Performing Behavioral Tasks in Subjects with Intracranial Electrodes

Abstract

Patients having stereo-electroencephalography (SEEG) electrode, subdural grid or depth electrode implants have a multitude of electrodes implanted in different areas of their brain for the localization of their seizure focus and eloquent areas. After implantation, the patient must remain in the hospital until the pathological area of brain is found and possibly resected. During this time, these patients offer a unique opportunity to the research community because any number of behavioral paradigms can be performed to uncover the neural correlates that guide behavior. Here we present a method for recording brain activity from intracranial implants as subjects perform a behavioral task designed to assess decision-making and reward encoding. All electrophysiological data from the intracranial electrodes are recorded during the behavioral task, allowing for the examination of the many brain areas involved in a single function at time scales relevant to behavior. Moreover, and unlike animal studies, human patients can learn a wide variety of behavioral tasks quickly, allowing for the ability to perform more than one task in the same subject or for performing controls. Despite the many advantages of this technique for understanding human brain function, there are also methodological limitations that we discuss, including environmental factors, analgesic effects, time constraints and recordings from diseased tissue. This method may be easily implemented by any institution that performs intracranial assessments; providing the opportunity to directly examine human brain function during behavior.

An intracerebral exploration of functional connectivity during word production

“…If the patient met study criteria, research staff not involved in the surgery implantation or post-surgical care contacted the patient for potential participation in the study. Participation in the study did not alter the patients' clinical care, particularly it had strictly no influence on the originally planned SEEG procedure (Johnson et al 2014). The participants' demographics are presented on Table 2.…”

“…The electrode contacts were 0.8 mm in diameter, 2 mm in length, and spaced 1.5 mm apart. Depth electrodes were inserted in either orthogonal or oblique orientations using a robotic surgical implantation platform (ROSA, Medtech Surgical Inc., USA) allowing intracranial recording from lateral, intermediate and/or deep cortical and subcortical structures in a three-dimensional arrangement (Johnson et al 2014). The day prior to surgery, volumetric preoperative MRIs (T1, contrasted with Multihance 0.1 mmol kg −1 ) were obtained and used to pre-operatively plan electrode trajectories.…”

Lucky Rhythms in Orbitofrontal Cortex Bias Gambling Decisions in Humans

“…In this study, aside from the behavioral experiments, no alterations were made to the patient’s clinical care including the placement of the electrodes24. All experimental protocols were approved by the Cleveland Clinic Institutional Review Board.…”

“…On the other hand, conclusions drawn from rat and monkey studies suffer from difficulties in translation to humans23. By taking advantage of Stereotactic ElectroEncephaloGraphy (SEEG) recordings in epileptic patients at the Cleveland Clinic24, we were able to examine local field potential activity of the OFC in five humans at high temporal resolution (1 or 2 kHz). With this technique, we can both analyze quick neural changes as well as draw straightforward conclusions for human OFC function.…”

Winning versus losing during gambling and its neural correlates

“…See II-B for details on the SEEG procedure. In this study, aside from the behavioral experiments, no alterations were made to the patient's clinical care, including the placement of the electrodes [8]. Subjects enrolled voluntarily and gave informed consent under criterion approved by the Cleveland Clinic Institutional Review Board.…”