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Michael Davis - One of the best experts on this subject based on the ideXlab platform.

  • lesions of the bed nucleus of the stria terminalis block sensitization of the acoustic Startle Reflex produced by repeated stress but not fear potentiated Startle
    Progress in Neuro-psychopharmacology & Biological Psychiatry, 1998
    Co-Authors: Jonatha C Gewirtz, Kenneth A Mcnish, Michael Davis
    Abstract:

    Abstract 1. 1. The effects of lesions of the bed nucleus of the stria terminalis (BST) on the acquisition of conditioned fear were examined. In Experiment 1, BST lesions did not block acquisition of fear-potentiated Startle to an explicit visual conditioned stimulus (CS) over 20 days of training. However, BST lesions blocked a gradual elevation in baseline Startle also seen over the course of training. 2. 2. The gradual increase in baseline Startle was replicated in Experiment 2 without the presence of an explicit CS, using unoperated subjects. Experiment 2 showed that the elevation was due to repetitive exposure to shock, because unshocked control subjects did not show any elevation over sessions. 3. 3. In Experiment 3, lesions of the BST did not disrupt rapid sensitization of the Startle Reflex by footshock, showing that different neural substrates underlie sensitization of Startle by acute and chronic exposure to footshock. 4. 4. These data indicate that the BST, despite its anatomical continuity with the amygdala, is not critically involved in the acquisition of conditioned fear to an explicit CS. Nevertheless, the BST is involved in mediating a stress-induced elevation in the Startle Reflex. This suggests that the BST and the CeA, which constitute part of the “extended amygdala” have complementary roles in responses to stress.

  • olfactory bulbectomy enhances sensitization of the acoustic Startle Reflex produced by acute or repeated stress
    Behavioral Neuroscience, 1997
    Co-Authors: Kenneth A Mcnish, Michael Davis
    Abstract:

    The effects of olfactory bulbectomy on the acoustic Startle Reflex and shock-induced sensitization of the Startle Reflex were examined in 3 experiments. In Experiment 1, bulbectomized animals showed a modest increase in baseline Startle responding following surgery, and normal acquisition of fear-potentiated Startle, but a pronounced increase in baseline Startle responding during the course of conditioning relative to sham-operated controls. In Experiments 2 and 3, bulbectomized animals showed shock-induced sensitization of the Startle Reflex to shock intensities that did not produce sensitization in sham and unoperated controls. These data suggest that olfactory bulbectomy results in an increased vulnerability to stressors, which may be mediated by a disinhibition of the amygdala or other structures involved in mediating stress and anxiety. Thus, the olfactory bulbectomy model of depression may share some similarities with other stress-induced models of depression.

  • exaggerated acoustic Startle Reflex in gulf war veterans with posttraumatic stress disorder
    American Journal of Psychiatry, 1996
    Co-Authors: Charles A Morgan, Michael Davis, Christian Grillon, Steven M Southwick, Dennis S Charney
    Abstract:

    Objective: Exaggerated Startle Reflex is reputed to be one ofthe cardinal symptoms of posttraumatic stress disorder (PTSD). The goal of this study was to assess the magnitude of the acoustic Startle Reflex in Gulf War veterans with PTSD. Method: The eye-blink component of the Startle Reflex was measured in response to six blocks ofpseudorandomized 40-msec white noise bursts of varying intensities (90, 96, 102, 1 08, and 1 14 dB) in 1 0 Gulf War veterans with PTSD, seven Gulf War veterans without PTSD, and I 5 civilian subjects without PTSD. Results: The magnitude ofthe first Startle response, as well as the magnitude ofStartle response averaged across blocks of testing, was significantly greater in Gulf War veterans with PTSD than in veteran and civilian comparison groups. Conclusions: Consistent with some clinical studies investigating the Startle response in Vietnam veterans with PTSD, this investigation provides evidence for exaggerated Startle response in this disorder. Preclinical studies of shock sensitization ofthe Startle response suggest that the higher levels ofStartle response seen in the PTSD subjects may reflect a sensitization of the fear/alarm response created by the stress of combat trauma. (AmJ Psychiatry 1996; 153:64-68)

  • acoustic Startle and anticipatory anxiety in humans effects of monaural right and left ear stimulation
    Psychophysiology, 1995
    Co-Authors: Christian Grillon, Michael Davis
    Abstract:

    The Startle Reflex elicited by binaural acoustic Startle stimuli is potentiated by the threat of electric shock. The present study explored the lateralization of this fear-potentiated Startle Reflex effect using acoustic Startle stimuli delivered binaurally or monaurally to the left or right ear and recorded from the left and right orbicularis oculi muscles. Consistent with previous results, the acoustic Startle to binaural stimulation was potentiated during the anticipation of shock. This effect was also present for monaural stimulation but was greater when Startle stimuli were delivered to the right than to the left ear. The results are discussed in terms of hemispheric lateralization during shock anticipation.

  • Prepulse inhibition of the acoustic Startle Reflex using visual and auditory prepulses: disruption by apomorphine.
    Psychopharmacology, 1995
    Co-Authors: Serge Campeau, Michael Davis
    Abstract:

    The amplitude of the acoustic Startle Reflex can be reduced reliably when preceded at short intervals by a weak stimulus (prepulse) which itself does not elicit Startle. The magnitude of this prepulse inhibition effect is attenuated by several dopamine agonists, such as apomorphine, especially when there is a relatively small difference between the intensity of the prepulse and the intensity of the background noise over which the prepulse is superimposed. One goal of the present experiment was to test the generality of this disruptive effect of apomorphine on prepulse inhibition by using either an auditory prepulse that included both a change in intensity and a change in frequency relative to the background noise or a visual prepulse stimulus. Apomorphine reduced auditory prepulse inhibition when induced by a small change in stimulus intensity, but not when induced by a change in both intensity and frequency. Apomorphine consistently reduced visual prepulse inhibition with a complete blockade at 100-ms test interval. However, it did not fully block the usual reduction in Startle onset latency or even attenuate the increase in Startle amplitude when a visual prepulse was presented 5, 10 or 15 ms before the Startle stimulus. Consistent with conclusions from other laboratories using auditory prepulse inhibition, these data suggest that apomorphine did not prevent the animal from detecting prepulse presentation under conditions where the drug completely blocked prepulse inhibition. Moreover, they indicate that the blockade of prepulse inhibition by apomorphine was independent of prepulse modality, adding generality to the original finding. Visual prepulse inhibition may be a useful alternative procedure for evaluating the effects of drugs on this attentional process.

Mark A Geyer - One of the best experts on this subject based on the ideXlab platform.

  • sensorimotor gating of the Startle Reflex what we said 25 years ago what has happened since then and what comes next
    Journal of Psychopharmacology, 2016
    Co-Authors: Neal R Swerdlow, David L Braff, Mark A Geyer
    Abstract:

    Our 1992 paper, 'The neural substrates of sensorimotor gating of the Startle Reflex: a review of recent findings and their implications', reviewed a series of (then) new and preliminary findings from cross-species studies of prepulse inhibition of the Startle Reflex, and commented on their implications. At the time that the report was composed, PubMed listed about 40 citations for studies using the search term 'prepulse inhibition'. In the ensuing 25 years, the field has added about 2700 such reports, reflecting the substantial growth in interest in prepulse inhibition and its utility across a number of different experimental applications. The 30th anniversary of the Journal of Psychopharmacology provides an opportunity to comment briefly on what was described in that 1992 report, how the field has progressed in the subsequent decades, and the paths forward for studies of prepulse inhibition and its use as an operational measure of sensorimotor gating. Among these future paths, we highlight the use of prepulse inhibition as: an endophenotype for genomic studies, and a biomarker for healthy brain circuitry, which may predict sensitivity to psychotherapeutics. Our 1992 report was highly speculative and based on paper-thin empirical data, yet viewed in a certain light, it appears to have contained a basic roadmap for a journey spanning the next 25 years of prepulse inhibition research… and 'what a long, strange trip it's been'.

  • prepulse inhibition of the Startle Reflex and its attentional modulation in the human s ketamine and n n dimethyltryptamine dmt models of psychosis
    Journal of Psychopharmacology, 2007
    Co-Authors: Karsten Heekeren, Mark A Geyer, A Neukirch, Jorg Daumann, M Stoll, M Obradovic, Karlartur Kovar, Euphrosyne Gouzoulismayfrank
    Abstract:

    Patients with schizophrenia exhibit diminished prepulse inhibition (PPI) of the acoustic Startle Reflex and deficits in the attentional modulation of PPI. Pharmacological challenges with hallucinogens are used as models for psychosis in both humans and animals. Remarkably, in contrast to the findings in schizophrenic patients and in animal hallucinogen models of psychosis, previous studies with healthy volunteers demonstrated increased levels of PPI after administration of low to moderate doses of either the antiglutamatergic hallucinogen ketamine or the serotonergic hallucinogen psilocybin. The aim of the present study was to investigate the influence of moderate and high doses of the serotonergic hallucinogen N,N-dimethyltryptamine (DMT) and the N-methyl-D-aspartate antagonist S-ketamine on PPI and its attentional modulation in humans. Fifteen healthy volunteers were included in a double-blind cross-over study with two doses of DMT and S-ketamine. Effects on PPI and its attentional modulation were investigated. Nine subjects completed both experimental days with the two doses of both drugs. S-ketamine increased PPI in both dosages, whereas DMT had no significant effects on PPI. S-ketamine decreased and DMT tended to decrease Startle magnitude. There were no significant effects of either drug on the attentional modulation of PPI. In human experimental hallucinogen psychoses, and even with high, clearly psychotogenic doses of DMT or S-ketamine, healthy subjects failed to exhibit the predicted attenuation of PPI. In contrast, PPI was augmented and the Startle magnitude was decreased after S-ketamine. These data point to important differences between human hallucinogen models and both animal hallucinogen models of psychosis and naturally occurring schizophrenia.

  • prepulse inhibition of the acoustically evoked Startle Reflex in patients with an acute schizophrenic psychosis a longitudinal study
    European Archives of Psychiatry and Clinical Neuroscience, 2004
    Co-Authors: Ulrich Meincke, B. Thelen, Mark A Geyer, Dina Morth, Tatjana Vos, Gouzoulis E Mayfrank
    Abstract:

    Deficits in sensorimotor gating as assessed by prepulse inhibition (PPI) of the Startle Reflex have been reported in schizophrenia. However, the state or trait nature of these deficits and the relationships with clinical features and psychopathological symptoms are not clear. To explore these issues, we performed a longitudinal study with schizophrenia inpatients.

  • Effects of the hallucinogen psilocybin on habituation and prepulse inhibition of the Startle Reflex in humans.
    Behavioural Pharmacology, 1998
    Co-Authors: Euphrosyne Gouzoulis-mayfrank, Karsten Heekeren, B. Thelen, H. Lindenblatt, Henning Sass, Mark A Geyer
    Abstract:

    Schizophrenic patients exhibit deficits in indices of sensorimotor gating, such as habituation and prepulse inhibition (PPI) of the Startle Reflex. Hallucinogenic drug-induced states are putative models for the early and acute stages of schizophrenic and schizophrenia-spectrum disorders. Hallucinoge

  • impaired prepulse inhibition of acoustic and tactile Startle response in patients with huntington s disease
    Journal of Neurology Neurosurgery and Psychiatry, 1995
    Co-Authors: Neal R Swerdlow, David L Braff, Mark A Geyer, Jane S Paulsen, Nelson Butters, Michael R Swenson
    Abstract:

    The corpus striatum serves a critical function in inhibiting involuntary, intrusive movements. Striatal degeneration in Huntington's disease results in a loss of motor inhibition, manifested by abnormal involuntary choreiform movements. Sensorimotor inhibition, or "gating", can be measured in humans using the Startle Reflex: the Startle Reflex is normally inhibited when the startling stimulus is preceded 30-500 ms earlier by a weak prepulse. In the present study, prepulse inhibition (PPI) was measured in patients with Huntington's disease to quantify and characterise sensorimotor gating. Compared with age matched controls, patients with Huntington's disease exhibit less PPI. Startle gating deficits are evident in patients with Huntington's disease when Startle is elicited by either acoustic or tactile stimuli. Even with stimuli that elicit maximal PPI in normal subjects, patients with Huntington's disease exhibit little or no PPI, and their pattern of Startle gating does not show the normal modulatory effects usually elicited by changing the prepulse interval or intensity. Startle amplitude and habituation and latency facilitation are largely intact in these patients, although Reflex latency is significantly slowed. In patients with Huntington's disease, Startle Reflex slowing correlates with cognitive impairment measured by the dementia rating scale, and with the performance disruptive effects of interference measured by the Stroop test. These findings document a profound disruption of sensorimotor gating in patients with Huntington's disease and are consistent with preclinical findings that identify the striatum and striatopallidal GABAergic efferent circuitry as critical substrates for sensorimotor gating of the Startle Reflex.

Neal R Swerdlow - One of the best experts on this subject based on the ideXlab platform.

  • sensorimotor gating of the Startle Reflex what we said 25 years ago what has happened since then and what comes next
    Journal of Psychopharmacology, 2016
    Co-Authors: Neal R Swerdlow, David L Braff, Mark A Geyer
    Abstract:

    Our 1992 paper, 'The neural substrates of sensorimotor gating of the Startle Reflex: a review of recent findings and their implications', reviewed a series of (then) new and preliminary findings from cross-species studies of prepulse inhibition of the Startle Reflex, and commented on their implications. At the time that the report was composed, PubMed listed about 40 citations for studies using the search term 'prepulse inhibition'. In the ensuing 25 years, the field has added about 2700 such reports, reflecting the substantial growth in interest in prepulse inhibition and its utility across a number of different experimental applications. The 30th anniversary of the Journal of Psychopharmacology provides an opportunity to comment briefly on what was described in that 1992 report, how the field has progressed in the subsequent decades, and the paths forward for studies of prepulse inhibition and its use as an operational measure of sensorimotor gating. Among these future paths, we highlight the use of prepulse inhibition as: an endophenotype for genomic studies, and a biomarker for healthy brain circuitry, which may predict sensitivity to psychotherapeutics. Our 1992 report was highly speculative and based on paper-thin empirical data, yet viewed in a certain light, it appears to have contained a basic roadmap for a journey spanning the next 25 years of prepulse inhibition research… and 'what a long, strange trip it's been'.

  • effects of pergolide on sensorimotor gating of the Startle Reflex in rats
    Psychopharmacology, 2001
    Co-Authors: Neal R Swerdlow, Amanda Platten, Jody M Shoemaker, Leia Pitcher, Pamela P Auerbach
    Abstract:

    Rationale: Prepulse inhibition (PPI), a cross-species measure of sensorimotor gating, is impaired in certain neuropsychiatric disorders, including schizophrenia. This study was designed to assess the effects of the D2-family agonist pergolide in rats, in anticipation of human studies of the dopaminergic regulation of PPI. Methods: The effects of pergolide (0.0001–0.5 mg/kg) on PPI of the acoustic Startle Reflex were studied in rats using a wide range of prepulse intensities [1–15 dB(A) over background] and prepulse intervals (5–100 ms, onset to onset). Studies also examined the effects of the D2 antagonist haloperidol on pergolide-induced changes in PPI. Results: Pergolide exhibited dose- and stimulus-dependent effects on PPI. Pergolide increased PPI when Startle stimuli were preceded by weak prepulses [1–5 dB(A) over background] at the longest prepulse interval (100 ms), or intense prepulses [15 dB(A) over background] at short prepulse intervals (5–20 ms). Pergolide (0.5 mg/kg) also decreased PPI elicited by intense prepulses at long intervals (60–100 ms). Both PPI-enhancing and PPI-disruptive effects of pergolide were reversed by the D2 antagonist haloperidol. Conclusions: These effects of pergolide suggest that D2 substrates mediate opposing influences on PPI under different stimulus conditions. The dopaminergic regulation of sensorimotor gating appears to interact with stimulus characteristics such as relative intensity and temporal separation, allowing for dynamic shifts in both the quantity and quality of "gated" information.

  • effects of caffeine on sensorimotor gating of the Startle Reflex in normal control subjects impact of caffeine intake and withdrawal
    Psychopharmacology, 2000
    Co-Authors: Neal R Swerdlow, A Eastvold, T Gerbranda, K M Uyan, P L Hartman, Q Doan, Pamela P Auerbach
    Abstract:

    Rationale: Prepulse inhibition (PPI), a cross–species measure of sensorimotor gating, is impaired in certain neuropsychiatric disorders. This study was designed to assess caffeine effects on PPI in normal humans, as part of an effort to understand cross-species differences and similarities in the neurochemical regulation of PPI. Methods: Startle was measured during a screening session; 7 days later, subjects were retested after placebo or caffeine (200 mg; double-blind design). Subjects were characterized as low versus high caffeine drinkers based on established scales (range 11–628 mg/day), and either maintained ad libitum caffeine intake (Ad lib study; n=18) or refrained from caffeine consumption for ≥15 h prior to testing (Withdrawal study; n=12). Autonomic and self-rating measures, acoustic and tactile Startle, and unimodal and cross-modal PPI, were measured in divided sessions for 3 h post-treatment. Results: There were significant effects of caffeine and/or caffeine withdrawal on several self-rating and autonomic measures, and on Startle Reflex habituation, but not on acoustic or tactile Startle magnitude or PPI. Difference scores of Startle data from screening versus test days revealed no group effects on Startle magnitude, but PPI difference scores revealed that caffeine had opposite effects on low versus high caffeine drinkers (means=57 versus 258 mg/day) in the two withdrawal states. In the absence of withdrawal, caffeine reduced PPI in heavy caffeine drinkers; during withdrawal, caffeine increased PPI in heavy caffeine drinkers. The opposite pattern was evident in low caffeine drinkers. Conclusions: While a physiologically active dose of caffeine has no simple effects on PPI in normal humans, both withdrawal states and normal levels of caffeine consumption may be important factors in understanding this drug's effects on sensorimotor gating.

  • mitochondrial toxin 3 nitropropionic acid produces Startle Reflex abnormalities and striatal damage in rats that model some features of huntington s disease
    Neuroscience Letters, 1997
    Co-Authors: M H Kodsi, Neal R Swerdlow
    Abstract:

    Systemic administration of the mitochondrial toxin 3-nitropropionic acid (3NP) to rats produces striatal lesions that mimic some aspects of pathology in Huntington's disease (HD). To evaluate whether 3NP-induced lesions cause sensorimotor gating deficits observed in HD, we measured prepulse inhibition (PPI) of the acoustic Startle Reflex after systemic administration of 3NP (10, 15, or 20 mg/kg) to 5-month-old rats. PPI, the reduction of Startle magnitude by a weak auditory prestimulus, is significantly reduced in patients with HD. Two daily injections of 3NP produced gross histologic evidence of striatal lesions in some rats and significantly reduced PPI. Striatal lesions also significantly disrupted amphetamine-induced stereotypy, another index of dorsal striatal function. 3NP thus reproduces a specific objective and quantifiable gating deficit found in patients with HD.

  • impaired prepulse inhibition of acoustic and tactile Startle response in patients with huntington s disease
    Journal of Neurology Neurosurgery and Psychiatry, 1995
    Co-Authors: Neal R Swerdlow, David L Braff, Mark A Geyer, Jane S Paulsen, Nelson Butters, Michael R Swenson
    Abstract:

    The corpus striatum serves a critical function in inhibiting involuntary, intrusive movements. Striatal degeneration in Huntington's disease results in a loss of motor inhibition, manifested by abnormal involuntary choreiform movements. Sensorimotor inhibition, or "gating", can be measured in humans using the Startle Reflex: the Startle Reflex is normally inhibited when the startling stimulus is preceded 30-500 ms earlier by a weak prepulse. In the present study, prepulse inhibition (PPI) was measured in patients with Huntington's disease to quantify and characterise sensorimotor gating. Compared with age matched controls, patients with Huntington's disease exhibit less PPI. Startle gating deficits are evident in patients with Huntington's disease when Startle is elicited by either acoustic or tactile stimuli. Even with stimuli that elicit maximal PPI in normal subjects, patients with Huntington's disease exhibit little or no PPI, and their pattern of Startle gating does not show the normal modulatory effects usually elicited by changing the prepulse interval or intensity. Startle amplitude and habituation and latency facilitation are largely intact in these patients, although Reflex latency is significantly slowed. In patients with Huntington's disease, Startle Reflex slowing correlates with cognitive impairment measured by the dementia rating scale, and with the performance disruptive effects of interference measured by the Stroop test. These findings document a profound disruption of sensorimotor gating in patients with Huntington's disease and are consistent with preclinical findings that identify the striatum and striatopallidal GABAergic efferent circuitry as critical substrates for sensorimotor gating of the Startle Reflex.

Ferran Balada - One of the best experts on this subject based on the ideXlab platform.

  • Startle Reflex modulation by affective face “Emoji” pictographs
    Psychological Research, 2020
    Co-Authors: Anton Aluja, Ferran Balada, Eduardo Blanco, Ignacio Lucas, Angel Blanch
    Abstract:

    The current research was designed to assess possible differences in the emotional content of pleasant and unpleasant face emoji using acoustically evoked eyeblink Startle Reflex response. Stimuli were selected from Emojipedia Webpage. First, we assessed these stimuli with a previous independent sample of 190 undergraduate students (46 males and 144 females) mean age of 21.43 years (SD 3.89). A principal axis method was performed using the 30 selected emoji faces, extracting two factors (15 pleasant and 15 unpleasant emoji). Second, we measured the acoustic Startle Reflex modulation in 53 young adult women [mean age 22.13 years (SD 4.3)] during the viewing of each of the 30 emoji emotional faces in the context of the theory of motivation and emotion proposed by Lang ( 1995 ), but considering only the valence dimension. We expected to find higher acoustically evoked Startle responses when viewing unpleasant emoji and lower responses for pleasant ones, similarly to the results obtained in the studies using human faces as emotional stimulus. An ANOVA was conducted to compare acoustic Startle responses associated with pleasant and unpleasant emoji. Results yielded main effects for picture valence ( λ  = 0.80, F (1, 50) = 12.80, p  = .001, η ^2 = 0.20). Post-hoc t test analysis indicated significant differences in the Startle response between unpleasant (50.95 ± 1.75) and pleasant (49.14 ± 2.49) emoji ( t (52) = 3.59, p  = .001), with a Cohen’s d  = 0.495. Viewing affective facial emoji expressions modulates the acoustic Startle Reflex response according to their emotional content.

  • examining habituation of the Startle Reflex with the reinforcement sensitivity theory of personality
    Psychophysiology, 2016
    Co-Authors: Angel Blanch, Anton Aluja, Ferran Balada
    Abstract:

    : The habituation of the acoustic Startle Reflex (ASR) was examined concerning individual differences in sensitivity to punishment (PUN) and sensitivity to reward (REW), within the general framework of the reinforcement sensitivity theory (RST) of personality. Two hypotheses derived from the RST were evaluated: the separable subsystems hypothesis and the joint subsystems hypothesis. In addition, we examined the direction of the relationship of PUN and REW with the habituation of the ASR. A habituation segment of electromyography recordings of the orbicularis oculi was assessed with an unconditional latent curve model. In accordance with the RST hypotheses, the relationship of PUN and REW on the habituation process was assessed with two conditional latent curve models. There was higher support for the separable subsystems hypothesis. In addition, PUN and REW related with the habituation trajectory of the ASR in the expected directions. Higher levels of PUN and lower levels of REW related with a slower habituation of the ASR, whereas lower levels of PUN and higher levels of REW related with a faster habituation of the ASR.

  • affective modulation of the Startle Reflex and the reinforcement sensitivity theory of personality the role of sensitivity to reward
    Physiology & Behavior, 2015
    Co-Authors: Anton Aluja, Angel Blanch, Ferran Balada
    Abstract:

    Abstract This study evaluated differences in the amplitude of Startle Reflex and Sensitivity to Reward (SR) and Sensitivity to Punishment (SP) personality variables of the Reinforcement Sensitivity Theory (RST). We hypothesized that subjects with higher scores in SR would obtain a higher Startle Reflex when exposed to pleasant pictures than lower scores, while higher scores in SP would obtain a higher Startle Reflex when exposed to unpleasant pictures than subjects with lower scores in this dimension. The sample consisted of 112 healthy female undergraduate psychology students. Personality was assessed using the short version of the Sensitivity to Punishment and Sensitivity Reward Questionnaire (SPSRQ). Laboratory anxiety was controlled by the State Anxiety Inventory. The Startle blink Reflex was recorded electromyographically (EMG) from the right orbicularis oculi muscle as a response to the International Affective Picture System (IAPS) pleasant, neutral and unpleasant pictures. Subjects higher in SR obtained a significant higher Startle Reflex response in pleasant pictures than lower scorers (48.48 vs 46.28, p

  • affective modulation of the Startle Reflex and the reinforcement sensitivity theory of personality the role of sensitivity to reward
    Physiology & Behavior, 2015
    Co-Authors: Anton Aluja, Angel Blanch, Eduardo Blanco, Ferran Balada
    Abstract:

    This study evaluated differences in the amplitude of Startle Reflex and Sensitivity to Reward (SR) and Sensitivity to Punishment (SP) personality variables of the Reinforcement Sensitivity Theory (RST). We hypothesized that subjects with higher scores in SR would obtain a higher Startle Reflex when exposed to pleasant pictures than lower scores, while higher scores in SP would obtain a higher Startle Reflex when exposed to unpleasant pictures than subjects with lower scores in this dimension. The sample consisted of 112 healthy female undergraduate psychology students. Personality was assessed using the short version of the Sensitivity to Punishment and Sensitivity Reward Questionnaire (SPSRQ). Laboratory anxiety was controlled by the State Anxiety Inventory. The Startle blink Reflex was recorded electromyographically (EMG) from the right orbicularis oculi muscle as a response to the International Affective Picture System (IAPS) pleasant, neutral and unpleasant pictures. Subjects higher in SR obtained a significant higher Startle Reflex response in pleasant pictures than lower scorers (48.48 vs 46.28, p<0.012). Subjects with higher scores in SP showed a light tendency of higher Startle responses in unpleasant pictures in a non-parametric local regression graphical analysis (LOESS). The findings shed light on the relationships among the impulsive-disinhibited personality, including sensitivity to reward and emotions evoked through pictures of emotional content.

Yuji Mori - One of the best experts on this subject based on the ideXlab platform.

  • Alarm Pheromone Is Detected by the Vomeronasal Organ in Male Rats
    Chemical senses, 2013
    Co-Authors: Yasushi Kiyokawa, Yukari Takeuchi, Yuka Kodama, Takahiro Kubota, Yuji Mori
    Abstract:

    It is widely known that a stressed animal releases specific pheromones, possibly for alarming nearby conspecifics. We previously investigated an alarm pheromone in male rats and found that this alarm pheromone evokes several responses, including increases in the defensive and risk assessment behaviors in a modified open-field test, and enhancement of the acoustic Startle Reflex. However, the role of the vomeronasal organ in these pheromone effects remains unclear. To clarify this point, vomeronasal organ-excising or sham surgeries were performed in male rats for use in 2 experimental models, after which they were exposed to alarm pheromone. We found that the vomeronasal organ-excising surgery blocked the effects of this alarm pheromone in both the modified open-field test and acoustic Startle Reflex test. In addition, the results of habituation/dishabituation test and soybean agglutinin binding to the accessory olfactory bulb suggested that the vomeronasal organ-excising surgery completely ablated the vomeronasal organ while preserving the functioning of the main olfactory system. From the above results, we showed that the vomeronasal organ plays an important role in alarm pheromone effects in the modified open-field test and acoustic Startle Reflex test.

  • Enhancement of the acoustic Startle Reflex by an alarm pheromone in male rats.
    Physiology & behavior, 2007
    Co-Authors: Hideaki Inagaki, Yasushi Kiyokawa, Yukari Takeuchi, Takefumi Kikusui, Yuji Mori
    Abstract:

    Recently, we reported that an alarm pheromone released from the perianal region of male rats aggravated stress-induced hyperthermia and increased defensive and risk assessment behaviors in recipient male rats. Based on these results, we hypothesized that the primary effect of the alarm pheromone is to increase anxiety; however, there is still no clear evidence for this pheromone effect. Therefore, we examined this issue by assessing the effect of the alarm pheromone on the acoustic Startle Reflex (ASR), which is a useful index for studying negative emotions such as anxiety in rats. The alarm pheromone enhanced the ASR for 105-dB auditory stimuli, but not for those of 90 and 120 dB, when these three intensities of sound were used randomly. The same results were obtained when one of these three intensities was used repeatedly. In addition, pretreatment with diazepam (i.p.) at doses of 0.7 and 2.0 mg/kg suppressed the ASR of the pheromone recipients, whereas the lower dose (0.2 mg/kg) slightly attenuated the pheromone effect and the control injection (vehicle) had no effect. These results indicate that the alarm pheromone enhances the ASR by increasing anxiety in recipient rats, suggesting that the primary effect of the alarm pheromone is to increase the anxiety level.