Studies in our laboratory have shown that modification of startle by lead stimuli with short- and long-lead-intervals is modulated by stimulus significance. The significant stimulus in a tone duration judgement task generates enhanced short-lead-interval startle inhibition as well as pronounced long-lead-interval startle facilitation. The present study was designed to compare tones with simple ...

BACKGROUND Previous research has demonstrated that the neuropeptide oxytocin modulates social behaviors and reduces anxiety. However, effects of oxytocin on startle reactivity, a well-validated measure of defense system activation related to fear and anxiety, have been inconsistent. Here we investigated the influence of oxytocin on startle reactivity with particular focus on the role of trait a...

Cocaine is a psychostimulant in the pharmacological class of drugs called Local Anesthetics. Interestingly, cocaine is the only drug in this class that has a chemical formula comprised of a tropane ring and is, moreover, addictive. The correlation between tropane and addiction is well-studied. Another well-studied correlation is that between psychosis induced by cocaine and that psychosis endog...

At a dose of 5 mg/kg, the tricyclic antidepressant drugs chlorimlpramine (ClMI), desipramine (DMI), Imipramlne (IMI), ii and chlordeslpramine (C-DMI) all blocked the excitatory effects of a low dose (30 _g/kg) of LSD on the acoustic startle response in the rat. Over a dose range from I-5 " , mg/kg, CIMI and DMI were about equally potent in blocking the LSD effect, despite the fact that both dru...

Bulimia nervosa (BN) and obsessive-compulsive disorder (OCD) co-occur at greater rates than chance and may have shared mechanisms of dysfunction. One of these proposed mechanisms is a hyper-responsive aversive system as indicated by heightened startle response to aversive stimuli. The present study examined this hypothesis using 2 types of aversive stimuli: disorder specific (e.g., high-caloric...

Emotional-motivational dysfunctions may significantly contribute to symptoms of attention-deficit/hyperactivity disorder (ADHD). Hyperactive-impulsive symptoms and sensation seeking could be the result of a search for reinforcers, and cognitive dysfunctions might be due to a low motivational drive. Emotional-motivational dysfunctions could also explain social dysfunctions in ADHD patients becau...

The startle response is composed by a set of reflex behaviors intended to prepare the organism to face a potentially relevant stimulus. This response can be modulated by several factors as, for example, repeated presentations of the stimulus (startle habituation), or by previous presentation of a weak stimulus (Prepulse Inhibition [PPI]). Both phenomena appear disrupted in schizophrenia that is...

development of brain structures and function. We studied the participation of proteins having neurotrophic and neurogrowth activities, like S 100beta and A3G7, in the adult rat model of short-and long-term habituation of acoustic startle reaction (ASR) with freezing behaviour recorded simultaneously. It was observed that rabbit polyclonal antibodies against protein S100beta, and monoclonal anti...

AIMS Prepulse inhibition (PPI) of the startle reflex, which refers to the ability of innocuous sensory events to reduce the startle reflex, has been described as an operational measure of sensorimotor gating that is reduced in several neuropsychiatric disorders, such as schizophrenia, but experience is lacking in addictions and alcoholism. The aim of this study was to examine the existence of i...

To provide insight into individual differences in fear learning, we examined the emotional and cognitive expressions of discriminative fear conditioning in direct relation to its neural substrates. Contrary to previous behavioral-neural (fMRI) research on fear learning--in which the emotional expression of fear was generally indexed by skin conductance--we used fear-potentiated startle, a more ...