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Michael Koch - One of the best experts on this subject based on the ideXlab platform.
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the acoustic Startle Response in rats circuits mediating evocation inhibition and potentiation
Behavioural Brain Research, 1997Co-Authors: Michael Koch, Hansulrich SchnitzlerAbstract:This review describes the neuronal mechanisms underlying the mediation and modulation of the acoustic Startle Response (ASR) in rats. The combination of anatomical, physiological and behavioral methods has identified pathways which mediate and modulate the ASR. The ASR is mediated by a relatively simple, oligosynaptic pathway located in the lower brainstem which activates spinal and cranial motor neurons. An important element of the pathway which mediates the ASR is the caudal nucleus of the pontine reticular formation (PnC). Interestingly, this nucleus is also the target of input from various brain nuclei which are involved in the modulation (e.g. fear-potentiation, sensitization, habituation, prepulse inhibition and pleasure-attenuation) of the ASR. Hence, the PnC can be described as a sensorimotor interface, where the transition of sensory input into the motor output can be directly influenced by excitatory or inhibitory afferents. On the basis of these facts we conclude that the ASR may be a valuable model for the study of general principles of sensorimotor-motivational information processing at the behavioral and neurophysiological level in mammals.
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Microinjections of the metabotropic glutamate receptor agonist,trans-(±)-1-amino-cyclopentane-1,3-dicarboxylate (trans-ACPD) into the amygdala increase the acoustic Startle Response of rats
Brain research, 1993Co-Authors: Michael KochAbstract:The present study examined the effect of intraamygdaloid application of the metabotropic glutamate receptor agonist trans-ACPD on the acoustic Startle Response. Trans-ACPD led to a disruption of between-session habituation which is normally seen after repeated testing after injections of the vehicle into the amygdala. More specifically, a statistically significant increase of the magnitude of the Startle Response was observed 4 h after injection of 30 nmol of trans-ACPD into the central amygdaloid nucleus. The present findings suggest a role for the metabotropic glutamate receptor in the amygdala in the enhancement of the acoustic Startle Response.
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microinjections of the metabotropic glutamate receptor agonist trans 1 amino cyclopentane 1 3 dicarboxylate trans acpd into the amygdala increase the acoustic Startle Response of rats
Brain Research, 1993Co-Authors: Michael KochAbstract:The present study examined the effect of intraamygdaloid application of the metabotropic glutamate receptor agonist trans-ACPD on the acoustic Startle Response. Trans-ACPD led to a disruption of between-session habituation which is normally seen after repeated testing after injections of the vehicle into the amygdala. More specifically, a statistically significant increase of the magnitude of the Startle Response was observed 4 h after injection of 30 nmol of trans-ACPD into the central amygdaloid nucleus. The present findings suggest a role for the metabotropic glutamate receptor in the amygdala in the enhancement of the acoustic Startle Response.
David L Braff - One of the best experts on this subject based on the ideXlab platform.
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the relationship of age to prepulse inhibition and habituation of the acoustic Startle Response
Biological Psychology, 2003Co-Authors: Joel Ellwanger, Mark A Geyer, David L BraffAbstract:Abstract Prepulse inhibition (PPI) of the Startle Response reflects an early stage of information processing that is abnormal in schizophrenia and certain other specific neuropsychiatric disorders that are distinguished by the inability to inhibit redundant or relatively irrelevant sensory, cognitive, or motor information. The goal of the present study was to characterize the effect of normal aging on PPI and habituation of the Startle Response and to examine the hypothesis that normal aging is characterized by a global decline in inhibitory function. Ninety-seven non-psychiatric controls (age range 18–88) were tested for Startle eyeblink Response using electromyogram (EMG) recording. Startle magnitude decreased and Startle latency increased with aging. PPI demonstrated an inverted U-shaped function with age (greatest PPI at intermediate ages) while there was no significant effect of age on Startle habituation. The results do not support the theory that aging is associated with a general decline in inhibitory function and contrast with previous studies that have compared only extreme age groups and have found no effects of age on PPI.
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modulation of the Startle Response and Startle laterality in relatives of schizophrenic patients and in subjects with schizotypal personality disorder evidence of inhibitory deficits
American Journal of Psychiatry, 2000Co-Authors: Kristin S Cadenhead, Neal R Swerdlow, Kathleen M Shafer, Martha Diaz, David L BraffAbstract:OBJECTIVE: Patients with schizophrenia spectrum disorders have been shown to have deficits in sensorimotor gating as assessed by prepulse inhibition of the Startle Response. The authors hypothesized that nonschizophrenic relatives of patients with schizophrenia would also have prepulse inhibition deficits, thereby reflecting a genetically transmitted susceptibility to sensorimotor gating deficits. METHOD: Twenty-five comparison subjects, 23 patients with schizophrenia, 34 relatives of the schizophrenic patients, and 11 subjects with schizotypal personality disorder were assessed in an acoustic Startle paradigm. The eye-blink component of the Startle Response was assessed bilaterally by using electromyographic recordings of orbicularis oculi. RESULTS: The patients with schizophrenia, their relatives, and subjects with schizotypal personality disorder all had reduced prepulse inhibition relative to comparison subjects, and these deficits were more evident in measures of right eye-blink prepulse inhibition. ...
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Prepulse inhibition and habituation of the Startle Response are stable neurobiological measures in a normal male population
Biological Psychiatry, 1999Co-Authors: Kristin S Cadenhead, Barbara S Carasso, Neal R Swerdlow, Mark A Geyer, David L BraffAbstract:Prepulse inhibition (PPI) and habituation of the Startle Response are operational measures of sensorimotor gating and information processing. Changes in the normal inhibition and habituation of the Startle Response may provide trait markers for illnesses such as schizophrenia that have altered neurotransmitter control of the neural circuitry that modulates these measures. The stability of PPI and habituation was assessed in 10 normal male subjects. Prepulse inhibition was found to be most stable in the more intense prepulse conditions, and habituation was most stable in the early portion of the test session. These data support the hypothesis that PPI and habituation are relatively stable neurobiological markers.
T Sharma - One of the best experts on this subject based on the ideXlab platform.
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prepulse inhibition of the Startle Response in risperidone treated patients comparison with typical antipsychotics
Schizophrenia Research, 2002Co-Authors: Veena Kumari, W Soni, T SharmaAbstract:Individuals with schizophrenia are known to show deficits in prepulse inhibition (PPI) of the Startle Response. PPI refers to a Response suppression in reaction to a strong startling stimulus, if preceded briefly by a weak non-startling stimulus and represents a well-established animal model to investigate information processing deficits in schizophrenia. This study examined PPI of the Startle acoustic Response in schizophrenic patients given typical antipsychotics or a second generation atypical antipsychotic, risperidone, using a naturalistic between-subjects design. Two groups of male schizophrenic patients: (i) stable on a range of typical antipsychotics (n = 20), and (ii) stable on risperidone (n = 10) were tested for PPI (prepulse-to-pulse intervals: 30, 60, and 120 ms, prepulses 15 dB above the background) of the acoustic Startle Response, and compared with a group of healthy male subjects (n = 20). Patients on typical antipsychotics showed significantly less PPI with 30 and 60 ms prepulse trials than healthy subjects. Risperidone-treated patients did not differ from healthy subjects for PPI with any prepulse trials. Further longitudinal within-subject studies are now required to examine whether risperidone is superior to typical antipsychotics in improving information processing functions, as assessed by PPI of the acoustic Startle Response, in treatment-responsive male patients with schizophrenia.
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influence of cigarette smoking on prepulse inhibition of the acoustic Startle Response in schizophrenia
Human Psychopharmacology-clinical and Experimental, 2001Co-Authors: Veena Kumari, W Soni, T SharmaAbstract:The prevalence of tobacco smoking is known to be higher in patients with schizophrenia than other psychiatric disorders and general population. These patients also show reduced prepulse inhibition (PPI) of the Startle Response. PPI refers to a reduction in Response to a strong startling stimulus if preceded shortly by a stimulus of sub-threshold intensity. PPI is thought of as an objective index of sensorimotor gating. Nicotine administered subcutaneously or via cigarette smoking enhances PPI in healthy human beings. It also enhances PPI at low, but not high, doses in the rat. We examined the influence of smoking on PPI of the acoustic Startle Response in 46 male patients with chronic schizophrenia. In a naturalistic design, patients (n = 9) who smoked a cigarette less than 10 min prior to being tested on PPI were compared with other smoking (n = 23) and non-smoking patients (n = 14). We found that the group of patients who smoked a cigarette prior to being tested had significantly greater PPI than other two groups. These observations suggest a PPI-enhancing effect of cigarette smoking on PPI in patents with schizophrenia. Higher prevalence of cigarette smoking in schizophrenic patients may reflect an attempt to improve sensorimotor gating deficits. Copyright © 2001 John Wiley & Sons, Ltd.
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prepulse inhibition of the Startle Response in men with schizophrenia effects of age of onset of illness symptoms and medication
Archives of General Psychiatry, 2000Co-Authors: Veena Kumari, W Soni, Vallakalil Mathew, T SharmaAbstract:Background Prepulse inhibition of the Startle reflex Response refers to the ability of a weak prestimulus to transiently inhibit the Response to a closely following strong sensory stimulus. This effect represents an operational index of sensorimotor gating and is found to be deficient in schizophrenia. Prepulse inhibition deficits in schizophrenia seem to be partially normalized by typical antipsychotics and more fully by some atypical antipsychotics. Early onset of schizophrenia, particularly in men, has been associated with abnormal brain maturation, profound neuropsychological deficits, and less responsiveness to antipsychotic medication. We evaluated the effects of the age of onset of illness, current positive and negative symptoms, and the type of medication (typical vs atypical) on prepulse inhibition of the Startle Response in schizophrenia. Methods Thirty-eight male schizophrenic patients and 20 healthy male controls underwent testing for prepulse inhibition of the acoustic Startle Response. Results Earlier onset of illness was associated with reduced prepulse inhibition, while adult onset of illness was not. No significant relationships occurred between current symptoms and prepulse inhibition. Patients given typical, but not atypical, antipsychotics exhibited less prepulse inhibition compared with healthy controls. Conclusion Early onset of illness is associated with profound deficits in prepulse inhibition of the Startle Response in men with schizophrenia.
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prepulse inhibition of the Startle Response in men with schizophrenia effects of age of onset of illness symptoms and medication
Archives of General Psychiatry, 2000Co-Authors: Veena Kumari, W Soni, Vallakalil Mathew, T SharmaAbstract:Background Prepulse inhibition of the Startle reflex Response refers to the ability of a weak prestimulus to transiently inhibit the Response to a closely following strong sensory stimulus. This effect represents an operational index of sensorimotor gating and is found to be deficient in schizophrenia. Prepulse inhibition deficits in schizophrenia seem to be partially normalized by typical antipsychotics and more fully by some atypical antipsychotics. Early onset of schizophrenia, particularly in men, has been associated with abnormal brain maturation, profound neuropsychological deficits, and less responsiveness to antipsychotic medication. We evaluated the effects of the age of onset of illness, current positive and negative symptoms, and the type of medication (typical vs atypical) on prepulse inhibition of the Startle Response in schizophrenia. Methods Thirty-eight male schizophrenic patients and 20 healthy male controls underwent testing for prepulse inhibition of the acoustic Startle Response. Results Earlier onset of illness was associated with reduced prepulse inhibition, while adult onset of illness was not. No significant relationships occurred between current symptoms and prepulse inhibition. Patients given typical, but not atypical, antipsychotics exhibited less prepulse inhibition compared with healthy controls. Conclusion Early onset of illness is associated with profound deficits in prepulse inhibition of the Startle Response in men with schizophrenia.
Dagmar Timmann - One of the best experts on this subject based on the ideXlab platform.
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involvement of the human medial cerebellum in long term habituation of the acoustic Startle Response
Experimental Brain Research, 2000Co-Authors: M Maschke, Florian P. Kolb, Hans-christoph Diener, Johannes Drepper, Kerstin Kindsvater, Dagmar TimmannAbstract:Animal studies have shown an involvement of the cerebellar vermis in long-term habituation of the acoustic Startle Response, but not in short-term habituation. The aim of the present study was to investigate whether short-term and long-term habituation of the acoustic Startle Response are impaired in patients with medial cerebellar lesions. Five patients with midline cerebellar lesions due to surgery for astrocytoma and ten healthy, age- and sex-matched subjects were studied. Subjects received 40 acoustic Startle stimuli each day on five successive days. Peak amplitudes of the Startle Response recorded at the orbicularis oculi and the sternomastoid muscles were obtained. Data were analyzed for Response decrement within the training session of one day (short-term habituation) and for a decrease in the Startle Response across the five training days (long-term habituation). Short- and long-term habituation of the Startle Response recorded at the sternomastoid muscles could be achieved in controls and in cerebellar patients. However, long-term habituation of the blink component of the acoustic Startle Response recorded at the orbicularis oculi muscles was significantly impaired in patients with cerebellar lesions compared with control subjects, whereas short-term habituation was preserved in both groups. The present findings suggest that the medial cerebellum is involved in long-term habituation of the blink component of the Startle Response in humans.
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Involvement of the human cerebellum during habituation of the acoustic Startle Response: A PET study
Journal of neurology neurosurgery and psychiatry, 1998Co-Authors: Dagmar Timmann, Christina Musso, Florian P. Kolb, Michel Rijntjes, Markus Jüptner, Stefan Müller, Hans-christoph Diener, Cornelius WeillerAbstract:The present study investigated the involvement of the human cerebellum in the habituation of the acoustic Startle Response using PET. The Startle Response was elicited in seven young, healthy subjects by a tone presented via headphones. Startle Responses were recorded from the right sternocleidomastoid muscle. Regional cerebral blood flow (rCBF) was assessed in nine scans and one Startle stimulus was applied during each scan. The reduction of size of the sternocleidomastoid muscle Response was correlated with changes in rCBF during the ongoing process of Startle Response habituation. A significant decrease of rCBF was found in the medial cerebellum. These data are consistent with an involvement of the medial parts of the human cerebellum in non-associative learning as proposed by previous animal studies.
Mark A Geyer - One of the best experts on this subject based on the ideXlab platform.
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patients with premenstrual dysphoric disorder have increased Startle Response across both cycle phases and lower levels of prepulse inhibition during the late luteal phase of the menstrual cycle
Neuropsychopharmacology, 2008Co-Authors: Kristiina Kask, Mark A Geyer, Torbjorn Backstrom, Maria Gulinello, Inger SundstromporomaaAbstract:Patients with premenstrual dysphoric disorder (PMDD) experience their most intense symptoms during the late luteal phase. The aim of the current study was to compare acoustic Startle Response and p ...
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the relationship of age to prepulse inhibition and habituation of the acoustic Startle Response
Biological Psychology, 2003Co-Authors: Joel Ellwanger, Mark A Geyer, David L BraffAbstract:Abstract Prepulse inhibition (PPI) of the Startle Response reflects an early stage of information processing that is abnormal in schizophrenia and certain other specific neuropsychiatric disorders that are distinguished by the inability to inhibit redundant or relatively irrelevant sensory, cognitive, or motor information. The goal of the present study was to characterize the effect of normal aging on PPI and habituation of the Startle Response and to examine the hypothesis that normal aging is characterized by a global decline in inhibitory function. Ninety-seven non-psychiatric controls (age range 18–88) were tested for Startle eyeblink Response using electromyogram (EMG) recording. Startle magnitude decreased and Startle latency increased with aging. PPI demonstrated an inverted U-shaped function with age (greatest PPI at intermediate ages) while there was no significant effect of age on Startle habituation. The results do not support the theory that aging is associated with a general decline in inhibitory function and contrast with previous studies that have compared only extreme age groups and have found no effects of age on PPI.
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Prepulse inhibition and habituation of the Startle Response are stable neurobiological measures in a normal male population
Biological Psychiatry, 1999Co-Authors: Kristin S Cadenhead, Barbara S Carasso, Neal R Swerdlow, Mark A Geyer, David L BraffAbstract:Prepulse inhibition (PPI) and habituation of the Startle Response are operational measures of sensorimotor gating and information processing. Changes in the normal inhibition and habituation of the Startle Response may provide trait markers for illnesses such as schizophrenia that have altered neurotransmitter control of the neural circuitry that modulates these measures. The stability of PPI and habituation was assessed in 10 normal male subjects. Prepulse inhibition was found to be most stable in the more intense prepulse conditions, and habituation was most stable in the early portion of the test session. These data support the hypothesis that PPI and habituation are relatively stable neurobiological markers.
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measurement of Startle Response prepulse inhibition and habituation
Current protocols in protein science, 1998Co-Authors: Mark A Geyer, Neal R SwerdlowAbstract:Abstract The Startle Response is comprised of a constellation of reflexes elicited by sudden, relatively intense stimuli. The Startle reflex is useful for studying fundamental properties of nervous function ranging from neurophysiological and anatomical relationships within the pons and reticular formation to forebrain regulation of complex behavioral states and cognitive processes. This unit presents protocols for measurement of the Startle Response in rats to acoustic stimuli, along with modifications encompassing an experimental manipulation such as drug treatment and measures of habituation of Startle; a method for measuring prepulse inhibition (PPI) of Startle; and specialized rat handling and calming techniques that supplement the Startle protocols.
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social isolation in the rat produces developmentally specific deficits in prepulse inhibition of the acoustic Startle Response without disrupting latent inhibition
Neuropsychopharmacology, 1994Co-Authors: Lawrence Stephen Wilkinson, Mark A Geyer, Simon Killcross, Trevor Humby, F S Hall, Trevor W RobbinsAbstract:A series of experiments examined the effects of 8 weeks of social isolation on spontaneous locomotor activity, prepulse inhibition (PPI) of the acoustic Startle Response, latent inhibition (LI) in a conditioned suppression paradigm, and basal and d-amphetamine stimulated dopamine (DA) release in the ventral striatum, as measured by in vivo microdialysis. Both isolation-reared animals (those isolated from the weaning age) and isolation-housed animals (those isolated as adults) were hyperactive when placed in a novel environment. Social isolation also led to deficits in PPI of the acoustic Startle Response that were specific to isolation-reared animals. Isolation rearing was without effect on the expression of LI but did lead to an enhanced Response to systemic d-amphetamine in terms of striatal DA release. The data are discussed with respect to the involvement of ventral striatal DA mechanisms in the expression of PPI and LI, differences in the impact of social isolation in young and adult animals, and the utility of social isolation model as a nonlesion, nonpharmacologic means of perturbing ventral striatal DA function.