Cognitive Neuroscience Flashcards
What does MRI provide?
Provides structural images of the brain as well as measures brain activation as well as how the brain responds to different cognitive conditions
Why should we study the brain?
Knowing when and where cognitive processes occur in the brain can help us understand the nature of those processes
What does the understanding of the neural basis of behaviour allow us to understand?
Allows us to understand cognitive disorders and to predict effects of damage to the brain
What is the N400?
It is an electrophysical signal that occurs when we hear an unexpected word
What is the N400 used for?
It is widely used to study how and when prediction occurs in language
When designing an experiment to investigate how neural activity and cognitive functions relate to one another, what are the two ways we can go?
(1) We can change behaviour and measure the effect on the brain
(2) Or we can change the state of the brain and measure the effect of behaviour
What is a recording study?
It is the first type of study where we manipulate behaviour and record what is going on in the brain
What are the causes of brain damage?
Surgery, tumour, stroke, traumatic brain injury, neurodegeneration
What are the two main types of stroke?
Ischemic and haemorrhagic stroke
What is an ischemic stroke?
Blockage in the blood vessel
What is a haemorrhagic stroke?
The wall of the blood vessel becomes weakened, and it bursts in the artery, depriving parts of the brain of oxygen
What is neuropsychology?
Learning about people with brain damage
What does cognitive neuropsychology rely on?
It relies on identifying dissociations and associations between different cognitive abilities
When studying single cases, we are looking at patients and looking for impairments in different areas of cognition. Alfonso Caramazza proposed 3 major assumptions that we need to make when we are doing this kind of single case research?
(1) Fractionation assumption –brain damage can selectively affect different cognitive/ neural systems
(Neural specialisation is a basic principle in cognitive neuroscience, and is agreed by many)
(2) Transparency assumption – brain lesions can affect existing cognitive systems but do not create new systems
(3) Universality assumption – all cognitive systems are basically the same
What does lesion-symptom mapping tell us?
Tell us important clinical-information about what deficits is likely to result from particular areas of damage
Aside from telling information about what deficits are likely to results from areas of damage, what else does lesion-symptom mapping tell us?
Tells us information about which cognitive processes are associated with which brain areas:
- important for developing theories of brain organisation
- but also, for testing cognitive level theories of processing
What are natural lesions?
Lesions that have been acquired through some sort of injury or disease?
What are limits of natural lesions?
1) we are limited to between-subject designs
2) damage frequently extends across multiple areas of the brain
3) possibility of reorganisation of function in people with long-standing neurological conditions (neural plasticity)
What is Transcranial Magnetic Stimulation (TMS)?
This is a safe, commonly used technique for temporarily disrupting neural activity in healthy participants
What happens in Transcranial Magnetic Stimulation (TMS)?
The function of a small area of cortex is disrupted through application of a rapidly changing magnetic field
In TMS what does the disruption of the small cortex measure?
This measures effects of disruption on particular cognitive processes or behaviours
What is TMS based on?
It is based on the principle of electromagentic induction
How does TMS work?
Alternating electrical current passed through a coil creates a rapidly changing magnetic field which will induce a current in a nearby coil
In TMS, the second coil is replaced with a brain: the magnetic field induces current in underlying brain tissue
What can we do with TMS?
We can create temporary ‘virtual lesions’ to small areas of the brain
What are the benefits of TMS?
1) we can choose where the lesions are
2) Because the effects are temporary, participants can act as their own control [within-subjects design]
3) Because the participants have healthy brains, there are no complications from recovery or plasticity that would affect results
4) can compare the baseline performance to post TMS performance
In TMS what are we observing?
We want to observe whether our participants slow down or make more errors after stimulation.
In TMS what do we want to infer?
We want to infer that the region we have stimulated must be very important for performing that task
What are possible alternative explanations of TMS effects?
(1) brain stimulation is a weird experience – maybe people are distracted and perform worse afterwards
(2) people may feel anxious beforehand – then they might be distracted before and perform better afterwards
(3) there may be a placebo effect – what if people expect to perform worse after receiving brain stimulation?