Does sex influence the natural history of idiopathic adult-onset dystonia?

BACKGROUND: Several earlier studies showed a female predominance in idiopathic adult-onset dystonia (IAOD) affecting the craniocervical area and a male preponderance in limb dystonia. However, sex-related differences may result from bias inherent to study design. Moreover, information is lacking on whether sex-related differences exist in expressing other dystonia-associated features and dystonia spread. OBJECTIVE: To provide accurate information on the relationship between sex differences, motor phenomenology, dystonia-associated features and the natural history of IAOD. METHODS: Data of 1701 patients with IAOD from the Italian Dystonia Registry were analysed. RESULTS: Women predominated over men in blepharospasm, oromandibular, laryngeal and cervical dystonia; the sex ratio was reversed in task-specific upper limb dystonia; and no clear sex difference emerged in non-task-specific upper limb dystonia and lower limb dystonia. This pattern was present at disease onset and the last examination. Women and men did not significantly differ for several dystonia-associated features and tendency to spread. In women and men, the absolute number of individuals who developed dystonia tended to increase from 20 to 60 years and then declined. However, when we stratified by site of dystonia onset, different patterns of female-to-male ratio over time could be observed in the various forms of dystonia. CONCLUSIONS: Our findings provide novel evidence on sex as a key mediator of IAOD phenotype at disease onset. Age-related sexual dimorphism may result from the varying exposures to specific age-related and sex-related environmental risk factors interacting in a complex manner with biological factors such as hormonal sex factors.

Does thyroid diseases contribute to the natural history of idiopathic adult-onset dystonia? Data from the Italian Dystonia Registry.

A few earlier observations and recent controlled studies pointed to the possible contribution of thyroid diseases in idiopathic adult-onset dystonia (IAOD). The aim of this study was to investigate the association between thyroid status and clinical characteristics of IAOD, focusing on dystonia localization, spread, and associated features such as tremors and sensory tricks. Patients were identified from those included in the Italian Dystonia Registry, a multicentre dataset of patients with adult-onset dystonia. The study population included 1518 IAOD patients. Patients with hypothyroidism and hyperthyroidism were compared with those without any thyroid disease. In the 1518 IAOD patients, 167 patients (11%; 95% CI 9.5-12.6%) were diagnosed with hypothyroidism and 42 (2.8%; 95% CI 1.99-3.74) with hyperthyroidism. The three groups were comparable in age at dystonia onset, but there were more women than men in the groups with thyroid disease. Analysing the anatomical distribution of dystonia, more patients with blepharospasm were present in the hyperthyroidism group, but the difference did not reach statistical significance after the Bonferroni correction. The remaining dystonia-affected body sites were similarly distributed in the three groups, as did dystonia-associated features and spread. Our findings provided novel information indicating that the high rate of thyroid diseases is not specific for any specific dystonia subpopulation and does not appear to influence the natural history of the disease.

Brain Networks Modulation during Simple and Complex Gait: A "Mobile Brain/Body Imaging" Study.

Walking encompasses a complex interplay of neuromuscular coordination and cognitive processes. Disruptions in gait can impact personal independence and quality of life, especially among the elderly and neurodegenerative patients. While traditional biomechanical analyses and neuroimaging techniques have contributed to understanding gait control, they often lack the temporal resolution needed for rapid neural dynamics. This study employs a mobile brain/body imaging (MoBI) platform with high-density electroencephalography (hd-EEG) to explore event-related desynchronization and synchronization (ERD/ERS) during overground walking. Simultaneous to hdEEG, we recorded gait spatiotemporal parameters. Participants were asked to walk under usual walking and dual-task walking conditions. For data analysis, we extracted ERD/ERS in α, ß, and γ bands from 17 selected regions of interest encompassing not only the sensorimotor cerebral network but also the cognitive and affective networks. A correlation analysis was performed between gait parameters and ERD/ERS intensities in different networks in the different phases of gait. Results showed that ERD/ERS modulations across gait phases in the α and ß bands extended beyond the sensorimotor network, over the cognitive and limbic networks, and were more prominent in all networks during dual tasks with respect to usual walking. Correlation analyses showed that a stronger α ERS in the initial double-support phases correlates with shorter step length, emphasizing the role of attention in motor control. Additionally, ß ERD/ERS in affective and cognitive networks during dual-task walking correlated with dual-task gait performance, suggesting compensatory mechanisms in complex tasks. This study advances our understanding of neural dynamics during overground walking, emphasizing the multidimensional nature of gait control involving cognitive and affective networks.

The Italian tremor Network (TITAN): rationale, design and preliminary findings.

INTRODUCTION: The recently released classification has revised the nosology of tremor, defining essential tremor (ET) as a syndrome and fueling an enlightened debate about some newly conceptualized entities such as ET-plus. As a result, precise information of demographics, clinical features, and about the natural history of these conditions are lacking. METHODS: The ITAlian tremor Network (TITAN) is a multicenter data collection platform, the aim of which is to prospectively assess, according to a standardized protocol, the phenomenology and natural history of tremor syndromes. RESULTS: In the first year of activity, 679 patients have been recruited. The frequency of tremor syndromes varied from 32% of ET and 41% of ET-plus to less than 3% of rare forms, including focal tremors (2.30%), task-specific tremors (1.38%), isolated rest tremor (0.61%), and orthostatic tremor (0.61%). Patients with ET-plus were older and had a higher age at onset than ET, but a shorter disease duration, which might suggest that ET-plus is not a disease stage of ET. Familial aggregation of tremor and movement disorders was present in up to 60% of ET cases and in about 40% of patients with tremor combined with dystonia. The body site of tremor onset was different between tremor syndromes, with head tremor being most commonly, but not uniquely, associated with dystonia. CONCLUSIONS: The TITAN study is anticipated to provide clinically relevant prospective information about the clinical correlates of different tremor syndromes and their specific outcomes and might serve as a basis for future etiological, pathophysiological, and therapeutic research.

Affective and cognitive theory of mind in patients with cervical dystonia with and without tremor.

Theory of mind (ToM) refers to an individual's ability to attribute mental states to predict and explain another person's behavior. It has been shown that patients with cervical dystonia (CD) present impaired ToM ability supporting the idea that CD is a network disorder. An emerging hypothesis is that different phenotypes of CD reflect distinct key nodes in the malfunctioning cerebral network. The aim of the present study was to investigate whether the presence of tremor as additional phenotypic feature of CD influences the ability to attribute a cognitive or emotional state to another person. We enrolled 35 patients with CD, 21 with tremor (CD-T) and 14 without tremor (CD-NT) and 47 age-matched healthy subjects (HS). The Emotion Attribution Task (EAT) was adopted to assess the affective ToM ability while the Advanced Test (AT) was used to investigate the cognitive ToM ability. Results showed that CD patients' performance was worse than HS in recognizing the emotional feelings expressed in the EAT situations, with no difference between CD-T and CD-NT. Regarding cognitive ToM, both CD-T and CD-NT performed worse than HS in the AT task. However, it also emerged that CD-T were more impaired in AT task than CD-NT. Our results indicate that both affective and cognitive aspects of ToM are impaired in CD and that cognitive ToM is more impaired in patients presenting tremor respect to those without. These findings support the hypothesis that the cerebral network responsible of motor and non-motor impairments is more widespread in CD-T than CD-NT.

Idiopathic Non-task-Specific Upper Limb Dystonia, a Neglected Form of Dystonia.

OBJECTIVE: The objective of this study was to describe the clinical and demographic features of idiopathic non-task-specific upper limb dystonia compared with the task-specific form. METHODS: In this retrospective study, adult patients with idiopathic upper limb dystonia, either focal or as part of a segmental/multifocal dystonia, from the Italian Dystonia Registry were enrolled. In patients with focal upper limb dystonia, dystonia spread was estimated by survival analysis. RESULTS: Of the 1522 patients with idiopathic adult-onset dystonia included in the Italian Dystonia Registry, we identified 182 patients with upper limb dystonia. Non-task-specific dystonia was present in 61.5% of enrolled cases. Women predominated among non-task-specific patients, whereas men predominated in the task-specific group. Peak age of upper limb dystonia onset was in the sixth decade in the non-task-specific group and in the fourth decade in the task-specific group. In both groups, upper limb dystonia started as focal dystonia or as part of a segmental dystonia. Segmental onset was more frequent among non-task-specific patients, whereas focal onset predominated among task-specific patients. Dystonic action tremor was more frequent among non-task-specific patients. No significant differences between groups emerged in terms of sensory trick frequency, rest tremor, or family history of dystonia. In patients with focal upper limb dystonia, dystonia spread was greater in the non-task-specific group. CONCLUSION: Novel information on upper limb dystonia patients suggests that non-task-specific and task-specific upper limb dystonia have different demographic and clinical features. However, it remains to be determined whether these differences also reflect pathophysiological differences. © 2020 International Parkinson and Movement Disorder Society.

Functional Correlates of Action Observation of Gait in Patients with Parkinson's Disease.

Background: Action observation (AO) relies on the mirror neuron system (MNS) and has been proposed as a rehabilitation tool in Parkinson's disease (PD), in particular for gait disorder such as freezing of gait (FOG). In this study, we aimed to explore the brain functional correlates of the observation of human gait in PD patients with (FOG+) and without (FOG-) FOG and to investigate a possible relationship between AO-induced brain activation and gait performance. Methods: Fifty-four participants were enrolled in the study (15 PD FOG+; 18 PD FOG-; 21 healthy subjects (HS)) which consisted of two tasks in two separate days: (i) gait assessment and (ii) task-fMRI during AO of gait. Differences between patients with PD (FOG+ and FOG-) and HS were assessed at the level of behavioral and functional analysis. Results: Gait parameters, including gait velocity, stride length, and their coefficients of variability (CV), were different in PD patients compared to HS, whereas gait performance was similar between FOG+ and FOG-. The PD group, compared to HS, presented reduced functional activation in the frontal, cingulum, and parietooccipital regions. Reduced activity was more pronounced in the FOG+ group, compared to both HS and FOG- groups. Gait variability positively correlated with precuneus neural activity in the FOG+ group. Discussion. Patients with PD present a reduced functional activity during AO of gait, especially if FOG+. A baseline knowledge of the neural correlates of AO of gait in the clinical routine "on" status would help for the design of future AO rehabilitative interventions.

Efficacy and safety of deferiprone for the treatment of superficial siderosis: results from a long-term observational study.

BACKGROUND: Superficial siderosis (SS) of the central nervous system is a rare and heterogeneous condition due to deposition of hemosiderin on the surface of the brain and spinal cord. The usually progressive clinical course is characterized by a combination of hearing loss, cerebellar ataxia, and myelopathy. There is no known treatment for SS, but the iron chelator deferiprone (DFP) has been proposed as a potentially useful treatment. METHODS: We present a long-term (average 3.7 years) evaluation of four cases of SS treated with DFP (15 mg/kg po bid). RESULTS: Treatment with DFP proved safe and well tolerated. Two out of the four subjects were unchanged while the other two presented a clinical improvement with reduction of postural instability and cerebellar signs. Blinded evaluation of magnetic resonance imaging (performed every 6 months during follow-up) showed a reduction of the abnormal iron deposition for all patients. CONCLUSIONS: This long-term observational study suggests that DFP may be effective in the management of the neurological manifestations associated with iron accumulation in SS. CLINICALTRIALS. GOV IDENTIFIER: NTC00907283.

Validation of the Italian version of the PSP Quality of Life questionnaire.

BACKGROUND: Progressive supranuclear palsy (PSP) is a rare rapidly progressive, neurodegenerative disease characterized by falls and ocular movement disturbances. The use of health-related quality of life (HR-QoL) measures allows assessing changes in health status induced by therapeutic interventions or disease progress in neurodegenerative diseases. The PSP-QoL is a 45-item, self-administered questionnaire designed to evaluate HR-QoL in PSP. METHODS AND RESULTS: Here, the PSP-QoL was translated into Italian and validated in 190 PSP (96 women and 94 men; mean age ± standard deviation, 72 ± 6.5; mean disease duration, 4.2 ± 2.3) patients diagnosed according to the Movement Disorder Society criteria and recruited in 16 third level movement disorders centers participating in the Neurecanet project. The mean PSP-QoL total score was 77.8 ± 37 (physical subscore, 46.5 ± 18.7; mental subscore, 33.6 ± 19.2). The internal consistency was high (Cronbach's alpha = 0.954); corrected item-total correlation was > 0.40 for the majority of items. The significant and moderate correlation of the PSP-QoL with other HR-QoL measures as well as with motor and disability assessments indicated adequate convergent validity of the scale. Gender and geographic location presented a significant impact on the PSP-QoL in our sample with women and patients from the South of Italy scoring higher than their counterparts. CONCLUSION: In conclusion, the Italian version of the PSP-QoL is an easy, reliable and valid tool for assessment of HR-QoL in PSP.

Validation of the Italian version of carers' quality-of-life questionnaire for parkinsonism (PQoL Carer) in progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a rare, rapidly progressive, neurodegenerative disease characterized by falls and ocular movement disturbances. Caring for a partner or relative who suffers from PSP entails a strenuous and demanding task, usually lasting for years that affects carers' everyday life routines and emotional and social well-being. The 26-item Parkinsonism Carers QoL (PQoL Carer) is a self-administered, concise instrument evaluating the quality of life of caregivers of patients with atypical parkinsonism (both PSP and multiple system atrophy). Here, the PQoL Carer was translated into Italian and validated in 162 carers of PSP patients (54.3% women; mean age (standard deviation), 62.4 (15.4)) diagnosed according to the Movement Disorder Society criteria and recruited in 16 third-level movement disorders centers participating in the Neurecanet project. The mean PQoL total score was 40.66 ± 19.46. The internal consistency was excellent (Cronbach's alpha = 0.941); corrected item-total correlation was > 0.40 for all the items. A correlation with other health-related quality of life measures as well as with behavioral assessments was shown suggesting adequate convergent validity of the scale. PQoL also correlated with patients' severity of disease. The discriminant validity of the scale was evidenced by its capacity to differentiate between carers with varying levels of self-reported health (p < 0.001). In conclusion, the Italian version of the PQoL Carer is an easy, consistent, and valid tool for the assessment of the quality of life in carers of PSP patients.

Training based on mirror visual feedback influences transcallosal communication.

Mirror visual feedback (MVF) therapy has been demonstrated to be successful in neurorehabilitation, probably inducing neuroplasticity changes in the primary motor cortex (M1). However, it is not known whether MVF training influences the hemispheric balance between the M1s. This topic is of extreme relevance when MVF training is applied to stroke rehabilitation, as the competitive interaction between the two hemispheres induces abnormal interhemispheric inhibition (IHI) that weakens motor function in stroke patients. In the present study, we evaluated, in a group of healthy subjects, the effect of motor training and MVF training on the excitability of the two M1s and the IHI between M1s. The IHI from the 'active' M1 to the opposite M1 (where 'active' means the M1 contralateral to the moving hand in the motor training and the M1 of the seen hand in the MVF training) increased, after training, in both the experimental conditions. Only after motor training did we observe an increase in the excitability of the active M1. Our findings show that training based on MVF may influence the excitability of the transcallosal pathway and support its use in disorders where abnormal IHI is a potential target, such as stroke, where an imbalance between the affected and unaffected M1s has been documented.

Modulation of response times in early-stage Parkinson's disease during emotional processing of embodied and non-embodied stimuli.

Valence (positive and negative) and content (embodied vs non-embodied) characteristics of visual stimuli have been shown to influence motor readiness, as tested with response time paradigms. Both embodiment and emotional processing are affected in Parkinson's disease (PD) due to basal ganglia dysfunction. Here we aimed to investigate, using a two-choice response time paradigm, motor readiness when processing embodied (emotional body language [EBL] and emotional facial expressions [FACS]) vs non-embodied (emotional scenes [IAPS]) stimuli with neutral, happy, and fearful content. We enrolled twenty-five patients with early-stage PD and twenty-five age matched healthy participants. Motor response during emotional processing was assessed by measuring response times (RTs) in a home-based, forced two-choice discrimination task where participants were asked to discriminate the emotional stimulus from the neutral one. Rating of valence and arousal was also performed. A clinical and neuropsychological evaluation was performed on PD patients. Results showed that RTs for PD patients were longer for all conditions compared to HC and that RTs were generally longer in both groups for EBL compared to FACS and IAPS, with the sole exception retrieved for PD, where in discriminating fearful stimuli, RTs for EBL were longer compared to FACS but not to IAPS. Furthermore, in PD only, when discriminating fearful respect to neutral stimuli, RTs were shorter when discriminating FACS compared to IAPS. This study shows that PD patients were faster in discriminating fearful embodied stimuli, allowing us to speculate on mechanisms involving an alternative, compensatory, emotional motor pathway for PD patients undergoing fear processing.

Artificial intelligence of imaging and clinical neurological data for predictive, preventive and personalized (P3) medicine for Parkinson Disease: The NeuroArtP3 protocol for a multi-center research study.

BACKGROUND: The burden of Parkinson Disease (PD) represents a key public health issue and it is essential to develop innovative and cost-effective approaches to promote sustainable diagnostic and therapeutic interventions. In this perspective the adoption of a P3 (predictive, preventive and personalized) medicine approach seems to be pivotal. The NeuroArtP3 (NET-2018-12366666) is a four-year multi-site project co-funded by the Italian Ministry of Health, bringing together clinical and computational centers operating in the field of neurology, including PD. OBJECTIVE: The core objectives of the project are: i) to harmonize the collection of data across the participating centers, ii) to structure standardized disease-specific datasets and iii) to advance knowledge on disease's trajectories through machine learning analysis. METHODS: The 4-years study combines two consecutive research components: i) a multi-center retrospective observational phase; ii) a multi-center prospective observational phase. The retrospective phase aims at collecting data of the patients admitted at the participating clinical centers. Whereas the prospective phase aims at collecting the same variables of the retrospective study in newly diagnosed patients who will be enrolled at the same centers. RESULTS: The participating clinical centers are the Provincial Health Services (APSS) of Trento (Italy) as the center responsible for the PD study and the IRCCS San Martino Hospital of Genoa (Italy) as the promoter center of the NeuroartP3 project. The computational centers responsible for data analysis are the Bruno Kessler Foundation of Trento (Italy) with TrentinoSalute4.0 -Competence Center for Digital Health of the Province of Trento (Italy) and the LISCOMPlab University of Genoa (Italy). CONCLUSIONS: The work behind this observational study protocol shows how it is possible and viable to systematize data collection procedures in order to feed research and to advance the implementation of a P3 approach into the clinical practice through the use of AI models.

Comparing Essential Tremor with and without Soft Dystonic Signs and Tremor Combined with Dystonia: The TITAN Study.

BACKGROUND: Tremor disorders remain as clinical diagnoses and the rate of misdiagnosis between the commonest non-parkinsonian tremors is relatively high. OBJECTIVES: To compare the clinical features of Essential Tremor without other features (pure ET), ET plus soft dystonic signs (ET + DS), and tremor combined with dystonia (TwD). METHODS: We compared the clinical features of patients with pure ET, ET + DS, and TwD enrolled in The ITAlian tremor Network (TITAN). Linear regression models were performed to determine factors associated with health status and quality of life. RESULTS: Three-hundred-eighty-three patients were included. Sex distribution was significantly different between the groups with males being more represented in pure ET and females in TwD. The initial site of tremor was different between the groups with about 40% of TwD having head tremor and ET + DS unilateral upper limb tremor at onset. This pattern mirrored the distribution of overt dystonia and soft dystonic signs at examination. Sensory trick, task-specificity, and position-dependence were more common, but not exclusive, to TwD. Pure ET patients showed the lowest degree of alcohol responsiveness and ET + DS the highest. Midline tremor was more commonly encountered and more severe in TwD than in the other groups. Regression analyses demonstrated that tremor severity, sex, age, and to a lesser degree the variable "group", independently predicted health status and quality of life, suggesting the existence of other determinants beyond tremor. CONCLUSIONS: Pure ET and TwD manifest with a phenotypic overlap, which calls for the identification of diagnostic biomarkers. ET + DS shared features with both syndromes, suggesting intra-group heterogeneity.

Neuropathy and levodopa in Parkinson's disease: evidence from a multicenter study.

The objectives of this study were to evaluate the risk of neuropathy in patients with Parkinson's disease (PD) and to evaluate the role of levodopa exposure as a potential risk factor. A multicenter study of 330 patients with PD and 137 healthy controls with a comparable age distribution was performed. With respect to levodopa exposure, 144 patients had long exposure (≥ 3 years) to levodopa (LELD), 103 patients had short exposure (<3 years) to levodopa (SELD), and 83 patients had no exposure to levodopa (NOLD). Nerve function was evaluated using the reduced total neuropathy score. Right sural sensory antidromic and peroneal motor nerve conduction studies were performed by neurophysiologists who were blinded to the existence of neuropathy clinical features or PD treatment. Overall, 19.40% of patients in the LELD group, 6.80% in the SELD group, 4.82% in the NOLD group, and 8.76% in the control group were diagnosed with neuropathy (axonal, predominantly sensory). Multivariate logistic analysis indicated that the risk of neuropathy was not influenced by disease duration, severity, or sex. The risk of neuropathy increased by approximately 8% for each year of age (P < 0.001; odds ratio [OR], 1.08; 95% confidence interval [CI], 1.037-1.128). The risk of neuropathy was 2.38 higher in the LELD group than in the control group (P = 0.022; OR, 2.38; 95% CI, 1.130-5.014). In a comparison between patients with and without neuropathy (Student's t test), the levodopa dose was higher (P < 0.0001), serum vitamin B12 levels were lower (P = 0.0102), and homocysteine levels were higher (P < 0.001) in the patients with neuropathy. Our results demonstrate that the duration of exposure to levodopa, along with age, is the main risk factor for the development of neuropathy. Screening for homocysteine and vitamin B12 levels and clinical-neurophysiological monitoring for neuropathy may be advisable in patients with PD who are receiving treatment with levodopa.

Neural oscillations modulation during working memory in pre-manifest and early Huntington's disease.

INTRODUCTION: We recently demonstrated specific spectral signatures associated with updating of memory information, working memory (WM) maintenance and readout, with relatively high spatial resolution by means of high-density electroencephalography (hdEEG). WM is impaired already in early symptomatic HD (early-HD) and in pre-manifest HD (pre-HD). The aim of this study was to test whether hdEEG coupled to source localization allows for the identification of neuronal oscillations in specific frequency bands in 16 pre-HD and early-HD during different phases of a WM task. METHODS: We examined modulation of neural oscillations by event-related synchronization and desynchronization (ERS/ERD) of θ, ß, gamma low, γLOW and γHIGH EEG bands in a-priori selected large fronto-parietal network, including the insula and the cerebellum. RESULTS: We found: (i) Reduced θ oscillations in HD with respect to controls in almost all the areas of the WM network during the update and readout phases; (ii) Modulation of ß oscillations, which increased during the maintenance phase of the WM task in both groups; (iii) correlation of γHIGH oscillations during WM task with disease burden score in HD patients. CONCLUSIONS: Our data show reduced phase-specific modulation of oscillations in pre-HD and early-HD, even in the presence of preserved dynamic of modulation. Particularly, reduced synchronization in the θ band in the areas of the WM network, consistent with abnormal long-range coordination of neuronal activity within this network, was found in update and readout phases in HD groups.

A case of Huntington disease-like 2 in a patient of African ancestry: the everlasting support of clinical examination in the molecular era.

Chorea, cognitive decline, and psychiatric symptoms are shared by Huntington's disease (HD) and similar conditions called HD phenocopies. We describe the first case reported in Italy of Huntington disease-like 2 (HDL2), clinically and radiologically indistinguishable from HD, showing the importance of considering African ancestry in the diagnostic process.

Motor Resonance Flexibility to Emotion-Enriched Context in Parkinson's Disease Patients.

In healthy people, motor resonance mechanisms are flexible to negative emotional contextual clues with greater motor resonance during the observation of a reach to grasp movement performed in an environment eliciting disgust. The link between emotion and motor control has become an interesting topic in Parkinson's disease (PD). Here, we aimed to study the response of the mirror neuron system, specifically motor resonance, to an emotion-enriched context in people with PD. Corticospinal excitability was recorded in a total of 44 participants, divided into two groups (23 PD patients and 21 healthy subjects). We recorded motor-evoked potentials from a muscle involved in the grasping movement while participants were watching the same reach-to-grasp movement embedded in surrounds with negative emotional valence, but different levels of arousal: sadness (low arousal) and disgust (high arousal). Basic motor resonance mechanisms were less efficient in PD than controls. Responsiveness to emotional contextual clues eliciting sadness was similar between PD and controls, whereas responsiveness to emotional contextual clues eliciting disgust was impaired in PD patients. Our findings show reduced motor resonance flexibility to the disgusting context, supporting the hypothesis that PD patients may have a deficit in "translating" an aversive motivational state into a physiologic response. The amygdala, which is implicated in the appraisal of fearful stimuli and response to threatening situations, might be implicated in this process.