L5: Cytoarchitectonics, TMS
and EEG
Comparing Methods
Cytoarchitectonics
Staining
Functional correlation
Transcranial magnetic stimulation TMS
How TMS works
How to measure effects of TMS?
Motor cortex stimulation
Quantifying motor responses with EMGs
Other cortical areas
Cross-modal plasticity in early blind individuals
Chronometry
Virtual lesions
Evaluation of TMS
EEG
Measuring electrical activity
Typical EEG set-up
Alpha rhythm and blockade
EEG-based parameters for biological psychology
Event-related oscillations
Comparing Methods
The ideal method?
Having a method that has good temporal/ spatial resolution while also
being non-invasive seems fitting. However, this could generate too
much data, making it hard to process/ interpret.
L5 Cytoarchitectonics, TMS and EEG 1
, Comparing methods on spatial resolution (x-axis), temporal resolution (y-axis) and
correlation/ interference (z-axis).
MRI based methods = good spatial resolution
EEG based methods = good temporal resolution
TMS high interference (reversibly disrupt brain function, so functional
significance of target area)
EEG/ fMRI high correlation (activation at time of event without showing
that the activation is essential to the event
Cytoarchitectonics
Based on structural information only
Borders of brain defined by segments according to appearances in the
microscope
Reflects predominant types of cells in that brain area
Types of cells sometimes correlate with function
Limitations:
L5 Cytoarchitectonics, TMS and EEG 2
, Time- and labour-intensive.
Rarely includes large sample sizes, limiting study of inter-individual
variation.
Requires viewing the brain from different points to study the desired
brain region (e.g medial, lateral viewpoint)
Spatial resolution: Fine
Brodmann 1900s) defined/ numbered areas of the brain with this method
Staining
Cortical tissue appears in the microscope in different ways depending
on staining.
Variation in layer thickness correlates with brain function.
L5 Cytoarchitectonics, TMS and EEG 3
, Layer V contains mostly cells
sending signals from the brain to
the periphery and is therefore
one of the output layers
Layer IV mostly contains cells
receiving input from the
periphery and is therefore an
input layer
A wide layer V and a thin
layer IV shown in this image
(top, bottom left) are typical Layer I (outermost) nearest to cortical
of the primary motor cortex surface.
in the central gyrus
Brodmann area 4
However, the image (bottom
right) shows a wide layer IV and a
thin layer V, seen in primary
somatosensory cortex, post-
central gyrus, Brodmann areas
3,1, and 2
Functional correlation
The cytoarchitectonic features of the brain areas correspond with their
main functions (e.g., input vs. output layers).
Layer IV Input layer (receives peripheral signals, primary
somatosensory cortex).
Layer V Output layer (sends signals to the periphery, motor cortex).
L5 Cytoarchitectonics, TMS and EEG 4
and EEG
Comparing Methods
Cytoarchitectonics
Staining
Functional correlation
Transcranial magnetic stimulation TMS
How TMS works
How to measure effects of TMS?
Motor cortex stimulation
Quantifying motor responses with EMGs
Other cortical areas
Cross-modal plasticity in early blind individuals
Chronometry
Virtual lesions
Evaluation of TMS
EEG
Measuring electrical activity
Typical EEG set-up
Alpha rhythm and blockade
EEG-based parameters for biological psychology
Event-related oscillations
Comparing Methods
The ideal method?
Having a method that has good temporal/ spatial resolution while also
being non-invasive seems fitting. However, this could generate too
much data, making it hard to process/ interpret.
L5 Cytoarchitectonics, TMS and EEG 1
, Comparing methods on spatial resolution (x-axis), temporal resolution (y-axis) and
correlation/ interference (z-axis).
MRI based methods = good spatial resolution
EEG based methods = good temporal resolution
TMS high interference (reversibly disrupt brain function, so functional
significance of target area)
EEG/ fMRI high correlation (activation at time of event without showing
that the activation is essential to the event
Cytoarchitectonics
Based on structural information only
Borders of brain defined by segments according to appearances in the
microscope
Reflects predominant types of cells in that brain area
Types of cells sometimes correlate with function
Limitations:
L5 Cytoarchitectonics, TMS and EEG 2
, Time- and labour-intensive.
Rarely includes large sample sizes, limiting study of inter-individual
variation.
Requires viewing the brain from different points to study the desired
brain region (e.g medial, lateral viewpoint)
Spatial resolution: Fine
Brodmann 1900s) defined/ numbered areas of the brain with this method
Staining
Cortical tissue appears in the microscope in different ways depending
on staining.
Variation in layer thickness correlates with brain function.
L5 Cytoarchitectonics, TMS and EEG 3
, Layer V contains mostly cells
sending signals from the brain to
the periphery and is therefore
one of the output layers
Layer IV mostly contains cells
receiving input from the
periphery and is therefore an
input layer
A wide layer V and a thin
layer IV shown in this image
(top, bottom left) are typical Layer I (outermost) nearest to cortical
of the primary motor cortex surface.
in the central gyrus
Brodmann area 4
However, the image (bottom
right) shows a wide layer IV and a
thin layer V, seen in primary
somatosensory cortex, post-
central gyrus, Brodmann areas
3,1, and 2
Functional correlation
The cytoarchitectonic features of the brain areas correspond with their
main functions (e.g., input vs. output layers).
Layer IV Input layer (receives peripheral signals, primary
somatosensory cortex).
Layer V Output layer (sends signals to the periphery, motor cortex).
L5 Cytoarchitectonics, TMS and EEG 4
