Equipment
The equipment used by our staff includes apparatus that collect EEG Data, measure eye tracking, and analyse acoustic responses. Our state-of-the-art systems and programs allow us to clearly interpret complex data from our large-scale studies.
- EEG Data Collection Equipment
Our laboratory accommodates one 256-channel and two 128-channel dense-array electroencephalogram (EEG) systems (GES 200), as well as one portable 128-channel dense-array EEG system (GES 300). All of our EEG equipment and acquisition software is developed and supported by Electrical Geodesics, Inc. in Eugene, Oregon. Net Station 4.2 controls all data acquisition on each system and features EEG acquisition up to 1000 Hz, user-controllable amplifier settings, a Fast Fourier Transform (FFT) device for near-real-time display of spectral data, and a digital-video device for synchronized video collection. Stimulus presentation and experimental design are controlled by Psychology Software Tools’ E-prime software.
Our EEG studies utilize the innovative Geodesic Sensor Nets (GSN 200 & Hydrocel GSN), allowing us to apply a net of 128 or 256 electrodes within minutes. Maximizing subject safety and comfort, the electrodes are embedded within soft, saline-soaked sponges containing a small amount of baby shampoo. Neither scalp abrasion nor harsh gels are used with this technique. With these electrode nets we routinely record the EEG of newborns, children, and adults.
Our lab is also equipped with a Geodesic Photogrammetry System (GPS) used for the reconstruction of 3D Geodesic Sensor Net electrode positions. The GPS uses 11 CCD cameras positioned on a polyhedron-based structure to acquire a single, simultaneous, digital image of each sensor on the subject’s scalp. Later, the technician registers each coordinate using Net Station. Unlike other electrode sensor registration methods, the GPS technique utilizes 5 minutes of the subjects’ time, significantly streamlining the process for both the subject and the technician.
- Eye Tracking System
The DEL includes an eye-tracking system, Smart Eye, integrated with the EEG and peripheral electrophysiology. Smart Eye can track head and eye movements up to 270 degrees. The key component of Smart Eye systems is the computerized analysis of video images. Our system uses two cameras together with IR-flash illuminators. These IR illuminators are controlled by customized hardware so that each system uses primarily its own illumination. This makes the system robust to a range of natural illumination conditions as well as the variable light caused by an experimental stimulus presentation monitor.
- Computer Equipment
Both of our stationary systems have a 1.8 GHz dual Power PC G5 with a 580 GB hard drive and 3 GB of RAM (OS 10.4.11) for data collection and analysis. Stimulus presentation, experimental design, and behavioral data analysis is conducted on two 3 GHz dual Dell Dimension 2350s with 100 GB hard drives and 1 GB of RAM (Windows XP). Data collection and analysis on our portable system is conducted on a 1.8 GHz Dual-Core 15-inch MacBook Pro with a 100 GB hard drive and 2 GB of RAM (OS 10.4.11). A 1.8 GHz 14-inch Toshiba Tablet with a 80 GB hard drive and 2 GB of RAM running Windows XP controls stimulus presentation.
Numerous systems are used for offline data analysis including one 2.0 GHz Dual-Core 13-inch MacBook, four 2.16 GHz Dual-Core 15-inch MacBook Pros, one 2.4 GHz Dual-Core 17-inch MacBook Pro, two 1.8 GHz dual Power PC G5s, two 1.2 GHz Power PC G4s, three 2.8 GHz dual Intel Pentium 4 Dell Optiplex 280s, and two 1.8 GHz dual Intel Pentium 4 Dell Dimension 2350s.
Server backups are written using a dedicated 2.8 GHz Quad-Core Mac Pro with 2 GB of RAM attached to a 2 TB Raid-5 array and powered by Mac OS X Server. Secondary backups are written to a 1 TB Lacie Ethernet Big Disk powered by Windows XP Embedded and a third archive of each EEG session is written on DVD using numerous 16x single-layer SuperDrives.
- Acoustic Startle and Peripheral Psychophysiology Equipment
Our laboratory is outfitted with peripheral electrophysiology monitoring capabilities for assessing the startle eye blink response, electromyogram, heart rate, and skin conductance in conjunction with high-density EEG. We have one stationary Coulbourn system and one portable Coulbourn system for use within the fMRI scanning facility of Yale’s Anlyan Center to permit co-registration of electrophysiology and BOLD response. We also have two portable San Diego startle systems that can be used in clinics, homes, or schools. All equipment interfaces with paradigms developed in the E-prime experimental platform.
- Analysis Software and Capabilities
Biosignal analysis within the laboratory is conducted on four portable and five stationary workstations by two dedicated, full-time professional staff with expertise in various software modalities. Electrical Geodesic’s Net Station 4.3 is used for electroencephalography signal processing, wavelet transform analysis, and for the extraction of event-related potentials from raw data. Brain Electrical Source Analysis (BESA) is also used for basic signal processing on select projects. BESA is our analysis package of choice for using multiple source montages to transform electrical activity recorded on the scalp into actual brain function. SPSS and MATLAB are used for basic statistics.