My brain.MePaul Cisek Ph.D.

Department of physiology
University of Montréal
2960 chemin de la tour, room 4117
Montréal (Québec) H3T 1J4 Canada
Phone : 514-343-6111 x4355
FAX : 514-343-2111
E-mail :

 


Research interests:

I am interested in how the brain controls behavior. Many scientists approach this very large question by starting with perception and asking how the brain builds an internal representation of the world, and how it then uses this representation to guide action. In contrast, I study behavior by starting with a concrete task such as a voluntary movement and asking what parameters of the task the brain must specify and control, and what information from the environment it may employ toward that specification. The goal here is an understanding of brain mechanisms for mediating interaction with the world, not necessarily of mechanisms for representing the world. A research program based on such an approach begins with questions concerning motor control and gradually works its way toward the perceptual systems which guide that control. One could say I'm going backwards through the brain...

Please check out my Curriculum Vitae.

Lab Personnel:

Marie-Claude Labonté: Laboratory technician

Alexandre Pastor Bernier: PhD student

Ignasi Cos: Postdoctoral fellow

David Thura: Postdoctoral fellow

Valeriya Gritsenko: Research scientist

Alumni:

Thomas Michelet: Postdoctoral fellow

Jean-Philippe Thivierge: Postdoctoral fellow

Geneviève Aude Puskas: Stagiaire de recherche

Stephany El-Murr: Stagiaire de recherche

Nicolas Bélanger: Stagiaire d’été

Julie Beauregard-Racine: Stagiaire d’été

Farid Medleg: Stagiaire de recherche

Charles-William Fradet: Stagiaire d’été

 

Text Box:  

Neural activity in the premotor cortex during a decision task: when two options are presented, two populations of cells become active in parallel; when the decision is made, one population increases activity while the other is suppressed.
Current projects:

My research projects are interdisciplinary, combining computational modeling with experimental data. The approach involves the development of models aimed at explaining existing neural and behavioral data, using these models to make predictions that inspire the design of experiments, conducting the experiments, and using the resulting data to modify and refine the models. Hopefully, this process will converge on insights into how the brain does what it does so well.

Computational modeling of action specification and selection: Recent results suggest that multiple movement plans can be prepared in just as much detail as can a single movement plan, and that part of perception is the recognition of potential actions the world affords. In other words, when we look at the world we see it not merely in terms of what is out there, but in terms of what we can do out there. I’ve recently developed a computational model (Cisek, 2006) which suggests how the brain uses visual information to specify multiple potential actions across the cerebral cortex, and the processes by which these potential actions compete for overt execution. The model is a source of predictions for many of the experiments done in the lab.

Neural recording experiments: We are conducting a series of experiments involving multi-electrode recording from the cerebral cortex during reach decision tasks. These experiments are designed to elucidate the dynamics of the processes by which different potential actions compete for overt execution in the fronto-parietal network. Future experiments will examine whether choices can be influenced by subthreshold microstimulation in these regions.

Guessing games: We are running behavioral experiments testing how human subjects make guesses, as the information for or against a given choice changes continuously. We analyze these results using models of decision-making, which can be used to look for signatures of the decision-making process in the brain using neural recording and fMRI.

Transcranial magnetic stimulation (TMS): We are using TMS to non-invasively stimulate the motor cortex to elicit small responses in muscle activity, whose size reveals the state of preparation for a given action. This allows us to probe the preparatory state during various decision-making tasks to gain insights into how decisions develop over time.

Executing the choice: We use a robotic manipulandum (KINARM) to measure and perturb the kinematics and dynamics of ongoing human movements, while applying TMS to probe the role of the primary motor cortex in the control of biomechanics.

Biomechanics of choices: We are investigating how the biomechanical factors associated with different potential actions influence our choices between them. This involves behavioral and kinematic measures, as well as TMS. Upcoming experiments will use the KINARM to examine how perturbations can influence the choice.

History of the nervous system: I'm also working on some side-projects of a more philosophical nature. Most of these are concerned with developing a theory of behavior from the perspective of the evolutionary history of nervous systems. The human brain was not picked ready-made from a tree; it struggled to survive in the bodies of countless fish, frogs, rodents, etc. This was a long journey of many small steps, and its twists and turns laid down the organization of even the most advanced modern brains. Understanding that journey provides invaluable insights into the “big picture” of neural organization.

Sample Publications:

Cisek, P. and Kalaska, J.F. (2010) “Neural mechanisms for interacting with a world full of action choices”. Annual Review of Neuroscience. 33: 269-298. [PDF]

Cisek, P., Puskas, G.A., and El-Murr, S. (2009) “Decisions in changing conditions: The urgency-gating model”. Journal of Neuroscience. 29(37): 11560-11571. [PDF]

Thivierge, J-P. and Cisek, P. (2008) “Non-periodic synchronization in heterogeneous networks of spiking neurons”. Journal of Neuroscience. 28(32): 7968-7978. [PDF]

Cisek, P. (2007) “Cortical mechanisms of action selection: The affordance competition hypothesis” Philosophical Transactions of the Royal Society B. 362: 1585-1599. [PDF] [suppl]

Cisek, P. (2006) “Integrated neural processes for defining potential actions and deciding between them: A computational model”. Journal of Neuroscience. 26(38): 9761-9770. [PDF] [suppl]

Cisek, P. & Kalaska, J.F. (2005) “Neural correlates of reaching decisions in dorsal premotor cortex: specification of multiple direction choices and final selection of action”. Neuron. 45(5): 801-814. [PDF]

Cisek, P. & Kalaska, J.F. (2004) “Neural correlates of mental rehearsal in dorsal premotor cortex”. Nature 431: 993-996. [PDF]

Cisek, P., Crammond, D.J., and Kalaska, J.F. (2003) “Neural activity in primary motor and dorsal premotor cortex in reaching tasks with the contralateral versus ipsilateral arm”. Journal of Neurophysiology. 89 (2): 922-942. [PDF]

Cisek, P. (1999) “Beyond the computer metaphor: Behaviour as interaction”. Journal of Consciousness Studies. 6(11-12): 125-142. [PDF]

Cisek, P. Grossberg, S., and Bullock, D. (1998) “A cortico-spinal model of reaching and proprioception under multiple task constraints”. The Journal of Cognitive Neuroscience. 10(4): 425-444. [PDF]

Hobbies:

Computer programming, the piano (esp. Chopin), contemporary music, skiing, tennis, literature, science-fiction, movies, chess, go, computer games...


This page is permanently under construction. Last update was on November 19, 2010.