This chapter discusses the contributions of functional imaging to our understanding of how action and tool concepts are represented and processed in the human brain. It is framed within the feature-based account of semantic memory. This approach assumes that conceptual knowledge is represented in a large distributed network, indexing a range of semantic features. Neurophysiological studies in non-human primates have suggested that the frontoparietal circuitry may play a role in visuomotor transformations and action matching, imitation and understanding. Studies of action observation and semantic retrieval provide converging evidence that left posterior middle temporal gyrus (LPMT) activation is commonly increased for hand manipulation and whole-body movements. The chapter revisits several themes that have emerged from functional imaging studies of tool and action processing. It evaluates the positive evidence for the feature-based account of semantic memory, and concludes by highlighting future directions to investigate the neural mechanisms of tool and action processing.

Neuropsychological, structural and functional imaging studies have broken new ground in demonstrating the existence of physiological and anatomical abnormalities in the olfactory system in schizophrenia. Since the pioneering psychophysical studies of odour recognition memory in patients with schizophrenia by Australian researchers Campbell and Gregson, a number of investigators have reported that schizophrenia patients exhibit olfactory dysfunction. In a 10-year longitudinal study, the presence of deviant olfactory experiences was found to significantly predict the development of future psychosis. The causes of olfactory impairments are numerous, including chemical, infectious, traumatic, metabolic and hormonal disturbances. Recent years have brought rapid expansion of structural and functional imaging technologies, including high-resolution structural magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission tomography (SPECT) and event-related potential (ERP). To characterise more directly the functional status of the olfactory system, ERPs have been employed to assess the physiological brain response to odour stimuli.