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Subjective tinnitus is the conscious perception of sound in the absence of any acoustic source. The literature suggests various tinnitus mechanisms, most of which invoke changes in spontaneous firing rates of central auditory neurons resulting from modification of neural gain. Here, we present an alternative model based on evidence that tinnitus is: (1) rare in people who are congenitally deaf, (2) common in people with acquired deafness, and (3) potentially suppressed by active cochlear implants used for hearing restoration. We propose that tinnitus can only develop after fast auditory fiber activity has stimulated the synapse formation between fast-spiking parvalbumin positive (PV+) interneurons and projecting neurons in the ascending auditory path and coactivated frontostriatal networks after hearing onset. Thereafter, fast auditory fiber activity promotes feedforward and feedback inhibition mediated by PV+ interneuron activity in auditory-specific circuits. This inhibitory network enables enhanced stimulus resolution, attention-driven contrast improvement, and augmentation of auditory responses in central auditory pathways (neural gain) after damage of slow auditory fibers. When fast auditory fiber activity is lost, tonic PV+ interneuron activity is diminished, resulting in the prolonged response latencies, sudden hyperexcitability, enhanced cortical synchrony, elevated spontaneous y oscillations, and impaired attention/stress-control that have been described in previous tinnitus models. Moreover, because fast processing is gained through sensory experience, tinnitus would not exist in congenital deafness. Electrical cochlear stimulation may have the potential to reestablish tonic inhibitory networks and thus suppress tinnitus. The proposed framework unites many ideas of tinnitus pathophysiology and may catalyze cooperative efforts to develop tinnitus therapies. ; German Research Foundation (DFG) DFG-Kni-316-4-1 SPP16-08 DFG Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) CONICYT FONDECYT 1161155 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) BASAL FB008 ICM P09-015F European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant 764604 722046 National Institute for Health Research (NIHR)

BackgroundPosttraumatic Stress Disorder (PTSD) is a major public health concern, especially given the recent wars in Iraq and Afghanistan. Nevertheless, despite a sharp increase in the incidence of psychiatric disorders in returning veterans, empirically based prevention strategies are still lacking. To develop effective prevention and treatment strategies, it is necessary to understand the underlying biological mechanisms contributing to PTSD and other trauma related symptoms.MethodsThe "Marine Resiliency Study II" (MRS-II; October 2011-October 2013) Neurocognition project is an investigation of neurocognitive performance in Marines about to be deployed to Afghanistan. As part of this investigation, 1195 Marines and Navy corpsmen underwent a fear conditioning and extinction paradigm and psychiatric symptom assessment prior to deployment. The current study assesses (1) the effectiveness of the fear potentiated startle paradigm in producing fear learning and extinction and (2) the association of performance in the paradigm with baseline psychiatric symptom classes (healthy: n=923, PTSD symptoms: n=42, anxiety symptoms: n=37, and depression symptoms: n=12).ResultsResults suggest that the task was effective in producing differential fear learning and fear extinction in this cohort. Further, distinct patterns emerged differentiating the PTSD and anxiety symptom classes from both healthy and depression classes. During fear acquisition, the PTSD symptom group was the only group to show deficient discrimination between the conditioned stimulus (CS+) and safety cue (CS-), exhibiting larger startle responses during the safety cue compared to the healthy group. During extinction learning, the PTSD symptom group showed significantly less reduction in their CS+ responding over time compared to the healthy group, as well as reduced extinction of self-reported anxiety to the CS+ by the end of the extinction session. Conversely, the anxiety symptom group showed normal safety signal discrimination and extinction of conditioned fear, but exhibited increased baseline startle reactivity and potentiated startle to CS+, as well as higher self-reported anxiety to both cues. The depression symptom group showed similar physiological and self-report measures as the healthy group.DiscussionThese data are consistent with the idea that safety signal discrimination is a relatively specific marker of PTSD symptoms compared to general anxiety and depression symptoms. Further research is needed to determine if deficits in fear inhibition vs. exaggerated fear responding are separate biological "domains" across anxiety disorders that may predict differential biological mechanisms and possibly treatment needs. Future longitudinal analyses will examine whether poor learning of safety signals provides a marker of vulnerability to develop PTSD or is specific to symptom state.

With this book, the author proposes that the economies of blackness, brownness, and dark brownness summon a new grammar for Latino/a studies that she names "Latinities." The author's innovative study argues that this ensnared economy of meaning startles the typical reading practices deployed for brown Latino/a embodiment. This book keeps company with and challenges existent models of Latinidad, demanding a distinct paradigm that puts into question what is understood as Latino and Latina.

OBJECTIVE: To provide a neurophysiological tool for assessing sensorimotor pathways, which may differ for those involving distal muscles in simple tasks from those involving distal muscles in a kinetic chain task, or proximal muscles in both. METHODS: We compared latencies and magnitudes of motor responses in a reaction time paradigm in a proximal (biceps brachii, BB) and a distal (first dorsal interosseous, FDI) muscle following electrical stimuli used as imperative signal (IS) delivered to the index finger. These stimuli were applied during different motor tasks: simple tasks involving either one muscle, e.g. flexing the elbow for BB (FLEX), or pinching a pen for FDI (PINCH); combined tasks engaging both muscles by pinching and flexing simultaneously (PINCH-FLEX). Stimuli were of varying intensity and occasionally elicited a startle response, and a StartReact effect. RESULTS: In BB, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities for non-startling trials, while for trials containing startle responses, latencies were uniformly shortened and response amplitudes similarly augmented across all IS intensities in both FLEX and PINCH-FLEX. In FDI, response latencies decreased gradually and response amplitudes increased progressively with increasing IS intensities in both PINCH and PINCH-FLEX for non-startling trials, but, unlike in BB for the simple task, in PINCH for trials containing startle responses as well. In PINCH-FLEX, FDI latencies were uniformly shortened and amplitudes similarly increased across all stimulus intensities whenever startle signs were present. CONCLUSIONS: Our results suggest the presence of different sensorimotor pathways supporting a dissociation between simple tasks that involve distal upper limb muscles (FDI in PINCH) from simple tasks involving proximal muscles (BB in FLEX), and combined tasks that engage both muscles (FDI and BB in PINCH-FLEX), all in accordance with differential importance in the control of movements by cortical and subcortical structures. SIGNIFICANCE: Simple assessment tools may provide useful information regarding the differential involvement of sensorimotor pathways in the control of both simple and combined tasks that engage proximal and distal muscles. ; All the funding received during this study are grants ESPY-112/18 from Instituto de Salud Carlos III and PRX12/00349 from Government of Spain to J. M. Castellote. There was no additional external funding received for this study. ; Sí

Blast-induced tinitus is the number one service-connected disability that currently affects military personnel and veterans. To elucidate its underlying mechanisms, we subjected 13 Sprague Dawley adult rats to unilateral 14 psi blast exposure to induce tinnitus and measured auditory and limbic brain activity using manganese-enhanced MRI (MEMRI). Tinnitus was evaluated with a gap detection acoustic startle reflex paradigm, while hearing status was assessed with prepulse inhibition (PPI) and auditory brainstem responses (ABRs). Both anxiety and cognitive functioning were assessed using elevated plus maze and Morris water maze, respectively. Five weeks after blast exposure, 8 of the 13 blasted rats exhibited chronic tinnitus. While acoustic PPI remained intact and ABR thresholds recovered, the ABR wave P1-N1 amplitude reduction persisted in all blast-exposed rats. No differences in spatial cognition were observed, but blasted rats as a whole exhibited increased anxiety. MEMRI data revealed a bilateral increase in activity along the auditory pathway and in certain limbic regions of rats with tinnitus compared to age-matched controls. Taken together, our data suggest that while blast-induced tinnitus may play a role in auditory and limbic hyperactivity, the non-auditory effects of blast and potential traumatic brain injury may also exert an effect.

Background: Posttraumatic Stress Disorder (PTSD) is associated with a number of negative physical and mental health consequences. Fear conditioning plays an important mechanistic role in PTSD, and PTSD patients also show deficits in safety signal learning. Sleep, particularly REM sleep, is linked to improved safety learning and extinction processes in animal models and healthy humans. No studies have examined the link between REM sleep and safety signal learning or extinction memory in clinical populations. Methods: This study examined the relationship between REM sleep, safety signal learning, and extinction processes in veterans with PTSD (n = 13). Patients' overnight sleep was characterized in the laboratory via polysomnography (PSG). The next day, participants underwent a fear conditioning paradigm during which they acquired fear toward a visual cue. This testing session also included a visual cue that became a safety signal (CS-). Following conditioning, the veterans' sleep was monitored overnight again, after which they underwent extinction training. Following a third night of sleep, extinction recall and safety recall were tested. Bivariate correlations examined the relationship between the slope of safety signal learning and subsequent REM sleep, as well as the relationship between REM sleep and subsequent extinction recall and safety recall on the last day of testing. Results: Veterans learned to differentiate the CS+ and the CS- on the first day of testing. Veterans who underwent safety learning more quickly on the first day of testing showed more efficient REM sleep that night (r =.607, p =.028). On the second day of testing, the patients successfully underwent extinction learning. Patients with a higher percentage of REM sleep on the last night of the study showed more safety recall early on the last day of testing (r =.688, p =.009). Conclusion: To our knowledge, this was the first study to examine the relationship between objective sleep and fear-potentiated startle performance in veterans with ...

Includes bibliographical references. ; Number of sources in the bibliography: 251 ; Thesis (Ph. D.) -- University of Cyprus, Faculty of Social Sciences and Education, Department of Psychology, 2019. ; The University of Cyprus Library holds the printed form of the thesis. ; Σε έναν κόσμο που γίνεται ολοένα και πιο ποικιλόμορφος και παγκοσμιοποιημένος, οι ταχείες κοινωνικές και πολιτικές μεταμορφώσεις οδηγούν στην ανάγκη καλύτερης κατανόησης της αλληλεπίδρασης μεταξύ ομάδων ανθρώπων. Ορισμένες μορφές διομαδικών συσχετίσεων, όπως η διομαδική αρνητική προκατάληψη και οι μεροληψίες, παρουσιάζουν ιδιαίτερο ενδιαφέρον, καθώς ενδέχεται να οδηγήσουν σε βίαιες συγκρούσεις και διαχωρισμό με βάση την ιδιότητα μέλους εθνικής ομάδας. Στο πλαίσιο αυτής της μελέτης η συναισθηματική διάσταση της προκατάληψης εξετάζεται μέσω πολλαπλών δεικτών. Συγκεκριμένα, μετρήσαμε την ενεργοποίηση του αυτόνομου νευρικού συστήματος (ενδεικτικό του συναισθήματος προτού επέλθει στη συνείδηση) μετά την δημιουργία συνθηκών ταύτισης με την ένδο-ομάδα με την έκθεση των ελληνοκύπριων συμμετεχόντων σε υποτιθέμενους Τουρκοκύπριους απεικονισμένοι σε οθόνη σε μορφή φωτογραφιών, και υποτιθέμενους Ισπανούς (ομάδα ελέγχου) επίσης απεικονισμένοι με τον ίδιο τρόπο. Μέσα από αυτή τη μελέτη εξετάσαμε πώς η προ-συνειδητή προκατάληψη, υπό τη μορφή διομαδικού άγχους, ξεδιπλώνεται σε ένα απλό πειραματικό μοντέλο προβολής εικόνων, το οποίο είναι ένας τύπος επαφής παρόμοιας με την έκθεση, λαμβάνοντας παράλληλα υπόψη τους σχετικούς με την Κύπρο παράγοντες που σχετίζονται με το συγκεκριμένο πλαίσιο. Επιπρόσθετα, εξετάσαμε κατά πόσον η επαφή μεταξύ των δύο κύριων εθνικών ομάδων στην Κύπρο, οι οποίες διαχωρίστηκαν ιστορικά και πολιτικά κατά μήκος των φυσικών γραμμών, επηρέασε το διομαδικό άγχος στις διάφορες πειραματικές συνθήκες. Τέλος, εξετάσαμε μια σειρά άλλων εμπειρικά προερχόμενων ατομικών μεταβλητών σε σχέση με την διομαδική προκατάληψη, όπως η προσωπικότητα και οι πολιτικές πεποιθήσεις, και κατά πόσο το διομαδικό άγχος μεσολαβεί στην επίδρασή τους στην διομαδική επαφή και στις αρνητικές στάσεις απέναντι στην εξω-ομάδα. Τα ευρήματα μας υποδεικνύουν ότι υπήρχαν διαφορές στην αυτόνομη ανταπόκριση μεταξύ πειραματικών συνθηκών με βάση την επαγωγή που έλαβαν, με την ομάδα που πίστευε ότι είδε εικόνες Τουρκοκύπριων να επιδεικνύουν την υψηλότερη αμυντική αυτόνομη αντιδραστικότητα. Η επαφή μεταξύ ομάδων εξάλειψε τις διαφορές στην μεταξύ συνθηκών στην μέτρηση της αγωγιμότητα του δέρματος αλλά όχι στην μέτρηση του αιφνιδιασμού. Τέλος, το αυτό-αναφερόμενο διομαδικό άγχος δεν είχε επίδραση διαμεσολάβησης μεταξύ των μεταβλητών που εξετάστηκαν, αλλά ήταν επιτυχής μόνο στην πλήρη μεσολάβηση της επίδρασης της συμπονετικής ανησυχίας στις αρνητικές στάσεις απέναντί στην εξω-ομάδα Τα αποτελέσματα των αναλύσεων μας για το φύλο δείχνουν ότι το φύλο των ερεθισμάτων (εικόνες) διαδραμάτισε σημαντικό ρόλο στην αλλαγή των αντιδράσεων, ενώ το φύλο των συμμετεχόντων δεν είχε αξιοσημείωτο αντίκτυπο. ; In a world that is quickly becoming increasingly diverse and global, rapid social and political transformations mean that a better understanding of interaction between identified groups of people (intergroup relations) becomes crucial. Certain types of intergroup relations, such as intergroup bias and prejudice, are of particular interest, as they may lead to violent conflict and segregation. Within the context of this study the affective dimension of prejudice is examined through multiple indices. Particularly we measured activation of the autonomous nervous system (indicative of preconscious emotion) after eliciting maximal social identity saliency by exposing Greek Cypriot participants (ingroup) to contact with supposed Turkish Cypriots (outgroup) and supposed Spaniards (control group) in a picture viewing paradigm. Through this study we examined how preconscious prejudice in the form of intergroup anxiety unfolds in a simple experimental picture viewing paradigm, which is a type of contact akin to exposure, while keeping in mind contextual factors that are relevant to Cyprus (i.e. no physical cues of difference between ingroup and outgroup faces) and relevant in general (i.e. gender). In addition, we examined whether intergroup contact between the two major ethnic groups in Cyprus, who have been historically and politically segregated along physical lines, altered group differences in intergroup anxiety. Finally, we examined a host of other empirically derived individual difference variables in relation to prejudice, such as personality and political attitudes, and the capacity of self-reported intergroup anxiety to mediate their effect on intergroup contact and negative outgroup attitudes. Our results indicate that there were differences in autonomous responding between groups based on the induction they received, with the group who believe they were witnessing pictures of Turkish Cypriots eliciting the highest defensive reactivity in the form of skin conductance and startle potentiation. Intergroup contact eliminated differences in group responding on skin conductance but not startle reactivity. And finally, self-reported intergroup anxiety did not have a cross-cutting mediation effect between the variables examined, rather, it was only successful in fully mediating the effect of empathic concern on negative outgroup attitudes. The results of our analyses on gender indicate that the sex of stimulus played a large role in altering responses, whereas gender of participants did not have a noteworthy impact.

Background:Posttraumatic Stress Disorder (PTSD) is associated with a number of negative physical and mental health consequences. Fear conditioning plays an important mechanistic role in PTSD, and PTSD patients also show deficits in safety signal learning. Sleep, particularly REM sleep, is linked to improved safety learning and extinction processes in animal models and healthy humans. No studies have examined the link between REM sleep and safety signal learning or extinction memory in clinical populations. Methods:This study examined the relationship between REM sleep, safety signal learning, and extinction processes in veterans with PTSD (n = 13). Patients' overnight sleep was characterized in the laboratory via polysomnography (PSG). The next day, participants underwent a fear conditioning paradigm during which they acquired fear toward a visual cue. This testing session also included a visual cue that became a safety signal (CS-). Following conditioning, the veterans' sleep was monitored overnight again, after which they underwent extinction training. Following a third night of sleep, extinction recall and safety recall were tested. Bivariate correlations examined the relationship between the slope of safety signal learning and subsequent REM sleep, as well as the relationship between REM sleep and subsequent extinction recall and safety recall on the last day of testing. Results:Veterans learned to differentiate the CS+ and the CS- on the first day of testing. Veterans who underwent safety learning more quickly on the first day of testing showed more efficient REM sleep that night (r = .607, p = .028). On the second day of testing, the patients successfully underwent extinction learning. Patients with a higher percentage of REM sleep on the last night of the study showed more safety recall early on the last day of testing (r = .688, p = .009). Conclusion:To our knowledge, this was the first study to examine the relationship between objective sleep and fear-potentiated startle performance in veterans with PTSD. Study methods were well tolerated by participants, supporting feasibility of the experimental design. Results indicated REM sleep was associated with both initial safety learning and subsequent safety recall. Taken together with previous studies in healthy controls, these preliminary results provide additional evidence suggesting REM sleep could play a mechanistic role in the maintenance of PTSD and thus identify a modifiable biological process to target in treatment of PTSD. These findings should be replicated in larger samples.

BackgroundPosttraumatic Stress Disorder (PTSD) is associated with a number of negative physical and mental health consequences. Fear conditioning plays an important mechanistic role in PTSD, and PTSD patients also show deficits in safety signal learning. Sleep, particularly REM sleep, is linked to improved safety learning and extinction processes in animal models and healthy humans. No studies have examined the link between REM sleep and safety signal learning or extinction memory in clinical populations.MethodsThis study examined the relationship between REM sleep, safety signal learning, and extinction processes in veterans with PTSD (n = 13). Patients' overnight sleep was characterized in the laboratory via polysomnography (PSG). The next day, participants underwent a fear conditioning paradigm during which they acquired fear toward a visual cue. This testing session also included a visual cue that became a safety signal (CS-). Following conditioning, the veterans' sleep was monitored overnight again, after which they underwent extinction training. Following a third night of sleep, extinction recall and safety recall were tested. Bivariate correlations examined the relationship between the slope of safety signal learning and subsequent REM sleep, as well as the relationship between REM sleep and subsequent extinction recall and safety recall on the last day of testing.ResultsVeterans learned to differentiate the CS+ and the CS- on the first day of testing. Veterans who underwent safety learning more quickly on the first day of testing showed more efficient REM sleep that night (r = .607, p = .028). On the second day of testing, the patients successfully underwent extinction learning. Patients with a higher percentage of REM sleep on the last night of the study showed more safety recall early on the last day of testing (r = .688, p = .009).ConclusionTo our knowledge, this was the first study to examine the relationship between objective sleep and fear-potentiated startle performance in veterans with PTSD. Study methods were well tolerated by participants, supporting feasibility of the experimental design. Results indicated REM sleep was associated with both initial safety learning and subsequent safety recall. Taken together with previous studies in healthy controls, these preliminary results provide additional evidence suggesting REM sleep could play a mechanistic role in the maintenance of PTSD and thus identify a modifiable biological process to target in treatment of PTSD. These findings should be replicated in larger samples.