MRC Cognition and Brain Sciences UnitResearch interests of Friedemann Pulvermüller
Welcome to my research interests page! This page has 5 parts:
A. Brain mechanisms of language and cognition: theory
B. Neuroimaging of language processes: metabolic and neurophysiological
C. Language outside the focus of attention
D. Neurocomputational model of the language cortex
E. Neurorehabilitation: language action therapy
Each part includes links to key publications. A longer list of publications is at the end of the page. Enjoy!
A. Brain mechanisms of language and cognition: theory and data
Pulvermüller, F. (1999). Words in the brain's language. Behavioral and Brain Sciences, 22, 253-336.
My main interests in science are in the neurobiological basis of language and cognition. Together with my colleagues at the Max Planck Institute of Biological Cybernetics in Tübingen, I developed the first mechanistic model of language processing in the human brain formulated at the level of nerve cell circuits. The key idea is that distributed and discrete neuronal circuits carry language, cognition and thought. Similar to what Hebb called cell assemblies, these circuits exhibit specific cortical topography and specific functionality. In particular, they bridge between brain systems devoted to perception and action systems, and can therefore be labelled action-perception circuits (Braitenberg & Pulvermüller, 1992; Pulvermüller, 1999, 2003; Pulvermüller & Preissl, 1991). The brain model of language and cognition specifies action-perception circuits for speech linguistic sounds, words, their meaning and the syntactic rules that bind words and morphemes and influence their order in time.
Words are envisaged to be represented in the brain by distributed neuronal assemblies and synfire chains whose cortical topographies reflect aspects of word meaning. Rules of syntax are proposed to be a product of the interplay between specialized neuronal units, called sequence detectors, and general principles of neuronal dynamics designed to control and regulate activity levels in cortical areas. These dynamical features produce a net effect equivalent to the functionality of a pushdown memory store, whereas sequence detectors implement short and long distance dependencies and agreement (Pulvermüller, 1993, 2003).
A practical contribution of all this theoretical and experimental work has been made to language therapy. In 2001, my colleagues and I could demonstrate for the first time that a new intensive approach to aphasia therapy grounded in neuroscience knowledge, called Constraint-Induced Aphasia Therapy, can improve language abilities even in patients with chronic language deficits due to stroke (Pulvermüller, Neininger et al., 2001). This new technique takes advantage of the fact that language and action systems of the brain are tightly interwoven.
B. Neuroimaging of language processes: metabolic and neurophysiological
Model predictions about language processes in the brain are being tested in a range of experiments with healthy individuals and patients using behavioural techniques and neuroimaging methods. Together with my Cambridge colleagues, especially Dr. Yury Shtyrov, Dr. Olaf Hauk and Dr. Max Garagnani, neuroimaging research focuses on brain processes of language with multiple imaging techniques, including magnetoencephalography (MEG), electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Magnetencephalography (MEG) has proven particularly fruitful in revealing the spatiotemporal signatures of cortical activation in cognitive and language processing (Pulvermüller, Shtyrov, & Ilmoniemi, 2003). We are presently in the process of moving forward, so to speak, from the era of photography (fMRI) to that of movies (MEG), where not just active areas, but more specific spatiotemporal activation patterns (areas with time markers attached so to speak) can be linked to cognitive, perceptual and action processing. The challenge is to define the spatiotemporal signatures of well-defined cognitive processes, including, for example, sound recognition, lexical access, semantic access, and syntactic analysis.
An additional focus is on alterations of language processes in the brain brought about by transcranial magnetic stimulation (TMS), focal cortical lesions, and presentation of linguistic information to different parts of the visual field. This work is eminent for neurocognitive theories as it overcomes a unique limitation of neuroimaging research: Such neuropsychological investigation addresses the critical question of whether a brain part or area just activates during a cognitive process or rather contributes to and is necessary for the process.
Research highlights of my recent research have been the discovery that a cortical binding response well known from perceptual processes in animals, gamma-band activity, is also a reliable indicator of higher perceptual and even language processes in humans (Lutzenberger, Pulvermüller, & Birbaumer, 1994; Pulvermüller, Birbaumer, Lutzenberger, & Mohr, 1997; Pulvermüller, Lutzenberger, & Preissl, 1999). My group was also the first to discover that aspects of the symbolic meaning of words referring to actions elicit cortical activation in motor systems that reflect that meaning (Hauk, Johnsrude, & Pulvermüller, 2004; Pulvermüller, Hummel, & Härle, 2001). A leg-related word such as "kick" even if only heard during a distraction task, would immediately spark the cortical leg area (Pulvermüller, Shtyrov, & Ilmoniemi, 2005). This neurophysiological manifestation of what is now called "semantic embodiment", especially its local specificity and its extremely rapid time course, has major implications for theories of semantic and conceptual processing (Pulvermüller, 2005). The motor mapping of meaning is not only effective during single word or simple sentence understanding, it emerges even when understanding abstract language to which the meaning of action words contributes (e.g., idioms such as "grasp the idea") (Boulenger, Hauk, & Pulvermüller, 2009). In future, we will investigate these issues further; a special focus on whether these activations reflecting the meaning of signs are functionally relevant and necessary for semantic processing as, for example, in degenerative brain disease.
Language-action links have also been demonstrated at the phonological level, between the sounds and the cortical motor patches that control the specific articulators that produce the sounds (D'Ausilio et al., 2009; Pulvermüller et al., 2006). We interpret these data as evidence for learned distributed cortical networks, action-perception circuits. These networks appear as the cortical basis of binding of linguistic information at different levels (phonological, lexical, semantic) (Pulvermüller, 2001). Interestingly, activation in the motor/premotor part of the circuits can both facilitate and hinder speech perception at the specific level of individual phoneme recognition, an observation that most strongly supports a role of the motor system in speech perception (D'Ausilio et al., 2009).
In future, a major emphasis will be on specific spatio-temporal predictions of the model, aiming not only at an answer to the "where"-question about cognitive processing in the human brain (Which areas are active during process X?), but, in addition, at a full account of the precise time course (measured in milliseconds) of the activation of relevant brain areas in language, conceptual and attention processing (Pulvermüller, Shtyrov, & Hauk, 2009). To achieve this, it is my aim to use neurophysiological imaging with EEG and/or MEG in conjunction with subdural or intracortical recordings in patients undergoing brain surgery.
C. Language outside the focus of attention
Much language processing takes place effortlessly and outside the focus of attention, so that even if we attend elsewhere, we still process aspects of the higher linguistic information that comes in. This has been shown for a range of higher linguistic processes, including lexical access (Pulvermüller, Kujala et al., 2001), syntactic processing (of agreement for example) (Shtyrov, Pulvermüller, Näätänen, & Ilmoniemi, 2003), semantic analysis (Pulvermüller, Shtyrov, & Ilmoniemi, 2005) and semantic context integration (Shtyrov & Pulvermüller, 2007a). The automatic language processes are early and probably followed by secondary deeper processing, especially if there is a processing problem. However, the effortless attention-independent early processes reflect an essential component of the language comprehension process (Pulvermüller & Shtyrov, 2006). A component of the event-related brain response called the Mismatch Negativity appears to be particularly fruitful in revealing brain mechanisms of early automatic language processing. Yury Shtyrov and I have discovered the significance of this component in language research and we continue to use it, especially for exploring the interplay between language and attention mechanisms. A major advantage of the Mismatch Negativity, its automaticity and robustness even under conditions where subjects do not, or cannot, attend, makes this brain response an ideal tool for clinical investigation, especially in patient groups with cognitive deficits of a neurological or psychiatric origin (Pulvermüller & Shtyrov, 2006; Shtyrov & Pulvermüller, 2007b).
D. Neurocomputational model of the language cortex
Dr. Max Garagnani (Cambridge) and Dr. Thomas Wennekers (Plymouth) and I have developed a new type of neuronal network whose structure and function imitates the anatomy and physiology of particular brain systems, especially the language cortex. Such realistic neurocomputational models can be used to explore theoretical implications of brain theories of cognition. The neurocomputational model of the language cortex, MLC, makes precise predictions on where and when in the brain activation emerges during the processing of specific types of linguistic and conceptual information. As a range of brain responses, which correlate with cognitive and language processes, still await an explanation in neural terms, we use the MLC to develop such explanations (Garagnani, Wennekers, & Pulvermüller, 2008, 2009). Furthermore, we use the MLC for simulating behavioural effects of cortical lesions (Pulvermüller & Preissl, 1991) and to predict and explain the time course and spreading of cortical activation as they are observed in neurophysiological experiments using MEG/EEG (Wennekers, Garagnani, & Pulvermüller, 2006). In turn, the experimental results allow us to refine the model and develop further the theory. The model itself will also be developed further, to cover a larger part of cortex and additional cognitive functions. An increase in neuroanatomical accuracy of the model is expected in light of recent DTI and tractography research that allows one to more precisely define corticocortical connectivity in the human brain.
E. Neurorehabilitation: language action therapy
I have a strong commitment to exploring ways in which our theoretical insights might benefit people. In the realm of language, i.e. linguistics and language philosophy, practical applicability is sometimes not easy to see. Likewise, theoretical neuroscience does not necessarily aim at translational impact. However, when bringing together insights from the language, psychological and brain sciences, it is sometimes possible to develop new methods for rehabilitation of individuals who suffer from disease of the brain. We have been using cognitive-linguistic and neuroscience knowledge emerging from experimental work in the development of new rehabilitation techniques, especially for the treatment of language deficits after stroke. New treatment approaches, for example Communicative Aphasia Therapy (Pulvermüller & Roth, 1991) and Constraint-Induced Aphasia Therapy (Pulvermüller, Neininger et al., 2001), are meanwhile used successfully in neurorehabilitation. The aim is now to optimize and enhance these approaches and monitor their effect of brain plasticity (Pulvermüller, Hauk, Zohsel, Neininger, & Mohr, 2005). The target is an optimal intensive intervention for chronic language and cognitive deficits due to stroke, possibly testable also in the domain of degenerative brain disease (Berthier et al., 2009; Pulvermüller & Berthier, 2008).
Cited References:
Berthier, M. L., Green, C., Lara, J. P., Higueras, C., Barbancho, M. A., Dávila, G., & Pulvermüller, F. (2009). Memantine and constraint-induced aphasia therapy in chronic post-stroke aphasia. Annals of Neurology, in press.
Boulenger, V., Hauk, O., & Pulvermüller, F. (2009). Grasping ideas with the motor system: Semantic somatotopy in idiom comprehension. Cereb Cortex, in press.
Braitenberg, V., & Pulvermüller, F. (1992). Entwurf einer neurologischen Theorie der Sprache. Naturwissenschaften, 79, 103-117.
D'Ausilio, A., Pulvermüller, F., Salmas, P., Bufalari, I., Begliomini, C., & Fadiga, L. (2009). The Motor Somatotopy of Speech Perception. Current Biology, in press.
Garagnani, M., Wennekers, T., & Pulvermüller, F. (2008). A neuroanatomically-grounded Hebbian learning model of attention-language interactions in the human brain. European Journal of Neuroscience, 27(2), 492-513.
Garagnani, M., Wennekers, T., & Pulvermüller, F. (2009). Recruitment and consolidation of cell assemblies for words by way of Hebbian learning and competition in a multi-layer neural network. . Cognitive Computation, in press.
Hauk, O., Johnsrude, I., & Pulvermüller, F. (2004). Somatotopic representation of action words in the motor and premotor cortex. Neuron, 41, 301-307.
Lutzenberger, W., Pulvermüller, F., & Birbaumer, N. (1994). Words and pseudowords elicit distinct patterns of 30-Hz activity in humans. Neuroscience Letters, 176, 115-118.
Pulvermüller, F. (1993). On connecting syntax and the brain. In A. Aertsen (Ed.), Brain theory - spatio-temporal aspects of brain function (pp. 131-145). New York: Elsevier.
Pulvermüller, F. (1999). Words in the brain's language. Behavioral and Brain Sciences, 22, 253-336.
Pulvermüller, F. (2001). Brain reflections of words and their meaning. Trends in Cognitive Sciences, 5(12), 517-524.
Pulvermüller, F. (2003). The neuroscience of language. Cambridge: Cambridge University Press.
Pulvermüller, F. (2005). Brain mechanisms linking language and action. Nature Reviews Neuroscience, 6(7), 576-582.
Pulvermüller, F., & Berthier, M. L. (2008). Aphasia therapy on a neuroscience basis. Aphasiology, 22(6), 563-599.
Pulvermüller, F., Birbaumer, N., Lutzenberger, W., & Mohr, B. (1997). High-frequency brain activity: its possible role in attention, perception and language processing. Progress in Neurobiology, 52(5), 427-445.
Pulvermüller, F., Hauk, O., Zohsel, K., Neininger, B., & Mohr, B. (2005). Therapy-related reorganization of language in both hemispheres of patients with chronic aphasia. Neuroimage, 28(2), 481-489.
Pulvermüller, F., Hummel, F., & Härle, M. (2001). Walking or Talking?: Behavioral and neurophysiological correlates of action verb processing. Brain and Language, 78(2), 143-168.
Pulvermüller, F., Huss, M., Kherif, F., Moscoso del Prado Martin, F., Hauk, O., & Shtyrov, Y. (2006). Motor cortex maps articulatory features of speech sounds. Proceedings of the National Academy of Sciences, USA, 103(20), 7865-7870.
Pulvermüller, F., Kujala, T., Shtyrov, Y., Simola, J., Tiitinen, H., Alku, P., Alho, K., Martinkauppi, S., Ilmoniemi, R. J., & Näätänen, R. (2001). Memory traces for words as revealed by the mismatch negativity. Neuroimage, 14(3), 607-616.
Pulvermüller, F., Lutzenberger, W., & Preissl, H. (1999). Nouns and verbs in the intact brain: evidence from event-related potentials and high-frequency cortical responses. Cerebral Cortex, 9, 498-508.
Pulvermüller, F., Neininger, B., Elbert, T., Mohr, B., Rockstroh, B., Koebbel, P., & Taub, E. (2001). Constraint-induced therapy of chronic aphasia following stroke. Stroke, 32(7), 1621-1626.
Pulvermüller, F., & Preissl, H. (1991). A cell assembly model of language. Network: Computation in Neural Systems, 2, 455-468.
Pulvermüller, F., & Roth, V. M. (1991). Communicative aphasia treatment as a further development of PACE therapy. Aphasiology, 5, 39-50.
Pulvermüller, F., & Shtyrov, Y. (2006). Language outside the focus of attention: the mismatch negativity as a tool for studying higher cognitive processes. Progress in Neurobiology, 79(1), 49-71.
Pulvermüller, F., Shtyrov, Y., & Hauk, O. (2009). Understanding in an instant: Neurophysiological evidence for mechanistic language circuits in the brain. Brain and Language, in press.
Pulvermüller, F., Shtyrov, Y., & Ilmoniemi, R. J. (2003). Spatio-temporal patterns of neural language processing: an MEG study using Minimum-Norm Current Estimates. Neuroimage, 20, 1020-1025.
Pulvermüller, F., Shtyrov, Y., & Ilmoniemi, R. J. (2005). Brain signatures of meaning access in action word recognition. Journal of Cognitive Neuroscience, 17(6), 884-892.
Shtyrov, Y., & Pulvermüller, F. (2007a). Early activation dynamics in the left temporal and inferior-frontal cortex reflect semantic context integration. Journal of Cognitive Neuroscience, 19(10), 1633-1642.
Shtyrov, Y., & Pulvermüller, F. (2007b). Language in the passive auditory oddball: motivations, benefits and prospectives. Journal of Psychophysiology, 21(3-4), 176-186.
Shtyrov, Y., Pulvermüller, F., Näätänen, R., & Ilmoniemi, R. J. (2003). Grammar processing outside the focus of attention: an MEG study. Journal of Cognitive Neuroscience, 15(8), 1195-1206.
Wennekers, T., Garagnani, M., & Pulvermüller, F. (2006). Language models based on Hebbian cell assemblies. J Physiol Paris, 100, 16-30.
