Alexithymia modulates the attitudes towards odors but not the olfactory abilities or the affective reactions to odors.

Although emotion and olfaction are closely linked, only a few studies have investigated olfactory processing in alexithymia, a condition characterized by altered emotional processing. These results do not allow comprehensive conclusions on whether individuals with alexithymia present lower olfactory abilities or only altered affective reactions and awareness of odors. Three pre-registered experiments were conducted to clarify this relation. We assessed olfactory functions, the affective qualities of odors, the awareness of odors, the attitudes towards them, and the ability to form olfactory images in the mind. Bayesian statistics were used to assess differences between low, medium and high alexithymia groups, and Linear Mixed Models (LMMs) were applied to investigate the modulation of the affective and cognitive components of alexithymia. We observed that individuals with a high level of alexithymia presented the same olfactory abilities, and did not show differences in their rating of odors compared to individuals with low alexithymia levels, while they reported lower levels of social and common odor awareness and a more indifferent attitude towards odors. Olfactory imagery was not affected by alexithymia level, and the affective and cognitive components of alexithymia, when considered separately, modulated olfactory perception differently. Learning more about olfactory perception in individuals with alexithymia leads to a better understanding of how alexithymia impacts the perception of hedonic stimuli coming from different sensory modalities. Our results imply that treatment goals for alexithymia should be the enhancement of the conscious perception of odors, supporting the use of mindfulness-based protocols in the alexithymia treatment.

sFEra APP: Description and Usability of a Novel Tablet Application for Executive Functions Training.

Executive functions include functions such as planning, working memory, inhibition, mental flexibility, and action monitoring and initiation, and are essential to carry out an independent everyday life. Individuals suffering from brain injury, such as a stroke, very commonly experience executive deficits that reduce the capacity to regain functional independence. In recent years, there has been a growing interest in developing tablet computer-based cognitive training programs for stroke patients and healthy aging adults since such programs can be included in non-supervised environments. In this respect, we described and evaluated the usability of a novel tablet application (app) for executive function training, developed in the context of the MEMORI-net project, a cross-border Italy-Slovenia program for the rehabilitation of stroke patients. We conducted a pilot study with a non-clinical sample of 16 participants to obtain information about the usability of the sFEra APP. Our descriptive analyses suggest that most users were satisfied with the overall experience and the app was highly usable, and instructions were clear, even with little previous experience with tablet applications. Acceptability and effectiveness will need to be evaluated in a clinical randomized controlled study.

Effects of tDCS on reward responsiveness and valuation in Parkinson's patients with impulse control disorders.

Parkinson's disease (PD) patients with impulse control disorders (ICD) frequently report hypersensitivity to rewards. However, a few studies have explored the effectiveness of modulation techniques on symptoms experienced by these patients. In this study, we assessed the effect of anodal tDCS over the DLPFC on reward responsiveness and valuation in PD patients with ICD. 43 participants (15 PD patients with ICD, 13 PD without ICD, and 15 healthy matched controls) were asked to perform a reward-craving test employing both explicit (self-ratings of liking and wanting) and implicit (heart rate and skin conductance response) measures, as well as two temporal discounting tasks with food and money rewards. Each participant performed the experimental tasks during active anodal tDCS of the left dorsolateral prefrontal cortex (DLPFC), anodal tDCS of the primary motor cortex (M1), and sham tDCS. Results showed increased wanting and a steeper temporal discounting of rewards in PD with ICD compared to the other groups. Moreover, we found that PD without ICD exhibit reduced liking for rewards. tDCS results capable to modulate the altered intensity of PD patients' liking, but not wanting and temporal discounting of rewards in PD patients with ICD. These findings confirm that alterations in reward responsiveness and valuation are characteristics of impulse control disorders in patients with PD but suggest that anodal tDCS over the left DLPFC is not capable to influence these processes. At the same time, they provide new insight into affective experience of rewards in PD.

Individual EEG profiling of attention deficits in left spatial neglect: A pilot study.

Electrophysiological group studies in brain-damaged patients can be run to capture the EEG correlates of specific cognitive impairments. Nonetheless, this procedure is not adequate to characterize the inter-individual variability present in major neuropsychological syndromes. We tested the possibility of getting a reliable individual EEG characterization of deficits of endogenous orienting of spatial attention in right-brain damaged (RBD) patients with left spatial neglect (N+). We used a single-trial topographical analysis (STTA; [39] of individual scalp EEG topographies recorded during leftward and rightward orienting of attention with central cues in RBD patients with and without (N-) neglect and in healthy controls (HC). We found that the STTA successfully decoded EEG signals related to leftward and rightward orienting in five out of the six N+, five out of the six N- patients and in all the six HC. In agreement with findings from conventional average-group studies, successful classifications of EEG signals in N+ were observed during the 400-800 ms period post-cue-onset, which reflects preserved voluntary engagement of attention resources (ADAN component). These results suggest the possibility of acquiring reliable individual EEG profiles of neglect patients.

Deficits of hierarchical predictive coding in left spatial neglect.

Right brain-damaged patients with unilateral spatial neglect fail to explore the left side of space. Recent EEG and clinical evidence suggests that neglect patients might suffer deficits in predictive coding, i.e. in identifying and exploiting probabilistic associations among sensory stimuli in the environment. To gain direct insights on this issue, we focussed on the hierarchical components of predictive coding. We recorded EEG responses evoked by central, left-side or right-side tones that were presented at the end of sequences of four central tones. Left-side and right-side deviant tones produce a pre-attentive Mismatch Negativity that reflects a lower-order prediction error for the 'Local' deviation of the tone at the end of the sequence. Higher-order prediction errors for the frequency of these deviations in the acoustic environment, i.e. 'Global' deviation, are marked by the P3 response. We show that when neglect patients are immersed in an acoustic environment characterized by frequent left-side deviant tones, they display no pre-attentive Mismatch Negativity both for left-side deviant tones and infrequent omissions of the last tone, while they have Mismatch Negativity for infrequent right-side deviant tones. In the same condition, neglect patients show no P300 response to 'Global' prediction errors for deviant tones, including those in the non-neglected right-side, and omissions. In contrast to this, when right-side deviant tones are predominant in the acoustic environment, neglect patients have pre-attentive Mismatch Negativity both for right-side deviant tones and infrequent omissions, while they display no Mismatch Negativity for infrequent left-side deviant tones. Most importantly, in the same condition neglect patients show enhanced P300 response to infrequent left-side deviant tones, notwithstanding that these tones evoked no pre-attentive Mismatch Negativity. This latter finding indicates that 'Global' predictions are independent of 'Local' error signals provided by the Mismatch Negativity. These results qualify deficits of predictive coding in the spatial neglect syndrome and show that neglect patients base their predictive behaviour only on statistical regularities that are related to the frequent occurrence of sensory events on the right side of space.

The Influence of Personality, Resilience, and Alexithymia on Mental Health During COVID-19 Pandemic.

Following the COVID-19 pandemic, many countries worldwide have put lockdowns in place to prevent the virus from spreading. Evidence shows that lockdown measures can affect mental health; it is, therefore, important to identify the psychological characteristics making individuals more vulnerable. The present study aimed, first, to identify, through a cluster analysis, the psychological attributes that characterize individuals with similar psychological responses to the COVID-19 home confinement; second, to investigate whether different psychological characteristics, such as personality traits, alexithymia, and resilience, specifically influence anxiety, stress, and depression, depending on the scope of the confinement. We analyzed data from 393 participants who completed an online survey on their experiences during two different phases of the Italian lockdown, characterized by more or less strict measures of confinement. Two clusters were identified which included participants reporting a better (+ER) and worse (-ER) emotional response to the lockdown, respectively. Individuals in the -ER group showed lower emotional stability, resilience, and higher alexithymia. Moreover, even if lifting part of the restrictions decreased psychological distress among all participants, a reduction in perceived stress was observed only among individuals with high resilience. Finally, personality traits, alexithymia, and resilience differently affected depression, anxiety, and stress. Our results suggest that different psychological interventions should be planned depending on the context: mental health professionals should focus on enhancing the individuals' coping strategies to alleviate stress in emergencies, while long-term intervention aiming at alleviating anxiety and depressive symptoms should focus on alexithymic tendencies and personality constructs.

Increased emotional eating during COVID-19 associated with lockdown, psychological and social distress.

Due to the spread of COVID 2019, the Italian government imposed a lockdown on the national territory. Initially, citizens were required to stay at home and not to mix with others outside of their household (Phase 1); eventually, some of these restrictions were lifted (Phase 2). To investigate the impact of lockdown on emotional and binge eating, an online survey was conducted to compare measures of self-reported physical (BMI), psychological (Alexithymia), affective (anxiety, stress, and depression) and social (income, workload) state during Phase 1 and Phase 2. Data from 365 Italian residents showed that increased emotional eating was predicted by higher depression, anxiety, quality of personal relationships, and quality of life, while the increase of bingeing was predicted by higher stress. Moreover, we showed that higher alexithymia scores were associated by increased emotional eating and higher BMI scores were associated with both increased emotional eating and binge eating. Finally, we found that from Phase 1 to Phase 2 binge and emotional eating decreased. These data provide evidence of the negative effects of isolation and lockdown on emotional wellbeing, and, relatedly, on eating behaviour.

Establishing links between abnormal eating behaviours and semantic deficits in dementia.

The hypothesis that semantic deficits in dementia may contribute in producing changes in eating preferences has never been experimentally investigated despite this association has been clinically observed. We administered tasks assessing semantic memory and the Appetite and Eating Habits Questionnaire (APEHQ) to 23 patients with dementia (behavioural frontotemporal dementia, primary progressive aphasia, and Alzheimer's disease) and to 21 healthy controls. We used voxel-based morphometry and diffusion tensor imaging to identify regions and white matter tracts of significant atrophy associated with the performance at the semantic tasks and the pathological scores at the APEHQ. We observed that the lower the patients' scores at semantic tasks, the higher their changes in eating habits and preferences. Both semantic disorders and eating alterations correlated with atrophy in the temporal lobes and white matter tracts connecting the temporal lobe with frontal regions such as the arcuate fasciculus, the cingulum, and the inferior longitudinal fasciculus. These results confirm that semantic deficits underlie specific eating alterations in dementia patients.

Obesity, subliminal perception and inhibition: Neuromodulation of the prefrontal cortex.

The prefrontal cortex (PFC) plays a central role in food choice, and may be partly dysfunctional in obesity - a condition linked to altered attention and inhibition processes, particularly in response to food-related stimuli. We investigated the role of the PFC in subliminal visual processing and response inhibition to food pictures using anodal, cathodal, or sham transcranial direct current stimulation (tDCS) in a sample of 53 normal weight, overweight, or obese participants. Subliminal processing was measured with a breaking continuous flash suppression task (bCFS), and inhibition with a Go/No-Go task. BMI was included in the analyses as a continuous predictor. Higher BMI was associated with prolonged subliminal processing for both food and nonfood pictures in the bCFS task, and with longer RTs in food Go trials in the Go/No-Go task. Therefore, higher BMI was associated with an attentional bias for food images during supraliminal, but not subliminal visual processing. Moreover, anodal tDCS resulted in shorter detection times in the bCFS task, especially in participants with higher BMI. We conclude that anodal tDCS affects subliminal perception and attentional processes, and speculate that these effects may explain previous reports of reduced craving and food intake after anodal tDCS.

Food knowledge depends upon the integrity of both sensory and functional properties: a VBM, TBSS and DTI tractography study.

Food constitutes a fuel of life for human beings. It is therefore of chief importance that their recognition system readily identifies the most relevant properties of food by drawing on semantic memory. One of the most relevant properties to be considered is the level of processing impressed by humans on food. We hypothesized that recognition of raw food capitalizes on sensory properties and that of transformed food on functional properties, consistently with the hypothesis of a sensory-functional organization of semantic knowledge. To test this hypothesis, patients with Alzheimer's disease, frontotemporal dementia, primary progressive aphasia, and healthy controls performed lexical-semantic tasks with food (raw and transformed) and non-food (living and nonliving) stimuli. Correlations between task performance and local grey matter concentration (VBM) and white matter fractional anisotropy (TBSS) led to two main findings. First, recognition of raw food and living things implicated occipital cortices, typically involved in processing sensory information and, second, recognition of processed food and nonliving things implicated the middle temporal gyrus and surrounding white matter tracts, regions that have been associated with functional properties. In conclusion, the present study confirms and extends the hypothesis of a sensory and a functional organization of semantic knowledge.

The Hemispheric Distribution of α-Band EEG Activity During Orienting of Attention in Patients with Reduced Awareness of the Left Side of Space (Spatial Neglect).

EEG studies in healthy humans have highlighted that alpha-band activity is relatively reduced over the occipital-parietal areas of the hemisphere contralateral to the direction of spatial attention. Here, we investigated the hemispheric distribution of alpha during orienting of attention in male and female right brain-damaged patients with left spatial neglect. Temporal spectral evolution showed that in patients with neglect alpha oscillations over the damaged hemisphere were pathologically enhanced both during the baseline-fixation period that preceded cued orienting (capturing tonic alpha changes) and during orienting with leftward, rightward, or neutral-bilateral spatial cues (reflecting phasic alpha changes). Patients without neglect showed a similar though significantly less enhanced hemispheric asymmetry. Healthy control subjects displayed a conventional decrease of alpha activity over the hemisphere contralateral to the direction of orienting. In right-brain-damaged patients, neglect severity in the line bisection task was significantly correlated both with tonic alpha asymmetry during the baseline period and with phasic asymmetries during orienting of attention with neutral-bilateral and leftward cues. Asymmetries with neutral-bilateral and leftward cues were correlated with lesion of white matter tracts linking frontal with parietal-occipital areas. These findings show that disruption of rostrocaudal white matter connectivity in the right hemisphere interferes with the maintenance of optimal baseline tonic levels of alpha and the phasic modulation of alpha activity during shifts of attention. The hemispheric distribution of alpha activity can be used as a diagnostic tool for acquired pathological biases of spatial attention due to unilateral brain damage.SIGNIFICANCE STATEMENT Alpha desynchronization over the hemisphere contralateral to the attended side of space is a reliable marker of attentional orienting in the healthy human brain: can the same marker be used to spot and quantify acquired disturbances of spatial attention after unilateral brain injuries? Are pathological modifications in the hemispheric distribution of alpha specifically linked to attentional neglect for one side of space? We show that in patients with right brain damage the pathological enhancement of alpha oscillations over the parietal and occipital areas of the injured hemisphere is correlated with reduced awareness for the left side of space and with the lesion of white matter pathways that subserve frontal modulation of alpha activity in posterior brain areas.

Temporal and Effort cost Decision-making in Healthy Individuals with Subclinical Psychotic Symptoms.

The value people attribute to rewards is influenced both by the time and the effort required to obtain them. Impairments in these computations are described in patients with schizophrenia and appear associated with negative symptom severity. This study investigated whether deficits in temporal and effort cost computations can be observed in individuals with subclinical psychotic symptoms (PS) to determine if this dysfunction is already present in a potentially pre-psychotic period. Sixty participants, divided into three groups based on the severity of PS (high, medium and low), performed two temporal discounting tasks with food and money and a concurrent schedule task, in which the effort to obtain food increased over time. We observed that in high PS participants the discounting rate appeared linear and flatter than that exhibited by participants with medium and low PS, especially with food. In the concurrent task, compared to those with low PS, participants with high PS exerted tendentially less effort to obtain snacks only when the required effort was high. Participants exerting less effort in the higher effort condition were those with higher negative symptoms. These results suggest that aberrant temporal and effort cost computations might be present in individuals with subclinical PS and therefore could represent a vulnerability marker for psychosis.

Cognitive, Olfactory, and Affective Determinants of Body Weight in Aging Individuals.

OBJECTIVE: A complex interplay of factors including cognitive, sensory and affective aspects has been associated in a controversial way with anthropometric measures related to body weight. METHODS: Here we propose two studies to investigate whether and how cognitive, olfactory and affective variables resulted associated with body weight during healthy aging. In Study 1, we investigated the cognitive status, the odor identification skills, and the BMI of 209 individuals (50-96 yo). In Study 2 an extensive evaluation of cognitive functions (in particular executive functions and memory), odor threshold, discrimination and identification and affective skills (i.e., depression and anxiety) was performed in a group of 35 healthy, free-living aging individuals (58-85 yo). RESULTS: In Study 1, greater BMI was not associated with performance on the odor identification task but was significantly associated with better cognitive skills. In Study 2, we observed that executive functions seemed to favor a successful managing of body weight, and individuals with greater BMI and waist circumference showed significantly better odor discrimination skills. Finally, lower waist circumference (but not BMI) was found significantly associated with greater levels of anxiety. CONCLUSIONS: These results confirm that cognitive, olfactory and affective factors may influence body weight during healthy aging.

Episodic memory for natural and transformed food.

It has been proposed that the conceptual knowledge of food and its putative subdivision into natural (i.e., fruit/vegetables) and transformed (i.e., food that underwent thermic or non-thermic processing) may follow the living/non-living distinction. In the present study, we investigated whether the advantage for living things compared to non-living things observed in episodic memory (the so-called animacy effect) extends to natural foods and transformed foods respectively. We pursued this issue in two experiments. In Experiment 1, we measured episodic memory for natural and transformed foods in young participants. In Experiment 2, we enrolled dementia-free centenarians, patients with Alzheimer's disease (DAT), Progressive primary aphasia (PPA), and healthy controls whose episodic memory was also tested for living/non-living things. Results showed that young participants had better recognition memory for transformed foods compared to natural foods. This difference disappeared in centenarians and patients. However, centenarians and PPA exhibited enhanced levels of false alarms (FA) with natural food, and DAT patients with both natural and transformed food. As far as the living/non-living distinction is concerned, the episodic memory for the living category appears more resilient to the decline compared to the non-living category in patients, particularly those with PPA. In conclusion, our study shows that transformed food is better remembered than natural food, suggesting that it is more salient and possibly relevant from an evolutionary perspective. The natural/transformed distinction appears susceptible to erosion only in the presence of a high degree of episodic memory impairment. These results offer novel insight on episodic memory of food, and also extend the current knowledge on the animacy effect in episodic memory.

How experience modulates semantic memory for food: evidence from elderly adults and centenarians.

In order to make sense of the objects we encounter in everyday life we largely rely on previous knowledge stored in our semantic memory. Semantic memory is considered dependent on lifelong experience and cultural knowledge. So far, a few studies have investigated the role of expertise on the organization of semantic memory, whereas life-long experience has largely been overlooked. In this study, we investigated this issue using food concepts. In particular, we administered different semantic tasks using food (natural and transformed) and non-food (living and non-living things) as stimuli to participants belonging to three different age cohorts (56-74, 75-91, 100-108), who were also asked to report on the dietary habits held throughout their life. In addition, we investigated to what extent psycholinguistic variables influence the semantic performance of different age cohorts. Results showed that Centenarians recognized natural food better than transformed food, while the other two groups showed the opposite pattern. According to our analyses, experience is responsible for this effect in Centenarians, as their dietary habits seem to suggest. Moreover, significant correlations between picture naming and age of acquisition, familiarity and frequency were observed. This study indicates that lifelong experience can shape conceptual knowledge of food concepts, and that semantic memory is less resilient to aging than initially thought.

Body weight and its association with impulsivity in middle and old age individuals.

Impulsivity, conceptualized as impulsive personality trait, poor inhibitory control and enhanced reward sensitivity, has been strongly linked to obesity. In particular, a disequilibrium between cognitive control and reward sensitivity has been observed in obese individuals in both behavioural and imaging studies. While this issue has been widely investigated in children and adults, it has received little attention in older adults. Here, obese and non-obese participants aged between 40 and 70 years completed the Barratt Impulsiveness scale (assessing motor, non-planning and attentional impulsiveness), a Go/no-go task with foods and non-foods (assessing inhibitory control) and a reward sensitivity battery with high and low caloric foods (assessing liking, wanting, tastiness and frequency of consumption). We observed that participants with higher BMI reported increased wanting for high calorie foods, but did not show poorer inhibitory control. Interestingly, participants who scored lower on the MMSE reported to consume high calorie more than low calorie foods. Finally, those who presented low scores on non-planning and motor impulsiveness subscales reported higher tastiness ratings for low calorie foods. These results show that increased reward sensitivity but not reduced inhibitory control may characterize higher BMI during aging. Importantly, they also highlight new findings concerning food preferences among older adults.

Reward sensitivity in Parkinson's patients with binge eating.

BACKGROUND: Parkinson's disease (PD) patients who are treated with dopamine replacement therapy are at risk of developing impulse control disorders (ICDs) (such as gambling, binge eating, and others). According to recent evidence, compulsive reward seeking in ICDs may arise from an excessive attribution of incentive salience (or 'wanting') to rewards. OBJECTIVES: In this study, we tested this hypothesis in patients with PD who developed binge eating (BE). METHODS: Patients with BE, patients without BE, and healthy controls performed different experimental tasks assessing food liking and wanting. Participants first rated the degree of liking and wanting for different foods using explicit self-report measures. They then performed an affective priming task that measured participants' affective reactions towards foods (liking), and a grip-force task that assessed their motivation for food rewards (wanting). All participants also completed several questionnaires assessing impulsivity, reward sensitivity, anxiety and depression, and underwent a neuropsychological evaluation. RESULTS: Patients with BE displayed an altered liking for sweet foods compared to controls but not to patients without BE. Furthermore, this difference emerged only when implicit measures were used. Importantly, an increased wanting was not associated with binge eating even if wanting, but not liking scores significantly correlated with LED levodopa, confirming the hypothesis of a distinction between the two components of rewards. Lastly, binge eating was associated with depression and lower working memory scores. CONCLUSIONS: Take together these results suggest that binge eating in PD is associated with cognitive abnormalities, and to lesser extent affective abnormalities, but not with an increased incentive salience.

Emotional reactions in moral decision-making are influenced by empathy and alexithymia.

The role of emotional processes in driving moral choices remains debated. In particular, diminished emotional processing and reduced empathy have been associated with unusual high rates of utilitarian responses in moral judgments while, to date, the effects of diminished emotional processing and empathy on moral decision-making have been only partially considered. In this study, we investigated the influence of empathy and alexithymia on behavior and emotional responses while participants performed a moral decision task. Self-report (valence and arousal ratings) and physiological (skin conductance and heart rate) measures were collected during the task. Results showed that empathy and alexithymia shaped emotional reactions to moral decisions but did not bias moral choices. The more empathic the participants, the more dilemmas were perceived as unpleasant and arousing, and the greater the increase in skin conductance. Conversely, alexithymia was characterized by a reduced physiological activation during moral decisions, but normal self-report ratings. Heart rate was not modulated by empathy or alexithymia. These results add new evidence to the field of moral decision showing that empathy and alexithymia modulate emotional reactions to moral decision.

The influence of visual and phonological features on the hemispheric processing of hierarchical Navon letters.

The possibility of allocating attentional resources to the "global" shape or to the "local" details of pictorial stimuli helps visual processing. Investigations with hierarchical Navon letters, that are large "global" letters made up of small "local" ones, consistently demonstrate a right hemisphere advantage for global processing and a left hemisphere advantage for local processing. Here we investigated how the visual and phonological features of the global and local components of Navon letters influence these hemispheric advantages. In a first study in healthy participants, we contrasted the hemispheric processing of hierarchical letters with global and local items competing for response selection, to the processing of hierarchical letters in which a letter, a false-letter conveying no phonological information or a geometrical shape presented at the unattended level did not compete for response selection. In a second study, we investigated the hemispheric processing of hierarchical stimuli in which global and local letters were both visually and phonologically congruent (e.g. large uppercase G made of smaller uppercase G), visually incongruent and phonologically congruent (e.g. large uppercase G made of small lowercase g) or visually incongruent and phonologically incongruent (e.g. large uppercase G made of small lowercase or uppercase M). In a third study, we administered the same tasks to a right brain damaged patient with a lesion involving pre-striate areas engaged by global processing. The results of the first two experiments showed that the global abilities of the left hemisphere are limited because of its strong susceptibility to interference from local letters even when these are irrelevant to the task. Phonological features played a crucial role in this interference because the interference was entirely maintained also when letters at the global and local level were presented in different uppercase vs. lowercase formats. In contrast, when local features conveyed no phonological information, the left hemisphere showed preserved global processing abilities. These findings were supported by the study of the right brain damaged patient. These results offer a new look at the hemispheric dominance in the attentional processing of the global and local levels of hierarchical stimuli.

Alexithymia and emotional reactions to odors.

Alexithymia is a psychological construct characterized by deficits in processing emotional stimuli. However, little is known about the processing of odours in alexithymia, even though there is extensive proof that emotion and olfaction are closely linked. The present study is aimed at investigating how alexithymic individuals process emotions conveyed by odors. Emotional responses to unpleasant, neutral odors and clean air were collected through self-report ratings and psychophysiological measures in a sample of 62 healthy participants with high (HA), medium (MA) and low (LA) levels of alexithymia. Moreover, participants performed tests on odors identification and threshold and completed questionnaires assessing olfactory imagery and awareness. Two main results have been found: first, HA and MA groups showed altered physiological responses to odors, compared to LA, while no differences among the groups were observed in odor ratings; and second, affective and cognitive alexithymia components were differently associated with the performance on olfactory tests, skin conductance response to odors, reaction times in the rating task, and scores on olfactory questionnaires. We conclude that alexithymia is characterized by altered physiological reactions to olfactory stimuli; moreover, we stress the importance of evaluating the different alexithymia components since they affect emotional stimuli processing in different ways.