cognitive neuroscience methods

which two methods have the highest temporal resolution?

MEG and EEG

fundamental principle of optogenetics

genetically modifying specific neurons to express light sensitive channels - activity can be controlled by lights

primary advantage of using brain lesions to study the brain?

causal links!

what occurs when the blood supply to then brain is suddenly disrupted, leading to tissue damage?

cerebral vascular accident (stroke)

which area of the cortex is particularly prone to damage from traumatic brain injury due to collision with the jagged surface of the skull

the orbitofrontal cortex

what is single dissociation?

impairment on one specific task but not on another

why does double dissociation provide stronger evidence for selective impairment than a single dissociation?

shows that two different groups with lesions in different areas have opposite patterns of task impairment - suggesting the functions are localised

damage to which lobe is typically associated with prosopagnosia?

temporal lobes

what is achromatopsia

colour blindness

what is homonymous hemianopia

visual loss in the contralateral hemifield of both eyes

what term described the ability to discriminate visual stimuli without conscious awareness of them

blindsight

in patients with blindsight who can discriminate motion, which visual area is found to be active?

the V5 (MT)

why are experimental lesions on animals better than natural lesions in humans?

experimental lesions can be precise and you can measure behaviour before and after

what is the receptive field

specific region of sensory space and the specific stimulus properties that cause a neuron to respond

what area is primarily associated with processing colour

V4

which area is primarily associated with processing motion

V5 (MT)

where are blobs and interblobs located?

V1 (PVC)

primary neural source of the signals measured in EEG

summed electrical dipoles generated by the activity of large populations of pyramidal neurons in the cerebral cortex

why are individual action potentials not measurable in EEG

too fast and too asynchronous

what structural arrangement of pyramidal cells in the neocortex allows their electrical activity to summate and be detected by EEG

organised in rigid parallel arrangement, their apical dendrites near the surface, dendrites extend deeper

what is the purpose of averaging the EEG data across many trials to create and ERP

averaging cancels out the random background noise, revealing the neural response to a specific stimulus

in ERP, what does N170 refer to?

a negative-going ERP component that typically peaks at 170 milliseconds after stimulus presentation

why can the location of an ERP effect on the scalp be misleading about the location of the activity?

cortical folds

why is MEG considered to have better spatial precision than EEG

magnetic fields are not significantly distorted or blurred by the skull and scalp

major practical disadvantage of MEG compared to EEG

MEG is extremely expensive

alpha oscillations (prominent in EEG recordings at around 10 Hz) are typically largest when a person is in what state?

relaxed and with eyes closed

what property of atomic nuclei, specifically their protons, is the basis for MRI

the fact that protons spin and possess a magnetic moment, causing them to align with a strong external magnetic field

what does Diffusion Tensor Imaging primarily measure

measures the diffusion of water molecules, which is used to map the orientation and integrity of white matter tracts in the brain

what does PET measure?

metabolic activity, typically detecting photons generated by the annihilation of positrons emitted by an injected radioactive tracer

what does BOLD stand for?

blood oxygenated level dependent

what physiological event triggers BOLD signal to increase

oversupply of oxygenated blood to an active neural region, which changes the local magnetic properties of the tissue

why is BOLD signal considered a slow and indirect measure of neural activity?

relies on haemodynamic response that peaks several seconds after the activity has occurred

what is rapid event related design in fMRI

discrete, brief events are presented with varied timing and order, allowing for statistical deconvolution of the BOLD response

what is the term for the brain’s ability to reorganise its structure and function?

plasticity

the phenomenon where a disproportionately large area of the area primary visual cortex is dedicated to processing information from the central visual

cortical magnification

what are the stripe-like patterns found in the primary visual cortex that represent alternating inputs from the left and right eyes

ocular dominance columns

boundaries between distinct visual field maps in the brain are often found at the representation of which parts of the visual field

the vertical or horizontal meridians

what type of photoreceptor is densely packed in the fovea and responsible for high-acuity vision in bright light

cones

which type of photoreceptor is absent from the central fovea and is responsible for vision in low light and levels

rods

how does the brain’s ability to remap in response to a retinal lesion differ if the lesion is acquired in adulthood vs present at birth

large-scale remapping does not typically occur when a lesion is acquired in adulthood

are blobs or interblobs more metabolically active?

blobs

what are blobs

a group of neurons within V1 that are sensitive to colour and project thin stripes in V2

what are interblobs

areas in V1 between blobs that respond best to lines of a particular orientation and projects to pale stripes of V2