Volitional control of Amygdala gamma band activity from depth electrodes in human subjects – a case study
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1
University of California Los Angeles, Department of Neurosurgery, David Geffen School of Medicine and Semel Institute for Neuroscience and Human Behavior, United States
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2
Tel Aviv Sourasky Medical Center, Israel
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3
Teesside University, School of Computing, United Kingdom
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4
University of Kent, School of Engineering and Digital Arts, United Kingdom
The use of deep brain stimulation devices (DBS) in a clinical setting for treating various neurological and psychiatric disorders is increasing. Using the stimulating electrodes as a recording electrode and assigning the signal in a closed-loop neural training procedure (NeuroFeedback, NF) might serve as an ecological procedure exploiting the natural neuroplasticity of the brain. Thus, it can add another level to the common treatment and use of DBS. The current study demonstrates the feasibility of using intracranial Amygdala gamma band power as a probe for NF training. Micro wires located in the Amygdala of epilepsy patients were used. The amygdala is a subcortical area involved in emotional processing and emotional regulation. Specifically, animal and human research revealed that heightened gamma power activity within the amygdala is correlated with aversive stimuli, fear and chronic stress. In this preliminary study we demonstrated that subjects can learn to volitionally regulate the amygdala while interacting with a complex noisy setting.
To facilitate subject engagement, we used a NF setting based on the simulation of a realistic situation rather than abstract feedback signals such as gauges, meters or sounds.
The virtual environment reproduces the waiting room of a hospital, populated with virtual characters waiting to be called at the admissions desk. It provides a useful metaphor for arousal, as characters can shift between two states: one patiently waiting and one is complaining at the front desk. The “global unrest” is defined as the ratio of characters complaining and is used to visualize the activity of the amygdala. This is further emphasized by a matching soundtrack. In the beginning of the baseline state all virtual patients take seats in the waiting room (low unrest level) and gradually congregate at the front desk also expressing their frustration through body language (high unrest level). The system is implemented using the Unreal Development Kit (UDK) game engine, which allows controlling walking animations for individual characters. Changes to the distribution of sat and standing characters are made as a function of the level of unrest by randomly selecting the next character to change state and triggering the corresponding animation.
A case study of one epilepsy patients with depth electrode implanted for pre-surgical mapping procedure of the suspected epileptic foci. electrode location was based on clinical criteria only. iEEG was sampled at 30 kHz and recorded using Neuroport (Blackrock microsystems). Gamma band activity (20-85Hz) was calculated online via welch method using Matlab (MathWorks, USA). The subject participated in 10 NF sessions. Each of the sessions included four to eleven baseline epochs of passive viewing of the waiting room environment (60 sec each) and equal number of successive active NF Blocks (60 sec each). The participants were instructed to “appease/agitate the waiting room using their brain activity”. No preferred behavioral strategy was specified for NF, to avoid influencing subject's mental strategy.
Preliminary analysis of the recordings suggests that participants acquired the ability to down/up-regulate their amygdala gamma band activity obtained by micro wires depth electrodes even with little training. Success was found in 36/54 (66%) and 17/29 (58%) of the up/down regulation blocks respectively. Furthermore the success rate tends to increase from session to session implying on learning by the user of an appropriate mental strategy.
Our preliminary results demonstrate that it is possible to train people to specifically modulate their amygdala's activity even under noisy dynamic environment. Results obtained are encouraging, in particular the relatively high success rate considering minimal training received by the subject, and the increased success between successive sessions. We aim to run more subjects with both micro and macro wires feedback to compare the ability to vocationally control the Amygdala activity in different settings.
We demonstrate a proof of concept of volitional control on local limbic activity recorded by micro wires in the amygdala while patients interact with a dynamic VR setting.
Acknowledgements
The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 604102 (Human Brain Project) and from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 602186.
Keywords:
Neurofeedback,
amygdala feedback,
intracranial recordings,
Microwires,
virtual environments
Conference:
SAN2016 Meeting, Corfu, Greece, 6 Oct - 9 Oct, 2016.
Presentation Type:
Poster Presentation in SAN2016 Conference
Topic:
Posters
Citation:
Tchemodanov
N,
Gazit
T,
Yamin
HG,
Raz
G,
Jackont
G,
Charles
F,
Cavazza
M,
Hendler
T and
Fried
I
(2016). Volitional control of Amygdala gamma band activity from depth electrodes in human subjects – a case study.
Conference Abstract:
SAN2016 Meeting.
doi: 10.3389/conf.fnhum.2016.220.00064
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Received:
29 Jul 2016;
Published Online:
01 Aug 2016.
*
Correspondence:
PhD. Hagar G Yamin, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, yaminhagar@yahoo.com