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PubMed1997

Odor-guided fear conditioning in rats: 2. Lesions of the anterior perirhinal cortex disrupt fear conditioned to the explicit conditioned stimulus but not to the training context.

Previous studies examining the neural substrates of fear conditioning have indicated unequivocally that the acquisition and expression of conditioned fear depends critically on the integrity of the amygdala. The extent to which the rhinal cortical areas contribute to fear conditioned to either the explicit conditioned stimulus (CS) or to the training context is less clear, however. The effects of pretraining lesions of the anterior perirhinal (PRH) cortex on fear conditioned to an explicit odor CS and to the context in which CS-unconditioned stimulus pairing took place was examined in rats. Rats with PRH cortex lesions demonstrated a robust attenuation of fear conditioned to the explicit CS, but no attenuation of fear conditioned to the training context. These data suggest that the PRH cortex is an important component of the neural system supporting the association between olfactory cues and footshock and add to a growing body of evidence implicating the rhinal cortical regions in associative learning.

Animals↗

PubMed2006

Neural systems involved in fear and anxiety measured with fear-potentiated startle.

A good deal is now known about the neural circuitry involved in how conditioned fear can augment a simple reflex (fear-potentiated startle). This involves visual or auditory as well as shock pathways that project via the thalamus and perirhinal or insular cortex to the basolateral amygdala (BLA). The BLA projects to the central (CeA) and medial (MeA) nuclei of the amygdala, which project indirectly to a particular part of the acoustic startle pathway in the brainstem. N-methyl-D-aspartate (NMDA) receptors, as well as various intracellular cascades in the amygdala, are critical for fear learning, which is then mediated by glutamate acting in the CeA. Less predictable stimuli, such as a long-duration bright light or a fearful context, activate the BLA, which projects to the bed nucleus of the stria terminalis (BNST), which projects to the startle pathway much as the CeA does. The anxiogenic peptide corticotropin-releasing hormone increases startle by acting directly in the BNST. CeA-mediated behaviors may represent stimulus-specific fear, whereas BNST-mediated behaviors are more akin to anxiety. NMDA receptors are also involved in extinction of conditioned fear, and both extinction in rats and exposure-based psychotherapy in humans are facilitated by an NMDA-partial agonist called D-cycloserine. ((c) 2006 APA, all rights reserved).

Amygdala↗

PubMed2006

Of snakes and flowers: does preferential detection of pictures of fear-relevant animals in visual search reflect on fear-relevance?

Previous research in visual search indicates that animal fear-relevant deviants, snakes/spiders, are found faster among non fear-relevant backgrounds, flowers/mushrooms, than vice versa. Moreover, deviant absence was indicated faster among snakes/spiders and detection time for flower/mushroom deviants, but not for snake/spider deviants, increased in larger arrays. The current research indicates that the latter 2 results do not reflect on fear-relevance, but are found only with flower/mushroom controls. These findings may reflect on factors such as background homogeneity, deviant homogeneity, or background-deviant similarity. The current research removes contradictions between previous studies that used animal and social fear-relevant stimuli and indicates that apparent search advantages for fear-relevant deviants seem likely to reflect on delayed attentional disengagement from fear-relevance on control trials.

Adolescent↗

PubMed2006

Extract of Ginkgo biloba EGb761 facilitates extinction of conditioned fear measured by fear-potentiated startle.

A standard extract of Ginkgo biloba (EGb761) has been used in the treatment of various common geriatric complaints including vertigo, short-term memory loss, hearing loss, lack of attention, or vigilance. We demonstrated that acute systemic administration of EGb761 facilitated the acquisition of conditioned fear. Many studies suggest the neural mechanism underlies extinction is similar to the acquisition. This raises a possibility that EGb761 may modulate and accelerate the fear extinction process. We tested this possibility by using fear-potentiated startle (FPS) on laboratory rats. Acute systemic injection of EGb761 (10, 20, or 50 mg/kg) 30 min before extinction training facilitated extinction in a dose-dependent manner. Intra-amygdaloid infusion of EGb761 (28 ng/side, bilaterally) 10 min before extinction training also facilitated extinction. Control experiments showed that facilitation effect of EGb761 was not the result of impaired expression of conditioned fear or accelerated forgetting. Rats previously injected with EGb761 showed significant FPS after retraining. Extinction of conditioned fear appeared to result from acute drug effects rather than from toxic action. Systemic administration of EGb761 immediately after extinction training did not facilitate extinction, suggested the EGb761 facilitation effect is contributed to the acquisition phase of extinction learning. Western blot results showed that extinction induced amygdaloid extracellular signal-regulated kinase (ERK1/2) phosphorylation was significantly elevated by EGb761 treatment. Intra-amygdala injection of ERK1/2 inhibitor PD98059 completely blocked the EGb761 effect. Therefore, acute EGb761 administration modulated extinction of conditioned fear by activating ERK1/2.

Amygdala↗

PubMed1995

The effect of prior fear levels on UCS-expectancy ratings to a fear-relevant stimulus.

This study investigated the effect of levels of prior fear to a fear-relevant stimulus on UCS expectancy ratings in a threat conditioning procedure. The results suggested that UCS-expectancy ratings are independently influenced by both the nature of the stimulus (whether it is fear-relevant or fear-irrelevant) and the level of prior fear to the stimulus. Furthermore, significantly higher UCS-expectancy levels caused by prior fear and stimulus type were accompanied in some stages of the experiment by greater magnitudes of skin conductance responses during the stimulus.

Adolescent↗

PubMed2002

MK-801 disrupts acquisition of contextual fear conditioning but enhances memory consolidation of cued fear conditioning.

The effects of pre-training or post-training subcutaneous injections of multiple doses of the non-competitive NMDA-receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) on cued and contextual fear conditioning were examined in F344 rats. Pre-training injections of MK-801 (0.3 and 1.0 mg/kg) disrupted contextual fear conditioning but not cued fear conditioning. Post-training injections of MK-801 did not disrupt cued or contextual fear conditioning. In fact, the 0.3 mg/kg dose of MK-801 enhanced cued fear conditioning. Finally, rats were tested for MK-801-induced alterations in sensitivity to pain using the formalin test for nociception. MK-801 did not reduce sensitivity to pain. These results suggest that NMDA receptors are involved in acquisition of contextual fear conditioning but not in memory consolidation of the learned response.

Animals↗

PubMed1990

Facial reactions to fear-relevant stimuli for subjects high and low in specific fear.

This study was performed to investigate whether subjects high and low in fear of snakes react with different facial electromyographic (EMG) responses when exposed to snakes. Two groups of subjects were exposed to slides of snakes or flowers. After the experiment they rated their fear of snakes on a questionnaire and based on these ratings they were divided into high and low fear groups. Facial EMG was measured from the corrugator and zygomatic muscle regions. As predicted the high fear group reacted with a facial response interpretable as a negative emotional reaction whereas the low fear group did not. This difference was specific to snakes because high and low groups did not differ in responses to slides of flowers. The results are consistent with the proposition that facial EMG technique is a sensitive tool to distinguish reactions between subjects high and low in specific fears.

Arousal↗

PubMed1989

Fears of children and adolescents: a cross-sectional Australian study using the Revised-Fear Survey Schedule for Children.

The Revised-Fear Survey Schedule for Children was administered to over 3000 Australian youths, aged 8-16 yrs. Consistent with previous findings, there was a significant age-related decline in fears. Females reported significantly more fears than males. The most common fears were similar to those reported by children and adolescents in the U.S.A. Nuclear war was added to the stimulus items and found to be the most commonly endorsed fear. Thus the self-reports of fear showed a concern for physical danger and harm.

Adolescent↗

PubMed1994

Assessing the fears of children with disability using the Revised Fear Survey Schedule for Children: a comparative study.

This study compared the self-reported fears of children with disability using the Fear Survey Schedule for Children-Revised (FSSC-R). Children with intellectual disability reported a significantly greater number of fears than children with no disability, children with hearing impairment and children with visual impairment. Also the children with intellectual disability reported more idiosyncratic fears related to the unknown, injury and small animals. Consistent with normative findings (King et al., 1989b; Ollendick, King & Frary, 1989), girls reported significantly more fears than boys. Methodological issues are discussed including the reliability and validity of self-reported fears for children with disability.

Adolescent↗

PubMed1998

Intensity and correlates of fear of falling and hurting oneself in the next year: baseline findings from a Roybal Center fear of falling intervention.

Fear of falling is highly prevalent and associated with restricted activity. To help inform design of interventions, the authors examined the correlates of this fear. Data came from baseline information on subjects in a community-based falls intervention study (N = 392). In a multivariate model, lower levels of fear of falling and hurting oneself in the next year were related to being younger, having higher levels of dysfunction, and having lower levels of perceived ability to manage falls, with the last two remaining significant even after controlling for generalized fearfulness. When analyzing specific domains of dysfunction, higher levels of fear of falling and hurting oneself in the next year were associated with higher levels of physical dysfunction. The findings lend support to the expanding awareness that fear of falling may imperil quality of life and suggest the importance of interventions aimed at enhancing ability to manage falls.

Accidental Falls↗

PubMed1999

Changes in women's fear of success and fear of appearing incompetent in business.

The primary purpose of this research was to examine whether fear of success and of appearing incompetent among women have changed recently. Another purpose was to examine whether such fears differed among women who hold Traditional views and those who hold Progressive views about the roles of women in the workplace. The Fear of Success Scale, the Fear of Appearing Incompetent Scale, and the Attitude Toward Women Scale were completed by 61 male and 52 female graduating seniors. Significant differences were found between the groups for scores on the Attitude Toward Women Scale, but none between the sexes for scores on the Fear of Success Scale or the Fear of Appearing Incompetent Scale. Significant differences were found, however, on the latter two scales when women were separated into Traditional and Progressive groups.

Adult↗

PubMed2004

Multimodal classical conditioning of fear: contributions of direct, observational, and verbal experiences to current fears.

The authors propose that a multimodal classical conditioning model be considered when clinicians or clinical researchers study the etiology of fears and anxieties learned by human beings. They argue that fears can be built through the combined effects of direct, observed, and verbally presented classical conditioning trials. Multimodal classical conditioning is offered as an alternative to the three pathways to fear argument prominent in the human fear literature. In contrast to the three pathways position, the authors present theoretical arguments for why "learning by observation" and "learning through the receipt of verbal information" should be considered classical conditioning through observational and verbal modes. The paper includes a demonstration of how data, commonly collected in research on the three pathways to fear, would be studied differently using a multimodal classical conditioning perspective. Finally, the authors discuss implications for assessment, treatment, and prevention of learned fears in humans.

Adolescent↗

PubMed1999

Pain pathways involved in fear conditioning measured with fear-potentiated startle: lesion studies.

It is well established that the basolateral amygdala is critically involved in the association between an unconditioned stimulus (US), such as a foot shock, and a conditioned stimulus (CS), such as a light, during classic fear conditioning. However, little is known about how the US (pain) inputs are relayed to the basolateral amygdala. The present studies were designed to define potential US pathways to the amygdala using lesion methods. Electrolytic lesions before or after training were placed in caudal granular/dysgranular insular cortex (IC) alone or in conjunction with the posterior intralaminar nuclei of the thalamus (PoT/PIL), and the effects on fear conditioning were examined. Pretraining lesions of both IC and PoT/PIL, but not lesions of IC alone, blocked the acquisition of fear-potentiated startle. However, post-training combined lesions of IC and PoT/PIL did not prevent expression of conditioned fear. Given that previous studies have shown that lesions of PoT/PIL alone had no effect on acquisition of conditioned fear, these results suggest that two parallel cortical (insula-amygdala) and subcortical (PoT/PIL-amygdala) pathways are involved in relaying shock information to the basolateral amygdala during fear conditioning.

Animals↗

PubMed1990

[A behavioral dental science research concerning prevention of dental fear. A report on the surveys of dental fear in four countries Japan, Indonesia, Brazil and Argentina].

We conducted a behavioral scientific research from the point of view of dental fear prevention. This time, the writers carried out the surveys with the goal of understanding and making clear the realities concerning dental anxiety in the four countries: Japan, Indonesia, Brazil and Argentina. The subjects were 728 dental students from the four countries, and the surveys consisted of 25 multiple choice questions which were divided into three major areas. The first area consisted of preliminary questions such as chief complaints and treatment experiences, the second area dealt with the reactions and physical responses on receiving dental treatment and the third area was on the different levels of anxiety shown during treatment expressed through feelings and reactions. We concluded as follows: 1. In Japan, 77% of the subjects reported having at least a little fear and this percentage was higher than those of other countries (45-65%). But in all countries, 4-7% of subjects reported having extreme dental fear. 2. In Japan and Brazil, women reported the higher fear than men. In Indonesia and Argentina, these results were the opposite. 3. According to canonical correlation analysis, a significant correlation between the level of physical reactions and the degree of dental anxiety was found in all countries. 4. In the high fear group, dental anxiety increased by psychological stress before treatment and the expressions of physical reactions were stronger than in the low fear group.

Argentina↗

PubMedDate not supplied

Children's dental fear picture test (CDFP): a projective test for the assessment of child dental fear.

A projective method, the Children's Dental Fear Picture test (CDFP), for measuring child dental fear was developed and tested for reliability in 146 Swedish children aged 5 to 12-years-old. The CDFP consists of three subtests: the Dental Setting Pictures (CDFP-DS), the Pointing Pictures (CDFP-PP), and a Sentence Completion test (CDFP-SC). Assessments of dental fear were made in each of the subtests as well as for the complete test (CDFP). Based on the assessments, the children were grouped into three categories: "fearful", "non fearful"c and "uncertain". The proportion of agreements between assessments of subtests and final assessment (CDFP) varied from 77.4 percent to 89.0 percent. Interexaminer reliability was computed from 27 testings assessed separately by two trained dentists. Full agreement in the final assessments (CDFP) was found between the dentists in 88.9 percent of the testings, indicating that the CDFP is a reliable method for measuring child dental fear.

Age Factors↗

PubMed1997

Fear of cancer recurrence--a literature review and proposed cognitive formulation to explain exacerbation of recurrence fears.

Modern treatments for cancer are resulting in cancer patients living longer with the risk of the disease returning at a later stage. Many patients who experience a recurrence blame themselves (Mahon et al., 1990), while those in remission live with the constant fear that the cancer may return. Although fear of recurrence is recognised in the literature, few researchers have focused on this aspect as a precursor to psychological distress. This paper reviews the literature about fear of recurrence and its measurement. Leventhal's Self Regulation Model of Illness is presented to help understand patients' reactions to cancer and fears for the future. The authors propose a formulation for fear of recurrence and examples of interventions that are indicated.

Adaptation, Psychological↗

PubMed2006

Drugs, sweat, and fears: a comparison of the effects of diazepam and methylphenidate on fear conditioning.

RATIONALE: Classical conditioning of a fear response involves the formation of an association between a stimulus and an emotional response and can be seen as a basic form of emotional memory. While both benzodiazepines and stimulant drugs may influence the formation of episodic memories for emotional events, their effects on fear conditioning are less clear. OBJECTIVES: This study compared the effects of diazepam with methylphenidate on fear conditioning. MATERIALS AND METHODS: In a single-session between groups design with three conditions [placebo, diazepam (10 mg), and methylphenidate (40 mg)], classical conditioning of a skin conductance response to a visual stimulus previously paired with a 100-db white noise was tested in 45 healthy volunteers. RESULTS: Diazepam blocked fear conditioning, despite responses to the unconditioned aversive stimulus and neutral control stimulus being unimpaired. Conditioning remained intact after methylphenidate. Conditioned responses were not extinguished completely by the end of the experiment, and it was not possible to draw conclusions about the effects of the drugs on extinction. CONCLUSIONS: Although diazepam has well-documented amnesic effects, it has not been found to affect implicit forms of memory like perceptual and conceptual priming. As the present study found impaired fear conditioning after diazepam, it adds weight to recent findings that emotional memories are disproportionately impaired by the benzodiazepines.

Adult↗

PubMed1985

Language conditioning, emotional instructions, and cognitions in conditioned responses to fear-relevant and fear-irrelevant stimuli.

This study compared the effects of experimentally induced self-verbalizations (SV) on conditioned responses to fear-relevant (snakes) and fear-irrelevant (rabbits) stimuli. To extend the analysis of "preparedness theory" beyond its former reliance on physiological measures of fear, subjective and behavioral measures were also included. Using aversive tones (UCS) and slides of snakes or rabbits (CS), fear was classically conditioned in 44 volunteers. In 20 subsequent language conditioning trials without aversive tones, the same slides were paired with verbalizations referring either to positive features of the animals (stimulus-referent SV) or to approach behavior (response-referent SV). Skin conductance responses to fear-relevant stimuli were more readily acquired, of higher magnitude, and more resistant to extinction. Extinction was differentially affected by the two types of SV. Snakes were consistently evaluated more negatively than rabbits and approached less in a behavior test. Results are discussed in relation to preparedness theory and interpreted within Staats' social-behavioral learning paradigm.

Adolescent↗