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Jean-Michel Hupé

contact: jean-michel.hupe at cerco.ups-tlse . fr

phone: +33 (0)5 6274 6124
postal address: CNRS CERCO UMR 5549, Pavillon Baudot, CHU Purpan, BP 25202, 31052 Toulouse Cedex

My research is focused on visual perception, with more and more emphasis on its subjective aspects.
For the full list of my publications and downloadable pdf files, please click here.

I did my Ph.D. thesis (1995-1999) in Lyon (France) with Jean Bullier on the role of feedback connections in motion perception. Then I spent three years at New York University working with Nava Rubin on motion perception using psychophysics methods and learning fMRI. I started to work on the bistable perception of ambiguous stimuli (see my NYU webpage, which is still accessible). I came back to France in 2002, in Toulouse's CerCo lab, where I was recruited in 2004 as a CNRS research scientist.

I have been working on three research projets, while trying to improve on methodological issues.

(1) Multistable perception, mostly in vision using plaid stimuli (demo), but also in audition thanks to the collaboration with Daniel Pressnitzer.

These are my two most representative publications in this field:
Hupé, J.-M., Rubin, N., 2003. The dynamics of bi-stable alternation in ambiguous motion displays: a fresh look at plaids. Vision Research 43, 531 - 548.
Pressnitzer, D., Hupé, J.-M., 2006. Temporal dynamics of auditory and visual bistability reveal common principles of perceptual organization. Current Biology 16, 1351-1357.

I am currently working on the dynamics of tristable perception. A paper just got published on this subject:
Hupé, J.M., Pressnitzer, D. 2012. The initial phase of auditory and visual scene analysis. Phil Trans R Soc B 367, 942-953. <link> Send me an e-mail to receive the pdf.

This article belongs to a special issue of the Philosophical Transactions of the Royal Society B: Biological Sciences:
Theme Issue 'Multistability in perception: binding sensory modalities' compiled and edited by Jean-Luc Schwartz, Nicolas Grimault, Jean-Michel Hupé, Brian C. J. Moore and Daniel Pressnitzer: 5 April 2012; Vol. 367, No. 1591. The Table of Contents is available here.

Meanwhile, I'm feeding John Rinzel and his postdoc Gemma Huguet at NYU with data so they can come up with nice theoretical explanations of what's going on.

(2) Synesthesia, since 2006 and in collaboration with Michel Dojat.
We studied grapheme color synesthesia extensively using phenomenological reports, psychophysics, functional and structural MRI.

The Neural Bases of Grapheme-Color Synesthesia Are Not Localized in Real Color-Sensitive Areas (2012)
Jean-Michel Hupé; Cécile Bordier; Michel Dojat
Cerebral Cortex, 22, 1622:1633.
Free-access links Abstract, Full Text, PDF

See also the related technical report.

Synesthésie, expression subjective d’un palimpseste neuronal ? (2012)
Jean-Michel Hupé
médecine/sciences, 28(8-9), 765-771. pdf

Mathieu Ruiz is currently doing his PhD project in Grenoble with Michel Dojat and myself.


(3) Mental images.

This is my latest research interest, triggered by the diversity of subjective reports gathered when working on synesthesia. The observation is simple: we do not think the same way, especially when dealing with so-called "mental images". The challenge is: how can we get an objective measure of this diversity of subjective experiences?


(4) Methodological developments.

In my papers, I tried to promote a rigorous usage of statistical tests, and to propose alternatives when validity conditions were not met.

-  In single-unit electrophysiology, I proposed to use bootstrap and randomization tests (Hupé et al 1998, 2001a,b).
-  For the analysis of response times, in particular in multistable perception, the Log transformation of the data is in most cases mandatory. cf Hupé & Rubin 2003, as well as http://cerco.ups-tlse.fr/~hupe/plaid_demo/suppl.htm.
-  Too weak effects or correlations mean nothing. see Hupé JM, Lamirel C, Lorenceau J. Pupil dynamics during bistable motion perception. J Vis 2009; 9: 1-19. <link>
Effect sizes should be always reported (Partial eta square seems the good choice).

For fMRI analysis, I criticized the confusion between "a priori" and 'hypothesis", leading to the propagation of false positive results. I also proposed an index to measure the reproducibility of results. See Hupé et al. 2011, Cerebral Cortex.

I'm also interested in oculomotor signals, in particular as a potential source of artefacts. In 2009, we showed pupil responses to button presses and blinks. We also measured the consequences of blinking on the BOLD signal measures with fMRI. We suggest that fMRI researchers should no longer ignore the existence of blinks:
Hupé J-M, Bordier C, Dojat M. A BOLD signature of eyeblinks in the visual cortex. Neuroimage 2012; 61: 149–61.<link>
 

METHODS
Psychophysics, eyetracking, fMRI

PRESENT, ACTIVE COLLABORATIONS
Michel Dojat, Grenoble Institut des Neurosciences
Daniel Pressnitzer, LPP & DEC, Paris.
John Rinzel, Center for Neural Science, New York University
CREMe Team at CerCo


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