Memantine Attenuates Salicylate-induced Tinnitus Possibly by Reducing NR2B Expression in Auditory Cortex of Rat

Memantine, a noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptor, suppresses the release of excessive levels of glutamate that may induce neuronal excitation. Here we investigated the effects of memantine on salicylate-induced tinnitus model. The expressions of the activity-regulated cytoskeleton-associated protein (ARC) and tumor necrosis factor-alpha (TNF α)genes; as well as the NMDA receptor subunit 2B (NR2B) gene and protein, were examined in the SH-SY5Y cells and the animal model. We also used gap-prepulse inhibition of the acoustic startle reflex (GPIAS) and noise burst prepulse inhibition of acoustic startle, and the auditory brainstem level (electrophysiological recordings of auditory brainstem responses, ABR) and NR2B expression level in the auditory cortex to evaluate whether memantine could reduce salicylate-mediated behavioral disturbances. NR2B was significantly upregulated in salicylate-treated cells, but downregulated after memantine treatment. Similarly, expression of the inflammatory cytokine genes TNFα and immediate-early gene ARC was significantly increased in the salicylate-treated cells, and decreased when the cells were treated with memantine. These results were confirmed by NR2B immunocytochemistry. GPIAS was attenuated to a significantly lesser extent in rats treated with a combination of salicylate and memantine than in those treated with salicylate only. The mean ABR threshold in both groups was not significant different before and 1 day after the end of treatment. Additionally, NR2B protein expression in the auditory cortex was markedly increased in the salicylate-treated group, whereas it was reduced in the memantine-treated group. These results indicate that memantine is useful for the treatment of salicylate-induced tinnitus.

Proposal of conditional random inter-stimulus interval method for unconstrained enclosure based GPIAS measurement systems

Gap prepulse inhibition of acoustic startle (GPIAS) method has been used effectively for the objective assessment of tinnitus in animals. Among two types of enclosures for the GPIAS, the unconstrained type carries less risk of animal death due to the absence of binding stress in the enclosure, and lack of need for alteration to animal size variation as it grows. However, animals' voluntary movements, which have no relation to the startles evoked by acoustic stimuli, are problematic, as they cannot be excluded in the case of the unconstrained enclosure based GPIAS measurement system. In order to discount voluntary movements which are not associated with external acoustic stimuli, we propose the conditional random interstimulus interval (CR ISI) method for unconstrained enclosure based GPIAS measurement. With the proposed ISI method, the unconstrained enclosure based acoustic startle response measurement system has been implemented in this paper. As a result, the effectiveness of the proposed CR ISI method has been verified and compared with those of conventional ISI methods through animal experiments using SD-rats. The experimental results showed that abnormal startle responses and invalid GPIAS values caused by motion were prevented when our proposed CR ISI method was applied to our implemented system. It was also verified that our proposed CR ISI method is advantageous in reducing the total experimental time for acquiring normal startle responses and valid GPIAS values, compared to conventional ISI methods, since our proposed CR ISI can begin the acoustic stimulation only when the animal gets stable and motionless.

Interrater reliability of the Saint-Anne Dargassies Scale in assessing the neurological patterns of healthy preterm newborns / Confiabilidade inter-observadores da Escala de Saint-Anne Dargassies na avaliação neurológica de recém-nascidos pré-termo sadios

Abstract Objectives: to assess the interrater reliability of the Saint-Anne Dargassies Scale in assessing neurological patterns of healthy preterm newborns. Methods: twenty preterm newborns met the inclusion criteria for participation in this prospective study. The neurologic examination was performed using the Saint-Anne Dargassies Scale, showing normal serial cranial ultrasound examination. In order to test the reliability, the study was structured as follows: group I (rater 1/physiotherapist; rater 2/neonatologist); group II (rater 3/physiotherapist; rater 4/child neurologist) and the gold standard (expert and professor in pediatric neurology). Results: high interrater agreement was observed between groups I - II compared with the gold standard in assessing postural pattern (p<0.01). Regarding the assessment ofprimitive reflexes, greater agreement was observed in the evaluation of palmar grasp reflex and Moro reflex (p< 0.01) for group I compared with the gold standard. An analysis of tone demonstrated heterogeneous agreement, without compromising the reliability of the scale. The probability of equality between measurements of head circumference in the two groups, compared with the gold standard, was observed. Conclusions: the Saint-Anne Dargassies Scale demonstrated high reliability and homogeneity with significant power of reproducibility and may be capable to identify preterm newborns suspected of having neurological deficits.

Resumo Objetivos: avaliar a confiabilidade inter-observadores na avaliação do padrão neurológico de recém-nascidos pré-termo saudáveis pela Escala de Saint-Anne Dargassies. Métodos: vinte recém-nascidos pré-termos foram selecionados com base nos critérios de inclusão para participarem deste estudo prospectivo. O exame neurológico foi realizado utilizando a Escala de Saint-Anne Dargassies e os exames de ultra-som craniano seriados normais. Para testar a confiabilidade da escala o estudo foi estruturado da seguinte forma: grupo I (examinador 1 /fisioterapeuta; examinador 2 / neonatologista); grupo II (avaliador 3 /fisioterapeuta; avaliador 4 / neurologista infantil) e o padrão-ouro (expert e professor em neurologia pediátrica). Resultados: foi observado uma concordância alta inter-observadores entre os grupos I -II em comparação com o padrão ouro na avaliação padrão postural (p<0,01). Em relação à avaliação dos reflexos primitivos, observou-se maior concordância na avaliação do reflexo palmar e do reflexo de Moro (p<0,01) para o grupo I em comparação com o padrão-ouro. Uma análise do tônus demonstrou acordo heterogêneo, sem comprometer a confiabilidade da escala. Observou-se a probabilidade de igualdade entre as medidas do perímetro cefálico nos dois grupos em comparação com o padrão-ouro. Conclusões: a Escala de Saint-Anne Dargassies demonstrou alta confiabilidade e homogeneidade com poder significativo de reprodutibilidade podendo identificar recém-nascidos pré-termo com suspeita de déficit neurológico.

Effects of 5HT1A Activation on Gating Profile Following 5HT Depletion in Rats Lacking Social Attachment Since Weanling

OBJECTIVE: Central 5-HT1A receptor is involved in the modulation of sensorimotor gating function. However, its precise role is not clearly defined in developmentally social deprived (isolation rearing, IR) rats featured with impaired sensorimotor gating ability. We therefore aimed to examine the effects of 5HT1A activation on acoustic startle response (ASR) and prepulse inhibition (PPI) in IR rats in a condition of compromised presynaptic 5-HT functions. METHODS: Social control (SOC) and IR rats received an intracerebraoventricular (ICV) injection of 5-HT depletor, 5,7-DHT. Seven days later rats entered a protocol of 8-OH-DPAT, a 5-HT1A agonist, in which locomotor activity, ASR and PPI and their tissue levels of 5-HT were measured. RESULTS: Our results found that both IR and 5,7-DHT decreased the tissue concentration of 5-HT. IR-induced hyperactivity and gating impairment were unaffected by 5-HT depletion. 8-OH-DPAT strengthened the ASR in IR but not SOC rats and the drug-reduced PPI could be adjusted by 5,7-DHT pretreatment. 8-OH-DPAT at 100 μg/kg enhanced PPI in 5-HT-depleted SOC rats. However for IR rats, 8-OH-DPAT strengthened PPI in sham rats but downgraded it in depletion condition. CONCLUSION: The integrity of central 5-HT system is important to 5-HT1A-modulated sensorimotor gating in isolation-reared rats.

Familiar Hyperekplexia, a Potential Cause of Cautious Gait: A New Korean Case and a Systematic Review of Phenotypes

Familial hyperekplexia, also called startle disease, is a rare neurological disorder characterized by excessive startle responses to noise or touch. It can be associated with serious injury from frequent falls, apnea spells, and aspiration pneumonia. Familial hyperekplexia has a heterogeneous genetic background with several identified causative genes; it demonstrates both dominant and recessive inheritance in the α1 subunit of the glycine receptor (GLRA1), the β subunit of the glycine receptor and the presynaptic sodium and chloride-dependent glycine transporter 2 genes. Clonazepam is an effective medical treatment for hyperekplexia. Here, we report genetically confirmed familial hyperekplexia patients presenting early adult cautious gait. Additionally, we review clinical features, mode of inheritance, ethnicity and the types and locations of mutations of previously reported hyperekplexia cases with a GLRA1 gene mutation.

An Infantile Case of Sandhoff Disease Presenting With Swallowing Difficulty

Infants with Sandhoff disease typically appear normal until 3–6 months of age. As the disease progresses, they present with symptoms such as loss of motor skills, exaggerated startle response to loud noise, seizures, visual loss, and paralysis. We encountered a rare case of a 22-month-old girl with Sandhoff disease characterized by progressive motor weakness and dysphagia, who initially showed signs of aspiration at 20 months of age. The major problems related to dysphagia were oromotor dysfunction and abnormal feeding posture. Within 3 months of identification of difficulty in swallowing, the patient showed a significant decrease in food intake, with rapid deterioration of nutritional status. We report our case with a review of the literature.

Modulation of the startle response in verbal aggressors: differences among stimuli with distinct affective social content

The emotional response to socially affective stimuli is an important variable to understand aggression. Research is lacking on the psychophysiological basis of verbal aggressiveness that would allow the identification of these emotional responses. The aim of the present study was to investigate modulation of the startle response in verbal aggressors during the presentation of visual stimuli with different affective social content. Acoustic startle probes were administered to 29 verbal aggressors and 28 non-verbal aggressors while viewing slides from the International Affective Picture System, which contains sexual, filial, neutral, unpleasant, and suffering of others pictures. Verbal aggressors showed a low startle response to sexual pictures compared with non-verbal aggressors and a potentiated startle response to neutral pictures compared with unpleasant, filial, and suffering of others pictures. These differences were observed among women. Based on previous studies, the present results may be explained by high testosterone levels, low cortisol levels, and moral disengagement exhibited by verbally aggressive women...

Differences in P50 and prepulse inhibition of the startle reflex between male smokers and non-smokers with first episode schizophrenia without medical treatment / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Nicotine may improve schizophrenia patient's cognitive deficit symptoms. This study was to explore the chronic effects of smoking on prepulse inhibition of the startle reflex (PPI) and P50 in the patients with first-episode schizophrenia (FES).</p><p><b>METHODS</b>The event-related potentials (ERP) recording and analysis instrument made by Brain Products, Germany, was used to detect PPI and P50 in 49 male FES patients (FES group, n = 21 for smokers and n = 28 for non-smokers) and 43 normal male controls (control group, n = 19 for smokers and n = 24 for non-smokers).</p><p><b>RESULTS</b>Compared with normal controls, the FES group had prolonged PPI latency when elicited by single stronger stimulus (P < 0.05); the FES group had prolonged PPI latency and increased PPI amplitude (P < 0.05, 0.01) when elicited by weak and strong stimuli. The FES group had lower PPI inhibition rate than normal controls (P < 0.05). Compared with normal controls, the FES group had increased P50-S2 amplitude and increased amplitude ratio S2/S1 (both P <0.05). In the control group, the smokers had a tendency of increase in P50-S2 amplitude (P > 0.05) and shorter P50-S2 latency (P < 0.05) than the non-smokers. The smokers had higher PPI amplitude than the non-smokers (P < 0.05). In the FES group, the smokers had higher P50-S1 amplitude, shorter P50-S2 latency, and higher amplitude ratio S2/S1 than the non-smokers (P < 0.05, 0.01). The smokers had higher PPI amplitude than the non-smokers (P < 0.05).</p><p><b>CONCLUSIONS</b>There is obvious PPI and P50 deficits in schizophrenic patients. However, these deficits are relatively preserved in the smokers compared with the non-smokers, which suggests that long-term smoking might partially improve the sensory gating in schizophrenic patients. Whether this conclusion can be deduced to female patients requires further follow-ups.</p>

The progress and prospect of prepulse inhibition in autism / 生理学报

Prepulse inhibition (PPI) is suppression of the startle reflex when an intense startling stimulus is preceded by a weaker sensory stimulus (the prepulse). It is an operational measurement of sensorimotor gating mechanism to help human adapt to complex environment. This weak prepulse protect central cognitive processing by damping the effect of intense stimuli. Autistics cannot select out behaviorally important information from a lot of irrelevant resources and reflect abnormal gating mechanism and attentional abnormalities. Previous studies have not made agreement on whether autistic patients demonstrated deficits in PPI, because the results depend on age, sex, severity of the disease as well as the experimental parameters used. Moreover, these studies have not covered whether autistics have suffered deficits in higher-order processing. In this review, the "top-down" modulation of selective attention and subjective emotion are introduced into the PPI experiment. We also introduce fear conditioning and perceived spatial separation paradigm to further explore the interaction between autistic cognitive process and gating mechanism.

Antipredator and alarm reaction responses of silver catfish (Rhamdia quelen) juveniles exposed to waterborne ammonia

Ammonia has relatively toxic effects on fish and other aquatic organisms. This study examined whether juvenile silver catfish exposed to alarm substances released by conspecifics and predators in water with different ammonia levels modify their behaviour in response to the perceived risk of predation. We used juvenile catfish that were naive to predators. The fish were raised from the larval stage in the laboratory and kept in 40-L aquaria at waterborne NH3 concentrations of 0, 0.05, 0.1, or 0.2 mg L-1 for 10 days. The alarm substances used were predator odour and skin extract from conspecifics. The juveniles were transferred to 2-L aquaria for the antipredator and alarm reaction behavioural tests, which were performed on days 1, 5 and 10 after initial exposure to ammonia. The test aquaria contained a shelter at one end of the tank. The trials consisted of a 10-min prestimulus and a 10-min poststimulus observation period. The results of the study suggest that naive juvenile catfish are able to identify predators and skin extract from conspecifics by odour. In addition, waterborne NH3 levels modify the antipredator response of this species.

Amônia possui efeito relativamente tóxico em peixes e outros organismos aquáticos. Este estudo examinou se juvenis de jundiás modificam seu comportamento em resposta a percepção do risco de predação quando expostos a substâncias de alarme liberadas por conspecíficos e predadores em água com diferentes concentrações de amônia. Foram utilizados juvenis de jundiá nunca expostos a predadores. Os peixes foram criados em laboratório desde a fase larval e mantidos em aquários de 40-L contendo diferentes concentrações de NH3: 0; 0,05; 0,1 e 0,2 mg L-1 por 10 dias. As substâncias de alarme utilizadas foram odor de predador e extrato de pele de conspecíficos. Os juvenis foram transferidos para aquários de 2-L para realização dos testes para comportamento antipredador e resposta à substância de alarme, os quais foram realizados nos dias 1, 5 e 10 a partir do início da exposição à amônia. O aquário teste continha um esconderijo em uma de suas extremidades. Foram feitas observações comportamentais 10-min pré-estímulo e 10-min pós-estímulo. Os resultados do estudo sugerem que juvenis de jundiá nunca expostos a predadores são capazes de identificar predadores e extrato de pele de conspecíficos pelo odor. Além disso, os níveis de NH3 na água alteram a resposta anti-predatória desta espécie.

Habituation of the eyeblink response in humans with stimuli presented in a sequence of incremental intensity

In an experiment we examined whether the repeated presentation of tones of gradually increasing intensities produces greater decrement in the eyeblink reflex response in humans than the repetition of tones of constant intensities. Two groups of participants matched for their initial level of response were exposed to 110 tones of 100-ms duration. For the participants in the incremental group, the tones increased from 60- to 90- dB in 3-dB steps, whereas participants in the constant group received the tones at a fixed 90-dB intensity. The results indicated that the level of response in the last block of 10 trials, in which both groups received 90-dB tones, was significantly lower in the incremental group than in the constant group. These findings support the data presented by Davis and Wagner (7) with the acoustic response in rats, but differ from several reports with autonomic responses in humans, where the advantage of the incremental condition has not been observed unambiguously. The discussion analyzes theoretical approaches to this phenomenon and the possible involvement of separate neural circuits.

Effect of high frequency hearing loss on the temporal processing in the low frequency regions of guinea pigs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To constitute the animal model of high frequency hearing loss and observer the temporal processing abilities of low frequency regions using prepulse inhibition of auditory startle response (gap-PPI).</p><p><b>METHODS</b>Ten guinea pigs were randomly grouped into two groups: the high frequency hearing loss group with six guinea pigs and the control group with four guinea pigs. The former group was exposed to 12 kHz tone at 110 dB SPL for 30 hours to establish the high frequency hearing loss above 8 kHz and the latter group received no stimulations. Before and two, four, six and eight weeks after noise exposure, gap-PPI and auditory brainstem response (ABR) were recorded in both groups. In the gap-PPI experiment, three different background noises as 0.5 - 2 kHz, 0.5 - 4 kHz and 0.5 - 8 kHz were applied to test the temporal gap.</p><p><b>RESULTS</b>High frequency hearing loss above 8 kHz was shown two weeks after noise exposure. The averaged ABR thresholds of 16 kHz, 32 kHz and 48 kHz were elevated about 55 dB and shown statistical significance compared to those before exposure (P < 0.05). No significant difference of ABR thresholds were shown between 1 kHz, 2 kHz, 4 kHz and 8kHz before and after noise exposure (P > 0.05). In the control group, the ABR thresholds remained stable during experiment. In the gap-PPI test, two weeks after noise exposure of 8 kHz, the experiment group showed attenuated inhibition ability and recovered gradually four weeks after noise exposure. No statistical differences of inhibition ability at time points of two, four, six and eight weeks after noise exposure of 4 kHz were detected when compared with that of pre-exposure. Under the background noise of 2 kHz, the inhibition ability attenuated and reached statistical significance at 6 - 8 weeks after noise exposure.</p><p><b>CONCLUSION</b>The high frequency hearing loss might induce an impairment of the temporal processing in the low frequency region.</p>

Prepulse Inhibition of Startle Response: Recent Advances in Human Studies of Psychiatric Disease

Prepulse inhibition (PPI) is considered to be one of the most promising neurophysiological indexes for translational research in psychiatry. Impairment of PPI has been reported in several psychiatric diseases, particularly schizophrenia, where PPI is considered a candidate intermediate phenotype (endophenotype) of the disease. Recent findings from a variety of research areas have provided important evidence regarding PPI impairment. Human brain imaging studies have demonstrated the involvement of the striatum, hippocampus, thalamus and frontal and parietal cortical regions in PPI. In addition, several genetic polymorphisms, including variations in the genes coding for Catechol O-methyltransferase, Neuregulin 1, nuclear factor kappa-B subunit 3 and serotonin-2A receptor were related to PPI; and these findings support PPI as a polygenetic trait that involves several neurotransmitter pathways. Early psychosis studies suggest that PPI disruption is present before the onset of psychosis. Also, discrepancy of PPI impairment between children and adults can be found in other psychiatric diseases, such as autistic spectrum disorders and posttraumatic stress disorder, and comprehensive investigation of startle response might contribute to understand the impairment of the neural circuitry in psychiatric diseases. Finally, recent studies with both Asian and Caucasian subjects indicate that patients with schizophrenia exhibit impaired PPI, and impaired sensorimotor gating might be a global common psychophysiological feature of schizophrenia. In conclusion, studies of PPI have successfully contributed to a better understanding of the fundamental neural mechanisms underlying sensorimotor gating and will certainly be most valuable in devising future approaches that aim to investigate the complex pathogenesis of psychiatric diseases.

The effects of acute fear stress on emotional behaviors, plasmic hormone levels and the activation of cerebral Erk1/2 of rats / 中国应用生理学杂志

<p><b>AIM</b>To study the effect of acute fear stress on emotional behaviors, Hormone levels, and the expression and activation of cerebra Erk1/2 of rats in vivo.</p><p><b>METHODS</b>Fourty eight male SD rats were divided randomly into control group and stress group. Rats of stress group received 30 min' s acute stress including foot shock and white noise, and then the emotional behaviors were observed. The hormone level in plasm and brain was determined by spectrophotofluorometry and radioimmunoassay kit. In the following experiments, Western blot was performed to determine the expression and phosphorylation of extracellular signal-regulated protein kinase (Erk) of four different regions of the brain.</p><p><b>RESULTS</b>Rats tested after acute fear stress displayed substantial decreases in open-field activity, increases in resistance to capture, and increases in fright reaction (P < 0.01). The stress also resulted in significantly higher plasmic and cerebral noradrenaline, corticosteroid, 5-hydroxytryptamine levels, and lower adrenomedulin level in comparison with the control (P < 0.01) after stress. At the time point of 0 min and 30 min after stress, the phosphorylation of Erk1/2 were increased in all four brain regions examined (hippocampus, striatum, prefrontal cortex and cerebellum).</p><p><b>CONCLUSION</b>Acute fear stress can induce abnormalities of emotional behaviors, such as behavioral habits, anxiety and defense, startle and delayed adaptation to startle, as well as the alteration of hormone levels. The phosphorylation of Erk1/2 may play a role in the abnormality of emotional behaviors of rats induced by acute fear stress.</p>

Hyperekplexia in two siblings.

Hyperekplexia is a rare, hereditary, non-epileptic disorder characterized by an exaggerated startle reaction to unexpected auditory, somatosensory and visual stimuli. The authors describe a one-day-old term neonate, who presented with jitteriness and episodic tonic spasms, and his elder sister with hyperekplexia. Hyperekplexia though is a rare disorder is one of the differential diagnoses for refractory tonic spasms in infancy. The prognosis is generally good in hereditary hyperekplexia. Recent molecular studies have revealed many associated mutations in the glycine receptor alpha and beta subunit genes.

Neonatal hyperekplexia: the Stiff-Baby syndrome.

Neonatal hyperekplexia is a rare autosomal dominant startle disorder. Presenting soon after birth, it is often mistakenly diagnosed as spastic quadriparesis, epilepsy etc. While the long-term prognosis is relatively benign, sudden death due to severe spasms have been seen in sporadic cases. We report a case of hyperekplexia with some typical and some unusual findings.

Routine post-weaning handling of rats prevents isolation rearing-induced deficit in prepulse inhibition

Rats reared under isolation conditions from weaning present a number of behavioral changes compared to animals reared under social conditions (group housing). These changes include deficits in prepulse inhibition (PPI) of the startle reflex to a loud sound. PPI refers to the reduction of the magnitude of the startle reflex when a relatively weak stimulus (the prepulse) precedes by an appropriate time interval the intense startle-elicing stimulus (the pulse). PPI is useful for studying sensorimotor integration. The present study evaluated the effect of handling on the impairment of PPI induced by isolation-rearing. Male Wistar rats (N = 11-15/group) were housed in groups (5 per cage and handled three times a week) or isolated (housed individually) since weaning (21 days) for 10 weeks when they reach approximately 150 g. The isolated rats were divided into "minimally handled" animals (handled once a week for cleaning purposes only) or "handled" animals (handled three times a week). This handling consisted of grasping the rat by the tail and moving it to a clean cage (approximately 5 s). A statistically significant reduction (52 percent) in the PPI test was found only in the isolated group with minimal handling while no difference was seen between grouped animals and isolated handled animals. These results indicate that isolation rearing causes disruption in the PPI at adult age, which serves as an index of attention deficit. This change in the sensory processing of information induced by post-weaning isolation can be prevented by handling during the development of the animal.

Asma infantil: conducta de los padres y factores coadyuvante / Children asthma: parents' behaviors and coadjutant factors

El presente estudio es derciptivo y transversal, para conocer la relación entre asma infantil y factores coadyuvantes (conflictos familiares, unión paterna, orden de nacimiento, sexo y edad), conductas de los padres, tiempo de evolución, frecuencia de las crisis asmáticas y severidad de la enfermedad. Se utilizó cuestionario debidamente validado, llenado por el investigador y por los padres. La muestra fue no probabilística, intencional y estuvo constituida por 103 niños asmáticos entre 1 y 12 años que asistieron a la emergencia pediátrica del Ambulatorio de Caricuao, entre Febrero y Julio de 2003. Se hizo cruce de variables y se determinó Chi cuadrado, con nivel de significancia de 0.05. Los resultados revelan mayor frecuencia de crisis asmática en niños varones, en familias con padres juntos, sin conflictos familiares; predominó el hijo menor, sin diferencias significativas con respecto a la severidad. Predominaron las crisis moderadas, con frecuencia de 1 a 5 crisis por año. El 53,40 por ciento de los padres tuvo percepción adecuada de las crisis, el 24,27 por ciento percepción aumentada y 22,33 por ciento percepción disminuida y fueron estadísticamente significativas con respecto a la severidad. El 78,64 por ciento de niños no tenía control médico y el 89,32 por ciento de los padres presentaron conductas inadecuadas

Behavioral modulation by mutilation pictures in women

Previous studies have shown that women are more emotionally expressive than men. It is unclear, however, if women are also more susceptible to the emotional modulation of behavior imposed by an affective stimulus. To investigate this issue, we devised a task in which female subjects performed six sequential trials of visual target detection following the presentation of emotional (mutilation and erotic) or neutral pictures (domestic utensils and objects) and compared the data obtained in the present study with those described in a previous study with male subjects. The experiment consisted of three blocks of 24 pictures and each block had an approximate duration of 4 min. Our sample consisted of 36 subjects (age range: 18 to 26 years) and each subject performed all blocks. Trials following the presentation of mutilation pictures (283 ms) had significantly slower reaction times than those following neutral (270 ms) pictures. None of the trials in the "pleasant block" (271 ms) was significantly different from those in the "neutral block". The increase in reaction time observed in the unpleasant block may be related in part to the activation of motivational systems leading to an avoidance behavior. The interference effect observed in this study was similar to the pattern previously described for men. Thus, although women may be more emotionally expressive, they were not more reactive to aversive stimuli than men, as measured by emotional interference in a simple reaction time task.