Value = 0.001% W B B W B W P P Relating imaging and patient studies of tool processing J. Devlin 1,2, C. Moore 1, C. Mummery 1, J. Phillips 1, M. Gorno-Tempini 1, M. Rushworth 1,2, and C. Price 1 1 Wellcome Department of Cognitive Neurology, Institute of Neurology 2 Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford StudyCategoriesStimuliTask 1. Mummery et al (1996)A, TSpoken words Category fluency 2. Mummery et al (1998)A, TWritten words Semantic & syllable decisions 3. Moore & Price (1999)A, F, T, VPicturesNaming 4. Moore & Price (1999)A, F, T, VWritten wordsMatching and pictures 5. Gorno-Tempini (2000)Fa, A, TPicturesNaming 6. Phillips et al (submitted)F, TWritten wordsSemantic & screen and picturessize decisions Abbreviations: A=animals, F=fruit, Fa=famous faces, T=tools, V=vehicles. Several functional neuroimaging studies have reported a region in the left posterior middle temporal cortex that is more active when words and pictures represent tools than other categories of objects (see Fig. 1 and ref. 14 for a review). This area is not damaged, however, by fronto- parietal lesions typically associated with selective deficits for man-made items 4. The lesion data is more consistent with the few imaging studies that have reported increased left pre-motor activation for tools 2, 7, 9. Background Activation in the left posterior middle temporal cortex (LPMT) and left pre-motor area in normals in a picture naming task from (Martin et al. 1996) Figure 1: Tools activate LPMT zThe current study investigated tool-associated brain activations in an attempt to reconcile the apparent discrepancies between the imaging and lesion literature. zData from 50 subjects performing 6 experiments were acquired on a single PET scanner (see Table) zSingle multi-factorial analysis with three factors: 1) Category (natural vs. man-made) 2) Task 3) Stimulus type zMan-made items divided in tools and non-tools. Current Study Table L Figure 2: Tools > Living things for semantic tasks only L. ventral pre-motor (-42, 4, 18) SPM{Z}=3.6 p<0.001 uncorrected L. posterior middle temporal cortex (-62, -58, 0) SPM{Z}=5.3 p<0.005 corrected L. anterior supramarginal (-60, -24, 34) SPM{Z}=3.8 p<0.001 uncorrected Figure 3: Effect sizes for tools %rCBF change 1. L. post. Middle temproal gyrus 2. L. ventral pre-motor area %rCBF change W B B W B W P P Contrasts 1. Syllable decisions Screen size decisions Semantic decisions Semantic decisions W-P matching Category fluency Naming pictures 6 8. Naming pictures L. anterior supramarginal gyrus Phonological tasksWWords Perceptual tasksPPictures Semantic decision tasksBBoth words and Word retrieval taskspictures Key zTasks without a strong semantic component (e.g. screen size decisions and syllable decisions) did not show a consistent advantage for tools zMore semantic tasks, on the other hand, such as semantic decisions and picture naming, revealed small ( living things W B B W B W P P zFirst study to demonstrate LPMT activation for tools relative to living things at a corrected level of significance. May be due to: zSmall effect sizes (<3% rCBF) and zContext-specific effects, i.e. category effects were only present in tasks required semantic processing zResults consistent with previous imaging studies showing Tools > Animals in ventral pre-motor cortex BUT also demonstrated that this effect was not present relative to fruit zNo area was activated only by tools Summary of results zTools relative to living things activated three regions in the left hemisphere (see Fig. 2): 1. Posterior middle temporal cortex (LPMT) 2. Ventral pre-motor cortex 3. Anterior supramarginal gyrus but only for tasks with a strong semantic component (see Fig. 3) Results Results (cont.) References 1. Binkofski et al. (1998). Human anterior intraparietal areas subserves prehension: a combined lesion and fMRI activation study. Neurology, 50, Chao, L. L., & Martin, A. (2000). Representation of manipulable man-made objects in the dorsal stream. NeuroImage, 12, Ehrsson et al. (2000) Cortical activity in precision- versus power-grip tasks: An fMRI study. J. Neurophysiology, 83, Gainotti, G. (2000). What the locus of brain lesion tells us about the nature of the cognitive deficit underlying category-specific disorders: a review. Cortex, 36, Gallese, V., & Goldman, A. (1998). Mirror neurons and the simulation theory of mind-reading. Trends in Cognitive Science, 2(12), Gorno-tempini, M. L., Cipolotti, L., & Price, C. J. (2000). Which level of object processing generates category specific differences in brain activation? Proceedings of the Royal Society, London B, Grabowski, T. J., Damasio, H., & Damasio, A. R. (1998). Premotor and prefrontal correlates of category-related lexical retrieval. NeuroImage, 7, Jeannerod, M., Arbib, M. A., Rizzolatti, G., & Sakata, H. (1995). Grasping objects: the cortical mechanisms of visuomotor transformation. Trends in Neuroscience, 18(7), Martin, A., Wiggs, C., Ungerleider, L., & Haxby, J. (1996). Neural correlates of category-specific knowledge. Nature, 379, Moore, C. J., & Price, C. J. (1999). A functional neuroimaging study of the variables that generate category specific object processing differences. Brain, 122, Mummery, C. J., Patterson, K., Hodges, J., & Wise, R. J. (1996). Generating 'tiger' as an animal name or a word beginning with T: Differences in brain activation. Proceedings of the Royal Society of London B Biological Sciences, 263, Mummery, C. J., Patterson, K., Hodges, J. R., & Price, C. J. (1998). Functional neuroanatomy of the semantic system: Divisible by what? Journal of Cognitive Neuroscience, 10(6), Phillips, J., Noppeney, U., Humphreys, G. W., & Price, C. J. (submitted). A positron emission tomography study of action and category. 14. Price, C. J. & Friston, K. J. (in press) What has neuroimaging contributed to category-specificity? In G. Humphreys & E. Forde (Eds.), Category specificity in mind and brain. Sussex, England: Psychology Press. Discussion zThese findings correspond well with the neurophysiological literature showing that in monkeys neurons in the ventral pre-motor area F5 respond to visually presented graspable objects such as tools and fruit 5, 8. zThis region is part of a visuo-action network including pre-motor (F5), anterior intra-parietal (AIP/7b), and inferior bank of the superior temporal sulcus (STS) regions (see Fig. 4) F5 AIP 7b STS Adopted from Jeannerod et al. (1995) Figure 4: Macaque visuo-action network zThe three regions identified in the current study may be homologues of this visuo-action network. zThe same regions often activated in human imaging studies of grasping or hand movements 1,3 zThese results provide a plausible explanation for patients with semantic impairments to man-made items who typically have large left fronto-parietal lesions: Although the LPMT is spared, the lesion can affect the inferior parietal and ventral pre-motor regions and the connections between them. Q: Were these activations truly category-specific? Relative effect sizes A Fr V T FF A Fr V T MN SN Word-picture matching 10 Picture naming 10 A Fr V T FF A Fr V T Key AAnimals FrFruit BPBody partsTTools Fa Famous FacesVVehicles FFFalse fonts 1. L. posterior middle temporal area? 2. L. ventral pre-motor area? 3. L. anterior supramarginal area? Fa A T BP Picture naming 6 Tools (T), simple non-objects (SN) and body parts (BP) all activated the LPMT. Relative effect sizes Word-picture matching 10 Picture naming 10 Fruit (Fr) and tools (T) both activate the ventral pre-motor region. Relative effect sizes Word-picture matching 10 Picture naming 10 A Fr V T FF A Fr V T Tools (T) and false fonts (FF) activated the anterior supramarginal region. LR LR LR Key AAnimals FFFalse fonts FrFruit TTools VVehicles Key AAnimals FFFalse fonts FrFruit TTools VVehicles