This Major Research Instrumentation award permits Dr. Alan Hartley and four co-investigators to purchase high-resolution (256 channel, dense array) electroencephalography/ event related potential (EEG/ERP) instrumention to be shared by faculty and students across three undergraduate consortium colleges (Scripps, Pitzer and Claremont). These will be used to investigate the spatial and temporal dimensions of brain activity associated with human cognition in infants, young adults, and older adults in typical and atypical (e.g., autistic) populations.
The participating researchers are all active researchers in the study of cognition and cognitive neuroscience. Five collaborative research projects are proposed. Project 1 will explore brain activations associated with carrying out two tasks at the same time, conditions under which it can/cannot be done, and age differences in performance and activation in dual-task situations. Project 2 will examine the neural correlates of risk propensity across the lifespan. Adolescents have been noted to have increased risk seeking propensity under certain conditions, in comparison to young adults and older adults. These changes have been linked to uneven development of different brain regions. This project will examine patterns of activation under different conditions of "hot" and "cold" decision-making. Project 3 will investigate the neural mechanisms of body-directed attention. The experiments employ variations on established visual paradigms to demonstrate how the body contributes to bottom-up sensory and top-down motivational influences on attentional control. Source-localized high-density EEG will allow characterization of the timing, amplitude, and distribution of individual and interactive effects. This research can be extended to examining failures of attention in older adults in important real-world situations such as walking or driving. Project 4 will explore temporal dynamics of neural systems for effective dyadic interaction, and examine the relations of these deficits to measures of naturalistic social behavior outside of the laboratory, in autism and older adults. Simultaneous, synchronized EEG data is recorded in real time as two individuals engage in joint action tasks. The resulting spatiotemporal patterns will be analyzed for group and individual differences in social cognition in autism and in older adults. The findings will add insight to the neural mechanisms of joint action and joint attention, and their relationship to social cognition outside of the laboratory. Project 5 will investigate a frequency-based EEG measure of attention in infants. It proposes to use steady state visually evoked potentials (SSVEP) as a potential index of attentional allocation in infants. These measures have advantages over behavioral gaze data because they record changes in processing without verbal or overt motor responses and are less prone to artifacts. If this measure is validated, it can be used to investigate gender differences in attention to objects and their mental manipulation (e.g., mental rotation).
This research and training program will implement a vertical integration from faculty research to advanced student research to student training to the classroom. Faculty already trained in neuroimaging techniques will gain ready access to modern instrumentation currently not available on site, enabling the continuation of this work as well as fostering new research programs and research collaborations within departments and across colleges. The instrumentation will draw a diverse array of undergraduate students into the use of electrophysiological imaging methods and into careers in cognitive neuroscience.
Cognitive neuroscience relates cognitive processes to brain activity. Electroencephalography /Event-Related Potential (EEG/ERP) measures allow the examination of changes in brain activity (specifically, scalp electrical activity) during cognitive processing. Neural activity may be time locked to specific psychological (internal) or experimental (external) events. The ERP has positive and negative electrical deflections (components) that serve as an index of psychological processes. Early components (P1, N1) are associated with more sensory-related activity. Later components (P3) represent processing of information at higher cognitive levels, such as context updating, attention allocation, or response to novel stimuli. On Scripps College campus, we established a leading-edge electrophysiology laboratory that is shared across faculty at three top-level undergraduate colleges. The laboratory offers relatively inexpensive and accessible methodology for spatiotemporal investigation of neural systems in human cognition. It is used for faculty research and student training, and has seeded additional funding for hypothesis-driven research. EEG/ERP data provides insight into cortical dynamics during cognition: it can indicate millisecond-level changes in neural activation patterns. By combining high-density 256-channel electrode arrays with electrode localization systems, we model both the spatial (where in the brain) and temporal (when in processing) dimensions of neural activity. Our laboratory has portable and stationary systems that can be used separately or together. These integrated EEG systems obtain accurate and localizable EEG signals. Used in conjunction with the 256-channel EGI system, the GPS system permits sensor registration and source localization to relate the temporal aspects of neural signals to the regions of the brain generating the signals. When the two EEG systems are used together we can measure simultaneous EEG signals from two individuals to understand how their brains might work together to perform a common task. The portable system allows us to conduct research on patient populations. We have trained over 30 undergraduate students in EEG/ERP methodology. Many of these students are women who are interested in pursuing careers in medicine and cognitive neuroscience. This lab has fostered several lines of research with a common theme: to examine age-related changes in neural processing. These projects investigate: 1) brain activations associated with carrying out two tasks at the same time and age differences in performance and activation; 2) the neural correlates of risk propensity across the lifespan; 3) the neural mechanisms of body-directed attention; 4) the temporal dynamics of neural systems for effective dyadic interaction, and 5) frequency-based EEG measures of attention in infants. We highlight some of our projects and their outcomes below: 1) Changes in cognitive and emotional functioning in old age: Examining the time course of processing of simple emotional facial expressions as well as novel, morphed combinations in younger and older adults, we found valence-related activations in peri-amygdalar cortex and orbitofrontal cortex; activations increased at later time periods in younger adults but not in older adults. 2) ERP responses to an irrelevant tone during dual-task processing manipulating workload: Examination of the auditory N1 component showed that older adults were slowed but cognitive load was no higher in older than younger adults. 2) Embodied contributions to attention: When and where in the neural system does hand position influence visual processing? Hand position biased attention differentially to target locations near the hands at both early (N1) and later (P3) ERP components. For older adults, the hand's influence occurs only later in processing (P3), recruiting frontal regions as well as parietal regions. 3) Is the quality of our social life in older adulthood associated with how ready we are to take turns with others? When two people engage in shared tasks like turn-taking, there is a sharing of signals between their brains, does turn-taking associate with real-world social outcomes? People who waited longer for others to take their turns also reported better, more satisfying social lives. 4) Does the shape of the mouth affect the perceived pitch of someone speaking? Mouth shape biased people’s judgments about the pitch of simple musical notes that were paired with mouth pictures, demonstrating that mouth shape affects pitch perception. Brain signals linked to the mouth-pitch effect occurred late and in a pattern that suggests processes involved in language processing. In summary, the NSF MRI grant established a multiuser EEG research laboratory. The research and training programs that were fostered from this laboratory facility implemented a vertical integration from faculty research to student research to student training to the classroom. Faculty trained in neuroimaging techniques gained ready access to modern instrumentation that was previously not available on site. These faculty were able to not only continue their current EEG work but also begin new research programs and research collaborations within departments and across colleges. Access to this equipment also attracted two new faculty hires who use EEG/ERP methods in their research. Finally, the equipment has drawn talented undergraduate students into the use of electrophysiological imaging methods and into careers in cognitive neuroscience.
