John Kounios - US grants

Reaction time (RT) is a pervasive dependent measure in many areas of psychological research. RT is pervasive because it can be an extremely useful source of evidence concerning a host of mental processes associated with perception, memory, attention, reasoning, judgment, problem solving, etc. However, the use of RT is frought with difficulties. It is possible to construct radically different models of mental functioning that predict similar effects on RT. So, without making strong assumptions about the organization of mental processes, RT frequently does not prove to be a highly diagnostic tool for answering certain.types of important theoretical questions, for instance, whether these processes yield outputs in a continuous stream, or in discrete quanta. A new experimental technique called speed-accuracy decomposition (SAD) overcomes many of the limitations of RT. By statistically decomposing distributions of RT trials and speed-accuracy tradeoff trials, this technique allows one to trace out the time-course of mental processes. Such information enables us to answer many important questions, such as whether process outputs are discrete or continuous. By using this technique to analyze subjects' performance in a broad variety of experimental tasks, it should be possible to derive a time-course "profile" for each task. Since processes with similar time courses should have certain architectural features in common, it should be possible to derive a general taxonomy of mental processes based on these profiles. Such a taxonomy could clarify relationships between theorizing in diverse areas of psychology, leading to new concepts and research ideas. These profiles and taxonomy could also provide a basis for diagnosing various forms of psychological and neurological pathology (e.g., if an individual's timecourse profile for a particular task does not conform to the standard for that task).

This research focuses on basic neural and cognitive processes related to the acquisition and retrieval of information from human memory. Specifically, subjects are required to form different types of associations between pairs of words or pairs of pictures of objects. Later, they are presented with these same stimuli plus stimuli not seen earlier, and, for each of these stimuli, are asked to judge whether the test stimulus had been presented earlier. In different experiments, these test stimuli may be individual words or pictures pairs of words/pictures in the original order, pairs of words/pictures in different orders, etc. During the encoding and test phases, the electrical activity of subjects' brains will be measured by the event-related potential (ERP) technique using an array of 128 electrodes. This wil yield a detailed millisecond by millisecond record of the brain's activity while forming associations and retrieving the resulting information from memory. IN addition, the dense electrode array will yield detailed spatial/topographic information about the areas of the brain that are involved. This temporal and spatial ERP evidence will then be combined with structural information about each subject's head obtained from an MRI scan using a new approach to ERP source localization whereby the MRI image is used to construct a mathematical model of the subject's head. This model is then used to guide a non-linear estimaiton procedure which searches for the best-fitting configuration of ERP sources in the brain. These sources are then plotted on the MRI. This approach should make it possible to localize brain signals corresponding to the formation/encoding of associations and the subsequent memory retrieval of individual items and associations between these items. This research is of importance not only for its value as basic research into the cognitive neuroscience of memory, but also for the insights it is likely to yield into memory disorders involved in aging and forms of amnesia resulting from temporal-lobe and thelamic brain damage. This follows because the elderly frequently have difficulty in "binding" or associating in memory different aspects of a situation, while amnesics frequently indiscriminately over-associate.

DESCRIPTION (provided by applicant): The application focuses on the neural substrates of semantic memory, which is a human's knowledge of the world. During the last two decades, a number of articles have described category-specific deficits in patients with damaged/diseased brains. These deficits involve selective degradation of one or more categories of knowledge. For instance, some patients exhibit loss of knowledge of animals, but not tools, while others show the reverse. During the 1990s, prominent neuroimaging studies using PET and fMRI have shown category-specific patterns of brain activation in healthy subjects. Together, these two sets of findings have spurred debate (but no definitive answers) regarding the nature and origin of category-specific effects. This application tackles this question by supplementing extant neuropsychological and neuroimaging research with data from event-related brain potentials (ERPs) recorded with a dense array of 128 electrodes analyzed with new methods for localizing the sources of scalp-recorded electrical activity in the brain co-registered with MRI. The basic idea is that in order to understand category-specific effects in both patient and nonpatient populations, it is important to determine what parts of the brain are actually representing semantic information. Static images of the parts of the brain that are involved in processing different categories of semantic knowledge are insufficient for determining the critical storage sites, because such neuropsychological and neuroimaging evidence does not easily distinguish areas that represent the information from areas that later perform other operations on this information. To localize semantic representation, it is necessary to isolate the access mechanisms that yield this information from the representation sites. This can be done using ERPs, because the superb temporal resolution of this technique allows one to focus on neural activity during the early time-window of processing during which semantic access predominates. Using new technologies, these mechanisms can be analyzed and localized in the brain. The proposed research involves applying this approach to a number of semantic memory paradigms in order to provide spatiotemporal information to help interpret neuroimaging/neuropsychological studies. Furthermore, the project will use such results to inform the development of connectionist attractor models of semantic memory. Isolating, localizing, and theoretically characterizing semantic representation and access should help in the understanding and diagnosis of disorders of semantic memory and should suggest possible therapies.

Creativity is an important and essential human ability. Cognitive neuroscientist Dr. John Kounios of Drexel University, with funding from the National Science Foundation, is investigating the brain mechanisms that enable creative problem solving, especially those underlying what psychologists call "insight," colloquially known as the "Aha" or "Eureka" phenomenon. This project investigates three questions. What is the relationship between "resting-state" brain activity, that is, brain activity when a person daydreams with no task to perform, and the experience of insight during a later test? Can samples of such resting-state brain activity be used to identify brain states that lead to insightful problem solving and individuals who tend to solve problems creatively? What environmental or contextual factors can influence such brain states to enhance creative thought? The investigator hypothesizes that there is a relationship between brain activity during daydreaming and later creative performance during problem solving and other tasks. This relationship can be used to develop a brain-based test of creative ability and can be used to identify target brain states for future training protocols for increasing creativity. In one study, the investigator is recording participants' electroencephalograms (EEGs) during multiple sessions on different days and measuring participants' creative problem-solving performance to examine whether differences in brain activity among individuals are associated with higher and lower creativity. Other studies modify brain activity by giving participants different kinds of cognitive tasks to perform; these brain-activity changes are expected to influence later problem-solving performance and other measures of creative thought, in some cases, enhancing creativity.

What are the origins of creative thought? This question is not merely academic. Economic success depends on flexible, creative thought and the innovation it empowers. Widespread concerns about waning innovation, fueled by recent research showing that creativity-test scores in the U.S. are decreasing, have brought to the forefront questions concerning the nature of creativity, and how it can be enhanced. Educational, business, and government organizations have focused on enhancing creativity, often without realizing that psychological and neuroscience research has begun to yield evidence concerning which strategies are effective for improving creativity and which are not. In particular, cognitive neuroscience, through new, advanced methods for measuring brain activity, has begun to focus on the topic of creativity, especially the phenomenon of sudden insight, a process that suddenly confers a new perspective or solution to a problem through an "Aha moment." The current NSF-funded project is isolating and analyzing brain states conducive to creative insight and investigating techniques for enhancing creativity by facilitating these brain states.