On Sept 28th 2020, the second virtual layer-fMRI event is scheduled.

This meeting is held as a succession of the first virtual dinner in May 2020: https://layerfmri.com/virtualevent1/

In this second event, it will be discussed how the research field can bridge the gap between layer-dependent activity measures that are obtained with fMRI and electrophysiology, respectively. Kamil Ugurbil will present the perspective of high resolution for human neuroscience, Lucia Melloni will present the perspective of depth-dependent electrophysiological recordings in humans, and Seong-Gi Kim will talk about the combination of both worlds, layer-fMRI and layer-dependent electrophysiological recordings. 

Below you find the important links of the the virtual event. Embedded videos of the talks, discussions, and a summary of the hot topics are going to be added on the day after the event.

• The meeting is organized and moderated by Luca Vizioli and Renzo Huber. This event is supported by CMRR (Essa Yacoub and Kamil Ugurbil) as well as the Maastricht-York partnership grant (PIs: Aneurin Kennerley and Renzo Huber).
• This link will forward the attendees to the zoom link: https://layerfmri.page.link/meeting_channel.
• The event will consist of three 20-30 min talks and a subsequent joint discussion.
• The duration of the event will be approximately 90 minutes.
• The event it open to everyone (there might be a limit of 200 simultaneous attendees).

Starting time of the virtual event: 

Sydney	Korea	Germany	UK/UTC	New York	Minnesota	San Francisco
Sept 28th	Sept 28th	Sept 28th	Sept 28	Sept 28th	Sept 28th	Sept 28th
11pm	10pm	3pm	2pm	9am	8am	6am

We apologize for the inconvenient time in Australia and Asia. 

Event recordings

Introduction 

---

Kamil Ugurbil

Title: High Resolution Neuroimaging: Accomplishments and Prospects.

Prof. Ugurbil’s talk is a bit more broad. The outline of this talk starts with an early view of the history on challenges and problems of columnar imaging and CMRR’s solutions to some of them.

Then he is talking about the ‘future’ of high resolution imaging starting from 2014.

The talk is concluded with some recent results of high-resolution fMRI at CMRR.

Ptof. Ugurbil does not see this presentation as a review of the field, but rather focuses of the contributions of CMRR.

.

.

.

.

Lucia Melloni

Title: Laminar electrophysiology: promises and challenges

Abstract:

Lucia starts her presentation by emphasizing that laminar fMRI opens the door to investigate the stream of neural communication across brain areas and thus, allows to address questions about phenomena of human cognition, including conscientiousness and language. 

Since the laminar architecture of the human brain differs from non-human brains, Lucia stressed the importance of validating the signal origin of laminar fMRI not only in animal models but also in humans. Lucia shows examples of how this can be done by means of depth-dependent electrophysiological recordings of epilepsy patients. 

One of the key functions of individual cortical layers can be understood in the predictive coding framework by means of prediction error calculation and error model updating. Lucia tested this predictive coding framework with an auditory mismatch-negativity task. She could confirm the prediction error activity (current source density) in superficial layers across patients, as expected in the predictive coding framework. 

In the final part of the presentation, Lucia discussed that there are layer-dependent differences of the spiking activity (MUA) and high gamma (aka broadband gamma) activity. While both measures are similar for early responses in deeper layers, they can differ in superficial and prolonged activity. The high gamma signal might reflect dendritic processes and they are a good proxy for laminar fMRI signal. 

.

.

.

.

Seong-Gi Kim

Title: Laminar-resolution fMRI in animal models:  Signal sources and Implications for human fMRI

Abstract: Mapping laminar activity is of great interest in human fMRI community due to increased availability of ultrahigh field MRI and a necessity to move toward to systems-level circuit mapping.  Recently, many laminar fMRI papers in humans have been published at high profile journals.  However, many unsettled questions arise such as whether the fMRI signals are closely related to neural activities at a level of layers, whether the spatial hemodynamic response is close to the neural spread, etc.  My lab has been working on understanding underlying vascular sources of laminar fMRI with BOLD, CBF, and CBV contrasts in the cat visual cortex (Zhao et al., Neuroimage, 2006; Jin & Kim, Neuroimage, 2008; Kim & Kim, JCBFM, 2011), and underpinning neural sources in rat olfactory (Poplawsky et al., J of Neurosci, 2015) and mouse somatosensory models.  I will present neural sources of laminar fMRI, and discuss outstanding issues and implications for laminar-resolution fMRI in humans.

. 

 

 

 

 

 

---

 

Discussion