UPCOMING
Symposium on microstructural imaging
The brain-in-depth (BID) Symposium is an anual symposium on layer-dependent imaging that my group organizes together with collaborators from the Otto-von-Guericke University Magdeburg, the DZNE, the Max Planck Institute for Human Cognitive and Brain Sciences and the Hertie Institute for Clinical Brain Research. The next BID Symposium will take place 14/15 March 2024 in Tübingen! More info soon!
Symposium on microstructural imaging
The brain-in-depth (BID) Symposium is an anual symposium on layer-dependent imaging that my group organizes together with collaborators from the Otto-von-Guericke University Magdeburg, the DZNE, the Max Planck Institute for Human Cognitive and Brain Sciences and the Hertie Institute for Clinical Brain Research. The next BID Symposium will take place 14/15 March 2024 in Tübingen! More info soon!
NEW
Column-based modeling of 7T-fMRI data
Shared response modeling (SRM) is a technique that allows group analyses by mapping individual stimulus-driven responses to a lower dimensional shared feature space. This can facilitate group analyses of ultra-high field imaging data, because no smoothing or normalization is needed. Here, we combine SRM with column-based decoding (C-SRM), and show that the number of columns that optimally describes finger maps in primary somatosensory cortex (SI) is higher in younger compared to older adults, indicating a greater columnar size in older adults’ SI. We provide first evidence that the columnar architecture of a functional area changes with increasing age. Read the full paper now accepted in Neuroimage [link].
Column-based modeling of 7T-fMRI data
Shared response modeling (SRM) is a technique that allows group analyses by mapping individual stimulus-driven responses to a lower dimensional shared feature space. This can facilitate group analyses of ultra-high field imaging data, because no smoothing or normalization is needed. Here, we combine SRM with column-based decoding (C-SRM), and show that the number of columns that optimally describes finger maps in primary somatosensory cortex (SI) is higher in younger compared to older adults, indicating a greater columnar size in older adults’ SI. We provide first evidence that the columnar architecture of a functional area changes with increasing age. Read the full paper now accepted in Neuroimage [link].
NEW
The 3D Architecture of the Human Hand Area is Non-Topographic
Septal boundaries in the barrel cortical field are a key feature of SI organization in mice and rats, and many monkey species are equipped with myelin-poor septa between individual finger representations. Here, we tested whether similar myelin-poor boundaries also exist in the human brain. We acquired functional and structural 7T MRI data in young adults, and combined layer-specific myelin mapping with population receptive field (pRF) mapping. We show that even though individual fingers are represented as distinct units, the underlying structural architecture is essentially non-topographic, and does neither show myelin-poor septa between finger representations nor structural differences between individual fingers. Read the paper for a full discussion of the findings: Döhler et al. 2023 J Neurosci [link].
The 3D Architecture of the Human Hand Area is Non-Topographic
Septal boundaries in the barrel cortical field are a key feature of SI organization in mice and rats, and many monkey species are equipped with myelin-poor septa between individual finger representations. Here, we tested whether similar myelin-poor boundaries also exist in the human brain. We acquired functional and structural 7T MRI data in young adults, and combined layer-specific myelin mapping with population receptive field (pRF) mapping. We show that even though individual fingers are represented as distinct units, the underlying structural architecture is essentially non-topographic, and does neither show myelin-poor septa between finger representations nor structural differences between individual fingers. Read the paper for a full discussion of the findings: Döhler et al. 2023 J Neurosci [link].
METHOD
Topographic layer imaging as a tool to track neurodegenerative disease spread in M1
One important feature that is often left out when diagnosing and analyzing disease spread in primary motor cortex (M1, for example in motor neuron disease) is the inhomogeneous architecture of M1 with respect to cortical layers but also topographic units. We therefore propose that combining 3D layer imaging with topographic mapping serves as ideal tool to understand which microstructural changes in M1 determine disease progression. Read the full article: [link]
Topographic layer imaging as a tool to track neurodegenerative disease spread in M1
One important feature that is often left out when diagnosing and analyzing disease spread in primary motor cortex (M1, for example in motor neuron disease) is the inhomogeneous architecture of M1 with respect to cortical layers but also topographic units. We therefore propose that combining 3D layer imaging with topographic mapping serves as ideal tool to understand which microstructural changes in M1 determine disease progression. Read the full article: [link]
METHOD
In vivo layer definition
The layer-dependent myeloarchitecture of the human cortex is used in post mortem tissue to define cortical layers, but has only recently been investigated in the living human brain. We used 0.5 mm isotropic qT1 tissue contrast acquired using a 7 T MRI scanner in living individuals to differentiate between outer layers, middle layers and inner layers in human primary somatosensory cortex (Döhler et al. 2023 J Neurosci [link]) and between superficial layers, layer 5a, layer 5b and layer 6 in human primary motor cortex (Northall et al. Neurobiol Aging [link]). This paves the way for using individualized segmentation and analyses methods to investigate the layer architecture of the living human cortex.
In vivo layer definition
The layer-dependent myeloarchitecture of the human cortex is used in post mortem tissue to define cortical layers, but has only recently been investigated in the living human brain. We used 0.5 mm isotropic qT1 tissue contrast acquired using a 7 T MRI scanner in living individuals to differentiate between outer layers, middle layers and inner layers in human primary somatosensory cortex (Döhler et al. 2023 J Neurosci [link]) and between superficial layers, layer 5a, layer 5b and layer 6 in human primary motor cortex (Northall et al. Neurobiol Aging [link]). This paves the way for using individualized segmentation and analyses methods to investigate the layer architecture of the living human cortex.
METHOD
Model the human cortex in 3D
In cognitive neuroscience, brain-behaviour relationships are usually mapped onto a two-dimensional cortical sheet. Cortical layers are a critical but often ignored third dimension of human cortical function. We explain why modelling the human cortex in three dimensions allows novel and unprecedented insights into the encoding schemes of human cognition. Key message: In different cortical layers, different computations take place. 3D models of human cognition allow to understand human cognition in its full complexity. Read the full paper: [link]
Model the human cortex in 3D
In cognitive neuroscience, brain-behaviour relationships are usually mapped onto a two-dimensional cortical sheet. Cortical layers are a critical but often ignored third dimension of human cortical function. We explain why modelling the human cortex in three dimensions allows novel and unprecedented insights into the encoding schemes of human cognition. Key message: In different cortical layers, different computations take place. 3D models of human cognition allow to understand human cognition in its full complexity. Read the full paper: [link]
METHOD
A new computational framework for 7T fMRI
One of the principal goals in fMRI is the detection of local activation in the human brain. However, lack of statistical power and inflated false positive rates have recently been identified as major problems. Here, we introduce a novel non-parametric and threshold-free software package called LISA to address this demand. LISA uses a non-linear filter for incorporating spatial context without sacrificing spatial precision. Compared to widely used other methods (e.g., SPM, FLS), it shows a boost in statistical power and allows a more reliable detection of small activation areas. Key application: The spatial sensitivity of LISA makes it especially suitable for the analysis of fMRI data acquired at ultrahigh field (≥7 Tesla). Read the full paper: [link]
A new computational framework for 7T fMRI
One of the principal goals in fMRI is the detection of local activation in the human brain. However, lack of statistical power and inflated false positive rates have recently been identified as major problems. Here, we introduce a novel non-parametric and threshold-free software package called LISA to address this demand. LISA uses a non-linear filter for incorporating spatial context without sacrificing spatial precision. Compared to widely used other methods (e.g., SPM, FLS), it shows a boost in statistical power and allows a more reliable detection of small activation areas. Key application: The spatial sensitivity of LISA makes it especially suitable for the analysis of fMRI data acquired at ultrahigh field (≥7 Tesla). Read the full paper: [link]
