Research in the lab focuses on the neural and cognitive mechanisms of human thought, reasoning and problem solving.
We examine both goal-directed thought processes as well as undirected thought processes that often occur spontaneously.
We are particularly interested in introspective thought processes, which we have linked to the functions of the rostrolateral prefrontal cortex (BA10), as well as spontaneous thought processes such as mind-wandering, which we have linked to the functions of temporal lobe structures.
We examine these topics using a combination of functional neuroimaging (fMRI) and behavioural testing. In addition, novel neuroimaging techniques such as real-time fMRI are being developed for clinical applications in psychiatric disorders such as depression and schizophrenia.
The PFC comprises multiple distinct sub-regions including the ventrolateral (VLPFC), dorsolateral (DLPFC), and rostrolateral (RLPFC) sectors. While considerable empirical work suggests that these sub-regions support distinct processes, a coherent theory of the functional organization of the PFC has remained elusive. This line of research is aimed at discerning this functional organization. We have found evidence for a rostro-to-caudal gradient of abstraction in the representations supported by the PFC, with concrete, moderately abstract, and highly abstract information being supported by the VLPFC, DLPFC, and RLPFC respectively (Christoff, Keramatian, Gordon, Smith, Maedler, 2009; Brain Research). This study complimented a review of episodic memory, working memory, reasoning, and multitasking studies suggesting a hierarchical organization of lateral PFC regions (Christoff & Gabrieli, 2000).
An ubiquitous aspect of daily life is periodically becoming engrossed in our thoughts and losing track of a task at hand (i.e., mind-wandering). Yet, the neural underpinnings of mind-wandering remain unknown. While prior work suggested that frontal and posterior regions along the medial wall of the cortex (so called “default network” regions) may be the principle substrate underlying mind-wandering, our recent work (Christoff, Gordon, Smallwood, Smith, & Schooler, 2009; PNAS) suggests that default network regions and executive network regions (e.g., lateral prefrontal cortex, dorsal anterior cingulate cortex) are concurrently engaged during mind-wandering—a finding predicted by behavioural theories of off-task thought. This research utilizes a combination of objective measure of mind-wandering (errors in task performance), subjective self-reports, and brain imaging.
The rostrolateral prefrontal cortex (RLPFC) plays a pivotal role in higher order cognition, enabling some of the most complex forms of human thought. We examined whether individuals can learn to regulate the level of activation in high level regions such as the RLPFC using real-time fMRI feedback training. We found that individuals can learn to successfully up-regulate activation in this region by turning attention inwardly towards their own thoughts (i.e., engaging in meta-cognitive awareness) and successfully down-regulate this region by turning attention to viscero-somatic sensations arising from the external world (McCaig, Keramatian, Liu, Dixon, & Christoff, submitted).
While it is clear that the RLPFC participates in a variety of complex cognitive processes, its precise contribution to human thought has been difficult to discern. Our neuroimaging findings (Christoff et al., 2001; Christoff, Ream, Geddes, & Gabrieli, 2003) suggest that introspective evaluation/meta-cognitive awareness may be a unifying principle to explain the role of the RLPFC in memory, reward learning, multitasking, and moral reasoning.
When there is no external task to perform, thoughts often flow in a spontaneous and unconstrained manner, and is a prevalent aspect of waking mental activity. We have begun to examine the neural basis of such spontaneous thought. An initial fMRI study (Christoff, Ream, & Gabrieli, 2004; Cortex) found evidence of a considerable contribution from regions in the medial temporal lobe, visual cortex, and the rostrolateral PFC, suggesting that long-term memory, visual imagery, and introspection may form the basis of spontaneous thought. Elucidating the cognitive and neural basis of spontaneous thought has important implications given that its association with creativity, memory consolidation, decision making, etc., (Christoff, Gordon, & Smith, in press).
Christoff, K., Cosmelli, D., Legrand, D., & Thompson, E., (2011). Specifying the self for cognitive neuroscience. Trends in Cognitive Science, 15(3). 104-112.
McCaig, R.G., Dixon, M.L., Keramatian, K., Liu, I., & Christoff, K., (2011). Improved modulation of rostrolateral prefrontal cortex using real-time fMRI training and meta-cognitive awareness. Neuroimage, 55. 1298-1305.
Dumontheil, I., Houlton, R., Christoff, K., & Blakemore, S.J. (2010). Non-linear development of relational reasoning during adolescence. Developmental Science, 13(6). 15-24.
Christoff, K., Gordon, A. M., Smallwood, J., Smith, R., & Schooler, J. W. (2009). Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proceedings of the National Academy of Sciences, 106 (21), 8719-8724.
Christoff, K., Keramatian, K., Alan, G.M., Smith, R., Maedler, B. (2009). Representational topography in lateral prefrontal cortex according to levels of abstraction. Brain Research, 1286, 94-105.
Christoff, K., Gordon, A., & Smith, R. (in press). The role of spontaneous thought in human cognition. In: Neuroscience of Decision Making. (Eds: O. Vartanian and D. R. Mandel) Psychology Press.
Crone, E.A., Wendelken, C., van Leijenhorst, L., Honomichl, R., Christoff, K. & Bunge, S.A. (2009). Neurocognitive development of relational reasoning . Developmental Science, 12(1), 55-66.
Winters, J., Christoff, K., & Gorzalka, B.B. (2009). Conscious regulation of sexual arousal in men. Journal of Sex Research, 46(4), 330-343.
Christoff, K. (2008). Applying neuroscientific findings to education: The good, the tough, and the hopeful. Mind, Brain, and Education, 2 (2), 55-58.
Smith, R., Keramatian, K. and Christoff, K. (2007) Functionally localizing the rostrolateral prefrontal cortex. Neuroimage, 36,1387-96.
Christoff, K. and Keramatian, K. (2007) Abstraction of mental representations: Theoretical considerations and neuroscientific evidence. In: Perspectives on Rule-Guided Behavior (Eds: S.A.Bunge and J.D.Wallis) Oxford University Press.
Christoff, K. and Owen, A.M., (2006) Improving reverse neuroimaging inference: Cognitive domain versus cognitive complexity. Trends in Cognitive Sciences, 10(8): 352-3.
Smith, R., Keramatian, K., Smallwood, J., Schooler, J., Luus, B. and Christoff, K. (2006) Mind-wandering with and without awareness: An fMRI study of spontaneous thought processes. Proceedings of the 28th Annual Conference of the Cognitive Science Society (Ed. R. Sun): 804-809. Vancouver: Erlbaum.
Narayanan , N.S., Prabhakaran, V., Bunge, S.A., Christoff., K., Fine, E.M. and Gabrieli, J.D.E. (2005) The role of the prefrontal cortex in the maintenance of verbal working memory: An event-related fMRI analysis. Neuropsychology, 19(2):223-232.
Christoff, K., Ream, J.M. and Gabrieli, J.D.E. (2004) Cognitive and neural basis of spontaneous thought processes. Cortex, 40: 623-630.
DeCharms, R.C., Christoff, K., Glover, G.H., Pauly, J.M., Whitfield, S. and Gabrieli, J.D.E. (2004) Learned regulation of spatially localized brain activation using real-time fMRI. NeuroImage. 21: 436-43.
Christoff, K., Ream, J.M., Geddes, L.P.T. and Gabrieli, J.D.E. (2003) Evaluating self-generated information: Anterior prefrontal contributions to human cognition. Behavioral Neuroscience, 117(6): 1161-1168.
Anderson , A.K., Christoff, K., Panitz, D., De Rosa, E. and Gabrieli, J.D.E. (2003) Neural correlates of the automatic processing of threat facial signals. Journal of Neuroscience 23(13), 5627-5633.
Anderson , A.K., Christoff, K., Stappen, I., Panitz, D., Gharamani, D.G., Glover, G., Gabrieli, J.D.E. and Sobel, N. (2003)Dissociated neural representations of intensity and valence in human olfaction. Nature Neuroscience 6(2), 192-202.
Christoff, K., Prabhakaran, V., Dorfman, J., Zhao, Z., Kroger, J.K., Holyoak, K.J. and Gabrieli, J.D.E. (2001). Rostrolateral prefrontal cortex involvement in relational integration during reasoning. NeuroImage 14(5), 1136-1149.
Christoff, K. and Gabrieli, J.D.E. (2000) The frontopolar cortex and human cognition: Evidence for a rostrocaudal hierarchical organization within the human prefrontal cortex. Psychobiology, 28(2), 168-186.
Christoff, K. (1999) Complexity and working memory resources: Task characteristics necessitating the executive control of attention. In: Ed. B. Kokinov, Perspectives on Cognitive Science: Volume 5. New Bulgarian University, Sofia.
PSYC 260 Experimental Psychology & Laboratory