(JHBI TS/Final Day2) 2023年11月9日(木)9:00


Chair:Sho K Sugawara and Kenji Ogawa

9:00-9:05 Opening Remarks and announcements 

Talk 1: Eiji Takasawa (Gunma University)


Talk 2:Daichi Ueda (The University of Electro-Communications)

9:35-9:45 Break

Lecture 1: Shahabeddin Vahdat (University of Florida)

10:30-11:15 Lecture 2:Dora Hermes (Mayo Clinic)

Free discussion between speakers and attendees
Open Discussion 



Talk 1:  Eiji Takasawa
Gunma University

Neurological Basis of Handedness: Brain-Spinal Networks, and Future Clinical Insights

Hand dexterity is a hallmark of higher primates, with humans displaying a consistent hand preference in daily activities. The evolution of direct, monosynaptic connection from the primary motor cortex to the spinal cord parallels the development of hand dexterity and lateralization of hand preference. In non-human mammals, indirect, multi-synaptic connections between bilateral primary motor cortices and the spinal cord also contribute to the control of dexterous hand movement. However, it remains unknown how the direct and indirect corticospinal pathways work in concert to control unilateral hand movement with lateralized preference in humans. Here we elucidated this puzzle by employing simultaneous functional magnetic resonance imaging of the brain and spinal cord with a combination of computational network modeling. In this talk, we will discuss an asymmetric functional organization of the two corticospinal networks and a functionally lateralized motor nervous system that underlies the behavioral asymmetry of handedness in humans. I will also provide insights into future projects, such as pain and perception, from a clinical perspective as a spine surgeon.

Talk 2:  Daichi Ueda
The University of Electro-Communications

Perceptual, behavioral, and neural adaptation to independent supernumerary sixth finger

Can the human brain adapt to a supernumerary limb? The rubber hand illusion experiments and other studies about the embodiment of body parts suggested the plasticity of our body representation in the brain. However, since previous studies focused on substitutional artificial limbs controlled by specific body movement, it remains unknown whether the human brain integrates independent artificial limbs into the body system. In this study, we developed an independent supernumerary sixth finger and performed cognitive measurements, behavioral tests, and brain imaging to examine whether body representation is altered by the training for using the sixth finger. Our results suggest that short-time (less than one hour) adaptation to the sixth finger enables participants to perceive a sense of ownership towards the sixth finger and the change of subjective perception correlates with that of the behavioral measurements. fMRI experiments also suggest that brain activity evoked by innate finger movements are altered by the adaptation to the sixth finger. To examine the effect of the difference in the position of attachment, we also developed another type of sixth finger that can be attached between the thumb and the index finger. We will discuss the preliminary results from experiments using this new sixth finger.


Lecture 1:  Shahabeddin Vahdat
University of Florida
Assessing the function of human ascending and descending pathways using fMRI
Many acquired injuries and movement disorders disrupt the function of the central nervous system at multiple levels, including both the brain and spinal cord. However, despite ample progress in human brain imaging, functional neuroimaging of the spinal cord has been limited due to a multitude of technical challenges. Furthermore, the brain and spinal cord are usually scanned separately, preventing the study of functional interaction between these structures. Recent work from my lab and others using simultaneous spinal cord-brain fMRI has offered a new approach to explore the function of ascending and descending pathways in humans. In this presentation, I will discuss common difficulties in neuroimaging of the human spinal cord, and describe a new integrated acquisition/processing pipeline for simultaneous spinal cord-brain fMRI to address these challenges. I will conclude with presentation of our preliminary findings in stroke patients as an example of how this method can be used in clinical populations to study changes in the function of ascending and descending pathways.
Lecture 2:  Dora Hermes
Mayo Clinic
Interpreting human brain signals during visual and electrical stimulation
The development of circuit-based therapeutics to treat neurological and neuropsychiatric diseases require detailed localization and understanding of electrophysiological signals in the human brain. Electrodes can record and stimulate circuits in many ways, and we often rely on non-invasive imaging methods to predict the location to implant electrodes. However, electrophysiological and imaging signals measure the underlying tissue in a fundamentally different manner. While we have gained insight from direct comparisons between mesoscale signals in the human brain, in this talk I will argue for an approach that considers how different measurements integrate signals across the underlying tissue. I will show how this approach helps relate fMRI and intracranial EEG measurements and provides new insights into how electrical stimulation influences human brain networks.