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Calixto C.V.

Hannover, Germany

Research Interests

My general research interest is the development of neuroprosthetics. To do so, it is essential we understand the underlying neural mechanisms and connectivity through in-vivo electrophysiological recordings. Therefore, most of my work has been the acquisition and analysis of neural recordings. I am also interested in the effect neuroprosthetics have on cerebral plasticity.

The goal of my research at the Hannover Medical University is the development of novel auditory neuroprosthetics to restore hearing to the deaf. Currently I am working on evaluating the effects of electrical stimulation to the midbrain on auditory perception in the primary auditory cortex of cats and guinea pigs. I am also involved in the evaluation of a new multi-shank midbrain implant to replace the technology currently in clinical trials. New clinical trials applying my findings and with the newly designed electrodes are to be carried out in 2011 in Hannover. We are currently evaluating the surgical approach in human cadavers using 3D navigation combined with post experimental histology and 3D reconstructions.

In contrast, while at the University of Alberta in Canada, my masters focused on the development of motor neuroprosthetics. I evaluated the responses of single cells to stimulation of the spinal pathways for locomotion. These results are being used towards the development of a novel spinal cord implant for restoration of locomotion post spinal cord injury.

When taken together, my experience with motor neuroprosthetics followed by sensory neuroprosthetics gives me a unique perspective to the input/output functionality of the brain. Aside from developing ways to return function to the brain, be it by complementing sensory input or mimicking motor output, these technologies permit us to map and discover the functionality of the CNS and its pathways. In addition, due to their strict tonotopic organization, the auditory pathways are an ideal test bed for evaluating plasticity and the effects that long term neuroprosthetic use has on the brain.

 

Ph.D.        

Medical University of Hannover Hannover Germany
Philosophy Doctor: Systems Neuroscience
October - 2011
Investigation of Novel Auditory Implants of the Inferior Colliculus

Supervisor: Prof. Dr. Thomas Lenarz

 

M.Sc.

University of Alberta Edmonton Canada
Masters of Science: Biomedical Engineering
July - 2007
Thesis:  Single Cell Recordings During Intraspinal Microstimulation of the Spinal Cord

Supervisor: Dr. Vivian Mushahwar; Co-  Dr. Keir Pearson

 

Eng.

University Tuiuti of Parana Curitiba Brazil
Degree of Computer Engineer
December - 2004
Honours Thesis: Thermography of the spinal column

 

Honours and Awards

Medical University of Hannover: Invited guest scientist  2007 
Neuromorphic Engineering workshop: Student scholarship 2005
University Tuiuti: Thesis max grade (10/10) 
2004

 

Scholarly Development: Publications

Book chapters:

"Assistive Technologies for Cognitive Augmentation". In: Cook and Hussey's Assistive Technologies: Principles and Practice edited by Dr. Al Cook and Dr. Janice Polgar, Mosby Press, 2007.

Articles:

Calixto R, Lenarz M, Neuheiser A, Scheper V, Lenarz T, Lim HH. Coactivation of different neurons within an isofrequency lamina of the inferior colliculus elicits enhanced auditory cortical activation. J Neurophysiol. 2012 Aug;108(4):1199-210.

Neuheiser A, Lenarz M, Reuter G, Calixto R, Nolte I, Lenarz T, Lim HH. Effects of pulse phase duration and location of stimulation within the inferior colliculus on auditory cortical evoked potentials in a Guinea pig model. J Assoc Res Otolaryngol 11(4): 689-708.

Coelho, Leandro dos Santos; Calixto, Roger. Wavelet neural networks and its applications in chaotic systems identification. 8th Online World Conference on Soft Computing in Industrial Applications. Springer-Verlag, 2003. v. 1, p. 1-6.

 

Scholarly Development: Presentations

Oral

Association for research in otolaryngology - 2011
Temporal integration within the thalamus due to electrical stimulation of the inferior colliculus. Roger Calixto, Minoo Lenarz, Thomas Lenarz, Hubert H. Lim

11th International Conference on Cochlear Implants and Other Implantable Auditory Technologies - 2010
The Next Step in Midbrain Stimulation: Multi-Shank Auditory Midbrain Implants. Roger Calixto, Minoo Lenarz, Thilo Rode, Behrouz Salamat, Guenter Reuter, Thomas Lenarz, Hubert H. Lim

10th International Conference on Cochlear Implants and Other Implantable Auditory Technologies - 2008
Auditory Midbrain Implant: Auditory Cortical Effects Of Multi-Site Stimulation In The Central Nucleus Of The Inferior Colliculus. R. Calixto, H. Lim, A. Neuheiser, G. Reuter, T. Lenarz, M. Lenarz

6th Annual Alberta Biomedical Engineering Conference - 2006
Single Cell Recordings during Intraspinal Microstimulation. R. Calixto, P. Musienko, S. Baker, J.Norton, V. Mushahwar

Alberta Motor Control - 2006
Understanding What Intraspinal Microstimulation acts on. R. Calixto, P. Musienko, S. Baker, J.Norton, V. Mushahwar

Alberta Motor Control - 2005
What does Intraspinal Microstimulation act on? R. Calixto, P. Musienko, S. Baker, J.Norton, V. Mushahwar

XXVI National Congress of Applied and Computational Mathematics, Brazil - 2003
Multivariable Controller Tuning Based on Genetic Algorithms for Mobile Robotics. R. Calixto, L.Coelho

Tuiuti Engineering week - 2002
The CRM Concept. R. Calixto

Tuiuti Engineering week - 2001
Manufacturing the Chip. R. Calixto

Poster

State of the Art Symposium on Auditory Brainstem Implants - 2010
Multi-Shank Auditory Midbrain Implant: studies in Guinea Pigs and Cats. Roger Calixto, Minoo Lenarz, Thilo Rode, Behrouz Salamat, Guenter Reuter, Thomas Lenarz, Hubert H. Lim

Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde - 2010
Inferior colliculus recordings to auditory nerve stimulation with penetrating electrodes. R. Calixto, M. Pietsch, H.H. Lim, T. Lenarz, M. Lenarz

Association for research in otolaryngology - 2010
Cortical Responses to a new Double-Shank Auditory Midbrain Implant (AMI) in the Guinea Pig. R. Calixto, M. Lenarz, A. Neuheiser, T. Lenarz, H. H. Lim

Conference on Implantable Auditory Prosthesis - 2009
Functional assessment of a new double-shank auditory midbrain implant in a guinea pig model. Roger Calixto, Minoo Lenarz, Anke Neuheiser, Thomas Lenarz, Hubert H. Lim

Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde - 2009
Auditory Midbrain Implant: Effects of multi-site stimulation of the inferior colliculus on the primary auditory cortex. Roger Calixto, Dr. Hubert H. Lim, Anke Neuheiser, Prof. Dr. Guenter Reuter, Prof. Dr. Thomas Lenarz, Dr. Minoo Lenarz

Society for Neuroscience - 2009
Auditory Cortical Effects of Deep Brain Stimulation of the Inferior Colliculus. Roger Calixto, Minoo Lenarz, Anke Neuheiser, Verena Scheper, Guenter Reuter, Thomas Lenarz, Hubert H. Lim

Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde - 2008
Auditory Midbrain Implant: Effects of multi-site stimulation along the isofrequency laminae of the inferior colliculus central nucleus on auditory cortical activity. R. Calixto, H. Lim, A. Neuheiser, G. Reuter, T. Lenarz, M. Lenarz

Society for Neuroscience - 2006
Modulation of single cell activity by intraspinal microstimulation in the lumbosacral enlargement of the cat spinal cord. R. Calixto, P. Musienko, J.Norton, V. Mushahwar

Alberta Neuroscience Research Day - 2006
Understanding how Intraspinal Microstimulation works. R. Calixto, P. Musienko, S. Baker, J.Norton, V. Mushahwar

6th Annual Alberta Biomedical Engineering Conference - 2005
What does Intraspinal Microstimulation act on? R. Calixto, P. Musienko, S. Baker, J.Norton, V. Mushahwar

 

Professional Associations

Institute of Electrical and Electronics Engineers (IEEE) member 2005 - present

IEEE Engineering in Medicine and Biology Society 2007-  present

Society for Neuroscience 2009- present

Society of Automotive Engineers 2002 - 2003

 

Professional Training

Workshops

8th Fall Course on Computational Neuroscience - 2010
Workshop intended to provide graduate students and young researchers from all parts of neuroscience with working knowledge of theoretical and computational methods in neuroscience and to acquaint them with recent developments in this field.

G-Node Winter Course in Neural Data Analysis - 2009
Hands on workshop on methods in neural data analysis. Covered topics included intracellular, extracellular, multi- and single-unit  analysis as well as some modeling.

Neuromorphic Engineering Workshop - 2005
3 week long workshop in Tellurid, CO on Neuromorphic Engineering. Defined as technologies inspired by biological systems, we were given project choices and a final competition decided the "winner" project based on the performance of a robot through an obstacle course. Project topics were Vision chips, artificial neural networks on a chip to control locomotion, artificial nose,hearing and speach procesing and sensors and robotics.

Workshop of Computer Systems Security - 2002
Conference on computer systems security with workshop covering detection and penetration systems and protocols.

Conferences without presentation

Society for Neuroscience annual meeting - 2010
International Functional Electrical Stimulation society - 2008
Materials Research Society Spring Meeting: symposium on implantable materials - 2007
NIH Neural Interfaces Workshop - 2006
1st International Conference on Bioinformatics and Computational Biology - 2003
XX Brazilian Symposium of Computer Networking - 2002

 

Languages

English  Fluent
Spanish Fluent
Portuguese Fluent
German Conversational

 

Other Professional Experience

Consultant: Artificial Intelligence 2003
Cia Shop, Brazil. The project consisted in the development of a specialist system and an Artificial Neural Network (ANN) to identify fraudulent credit card transactions for e-commerce applications. Among the tested ANNs were Anfis, MLP, RBF and FAN using 3 predetermined characteristics of the ongoing database. The final version used a FAN as the ANN and an 18 dimension matrix for processing.

CRM Interface team leader 2000-2003
Global Village Telecom, Brazil. As the interface team leader it was my responsibility to oversee the development and maintenance of all the system interfaces with the customer relationship management system (Siebel). Database solutions and system migrations were a commonplace in this environment. I started in GVT as a junior analyst when the company was only a start-up in 2000 and eventually worked my way to team leader. Our implementation of Siebel was the largest of its time and was delivered “online” on time and in budget.

English Teacher 1998-2000
Words English Schools, Brazil. As an English as a Second Language (ESL) teacher I had the opportunity to teach all levels. I focused mainly on advanced courses for adults which applied the Cambridge and Oxford teaching methods and
their corresponding books. Conversation classes were also common, to reinforce the oral practice necessary for TOEFL tests and Cambridge Proficiency tests