpreting and predicting cognition in action
Neuroimaging allows us to
Dress some of the goals of cognitive ethology - to take a more holistic approach observe brain behaviour directly
Functional perception vs gears
When you slow the gears alternating back and forth it tells you there is more information you can make different sense of movement
Where will the eyes focus on a static picture vs video
Eyes vs mouth
Examples brain injury
Muhammad Ali -
Ronald Reagan - Alzheimer
Margaret Thatcher - Demencia
Phineas Gage (1848) -
Gabrielle Giffords - Shot left side / language
What is cognitive neuroscience
Combination of neuroscience and psychology
specific cognitive mechanisms are associated with specific brain areas
brain mechanisms give rise to mental functions (memory, attention, language)
Assumes the brain is made up of specific modules
What are 3 basic principles of phrenology
- The brain is the sole organ of the mind
- Basic character and traits are innately determined
- Differences in character = differences in brains
They thought these showed up in the shape of the skull… higher function larger it would be on the skull…
Study of mice to localize functions
Shepherd Ivory Franz & Karl Lashley
*Ablation of frontal lobes in mice
Findings - it did not matter where the lesion was (as long as enough tissue left)
Takeway the brain as a whole is important!
Lashley’s findings resulted to two laws
- Law of mass action
- Law of equipotentiality
Lashely’s 1. law of mass action
learning and memory depend on the total mass of brain tissue remaining
Lashley’s 2. Law of equipotentiality
although some areas of the cortex may become specialized for certain tasks,
any part of an area can, within limits, do the job of any other part of that area
Types of methods to understand the brain
- Animal studies
- Behavioural studies
Behavioural research looking at sensory systems consider the following six sensory systems:
- vision
- Audition
- Taste
- Smell
- Somatosensory (joint movement etc)
- Vestibular (balance / orientation)
What is a sensory system
A system that links the physical and perceptual worlds via the nervous
system; composed of sensory receptors, neural pathways, and distinct
regions of the brain preferentially dedicated to the perception of information.
Are aphasia well defined?
No (these studies are suggestive but rarely definitive)
What we do know Wernicke’s is receptive & Broca’s is expressive
Interhemispheric transfer and interaction (Roger Sperry)
Nobel prize - communication between the two hemisphere have specific abilities but both together adds the perception and consciousness …
Corpus colosseum severed split brain functioning
Left hemeshere
Analytic and language
Right hemisphere
Non verbal intuitive Gestalt etc
What did Sperry argue
Consciousness is an emergent property of the brain (not reducible)
Emergent property for Sperry
In Sperry’s sense, a property that “emerges” as a result of brain
processes, but is not itself a component of the brain.
the mind = consciousness is neither reducible to, nor a property of, a particular brain structure or region.
What are event-related potentials
An electrical signal emitted by the brain after the onset of a stimulus.
Differences in neural activity can be recorded with many observations
What is connectionist theory
A theory that focuses on the way cognitive processes work at the physiological/ neurological (as opposed to information-processing) level.
It holds that the brain consists of an enormous number of interconnected neurons and attempts to model cognition as an emergent process of networks of simple units (e.g., neurons) communicating with one another.
Connectionist model (2 basic ideas)
- Information can be broken down into elementary unit (neuron)
- Connection between the units (forming neural netwarks)
Combining methods
Can inform the outcomes, since conclusions are hard to make in cognitive neuropsychological studies
Combining methods
Can inform the outcomes, since conclusions are hard to make in cognitive neuropsychological studies
mapping imaging and behavioural data for example can enrich the reflection
There can be measurement error
Yep
