Summary Self study assignments Neuroscience 2016-2017
Self Study Assignment 1
Questions for Amunts, Schleicher & Zilles: Cytoarchitecture of the cerebral
cortex – More than
localization, Neuroimage 2007
Link to the article:
http://www.ncbi.nlm.nih.gov/pubmed/17870622
Question 1:
What superficial structures in the human cortex were and are still being used for locating
Brodmann areas in an individual patient’s brain? Why is such an approach problematic?
Gyri and sulci, Many cytoarchitectonic borders are located outside of a sulcus (e.g., major parts of the
anterior border of area 4). Only the borders of a few architectonically defined areas show a sufficiently
precise association with sulci, e.g., the posterior border of the primary motor to the somatosensory
cortex which is located in the fundus of the central sulcus. However, the anterior border of the primary
motor cortex shifts from a more rostral position to a more caudal position hidden in the central sulcus
when moving on the brain surface in medio-lateral direction. The anterior border is not related either to
the precentral or any other sulcus (Geyer and Zilles, 2005; Geyer et al., 1996). The primary visual cortex
is always found in the calcarine sulcus, but its outer borders to V2 are not associated with a sulcus, and
their positions may vary considerably among individuals (Amunts et al., 2000). The primary auditory
cortex is always found on the Heschl gyrus, but its anterior border cannot be defined by a
macroanatomical landmark (Morosan et al., 2001). Therefore, it may be sufficient to identify a gyrus or
sulcus in order to define the localization of an activation in functional neuroimaging, but the
underlying and functionally relevant structural segregation of an individual brain remains unknown
unless the activation is registered on (cyto)- architectonic maps. The borders aren’t well defined, it
loos similar but it is not always the case. The borders are in the deep inside of the sulci. In the
borderline you are in trouble.
Question 2:
Which approaches are necessary to perform for establishing cytoarchitectonic probability
maps? Which one would you expect to be the technically most demanding one? Give
reasons for your answer.
Probabilistic cytoarchitectonic maps of cortical areas are based on (i) observer-independent definitions
of areal borders (Schleicher et al., 1999) in cell body stained histological sections of ten, completely and
serially sectioned post-mortem brains, (ii) 3D reconstruction of these sections using the MR data set of
the same post-mortem brain prior to its embedding in paraffin and sectioning, and (iii) registration of
these 3D data sets to a living standard reference brain as common reference space for cytoarchitectonic
maps and functional imaging data (Zilles et al., 2002b; Amunts and Zilles, 2006).
Self Study Assignment 1
Questions for Amunts, Schleicher & Zilles: Cytoarchitecture of the cerebral
cortex – More than
localization, Neuroimage 2007
Link to the article:
http://www.ncbi.nlm.nih.gov/pubmed/17870622
Question 1:
What superficial structures in the human cortex were and are still being used for locating
Brodmann areas in an individual patient’s brain? Why is such an approach problematic?
Gyri and sulci, Many cytoarchitectonic borders are located outside of a sulcus (e.g., major parts of the
anterior border of area 4). Only the borders of a few architectonically defined areas show a sufficiently
precise association with sulci, e.g., the posterior border of the primary motor to the somatosensory
cortex which is located in the fundus of the central sulcus. However, the anterior border of the primary
motor cortex shifts from a more rostral position to a more caudal position hidden in the central sulcus
when moving on the brain surface in medio-lateral direction. The anterior border is not related either to
the precentral or any other sulcus (Geyer and Zilles, 2005; Geyer et al., 1996). The primary visual cortex
is always found in the calcarine sulcus, but its outer borders to V2 are not associated with a sulcus, and
their positions may vary considerably among individuals (Amunts et al., 2000). The primary auditory
cortex is always found on the Heschl gyrus, but its anterior border cannot be defined by a
macroanatomical landmark (Morosan et al., 2001). Therefore, it may be sufficient to identify a gyrus or
sulcus in order to define the localization of an activation in functional neuroimaging, but the
underlying and functionally relevant structural segregation of an individual brain remains unknown
unless the activation is registered on (cyto)- architectonic maps. The borders aren’t well defined, it
loos similar but it is not always the case. The borders are in the deep inside of the sulci. In the
borderline you are in trouble.
Question 2:
Which approaches are necessary to perform for establishing cytoarchitectonic probability
maps? Which one would you expect to be the technically most demanding one? Give
reasons for your answer.
Probabilistic cytoarchitectonic maps of cortical areas are based on (i) observer-independent definitions
of areal borders (Schleicher et al., 1999) in cell body stained histological sections of ten, completely and
serially sectioned post-mortem brains, (ii) 3D reconstruction of these sections using the MR data set of
the same post-mortem brain prior to its embedding in paraffin and sectioning, and (iii) registration of
these 3D data sets to a living standard reference brain as common reference space for cytoarchitectonic
maps and functional imaging data (Zilles et al., 2002b; Amunts and Zilles, 2006).
