-
Behaviour Research and Therapy May 2018Although avoidance and escape behaviors each contribute to maintaining anxiety disorders, only avoidance completely eliminates exposure to the aversive context. Current...
Although avoidance and escape behaviors each contribute to maintaining anxiety disorders, only avoidance completely eliminates exposure to the aversive context. Current research compared anticipatory defensive engagement when aversion could either be completely avoided or escaped after initial exposure; in addition, this research examined the impact of trait anxiety on coping-related defensive engagement. Cues signaled that upcoming rapid action would avoid (block), escape (terminate), or not affect subsequent aversive exposure; the acoustic startle reflex was measured during each anticipatory interval to index defensive engagement, and blink magnitudes were compared across low-, moderate-, and high-anxious individuals. For all participants, startle was potentiated when aversive exposure was uncontrollable and attenuated when aversion was avoidable. On escape trials, on the other hand, startle potentiation increased with rising participant anxiety. Results suggest 1) defensive engagement is generally reduced in avoidance contexts relative to contexts in which exposure is certain, and; 2) trait anxiety increases defensive engagement specifically when aversive exposure can be controlled but remains certain.
Topics: Adolescent; Anxiety; Autonomic Nervous System; Fear; Female; Galvanic Skin Response; Heart Rate; Humans; Male; Reaction Time; Reflex, Startle; Young Adult
PubMed: 29549752
DOI: 10.1016/j.brat.2018.03.002 -
Psychiatry Research Jul 2010Prepulse inhibition (PPI) is an acoustic startle paradigm that has been used as an operational measure of sensorimotor gating. Many patients with schizophrenia have...
Prepulse inhibition (PPI) is an acoustic startle paradigm that has been used as an operational measure of sensorimotor gating. Many patients with schizophrenia have impaired PPI, and several lines of evidence suggest that PPI may represent a heritable endophenotype in this disease. We examined startle magnitude and latencies in 40 schizophrenia patients, 58 first-degree relatives of these patients, and 100 healthy controls. After removing low-startlers, we investigated PPI and startle habituation in 34 schizophrenia patients, 43 relatives, and 86 control subjects. Heritability analyses were conducted using a variance-component approach. We found significant heritability of 45% for PPI at the 60-ms interval and 67% for startle magnitude. Onset latency heritability estimates ranged between 39% and 90% across trial types, and those for peak latency ranged from 29% to 68%. Heritability of startle habituation trended toward significance at 31%. We did not detect differences between controls and either schizophrenia patients or their family members for PPI, startle magnitude, or habituation. Startle latencies were generally longer in schizophrenia patients than controls. The heritability findings give impetus to applying genetic analyses to PPI variables, and suggest that startle latency may also be a useful measure in the study of potential endophenotypes for schizophrenia.
Topics: Acoustic Stimulation; Adult; Family Health; Female; Habituation, Psychophysiologic; Humans; Male; Middle Aged; Neural Inhibition; Neuropsychological Tests; Reaction Time; Reflex, Startle; Schizophrenia; Schizophrenic Psychology
PubMed: 20483176
DOI: 10.1016/j.psychres.2009.11.012 -
Journal of Psychopharmacology (Oxford,... Nov 2022Prepulse-induced startle modulation occurs when a weak sensory stimulus ('prepulse') is presented before a startling sensory stimulus ('pulse'), producing an inhibited...
The influence of stimulus onset asynchrony, task order, sex and hormonal contraception on prepulse inhibition and prepulse facilitation: Methodological considerations for drug and imaging research.
BACKGROUND
Prepulse-induced startle modulation occurs when a weak sensory stimulus ('prepulse') is presented before a startling sensory stimulus ('pulse'), producing an inhibited (Prepulse Inhibition, PPI) or facilitated (Prepulse Facilitation, PPF) startle response. We recently identified several gaps and outlined future lines of enquiry to enable a fuller understanding of the neurobiology of PPI and PPF in healthy and clinical populations. However, before embarking on these studies, it is important to consider how task and population characteristics affect these phenomena in healthy humans.
METHODS
We examined PPI and PPF in separate tasks, with counterbalanced task order across participants in one session, using a range of stimulus onset asynchronies (SOAs), in 48 healthy adults (23 men, 25 women; 10 hormonal contraceptive users) to determine which SOAs produce the strongest PPI and PPF and also explored how sex and hormonal contraception might influence PPI and PPF under these experimental conditions.
RESULTS
Both PPI and PPF were affected by SOA, with greatest PPI observed at 60 and 120 ms, and greatest PPF at 4500 and 6000 ms. PPI was influenced by sex (more PPI in men than women) and hormonal contraception, whereas PPF was affected by task order (greater PPF when the PPF task followed, rather than preceded, the PPI task).
CONCLUSIONS
Our findings indicate that studies of PPI and PPF need to consider, not only sex and hormonal status of study participants, but also task characteristics and presentation order to reduce variance and increase replicability across studies.
Topics: Adult; Male; Humans; Female; Prepulse Inhibition; Acoustic Stimulation; Hormonal Contraception; Reflex, Startle
PubMed: 36268723
DOI: 10.1177/02698811221133469 -
Psychophysiology Oct 2014The startle reflex is potentiated when anticipating emotional, compared to neutral, pictures. This study investigated the time course of reflex modulation during...
The startle reflex is potentiated when anticipating emotional, compared to neutral, pictures. This study investigated the time course of reflex modulation during anticipation and the impact of informative cuing on picture perception. Colors were used to signal the thematic content of emotional and neutral scenes; blink response modulation was measured by presenting acoustic startle probes 3, 2, or 1 s before picture onset or 2 s after picture onset. During anticipation of neutral scenes, blink magnitude showed increasing attenuation as picture onset approached, consistent with a modality-directed vigilance account. Conversely, when anticipating emotional scenes, reflex magnitude did not change over time, and blinks elicited closest to picture onset were potentiated compared to neutral. During perception, the expected reflex potentiation for unpleasant pictures was not found, suggesting that cuing may dampen defensive activation.
Topics: Arousal; Attention; Cues; Emotions; Female; Humans; Male; Photic Stimulation; Reflex, Startle; Visual Perception
PubMed: 24980898
DOI: 10.1111/psyp.12244 -
Journal of Neuroscience Methods Oct 2020The acoustic startle response (ASR) is a simple reflex that results in a whole body motor response after animals hear a brief loud sound and is used as a multisensory...
BACKGROUND
The acoustic startle response (ASR) is a simple reflex that results in a whole body motor response after animals hear a brief loud sound and is used as a multisensory tool across many disciplines. Unfortunately, a method of how to record, process, and analyze ASRs has yet to be standardized, leading to high variability in the collection, analysis, and interpretation of ASRs within and between laboratories.
NEW METHOD
ASR waveforms collected from young adult CBA/CaJ mice were normalized with features extracted from the waveform, the resulting power spectral density estimates, and the continuous wavelet transforms. The features were then partitioned into training and test/validation sets. Machine learning methods from different families of algorithms were used to combine startle-related features into robust predictive models to predict whether an ASR waveform is a startle or non-startle.
RESULTS
An ensemble of several machine learning models resulted in an extremely robust model to predict whether an ASR waveform is a startle or non-startle with a mean ROC of 0.9779, training accuracy of 0.9993, and testing accuracy of 0.9301.
COMPARISON WITH EXISTING METHODS
ASR waveforms analyzed using the threshold and RMS techniques resulted in over 80% of accepted startles actually being non-startles when manually classified versus 2.2% for the machine learning method, resulting in statistically significant differences in ASR metrics (such as startle amplitude and pre-pulse inhibition) between classification methods.
CONCLUSIONS
The machine learning approach presented in this paper can be adapted to nearly any ASR paradigm to accurately process, sort, and classify startle responses.
Topics: Acoustic Stimulation; Animals; Machine Learning; Mice; Mice, Inbred CBA; Prepulse Inhibition; Reflex, Startle
PubMed: 32668315
DOI: 10.1016/j.jneumeth.2020.108853 -
Nature Communications Nov 2021The reticulotegmental nucleus (RtTg) has long been recognized as a crucial component of brainstem reticular formation (RF). However, the function of RtTg and its...
The reticulotegmental nucleus (RtTg) has long been recognized as a crucial component of brainstem reticular formation (RF). However, the function of RtTg and its related circuits remain elusive. Here, we report a role of the RtTg in startle reflex, a highly conserved innate defensive behaviour. Optogenetic activation of RtTg neurons evokes robust startle responses in mice. The glutamatergic neurons in the RtTg are significantly activated during acoustic startle reflexes (ASR). Chemogenetic inhibition of the RtTg glutamatergic neurons decreases the ASR amplitudes. Viral tracing reveals an ASR neural circuit that the cochlear nucleus carrying auditory information sends direct excitatory innervations to the RtTg glutamatergic neurons, which in turn project to spinal motor neurons. Together, our findings describe a functional role of RtTg and its related neural circuit in startle reflexes, and demonstrate how the RF connects auditory system with motor functions.
Topics: Acoustic Stimulation; Animals; Auditory Pathways; Brain Stem; Cochlear Nerve; Mice; Mice, Inbred C57BL; Reflex, Startle
PubMed: 34737329
DOI: 10.1038/s41467-021-26723-9 -
Genes, Brain, and Behavior Mar 2015Fear-potentiated acoustic startle paradigms have been used to investigate phasic and sustained components of conditioned fear in rats and humans. This study describes a...
Fear-potentiated acoustic startle paradigms have been used to investigate phasic and sustained components of conditioned fear in rats and humans. This study describes a novel training protocol to assess phasic and sustained fear in freely behaving C57BL/6J mice, using freezing and/or fear-potentiated startle as measures of fear, thereby, if needed, allowing in vivo application of various techniques, such as optogenetics, electrophysiology and pharmacological intervention, in freely behaving animals. An auditory Pavlovian fear conditioning paradigm, with pseudo-randomized conditioned-unconditioned stimulus presentations at various durations, is combined with repetitive brief auditory white noise burst presentations during fear memory retrieval 24 h after fear conditioning. Major findings are that (1) a motion sensitive platform built on mechano-electrical transducers enables measurement of startle responses in freely behaving mice, (2) absence or presence of startle stimuli during retrieval as well as unpredictability of a given threat determine phasic and sustained fear response profiles and (3) both freezing and startle responses indicate phasic and sustained components of behavioral fear, with sustained freezing reflecting unpredictability of conditioned stimulus (CS)/unconditioned stimulus (US) pairings. This paradigm and available genetically modified mouse lines will pave the way for investigation of the molecular and neural mechanisms relating to the transition from phasic to sustained fear.
Topics: Animals; Behavior, Animal; Conditioning, Classical; Fear; Freezing; Male; Mice; Mice, Inbred C57BL; Models, Animal; Noise; Reflex, Startle
PubMed: 25761115
DOI: 10.1111/gbb.12211 -
Scientific Reports Feb 2022Looking at pictures of loved ones, such as one's romantic partner or good friends, has been shown to alleviate the experience of pain and reduce defensive reactions....
Looking at pictures of loved ones, such as one's romantic partner or good friends, has been shown to alleviate the experience of pain and reduce defensive reactions. However, little is known about such modulatory effects on threat and safety learning and the psychophysiological processes involved. Here, we explored the hypothesis that beloved faces serve as implicit safety cues and attenuate the expression of fear responses and/or accelerate extinction learning in a threatening context. Thirty-two participants viewed pictures of their loved ones (romantic partner, parents, and best friend) as well as of unknown individuals within contextual background colors indicating threat-of-shock or safety. Focusing on the extinction of non-reinforced threat associations (no shocks were given), the experiment was repeated on two more test days while the defensive startle-EMG, SCR, and threat ratings were obtained. Results confirmed pronounced defensive responding to instructed threat-of-shock relative to safety context (e.g., threat-enhanced startle reflex and SCR). Moreover, threat-potentiated startle response slowly declined across test days indicating passive extinction learning in the absence of shocks. Importantly, neither a main effect of face category (loved vs. unknown) nor a significant interaction with threat/safety instructions was observed. Thus, a long-term learning history of beneficial relations (e.g., with supportive parents) did not interfere with verbal threat learning and aversive apprehensions. These findings reflect the effects of worries and apprehensions that persist despite the repeated experience of safety and the pictorial presence of loved ones. How to counter such aversive expectations is key to changing mal-adaptive behaviors (e.g., avoidance or stockpiling), biased risk perceptions, and stereotypes.
Topics: Adult; Anxiety; Attention; Conditioning, Classical; Cues; Defense Mechanisms; Extinction, Psychological; Face; Family; Fear; Female; Friends; Healthy Volunteers; Humans; Love; Male; Reflex, Startle; Young Adult
PubMed: 35169193
DOI: 10.1038/s41598-022-06514-y -
Developmental Psychobiology May 2017Reduced habituation to aversive stimuli has been observed during adolescence and may reflect an underlying mechanism of vulnerability for anxiety disorders. This study...
Reduced habituation to aversive stimuli has been observed during adolescence and may reflect an underlying mechanism of vulnerability for anxiety disorders. This study examined the startle reflex during a fear-learning task in 54 8-14-year-old girls. We examined the relationship between mean startle, startle habituation, pubertal development, and two measures linked to risk for anxiety: behavioral inhibition system (BIS) and the error-related negativity (ERN). Puberty, BIS, and the ERN were unrelated to mean startle; however, each measure modulated startle habituation. Greater pubertal development was associated with reduced startle habituation across the CS+ and CS-. Higher BIS related to a larger ERN, and both were associated with reduced startle habituation specifically to the CS+. All effects were independent of each other. Findings suggest that puberty alters habituation of defense system activation to both threat and safety cues, and this is independent of risk for anxiety, which uniquely impacts habituation to threat cues.
Topics: Adolescent; Anxiety; Child; Evoked Potentials; Female; Habituation, Psychophysiologic; Humans; Puberty; Reflex, Startle
PubMed: 28383759
DOI: 10.1002/dev.21506 -
Biological Psychiatry Dec 1998Although there is a close correspondence between fear and anxiety, and the study of fear in animals has been extremely valuable for understanding brain systems that are... (Review)
Review
Although there is a close correspondence between fear and anxiety, and the study of fear in animals has been extremely valuable for understanding brain systems that are important for anxiety, it is equally clear that a richer animal model of human anxiety disorders would include measures of both stimulus-specific fear and something less stimulus specific, more akin to anxiety. Studies in patients with posttraumatic stress syndrome indicate these individuals seem to show normal fear reactions but abnormal anxiety measured with the acoustic startle reflex. Studies in rats, also using the startle reflex, indicate that highly processed explicit cue information (lights, tones, touch) activates the central nucleus of the amygdala, which in turn activates hypothalamic and brain stem target areas involved in specific signs of fear. Somewhat less explicit information, such as that produced by exposure to a threating environment for several minutes or by intraventricular administration of the peptide corticotropin-releasing hormone may activate a brain area closely related to the amygdala, called the bed nucleus of the stria terminalis, which in turn activates hypothalamic and brain stem target areas involved in specific signs of fear or anxiety. Because the nature of this information may be less specific than that produced by an explicit cue, and of much longer duration, activation of the bed nucleus of the stria terminalis may be more akin to anxiety than to fear.
Topics: Amygdala; Animals; Anxiety; Fear; Humans; Rats; Reflex, Startle
PubMed: 9861467
DOI: 10.1016/s0006-3223(98)00288-1