SYMPOSIUM
Symposium on layer-dependent imaging May 6/7 2021
The brain-in-depth (BID) symposium is an anual symposium on layer-dependent imaging that I organize together with collaborators from the Otto-von-Guericke University Magdeburg and the Max Planck Institute for Human Cognitive and Brain Sciences. In 2021, it took place as an online event including talks and poster sessions. [more info]
Symposium on layer-dependent imaging May 6/7 2021
The brain-in-depth (BID) symposium is an anual symposium on layer-dependent imaging that I organize together with collaborators from the Otto-von-Guericke University Magdeburg and the Max Planck Institute for Human Cognitive and Brain Sciences. In 2021, it took place as an online event including talks and poster sessions. [more info]
METHOD
Layer-dependent mapping of cortical myelin
The layer-dependent myeloarchitecture of the human cortex has long been studied in post mortem tissue (see e.g. work of Paul Flechsig around the 1920s), but has only recently been investigated in the living human brain using ultra-high field imaging 7+ Tesla. This novel method allows layer-dependent, multi-modal in-vivo human cortex parcellation.
Read more: [link]
Layer-dependent mapping of cortical myelin
The layer-dependent myeloarchitecture of the human cortex has long been studied in post mortem tissue (see e.g. work of Paul Flechsig around the 1920s), but has only recently been investigated in the living human brain using ultra-high field imaging 7+ Tesla. This novel method allows layer-dependent, multi-modal in-vivo human cortex parcellation.
Read more: [link]
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. In this TICS article, 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. In this TICS article, 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]
KEY-FINDING
Septa in the human brain
Monkeys' and rodents' somatosensory cortices are equipped with myelin-poor septa that separate adjacent body part representations. We showed using 7 Tesla MRI that similar boundaries also exist in the human brain. Human septa seem to be most pronounced in input and output layers of MI, and in input layers of SI. Key insight: Cortical myelin boundaries separate body part representations in the human brain.
Read the full paper: [link]
Septa in the human brain
Monkeys' and rodents' somatosensory cortices are equipped with myelin-poor septa that separate adjacent body part representations. We showed using 7 Tesla MRI that similar boundaries also exist in the human brain. Human septa seem to be most pronounced in input and output layers of MI, and in input layers of SI. Key insight: Cortical myelin boundaries separate body part representations in the human brain.
Read the full paper: [link]
KEY-FINDING
Non-afferent topographic maps in S1
The human primary somatosensory cortex (SI) has long been believed to only code self-perceived (afferent) touch. We show using 7 Tesla fMRI that feeling touch on the hand and observing touch at another person's hand activates similar fine-grained topographic maps in SI and similar inhibitory receptive field interactions in SI. Key insight: Topographic maps in S1 can also arise from non-afferent sources.
Read the full papers: [link] [link]
Non-afferent topographic maps in S1
The human primary somatosensory cortex (SI) has long been believed to only code self-perceived (afferent) touch. We show using 7 Tesla fMRI that feeling touch on the hand and observing touch at another person's hand activates similar fine-grained topographic maps in SI and similar inhibitory receptive field interactions in SI. Key insight: Topographic maps in S1 can also arise from non-afferent sources.
Read the full papers: [link] [link]
RESEARCH
Do visual signals integrate into deeper layers of S1?
When parts of the skin are stimulated for prolonged periods of time, this leads to Hebbian-mediated tactile plasticity in the corresponding tactile receptive field in primary somatosensory cortex (S1) (REF). Because NMDA-receptors are most prevalent in superficial cortical layers of S1, this effect is likely mediated by superficial layers of S1. Behaviorally, this leads to improved spatial tactile discrimination thresholds as for example measured by the 2-point discrimination task. We used improvements in the 2-point discrimination threshold after skin stimulation to investigate whether observing touches on video boosts Hebbian plasticity in superficial layers of S1. Our study showed that there is no beneficial effect of touch observation on tactile plasticity. We suggest that this is due to an integration of visual signals into deep layers of S1.
Read the full paper: [link]
Do visual signals integrate into deeper layers of S1?
When parts of the skin are stimulated for prolonged periods of time, this leads to Hebbian-mediated tactile plasticity in the corresponding tactile receptive field in primary somatosensory cortex (S1) (REF). Because NMDA-receptors are most prevalent in superficial cortical layers of S1, this effect is likely mediated by superficial layers of S1. Behaviorally, this leads to improved spatial tactile discrimination thresholds as for example measured by the 2-point discrimination task. We used improvements in the 2-point discrimination threshold after skin stimulation to investigate whether observing touches on video boosts Hebbian plasticity in superficial layers of S1. Our study showed that there is no beneficial effect of touch observation on tactile plasticity. We suggest that this is due to an integration of visual signals into deep layers of S1.
Read the full paper: [link]
REVIEW
How visual body perception influences somatosensory plasticity
In this recent review paper, Prof. Burkhard Pleger and myself provide an overview about how viewing the body influences plasticity mechanisms in the human somatosensory system. This review offers a contribution to understanding the complex interactions between social perception and somatosensory learning by focusing on a novel research field: socially mediated sensory plasticity.
Read the full paper: [link]
How visual body perception influences somatosensory plasticity
In this recent review paper, Prof. Burkhard Pleger and myself provide an overview about how viewing the body influences plasticity mechanisms in the human somatosensory system. This review offers a contribution to understanding the complex interactions between social perception and somatosensory learning by focusing on a novel research field: socially mediated sensory plasticity.
Read the full paper: [link]
DISSERTATION
OPEN BODY MAPS
In my dissertation, I show that primary somatosensory cortex (S1) responds to both afferent (tactually perceived) and non-afferent (observed) touch. I argue that this speaks in favour of "open body maps" - a concept that I associate to the "open minds"-concept introduced by Prof. Wolfgang Prinz.
Read full dissertation:
OPEN BODY MAPS
In my dissertation, I show that primary somatosensory cortex (S1) responds to both afferent (tactually perceived) and non-afferent (observed) touch. I argue that this speaks in favour of "open body maps" - a concept that I associate to the "open minds"-concept introduced by Prof. Wolfgang Prinz.
Read full dissertation:
