Hi, I am Pamela Douglas, postdoctoral scholar at the UCLA Semi Institute and Licensed hypnotist. In the following presentation, we demonstrate our method for concurrent collection of E-E-G-F-M-R-I data and an MR compatible device for differential thermometry. We present this method using a unique paradigm referred to here as the cold glove experiment and record data, both before and after hypnotic induction.
We first collect concurrent E-E-G-F-M-R-I data and hand temperature measurements while subjects listen to an audio tape via MRI compatible headphones that instructs them to imagine that their left hand is growing colder, otherwise known as the cold glove paradigm. Single modality EEG data are then recorded during hypnotic induction. Simultaneous E-E-G-F-M-R-I cold glove data are recorded once again following hypnotic induction and hand temperature measurements are recorded throughout the experiment using our MR compatible differential thermometry device.
Ultimately, our method for E-E-G-F-M-R-I data collection may be useful in a number of experimental paradigms by providing multimodal data with high temporal and spatial resolution non-invasively. Importantly, the non-stationary aspects of brain signal processing make concurrent recordings highly advantageous over serial data collection. Hi, I'm Mark Cohen, the technical director of the Staglin Center for Cognitive Neuroscience at the UCLA, Semial Institute for Neuroscience and Human Behavior.
In this video, we will demonstrate how to concurrently record ELECTROENCEPHALOGRAPHIC or EEG data, functional magnetic resonance images and hand temperature measurements, all of which are altered quantitatively under hypnosis. We developed and utilized specialized technologies for these measurements, coupled with a hypnotic induction procedure designed to specially to accommodate the experimental protocol. The simultaneous collection of EEG and FMRI is particularly difficult because each of the devices creates artifacts in the other.
The MRI effects on EEG are especially challenging as the RF portion of the imaging system utilizes signals of up to several hundred volts while the gradients imposed time varying magnetic fields at upwards of 45 Tesla per second. At the same time, the tiny EEG signal at the scalp is just a few microvolts. Even measuring temperature in the MRI has obstacles.
The parasitic radio frequency currents traveling through electronic apparatus are an apriori safety concern and low level emissions from the digital temperature recording devices can contaminate the MR images. The EEG amplifier is designed specially by electrical geodesics to operate in very, very close proximity to the imaging magnet. Virtually all of the ferromagnetic components of the AMP were removed, which was then enclosed in the field Isolation containment system or fix.
You can get a sense of the fix enclosure by comparing its size to a standard EEG AMP by the same company. Each of the EEG inputs are electrically filtered to exclude the coupling of radio frequency energy into the battery powered amplifier. In order to collect EEG and FMRI together, the timing of both instruments must be aligned with nanosecond precision.
However, to preserve shielding wired electrical signals should not be carried in or out of the scan room. To ensure this, the engineers at electrical geodesics constructed our simultaneous E-E-G-F-M-R-I system, such that both the timing signals and the digitized data are carried over optical fibers through these ports. Hypnotic induction begins with a brief interview by the hypnotherapist.
An idio motor suggestion known as the arm raising technique is then used for hypnotic induction process. EEG data are recorded using a 2 56 channel MRI compatible. GEODESIC sensor net impedance levels in electrodes should be monitored at approximately 20 minute intervals throughout the experiment.
Hypnotic susceptibility is then assessed via the 12 point Stanford scale of hypnotic susceptibility form C.The subject then enters the MRI scanning room for simultaneous E-E-G-F-M-R-I data collection. Following hypnotic induction, We developed a device to collect differential hand temperature measurements during simultaneous E-E-G-F-M-R-I following the hypnotic cold glove suggestion. The device consists of two L 34 temperature sensors connected to an amplifier and a digital display.
Two nine volt batteries supply power to the internal electronics. We chose the LN 34 sensors because of their linear temperature response within physiological ranges. We performed a calibration step in order to address any nonies in the components.
Just prior to the experiment, we determined the zero point for the device by submerging both temperature sensors in a water bath. During the experiment, any deviation from the zero point indicated a difference between the temperatures of the subject's hands. This recorded temperature difference allowed us to quantify the effects of the cold glove suggestion, And I want you to visualize and imagine that you see from your fingertips into your fingers, into your hand, into your wrist is completely submerged.
Underneath your left hand is completely submerged in the ice water. As you continue to visualize, imagine, create this amazing sensation that your left hand is completely cold and numb, numb and cold, there's no sensation in the hand completely. The more you try to feel it, the less sensations you'll have, and the right hand continues to become warmer.
As the left hand continues to become ice cold, ice cold, it's almost like your hands turning blue. You can even believe it's capable of doing it, but it's doing it from the fingertips to the fingers to the wrist. We have presented a method of multimodal recording to reveal electrophysiological, motoric, and neurovascular associates of an otherwise invisible cognitive process.
Unlike the established means of collecting FMRI or EEG and isolation, the combined method can expose linkages between the two brain signals, Quint coupled with ultra high density 256 channel EEG. It's possible to co localize the signals and to draw reasonable inferences as to electrical sources that appear as regions of altered blood flow in magnetic resonance studies.
