cortiQ Rapid Cortical Mapping | g.tec medical engineering GmbH

cortiQ is a new way of brain mapping for the operating room and neuro monitoring unit that is used with epilepsy or brain tumor patients. cortiQ determines functional areas as those whose electrocorticographic (ECoG) activity increases with tasks such as motor movement or speech production.

cortiQ allows neurologists and neurosurgeons to localize eloquent brain areas and provides additional information for surgical resection with a low risk of neurological deficits. cortiQ software can readily be used in addition to traditional mapping procedures such as electrical cortical stimulation (ECS) mapping or fMRI.


real-time brain mapping in the operating room or neuro monitoring unit
minimize hospital time and costs
rapid mapping procedure
customizable for individual surgical needs
optimize surgical procedures
reduce risks for patients
can be used in very young patients, too
FDA cleared and CE123 certified medical product


ADC24 Bit, one per channel
ECoG channels80, 144 or 256
Oversampling614.14 kHz to 2.4 kHz
Anti-aliasingUltra-steep in 2 co-processors

Passive high-gamma mapping represents a physiologically elegant and clinically relevant paradigm shift for identifying essential cortical functions.

Anthony Ritaccio, PhD, MD - Mayo Clinic, Florida, USA

I use ECoG electrodes for real-time brain mappings to find and interpret functional activity in the brain at the bed-side, and during awake craniotomy for brain surgery. I can reduce electrical cortical stimulations (ECS) to minimize related seizures and shorten clinical examinations. Otherwise, I would miss an opportunity to improve existing brain mapping procedures and learn the bigger picture.

Kyousuke Kamada, PhD, MD - Hokashin Group Megumin Hospital, Sapporo, Japan

cortiQ mapping is based on passive recordings and statistical evaluations of ECoG, rather than on active electrical stimulation and visual observation of behavior. It can be used to map motor, expres­sive or receptive language, and other functions, and has been shown to have good concordance to results from other imaging techniques. Brain mapping can be achieved in minutes with adults or children, and performed in the extra­operative or intraoperative scenario.

Dr. Christoph Guger - g.tec medical engineering GmbH


Epilepsy is a common neurological disorder that affects a large portion of the world population. Many of the affected people can control epileptic seizures with the use of medication, but for around 15–20% of this population, medication is not effective, and some of these patients choose surgery. Brain cancer is another reason for brain surgery. There are various types of brain tumors, and the aim of the surgery is to remove the tumor (or at least parts of it).


Functional brain mapping of the cortex is an essential step when planning resective brain surgeries. Mapping techniques like electrical cortical stimulation (ECS) and functional magnetic resonance imaging (fMRI) are well-established in clinical practice. However, these procedures have disadvantages, since ECS is time consuming, can trigger seizures, and fMRI is not always reliable.


A passive brain mapping procedure based on electrocorticographic (ECoG) signals is a fast and precise mapping technique without the risk of causing pain or seizures. ECoG has repeatedly demonstrated that it can accurately identify cortical regions related to receptive and expressive language functions, motor functions and the somatosensory system in the brain. For that reasons, g.tec medical engineering developed the cortiQ rapid cortical mapping system.


cortiQ is a new rapid functional mapping technique of the cortex using the Electrocorticogram (EcoG) for patients who suffer from epilepsy with intractable seizure disorders or brain tumors. cortiQ helps surgeons identify functional brain regions with high-gamma activity before surgical resection. cortiQ maps the brain regions related to a certain task that the patient is performing. Neurosurgeons will be able to use and modify cortiQ paradigms based on individual surgical needs.


The video shows the temporal dynamics of cortiQ mapping. As soon as the patient sees the instruction the temporal base is activated and few seconds later the motor cortex, the auditory cortex and Wernicke’s area show the functional regions.



For example, if pathological tissue is close to the motor area, cortiQ will ask the patient to move arms, feet or even lips. The brain activity patterns produced during these movements will be transmitted in real-time to cortiQ, notifying the neurosurgeon what parts are important for a certain movement and therefore should remain untouched.



After successful implantation of cortiQ ECoG electrodes, there are two ways of how to perform the brain mapping: intra-operative or bedside. These two approaches open many more opportunities with a minimal risk for the patient.

A brand new feature of cortiQ is the real-time 3D visualization of brain activity.



Unlike ECS, cortiQ does not produce artificial seizures and cannot produce pain. However, ECS might be required in some cases.

Therefore, cortiQ can identify neural areas that are “active” in a task decided by the surgeon and thereby provide a fast pre-screening mechanism that might be used for optimized ECS mapping and surgical removal of affected tissue.



  • During brain surgery, invasive electrode grids are placed on the cortex or are inserted into the brain covering the specific areas that need to be mapped.
  • The patient performs preprogrammed tasks, e.g. moving limbs, listening to a story, calculating or speaking, which support the neurosurgeon to get a better understanding of the individual functional regions of the brain.
  • cortiQ creates a real-time mapping of the brain, showing what brain areas are active during a specific task.
  • Finally, brain surgery can be prepared and performed safely in record time and with reduced costs.


The awake surgery case is critical in time. First, a craniotomy is performed to implant the electrodes. Then functional real-time mappings are performed just before the brain tissue resection. Validation with ECS must be done during the surgery.


The bedside case usually requires two surgeries. In the first surgery, electrodes will be implanted and functional real-time mappings are performed at the bedside. Validation with ECS can be done at the beside, too. In the second surgery, electrodes will be removed and the affected brain tissue will be resected.


In this publication, cortiQ was used for passive language mapping under general anesthesia of an elderly patient with left temporal glioma. The patient’s language function was well-preserved postoperatively.



In this publication, we studied the activity of a patient’s brain while he looked at different objects. If we stimulated these areas, the patient reported seeing faces or colors, even if he was looking at something else! The results of this study help show how different parts of the brain perform different tasks, and could lead to safer, more precise brain surgery.



g.tec offers scientific services for cortiQ including mappings in your hospital in the USA, Europe and Japan and our scientific team can analyse the data for you. Furthermore, we can adapt the cortiQ paradigms for your mapping needs.



What brain areas can be mapped with cortiQ?

  • Wernicke’s area (Receptive language)
  • Broca’s area (Expressive language)
  • Auditory cortex
  • Visual cortex
  • Somatosensory system
  • Motor cortex
  • Face recognition
  • Color system
  • Memory function
What scientific publications are available for cortiQ?

Yes. Here is a list of all import publications:

Kanaya, K., Mitsuhashi, T., Kiuchi, T. and Kobayashi, S., 2021. The Efficacy of Intraoperative Passive Language Mapping for Glioma Surgery: A Case ReportFrontiers in neurology, p.1339.

Sanada, T., Kapeller, C., Jordan, M., Grünwald, J., Mitsuhashi, T., Ogawa, H., Anei, R. and Guger, C., 2021. Multi-modal mapping of the face selective ventral temporal cortex–a group study with clinical implications for ECS, ECoG, and fMRI. Frontiers in Human Neuroscience15.

Jiang, T., Pellizzer, G., Asman, P., Bastos, D., Bhavsar, S., Tummala, S., … & Ince, N. F. (2020). Power Modulations of ECoG Alpha/Beta and Gamma Bands Correlate With Time-Derivative of Force During Hand Grasp. Frontiers in Neuroscience14.

Crowther, L. J., Brunner, P., Kapeller, C., Guger, C., Kamada, K., Bunch, M. E., … & Schalk, G. (2019). A quantitative method for evaluating cortical responses to electrical stimulation. Journal of neuroscience methods311, 67-75.

Ritaccio AL, Brunner P, Schalk G. Electrical Stimulation Mapping of the Brain: Basic Principles and Emerging Alternatives. Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society. 2018 Mar;35(2):86-97.

Swift, J.R., Coon, W.G., Guger, C., Brunner, P., Bunch, M., Lynch, T., Frawley, B., Ritaccio, A.L. and Schalk, G., 2018. Passive Functional Mapping of Receptive Language Areas Using Electrocorticographic Signals. Clinical Neurophysiology.

Kapeller, C., Ogawa, H., Schalk, G., Kunii, N., Coon, W.G., Scharinger, J., Guger, C. and Kamada, K., 2018. Real-Time Detection and Discrimination of Visual Perception Using Electrocorticographic Signals. Journal of Neural Engineering, 15(3), 036001.

Schalk, G., Kapeller, C., Guger, C., Ogawa, H., Hiroshima, S., Lafer-Sousa, R., Saygin, Z.M., Kamada, K. and Kanwisher, N., 2017. Facephenes and rainbows: Causal evidence for functional and anatomical specificity of face and color processing in the human brainProceedings of the National Academy of Sciences, p.201713447.

Ogawa H, Kamada K, Kapeller C, Prueckl R, Takeuchi F, Hiroshima S, Anei R, Guger G, Clinical Impact and Implication of Real-Time Oscillation Analysis for Language Mapping, World Neurosurgery, Available online 28 September 2016, ISSN 1878-8750

Tamura Y, Ogawa H, Kapeller C, Prueckl R, Takeuchi F, Anei R, Ritaccio A, Guger C, Kamada K, Passive language mapping combining real-time oscillation analysis with cortico-cortical evoked potentials for awake craniotomy. 2016, Journal of Neurosurgery, 1.

Ritaccio, A., Matsumoto, R., Morrell, M., Kamada, K., Koubeissi, M., Poeppel, D., … & Schalk, G. (2015). Proceedings of the Seventh International Workshop on Advances in Electrocorticography. Epilepsy & Behavior, 51, 312-320.

Christoph Kapeller (2015): Online Control of a Humanoid Robot through Hand Movement Imagination using CSP and ECoG based Features. Presentation.

Kapeller C, Korostenskaja M, Prueckl R, Chen PC, Lee KH, Westerveld M, Salinas CM, Cook JC, Baumgartner JE, Guger C., CortiQ-based Real-Time Functional Mapping for Epilepsy Surgery. J Clin Neurophysiol. 2015 Jun;32(3):e12-22. doi: 10.1097/WNP.0000000000000131

Kapeller C, Kamada K, Ogawa H, Prückl R, Kunii N, Schnürer A, Guger C. P87. Expressive and receptive language mapping using ECoG and ECS. Clinical Neurophysiology. 2015 Aug 31;126(8):e146.

Kapeller C, Schneider C, Kamada K, Ogawa H, Kunii N, Ortner R, Prückl R, Guger C. Single trial detection of hand poses in human ECoG using CSP based feature extraction. In2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society 2014 Aug 26 (pp. 4599-4602). IEEE.

Kapeller, C., Kamada, K., Ogawa, H., Prueckl, R., Scharinger, J., & Guger, C. (2014). An electrocorticographic BCI using code-based VEP for control in video applications: a single-subject study. Frontiers in systems neuroscience, 8.

Prueckl, R., et al. “Real-Time Software for Functional Mapping of Eloquent Cortex Using Electrocorticography.” Biomedical Engineering/Biomedizinische Technik (2013).

Roland, Jarod, et al. “Passive real-time identification of speech and motor cortex during an awake craniotomy.” Epilepsy & Behavior 18.1 (2010): 123-128.

Kapeller, Christoph; Kamada, Kyousuke; Ogawa, Hiroshi; Kunii, Naoto; Prueckl, Robert; Kawai, Kensuke; Schalk, Gerwin; Guger, Christoph. Comparison of ECoG and ECS Language Mapping with High-Density Electrodes. 2013 IEEE Neural Engineering Short Papers No. 0521.

Prueckl R, Kapeller C, Potes C, Korostenskaja M, Schalk G, Lee KH, Guger C., CortiQ – clinical software for electrocorticographic real-time functional mapping of the eloquent cortex. Conf Proc IEEE Eng Med Biol Soc. 2013;2013:6365-8. doi: 10.1109/EMBC.2013.6611010.

Korostenskaja, Milena, et al. “Real-Time Functional Mapping With Electrocorticography in Pediatric Epilepsy Comparison With fMRI and ESM Findings.” Clinical EEG and neuroscience 45.3 (2014): 205-211.

Kamada K, Ogawa H, Kapeller C, Prueckl R, Guger C., Rapid and low-invasive functional brain mapping by realtime visualization of high gamma activity for awake craniotomy. Conf Proc IEEE Eng Med Biol Soc. 2014;2014:6802-5. doi: 10.1109/EMBC.2014.6945190.

Ogawa H, Kamada K, Kapeller C, Hiroshima S, Prueckl R, Guger C., Rapid and minimum invasive functional brain mapping by real-time visualization of high gamma activity during awake craniotomy. World Neurosurg. 2014 Nov;82(5):912.e1-10. doi: 10.1016/j.wneu.2014.08.009. Epub 2014 Aug 7. PMID: 25108295.

Brunner, Peter, et al. “A practical procedure for real-time functional mapping of eloquent cortex using electrocorticographic signals in humans.” Epilepsy & Behavior 15.3 (2009): 278-286.

G. Schalk, E. C. Leuthardt, P. Brunner, J. G. Ojemann, L. A. Gerhardt, J. R. Wolpaw, Real-time detection of event-related brain activity, Neuroimage 43 (2) (2008) 245–249.


Can I use cortiQ in Epilepsy Monitoring Units (EMU)?

Yes, absolutely.  In the first surgery, ECoG electrodes will be implanted, but the functional real-time mappings are performed in the Epilepsy Monitoring Unit. This allows neurosurgeons to modify test paradigms based on individual surgical needs. These tests can be performed repeatedly over a longer period of time. This gives the neurosurgeon more time to plan and optimize the surgical resection better with more detailed information and less preparatory work. cortiQ can greatly reduce the risk of artificial seizures during surgery and cannot produce pain for the patient. It’s less consuming and the risk of damage during surgery can be avoided.

Can I perform intraoperative neuromonitoring (IONM) with cortiQ?

Yes, cortiQ can be used for intraoperative monitoring of the brain. It allows real-time brain mappings in the operating room to identify functional brain regions with high-gamma activity before surgical resection. For example, if pathological tissue is close to the motor area, cortiQ will ask the patient to move arms, feet or even lips. The brain activity patterns produced during these movements will be transmitted in real-time to cortiQ, notifying the neurosurgeon what parts are important for a certain movement and therefore should remain untouched.

How long does the cortiQ brain mapping last?

A mapping that highlights four activation maps usually lasts about 6 min.

Is language mapping possible?

Yes, cortiQ comes with a passive listening paradigm that maps the auditory cortex, including the receptive language area, and it can play back language related paradigms like picture naming tasks and map expressive language related cortical regions.

What is the goal of cortiQ rapid cortical mapping?

Support surgeons’ planning for brain surgeries by providing additional information about functional brain regions.

What useful information can we get with cortiQ brain mapping procedure in addition to the ECS?

The activated neural network is highlighted based on natural behaviors, such as speech or movement. The ECS can only investigate symptoms caused by local dysfunction due to electrical stimulation.

Does the cortiQ brain mapping work with stereo-EEG or depth electrodes? Why show results in real-time?

The mapping procedure works with electrode grids and stereo-EEG recordings with depth electrodes.

How can the brain mapping result be compared with other methods and ECoG analysis?

cortiQ stores the recorded EEG synchronized with the mapping paradigm and provides an importer for MATLAB (The MathWorks Inc., USA). cortiQ mapping results are stored in CSV format for further comparison.

Why show brain mapping results in real-time?

The supervisor can immediately check the quality of the mapping session and stop/change the paradigm at any time. No further offline processing is necessary.

What information is used to perform the brain mapping?

The power of the high-gamma frequency band (60-170Hz) derived from electrocorticographic (ECoG) signals.

How does cortiQ brain mapping work and what do the results mean?

The system compares high-gamma activity in the ECoG during resting and active conditions. Changes in the power of the high-gamma band indicate activated neurons with respect to the electrode position. A group of highlighted electrode groups shows an activated neural network. The system updates the activation map in real-time.

This allows the user to interpret the activation during the experiment and to stop the paradigm anytime. The longer the paradigm lasts, the more noise is eliminated, and hence only task-related electrodes are highlighted. A recommended setup contains around 45s active and 45s resting state per task.

Who will benefit from cortiQ brain mapping procedure?

Neurosurgeons who want to get additional information about the eloquent cortex and other specific regions, and research groups who want to investigate functional regions of the cortex. Neurosurgeons also benefit from cortiQ’s ability to provide maps in real-time instead of hours or days. Patients benefit from reductions in the time needed for mapping, need for additional mapping procedures, chance of accidental seizures resulting from ECS, and the risk of accidental removal of too little or too much brain tissue.

What are the benefits of cortiQ compared to the clinical practice?

Unlike ECS, cortiQ does not produce artificial seizures. CortiQ cannot produce dural pain caused by bad electrode contacts. CortiQ shows the neural areas involved in a given task and allows very fast pre-screening that may be used for planning ECS mapping and surgical removal of affected tissue.


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