fMRI STUDY OF SMELL: PERCEPTUAL, COGNITIVE AND SEMANTIC COMPONENTS OF CORTICAL ELABORATION OF 3 FAMILIAR AROMAS. Laura Romoli PhD PP Battaglini, B.R.A.I.N. Trieste Furio Suggi Liverani (illycaffè s.p.a.)

AIMS STUDYING HOW 3 FAMILIAR AROMAS ARE ELABORATED BY THE BRAIN SPECIFICALLY: WHICH ARE THE ACTIVACTIONS IN COMMON BETWEEN ALL THE STIMULI? WHICH ACTIVACTIONS ARE DISTINCTIVE FOR EACH AROMA? THERE IS ANY DIFFERENCE IN THE ELABORATION OF THE STIMULI DURING THE FIRST PHASE OF ELABORATION AND THE SECOND (SEE PARADIGM)? AND, IF YES, WHICH?

LIMITS OF THE STUDY TECNICHAL DIFFICULTS TO DELIVERY AROMAS TO THE SUBJECTS SITUATED IN THE MR SCANNER POOR fMRI LITERATURE REGARDING THE STUDY OF PERCEPTUAL AND COGNITIVE ASPECTS OF SMELL INTEREST OF THE STUDY: INNOVATIVE!

OLFACTORY SYSTEM

THE COMPLEXITY OF THE SMELL CORTICAL ELABORATION

SMELL AND PERCEPTION PERCEPTION INTEGRATES A GREAT NUMBER OF SENSATION (SINGLE SENSORY STIMULI) PERCEPT: THE RESULTING MENTAL RECREATION OF THE DISTAL STIMULUS DETENCTION OF THE STIMULUS RECOGNITION : THE MOMENT IN WHICH THE STIMULUS REACHS THE CEREBRAL CORTEX (REACTIVACTING A NEURONAL NODE)

SMELL AND COGNITION MEMORY EMOTION LANGUAGE HEDONISM

MATERIAL AND METHODS

TECHNIQUE: fMRI PHILIPS GYROSCAN ACHIEVA 1,5 T In collaboration with Cattinara Hospital, Trieste, Italy SUBJECTS: 13 HEALTY RIGHT-HANDED SUBJECTS (5 MALES, MEAN AGE 34,9 y.o.) ALL SUBJECTS WERE TESTED WITH THE BRIEF SMELL IDENTIFICATION TEST TR DYNAMIC IMAGES TIME OF ACQUISITION: MIN STIMULI: CITRUS FRUIT, CHOCOLATE, FLOWER, PURE AIR (NEUTRAL, AS CONTROL)

EXPERIMENTAL DESIGN Participants received 2 seconds of aromas stimulation directly in their nose through 4 polythene tubes converging in a facial mask Previously instructed to do not move and pay attention to the aroma, trying to recognize it. Trial 24 sec aroma 2 air washing 5 during 5 after 5 Timing for analysis

EXPERIMENTAL DESIGN_2 3 repetitions of the paradigm each repetition consisted of 12 tasting trials (4 citrus, 4 chocolate, 4 flower, randomly organized) alternated by neutral (12) STIMULUS TRIAL NEUTRAL TRIAL

STIMULI citrus : edible, generally associated with the orange or the lemon; extremely scented. This stimulus is characterized by the color, varying from orange to yellow (all nuances belonging to the same family of colour). chocolate : edible; generally more linked to its taste than its smell; child taste and normally associated with one of the most familiar satysfying/rewarding sweets. flower : not edible; this aroma result difficult to categorize, due to the fact that the variability of flowers is so huge in nature, increased by the fact that a lot of products (e.g. detergents) are flower scented. Pure air: neutral stimulus to compare to all stimuli during the analysis and usefull as washing stimulus during the experiment Timing, amount and order of presentation were controlled by the computerized olfactometer

TIMING OF ANALYSIS DURING period of 5 sec corresponding to the aromas stimulation (2 sec) and the few sec immediately after it is supposed to be the perceptual level of cortical elaboration AFTER period of 5 sec corresponding to the seconds after the aromas stimulation during which subjects had to do nothing it is supposed to be the semantic/hedonistic level of cortical elaboration

DATA ANALYSIS the fMRI data were analysed using the SPM5 package the images were first corrected to remove the effects of subjects moving whilst in the MR scanner which would reduce the power of the analysis the brain images for each subjects were morphed to make them all the same shape so that we can be sure that each part of the brain image refers to the same brain region in all subjects we then carried out statistical analysis to detect the particular effects that we are interested in (e.g. smelling citrus aroma compared with smelling neutral –air)

DATA ANALYSIS_2 the analysis were conducted for each aroma (compared to neutral), both for the during period and after period we had to excluded 2 subjects (6 blocks of functional images) from analysis (movement artifacts) the analysis were conducted on 33 blocks of functional images (11 subjects) we found differences both for each aroma and for timing of elaboration

RESULTS

CITRUS DURING ANATOMY (MNI coordinates) Right/Left BA 17 Right/Left BA 18 Right Middle Occipital Gyrus Left Postcentral Gyrus (BA2/1)

CITRUS AFTER ANATOMY (MNI coordinates) Right SMA BA 6 Left Superior Frontal Gyrus Left Middle Frontal Gyrus

CHOCOLATE DURING ANATOMY (MNI coordinates) Left Inferior Frontal Gyrus (p.triang.) Left Middle Frontal Gyrus Right Calcarine Gyrus (BA 17/18) Cerebellar Vermis (lobule V)

CHOCOLATE AFTER ANATOMY (MNI coordinates) Left Superior Frontal Gyrus (BA6) Right Mid Orbital Gyrus Right Superior Medial Gyrus Left Inferior Frontal Gyrus (p.orbit)

FLOWER DURING ANATOMY (MNI coordinates) BA 3a BA 6 Left/right Inferior Frontal Gyrus (p.triang.) Right Middle Cingulate Cortex Left Middle Frontal Gyrus Left/right Inferior Frontal Gyrus (p.orbit.) Right Middle Temporal Gyrus Left Anterior Cingulate Cortex Left Insula Lobe

FLOWER AFTER ANATOMY (MNI coordinates) Left Anterior Cingulate Cortex Right/Left Superior Frontal Gyrus Left Inferior Frontal Gyrus (p.orbit) Left Superior Medial Gyrus Left/Right Middle Frontal Gyrus Left Precentral Gyrus

TIMES EFFECT

TIMES EFFECT CITRUS During BILATERAL OCCIPITAL LOBE; LEFT SOMATOSENSORY CORTEX (sensory mirror neurons) Citrus works as a synestetyc stimulus: the olfactory stimulus reactivates the semantic node of citrus After Cortical elaboration becomes more central and frontal: these area are the common areas involved in the elaboration of hedonic, emotional and olfactory The activation becomes more similar to the cortical elaboration found for other olfactory stimuli (hedonistic judgment)

TIMES EFFECT CHOCOLATE During Frontal areas, visual areas (BA 17,18), right cerebellar vermis Frontal areas (hedonistic/emotional judgment), occipital activation (visual (imagination) After The elaboration becomes only frontal (attention, hedonism, emotion) Working memory, memory retrieval, semantic labels and hedonist judgment

TIMES EFFECT FLOWER During Spread activation : frontal areas, limbic system, hippocampal region and somatosensory Peculiarity of the stimulus: flower activates more strongly motor control regions, and cortical areas involved in retrieve of autobiographical memories After Activation remain the same; little anatomical modification, without functional change Retrieve of autobiographical memories, motory and sensory imagination and sematic labels of olfactory

CONCLUSION each aroma seems to stimulate different cerebral regions according to its semantic characteristics, especially during the early phase of elaboration from the results it seems that : Citrus: it is characterized by the perceptual aspects, especially visual, during the first phase of elaboration Chocolate: involves stronger the cingulate cortex and the frontal cortex immediately Flower: seems to be the most difficult stimulus to describe and recognize, and the one that most activated areas implicated in the recollection of autobiographical memory

CONCLUSION_2 this experiment confirms that odors can affect a variety of perceptual, motor and cognitive functions in addition we found that the timing of elaboration is an important aspect of odors responses and seems to be linked to the type of stimulus

THANKS FOR YOUR ATTENTION!