Cognitive Neuroscience Flashcards
What is Cognitive Neuroscience?
The study of how brain structures and processes mediate cognitive behaviour
More progress in CN in the last 20 years than in most disciplines in a lifetime.
What are the challenges for Cognitive Neuroscience?
Brain is a complex system (around 1 million neurons in 1mm^2 of the brain).
The Signal:Noise ratio, difficult to extract the signal from the noise.
Between Individual Differences - in terms of structure and function, experience, individual variability, genetics
Within Individual Differences - tiredness on different days, strategy, mood, task difficulty.
What are the main advantages and disadvantages of fMRI?
Advantages:
-Tells us which parts of the brain are used in tasks
-Reasonable temporal solution
-Get structural data within the same session
Disadvantages:
-Claustrophobic, very noisy, movement artefacts
-Can’t have metal based equipment for stimulus presentation
-BOLD isn’t a direct measure of activity (physiological response 4secs after activity) and care should be taken interpreting it.
What are the main principles of TMS?
Non-invasive and causes depolarisation/hyper-polarisation of neurons in the brain.
Uses electromagnetic induction to induce weak electric currents in the cortex.
Can cause motor evoked potential
Can produce a temporary simulated ‘lesion’ of a brain region.
What are the advantages and disadvantages of TMS?
Advantages: -Near portable -Can stimulate/lesion Disadvantages: -Difficult to specify precise regions -Only surface regions.
What are the main principles of MEG?
When pyramidal cells of the cortex are active they generate a significant magnetic field
MEG records these magnetic fields.
Magnetic fields are less distorted by the scalp than electrical fields.
What are the advantages and disadvantages of MEG?
Advantages:
-Excellent temporal resolution
-Good spatial resolution especially if combined with MRI.
Disadvantages:
-Expensive
-Inverse problem as its not a direct measure.
What are the advantages and disadvantages of EEG?
Advantages:
-Very good temporal resolution
-Less subject to motion artefacts, not claustrophobic, can be used on infants, major artifact is eye blinks but can be eliminated by monitoring eyelid.
Disadvantages:
-Weak spatial resolution
-How do you determine which brain regions caused the pattern of activity.
What is an ERP?
Event-related potential
A measurement of the brain’s response to a stimulus
What is the Visual Evoked Potential?
A specific type of ERP which is a neural response to a visual stimulus.
Where does early visual processing happen?
In the primary visual cortex (V1). (Through fMRI scans)
How do we know where face processing happens in the brain.
EEG and fMRI are used to compare data and see which brain activations were responsible for the N170 response (a neural response that peaks around 170 ms after presenting a face). A large N170 response to upright faces corresponded to greater activity in the right Superior Temporal Sulcus and a lower N170 response to inverted faces corresponded to greater activity in the medial form of the fusiform gyrus.
Outline tDCS and its As&Ds
Delivers a small electric current to the brain through electrodes attached to the scalp, can either excite or inhibit neuron activity.
Cheaper and easier to use than TMS.
Has weaker effect on neuron activity.
