The effects of rTMS on primary motor cortex: the link between action and language ( preliminary results) Claudia Repetto Department of Psychology, Catholic University of Sacred Heart, Milan, Italy EMBODIED LANGUAGE New College Oxford September 2011
RATIONAL EMBODIED COGNITION EMBODIED SEMANTICS
Experimental data Verbs indicating actions performed with different body parts activate the portions of the premotor cortex involved in the real action
Experimental data Verbs indicating actions performed with different body parts activate the portions of the premotor cortex involved in the real action (Hauk, Johnsrude, & Pulvermüller, 2004)
Experimental data Verbs indicating actions performed with different body parts activate the portions of the premotor cortex involved in the real action (Hauk, Johnsrude, & Pulvermüller, 2004) (Tettamanti et al., 2005)
Experimental data Several studies indicate that even the primary motor cortex (M1) is involved in language processing, but results are sometimes contrasting VS Tools:Tasks:
Birra…Firra... Buffo…Biffo Birra…Firra... Buffo…Biffo birra biffobuffo firra (Fadiga et al., 2002) o Increase of MEP recorded from the listeners' tongue muscles when the presented words strongly involve, when pronounced, tongue movements
o The processing of verbs indicating actions performed with different body parts modulate the activity of the portions of the primary motor cortex (M1) involved in the real action (Buccino et al., 2005) he played the piano he jumped the rope he loved his wife
o The comprehension of effector specific action word meanings did not elicit preferential activity corresponding to the somatotopic organisation of effectors in either primary or premotor cortex (Postle et al., 2008) But on the other hand….. + +
GOALS OF THE EXPERIMENT
METHOD 10 students, 5 males and 5 females (age: 21-46; mean: 28.7; st. dev.: 9.57 education:16-20; mean: 16.7; st. dev.:1.25) Low-frequency rTMS Verbs comprehension (semantic judgment)
MATERIAL 24 ACTION VERBS + 24 ABSTRACT VERBS applaudire (to clap) abbottonare (to button) firmare (to sign) ……. apprezzare (to appreciate) immaginare (to imagine) scordare (to forget) …….
MATERIAL 24 ACTION VERBS + 24 ABSTRACT VERBS 48 items x 3 blocks i.e. firmavo-firmavi-firmava; scordavo-scordavi-scordava
TASK ++firmava 2 sec 5 sec ++ 5 minutes
PROCEDURE Practice session task Off-line rTMS session over M1 task 45 min
PROCEDURE Practice session task Off-line rTMS session over M1 task 45 min
PROCEDURE Practice session task 45 min RIGHT M1 RIGHT HAND
PROCEDURE Practice session task 45 min RIGHT M1 RIGHT HAND LEFT HAND LEFT M1
EXPERIMENTAL DESIGN 2 (stimulation) 2 (stimulation) x NOtms M1 2 (side) 2 (side) 2 (verbs) 2 (verbs) right left abstract concrete x
RESULTS o main effect of stimulation [F(1,9)= 55.11;p<0.001] o main effect of verb [F(1,9)=38.708; p<0.001] o interaction stimulation x verb [F(1,9)=11.272; p=0.008]
DISCUSSION Methodological issues: variable stimulation not counterbalanced ?
Possible explanations… (to be completed…) 1.M1 is not involved the lower RTs post stimulation are due to a learning effect Control group: 18 students, comparable for age and education NO effect of time [F(1,16)= 1.657; p= 0.216] NO interaction time x verb [F(1,16)= 0.01; p=0.975]
Possible explanations… (to be completed…) 2.M1 is involved in different ways depending on the type of verb (action/abstract) M1 Action verbs Abstract verbs
Possible explanations… (to be completed…) 2.M1 is involved in different ways depending on the type of verb (action/abstract) M1 Action verbs slower RTs (with respect to the gain between baseline and post- tms with abstract verbs) Abstract verbs jump a step faster RTs x x See Papeo et al. (2009)
Future perspectives o sample completion (with sessions counterbalanced) to disambiguate between the hypothesis of involvment and non- involvment of M1 to investigate the different involvment during abstract vs action verbs processing To interpret the complete set of data and give a contribution to the study of embodied language
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