Cognitive Neuroimaging

Lead Research Organisation: MRC Clinical Sciences Centre

Abstract

We are using functional imaging techniques that measure the activity of the brain when performing mental work. We are particularly interested in studying the systems in the brain that are used in communication. This covers understanding speech and written texts and producing speech and writing. Although our previous work has concentrated on the way the brain processes the units of language, namely words, inevitably we have been drawn into research on the memory systems of the brain. Thus, for example, to understand we have to have memories based on general knowledge, known as semantic memory. More specifically, if we hear something novel, we remember this as an item of information heard at a particular time and in a particular place - a so-called episodic memory. These same systems are used when retrieving semantic and episodic memories during spontaneous speech, such as when talking about ones last holiday. Therefore, our research incorporates the investigation of many different brain systems, working in parallel when we communicate with each other. Research in normal subjects is extended into patients with a number of different brain disease, particularly stroke, so that we can better understand recovery after focal brain injury, and how we might improve rehabilitation.

Technical Summary

We have developed an anatomical model of language processing that considerably extends the Broca-Wernicke language model. This has resulted in specific hypotheses to investigate behavioural and pharmacological strategies to rehabilitate chronic aphasic stroke.||Objectives:||1. Develop activation studies in both PET and fMRI that investigate normal language perception and production, and determine which scanning technique is most suitable for studying rehabilitative strategies after aphasic stroke.||2. Study stroke and temporal lobe epilepsy patients to further determine the roles of rostral temporal cortex in speech perception and comprehension, and the potential for spontaneous relateralisation of these functions.||3. Investigate acute plastic changes in residual left and intact right superior temporal cortex in aphasic patients with left temporal lobe damage.||4. Perform further studies to investigate the role of PFC in human communication: and by modulating its function with drugs acting on the monoaminergic systems, investigate the potential to augment behavioural training through fronto-temporal connections.||5. Institute a specific programme of behavioural retraining with or without acute drug treatment at each training session, to investigate whether speech comprehension can be improved in the chronic phase of posterior aphasic stroke.

Publications


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Agnew Z (2008) Separate areas for mirror responses and agency within the parietal operculum. in The Journal of neuroscience : the official journal of the Society for Neuroscience
Awad M (2007) A common system for the comprehension and production of narrative speech. in The Journal of neuroscience : the official journal of the Society for Neuroscience
Crinion JT (2003) Temporal lobe regions engaged during normal speech comprehension. in Brain : a journal of neurology
Dhanjal NS (2008) Perceptual systems controlling speech production. in The Journal of neuroscience : the official journal of the Society for Neuroscience