Chapter 2 Flashcards
Who was Lashley and what was he known for?
Student of Franz and studied the effects of ablation is the frontal lobes in rats.
Lashely lesioned the cortex of rats in different places and to different degrees and studied rats abilities to learn or remember mazes. He found little to no reduction in performance with small brain damage and/or simple mazes, but more reduction in performance as the amount of damage increased.
He suggested that learning was directly proportional to the extent of brain damage rather than to the location of the damage
What were Lashley’s results formulated as?
The law of mass action: learning and memory depend on the total mass of brain and tissue remaining rather than the properties of the individual cells
The law of equipotentiality: although some area of the cortex maybe become specialized for certain tasks, any part of an area can (within limits) do the job of any other part of that area
Distinguish between consciousness and mind.
Consciousness: narrower concept; what we are aware of at any point in time
Mind: broader concept; includes consciousness, but also encompasses processes that may take place outside our awareness
What are the 4 classic approaches to understanding how the mind and brain are integrated?
1) interactionism (Descartes)
2) epiphenominalism
3) parallelism
4) isomorphism
Define Interactionism and who is it associated with?
- Mind and brain are separate entities that interact and influence each other.
- Descartes
- speculated that the pineal gland is where the mind & brain interacts
- this view was not widely adopted by subsequent researchers, with the exception of Roger Sperry
Define Epiphenomenalism
Mind is simple a by-product of brain processes & has no causal role in determining behaviour
Mind is a by-product of the brain
Define Parallelism
Mind and brain are two aspects of the same reality, and they operate in parallel. Every event in the mind has a corresponding event in the brain
Define Isomorphism
Gesalt Psychologists (Wolfgang) argued that consciousness tends to be organized into a coherent whole. Experience and it’s corresponding brain pattern share the same pattern in all their structural characteristics
What’s the difference between parallelism & isomorphism?
Isomorphism sees more than a simple point-for-point correspondence between mental events and brain events
“Psychological facts & underlying events in the brain resemble each other in all their structural characteristics”
Necker’s Cube
Illustrates isomorphism because “the same external stimulus can produce different internal experiences”. Therefore, there must be a corresponding change in the underlying brain processes.
The area in the brain that is responsible for processing & creating a representation of the figure becomes fatigued, or only weakly capable of supporting electrical fields and so another part of the cortex begins to take over the task
Define 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 that translates physical world into perceptual experiences.
What are the 6 main sensory systems?
1) vision
2) audition
3) taste
4) smell
5) somatosensory (touch as well as other perceptions, such as muscle and joint movement)
6) vestibular (balance and spatial orientation)
Define Broca’s aphasia
A deficit in the ability to produce speech as a result of damage to Broca’s area.
Language comprehension remains intact, but ability to produce speech is severely compromised.
Define Broca’s area
The area of the brain’s left hemisphere that is responsible for how works are spoken
Define Wernickie’s area
Area of the brain’s left hemisphere that is responsible for processing the meaning of words
Define Wernickie’s aphasia
A deficit in the ability to comprehend speech as a result of damage to Wernickie’s area
Language comprehension is compromised, and the affected individual produces incoherent speech.
Define interhemispheric transfer and who is it associated with?
Communication between the brain’s hemispheres, enabled in part by the corpus callosum.
Done by Roger Sperry
What work did Roger Sperry do involving interhemispheric transfer?
Severed optic chiasm and corpus callosum in cats.
Result: information coming from right eye, processed in right hemisphere and vice versa
Severing the corpus callosum showed that it plays a dominant role in the inter-hemispheric interaction
Define split brain
A condition created by severing the corpus callosum
According to Sperry, which hemisphere of the brain managed what type of tasks?
Left hemisphere - analytic tasks
Right hemisphere - holistic tasks
Holistic: non-verbal, intuitive
Describe Sperry’s work on consciousness.
He argued that consciousness is an emergent property of the brain, meaning that it is neither reducible to nor a product of other features of the brain. Once consciousness emerges then it can have an influence on lower-level functions, a process that maybe termed emergent causation.
Thus, the mind is supervenient: mental states are determined by constituent neuronal events while they are exerting control over them
Define emergent property and who was it associated with?
In Sperry’s sense, a property that ‘emerges’ as a result of brain processes, but is not itself a component of the brain.
In the case of the mind, this means that consciousness is neither reducible to, nor a property of, a particular brain structure or region
Define emergent causation and who was it associated with?
In Sperry’s sense, causation brought about by an emergent property. Once the “mind” emerges from the brain, it has the power to influence lower-level processes
Define supervenient and who was it associated with?
In Sperry’s sense, describes mental states that may simultaneously influence neuronal events and be influenced by them
What does a CT and MRI do? What’s the difference between them?
CT: provided detailed anatomical data
MRI: provided similar images with higher spatial resolution
Define ERP’s. What are they used for? Who are they associated with?
An electrical signal emitted by the brain after the onset of a stimulus.
Represented by waveforms
Rugg - his review suggests that the waveform for items that will be remembered is different from the waveform for items that will be forgotten
What’s an EEG used for?
The electrical signals emitted by the brain can be recorded using electrodes places on the scalp: EEG
Non-invasive and non-precise
What’s the assumption underlying PET scan?
When a specific psychological function is engaged, then only those parts of the brain are responsible for that function will also be engaged.
Define PET scan and how does it work?
An imaging technique in which a participant is injected with a radioactive substance that mingles with the blood and circulated to the brain. A scanner is then used to detect the flow of blood of particular areas of brain
What’s one limit/problem with PET methodology?
There’s a limit to the amount of radiation a participant can be exposed to, and therefore limits to be amount of information that can be obtained.
What’s one limit to standard MRI?
Doesn’t indicate what areas of the brain are involved in any specific behaviour
Define fMRI.
A non-radioactive magnetic procedure for detecting the flow of oxygenated blood to the various parts of the brain
2 advantages of fMRI
1) doesn’t depend on radioactive signal
2) data can be acquired more rapidly using fMRI than PET
How does a fMRI work?
It uses a large magnet to detect brain areas in a given cognitive task.
Oxygenated blood reacts differently in the magnetic field than de-oxygenated blood.
This information is used to create an image of brain activity.
What was the procedure and results of Bavalier’s fMRI study?
Bavalier conducted a study that looked at brain activity in Broca’s and Wernickie’s area of participants while they were reading sentences and consonant strings.
The results showed that reading sentences resulted in more activation in Broca’s and Wernickie’s area than viewing consonant strings. Other areas were also activated with variation across participants
Conclusion: language processing is not localized in only a few brain areas
Define MEG
A non-invasive brain imaging technique that directly measures neural activity
It combines the spatial resolution of fMRI and temporal resolution of ERP’s
3 advantages of MEG
1) much better temporal resolution
2) direct measurement of neural activity
3) irregularities in the skull don’t have much affect on magnetic fields produced by neural activity
2 limitations of MEG
1) decay of magnetic fields with increased distance. Therefore, MEG is only good for detecting activity near the cortical surface of the brain
2) not widely available
Define connectionism
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 numbers of interconnected neurons and attempts to model cognition as an emergent process of networks of simple units (eg: neurons) communicating with one another
Define DTI
An MRI-based neuroimaging technique that makes it possible to visualize the white-matter tracts within the brain
Can help to show how info flows between and within brain regions
What are the 2 basic connectionist ideas?
a) Information can be broke down into elementary units (neurons)
b) there are connections between these units
These connections have different strengths and a neural network learns by modifying the strength of connections between elements do that the proper output occurs in response to a particular input
Define neural network
Neurons that are functionally related or connected
State the Hebb’s rule
A connection between the two neurons takes place only if both neurons are firing at approximately the same time
What’s an important connectionist assumption
Many connections can be active at the same time - an example of parallel processing
Define parallel processing
Many neural connections maybe active at the same time - an important connectionist assumption
Define serial processing
Only one neural activity may take place at the one time
What are the 2 connectionist assumptions?
Hebb’s rule
parallel processing
