Neuroscience Methods I Flashcards
MRI spatial resolution is good enough to…
distinguish within cortical maps
MRI considerably better than…
the spatial resolution achieved by EEG-based methods
What would be an ideal method?
(not method just measures)
- spatial resolution at the cellular level
- temporal resolution on a millisecond scale
- allows to study the whole brain studied simultaneously, in a non-invasive method?
Relatively wide output layers are typical of
brain areas like primary motor cortex
Cytoarchitectonics
anatomical method based on segmenting the brain according to its appearance under the microscope
characterized by its very fine spatial resolution
structural information only
Brodmann areas 3,1, and 2.
wide layer IV - seen in primary somatosensory cortex, postcentral gyrus
Brodmann area 4
A wide layer V and a thin layer IV - typical of primary motor cortex in the precentral gyrus
unusual for cytoarchitectonic studies to include large numbers of brains as;
time-and labour-intensive process. Only studies with larger numbers of participants allow to study inter-individual variation in cytoarchitectonics
Transcranial magnetic stimulation/TMS
millisecond temporal resolution like EEG-based methods
like fMRI can resolve within cortical maps
TMS can only be applied to a single location at any given time point
TMS is useful to study
- behaviour during experimentally controlled “virtual brain lesions” which are fully reversible,
- chronometryin brain activation,
- functional connectivity.
How to measure effects of TMS?
Frontal cortex stimulation
Auditory cortex stimulation
Motor cortex stimulation
Occipital cortex stimulation
Somatosensory cortex stimulation
FAMOS
…. cortex stimulation
Disadvantages of Hamilton TMS blind study
the advantages of TMS only become apparent in a study with clearly defined hypotheses (can’t study whole brain, only specific locations) and the experimental setup can be quite complicated
Small number of participants, though.
Advantages of Hamilton TMS blind study
potential of TMS due to high temporal resolution and good example of experimental design, with various control conditions
TMS ADVANTAGES
Temporal resolution in millisecond range
Virtual lesion in subject may be better defined than lesion in patient
Short duration of experiment minimises risk of plasticity
Repeated studies in the same subject
Group studies with standardised experimental setup
Study double dissociations: stimulate or temporarily disrupt diff cortical regions during one task, one region during diff tasks
TMS DISADVANTAGES
Spatial under sampling (only one area at a time)
Only cortical areas accessible
Auditory cortex stimulation problematic
Loud coil click, need “sham stimulation”
