Исследование нейронных механизмов сознавая и не зная страха памяти с МРТ
Summary
Методология для исследования нервных механизмов, которые поддерживают знают и не знают процессов памяти во время страха кондиционирования описано. Этот метод отслеживает уровень кислорода в крови зависимые (BOLD) функциональной магнитно-резонансной томографии, ответ проводимости кожи, и безусловных продолжительность стимула во время павловской кондиционирования страха для оценки нейронных коррелятов различных процессов памяти.
Abstract
Pavlovian fear conditioning is often used in combination with functional magnetic resonance imaging (fMRI) in humans to investigate the neural substrates of associative learning 1-5. In these studies, it is important to provide behavioral evidence of conditioning to verify that differences in brain activity are learning-related and correlated with human behavior.
Fear conditioning studies often monitor autonomic responses (e.g. skin conductance response; SCR) as an index of learning and memory 6-8. In addition, other behavioral measures can provide valuable information about the learning process and/or other cognitive functions that influence conditioning. For example, the impact unconditioned stimulus (UCS) expectancies have on the expression of the conditioned response (CR) and unconditioned response (UCR) has been a topic of interest in several recent studies 9-14. SCR and UCS expectancy measures have recently been used in conjunction with fMRI to investigate the neural substrates of aware and unaware fear learning and memory processes 15. Although these cognitive processes can be evaluated to some degree following the conditioning session, post-conditioning assessments cannot measure expectations on a trial-to-trial basis and are susceptible to interference and forgetting, as well as other factors that may distort results 16,17 .
Monitoring autonomic and behavioral responses simultaneously with fMRI provides a mechanism by which the neural substrates that mediate complex relationships between cognitive processes and behavioral/autonomic responses can be assessed. However, monitoring autonomic and behavioral responses in the MRI environment poses a number of practical problems. Specifically, 1) standard behavioral and physiological monitoring equipment is constructed of ferrous material that cannot be safely used near the MRI scanner, 2) when this equipment is placed outside of the MRI scanning chamber, the cables projecting to the subject can carry RF noise that produces artifacts in brain images, 3) artifacts can be produced within the skin conductance signal by switching gradients during scanning, 4) the fMRI signal produced by the motor demands of behavioral responses may need to be distinguished from activity related to the cognitive processes of interest. Each of these issues can be resolved with modifications to the setup of physiological monitoring equipment and additional data analysis procedures. Here we present a methodology to simultaneously monitor autonomic and behavioral responses during fMRI, and demonstrate the use of these methods to investigate aware and unaware memory processes during fear conditioning.
Protocol
Discussion
Методология страх кондиционирования описано здесь служит средством для исследования нейронных механизмов знают и не знают страха процессов памяти. Этот метод использует преимущества одновременного мониторинга поведенческих, вегетативных и МРТ данных. Мониторинг поведенческих (нап…
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
Поддержка, оказываемая Университета Алабамы в Бирмингеме факультета Программа развития Грант.
Materials
| Equipment | Company | Item number |
| Integrated Functional Imaging System (IFIS-SA) | Invivo Corp., Orlando, FL | |
| Master Control Unit (located in the control room) Peripheral Interface Unit (located in the MRI chamber) Audio/Visual Display Unit (located in the MRI chamber), includes:
|
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| PHYSIOLOGICAL MONITORING SYSTEM | Biopac Systems, Inc., Goleta, CA | |
| Data Acquisition and Analysis System for Windows (MP150) Isolated Digital Interface (Digital Interface) Galvanic Skin Response (GSR) Amplifier MRI Cable/Filter System to Transducer Amplifier set, includes:
DB25 M/F ribbon cable Disposable radiotranslucent electrodes Carbon fiber leads |
MP150WSW STP100C EDA100C-MRI MECMRI-TRANS – MECMRI-1 – MRIRFIF – MECMRI-3 CBL110C EL508 LEAD108 |
|
| JOYSTICK | Current Designs, Inc., Philadelphia, PA | |
| Legacy Joystick | HH-JOY-4 | |
| Legacy fORP Interface | FIU-005 |
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