Effects of omega-3 supplementation on anxiety-like behaviors and neuroinflammation in Wistar rats following cafeteria diet-induced obesity.

ABSTRACTObjetives: Omega-3 (n3) fatty acids have been studied as an option to alleviate the harmful effects of obesity. However, its role in obesity-related behavioral changes is still controversial. This study aimed to evaluate the effects of n3 on behavior and neuroinflammation in obese animals. Methods: Male Wistar rats were divided into four groups: control diet (CT), CT+n3, cafeteria diet (CAF), and CAF+n3. Diet was administered for 13 weeks, and n3 was supplemented during the last 5 weeks. Metabolic and biochemical parameters were evaluated, as well as anxiety-like behaviors. Immunoblots were conducted in the animals' cerebral cortex and hippocampus to assess changes in neuroinflammatory markers.Results: CAF-fed animals showed higher weight gain, visceral adiposity, fasting glucose, total cholesterol, triglycerides, and insulin levels, and n3 improved the lipid profile and restored insulin sensitivity. CAF-fed rats showed anxiety-like behaviors in the open field and light-dark box tasks but not in the contextual aversive conditioning. Omega-3 did not exert any effect on these behaviors. Regarding neuroinflammation, diet and supplementation acted in a region-specific manner. In the hippocampus, CAF reduced claudin-5 expression with no effect of n3, indicating a brain-blood barrier disruption following CAF. Furthermore, in the hippocampus, the glial fibrillary acidic protein (GFAP) and toll-like receptor 4 (TLR-4) were reduced in treated obese animals. However, n3 could not reverse the TLR-4 expression increase in the cerebral cortex.Discussion: Although n3 may protect against some neuroinflammatory manifestations in the hippocampus, it does not seem sufficient to reverse the increase in anxiolytic manifestations caused by CAF.

Role of nitric oxide on defensive behavior and long-term aversive learning induced by chemical stimulation of the dorsolateral periaqueductal gray matter.

The midbrain periaqueductal gray matter, especially the dorsolateral portion (dlPAG), coordinates immediate defensive responses (DR) to threats, but also ascends forebrain information for aversive learning. The synaptic dynamics in the dlPAG regulate the intensity and type of behavioral expression, as well as long-term processes such as memory acquisition, consolidation, and retrieval. Among several neurotransmitters and neural modulators, nitric oxide seems to play an important regulatory role in the immediate expression of DR, but it remains unclear if this gaseous on-demand neuromodulator contributes to aversive learning. Therefore, the role of nitric oxide in the dlPAG was investigated, during conditioning in an olfactory aversive task. The behavioral analysis consisted of freezing and crouch-sniffing in the conditioning day after glutamatergic NMDA agonist injection into the dlPAG. Two days later, rats were re-exposed to the odor cue and avoidance was measured. 7NI, a selective neuronal nitric oxide synthase inhibitor (40 and 100 nmol), injected before NMDA (50 pmol) impaired immediate DR and consequent aversive learning. The scavenging of extrasynaptic nitric oxide by C-PTIO (1 and 2 nmol) induced similar results. Moreover, spermine NONOate, a nitric oxide donor (5, 10, 20, 40, and 80 nmol), produced DR by itself, but only the low dose also promoted learning. The following experiments utilized a fluorescent probe, DAF-FM diacetate (5 µM), directly into the dlPAG, to quantify nitric oxide in the three previous experimental situations. Nitric oxide levels were increased after NMDA stimulation, decreased after 7NI, and increased after spermine NONOate, in line with alterations in defensive expression. Altogether, the results indicate that nitric oxide plays a modulatory and decisive role in the dlPAG regarding immediate DR and aversive learning.

Human Sensory Cortex Contributes to the Long-Term Storage of Aversive Conditioning.

Growing animal data evince a critical role of the sensory cortex in the long-term storage of aversive conditioning, following acquisition and consolidation in the amygdala. Whether and how this function is conserved in the human sensory cortex is nonetheless unclear. We interrogated this question in a human aversive conditioning study using multidimensional assessments of conditioning and long-term (15 d) retention. Conditioned stimuli (CSs; Gabor patches) were calibrated to differentially activate the parvocellular (P) and magnocellular (M) visual pathways, further elucidating cortical versus subcortical mechanisms. Full-blown conditioning and long-term retention emerged for M-biased CS (vs limited effects for P-biased CS), especially among anxious individuals, in all four dimensions assessed: threat appraisal (threat ratings), physiological arousal (skin conductance response), perceptual learning [discrimination sensitivity (d') and response speed], and cortical plasticity [visual evoked potentials (VEPs) and cortical current density]. Interestingly, while behavioral, physiological, and VEP effects were comparable at immediate and delayed assessments, the cortical substrates evolved markedly over time, transferring from high-order cortices [inferotemporal/fusiform cortex and orbitofrontal cortex (OFC)] immediately to the primary and secondary visual cortex after the delay. In sum, the contrast between P- and M-biased conditioning confirms privileged conditioning acquisition via the subcortical pathway while the immediate cortical plasticity lends credence to the triadic amygdala-OFC-fusiform network thought to underlie threat processing. Importantly, long-term retention of conditioning in the basic sensory cortices supports the conserved role of the human sensory cortex in the long-term storage of aversive conditioning.SIGNIFICANCE STATEMENT A growing network of neural substrates has been identified in threat learning and memory. The sensory cortex plays a key role in long-term threat memory in animals, but such a function in humans remains unclear. To explore this problem, we conducted multidimensional assessments of immediate and delayed (15 d) effects of human aversive conditioning. Behavioral, physiological, and scalp electrophysiological data demonstrated conditioning effects and long-term retention. High-density EEG intracranial source analysis further revealed the cortical underpinnings, implicating high-order cortices immediately and primary and secondary visual cortices after the long delay. Therefore, while high-order cortices support aversive conditioning acquisition (i.e., threat learning), the human sensory cortex (akin to the animal homolog) underpins long-term storage of conditioning (i.e., long-term threat memory).

Effects of aversive conditioning on expression of physiological stress in honey bees (Apis mellifera).

Stress is defined as any deviation from an organism's baseline physiological levels. Therefore, introduction of new stimuli and information, such as in learning, can be defined as a stressor. A large body of research exists examining the role that stress plays in learning, but virtually none addresses whether or not learning itself is a measurable cause of stress. The current study used a wide variety of learning centric stress responses. Researchers examined changes in expression of ten stress and learning related genes in various physiological systems in domesticated honey bees (Apis mellifera) as a result of exposure to an aversive conditioning task. Gene expression was examined using quantitative real-time polymerase chain reaction following the learning task. Results indicate that learning affects expression of some stress related genes.

Taste association capabilities differ in high- and low-yawning rats versus outbred Sprague-Dawley rats after prolonged sugar consumption.

Yawning is a stereotypical behavior pattern commonly associated with other behaviors such as grooming, sleepiness, and arousal. Several differences in behavioral and neurochemical characteristics have been described in high-yawning (HY) and low-yawning (LY) sublines from Sprague-Dawley (SD) rats that support they had changes in the neural mechanism between sublines. Differences in behavior and neurochemistry observed in yawning sublines could also overlap in processes needed during taste learning, particularly during conditioned taste aversion (CTA) and its latent inhibition. Therefore, the aim of this study was to analyze taste memory differences, after familiarization to novel or highly sweet stimuli, between yawning sublines and compare them with outbred SD rats. First, we evaluated changes in appetitive response during long-term sugar consumption for 14 days. Then, we evaluated the latent inhibition of CTA strength induced by this long pre-exposure, and we also measured aversive memory extinction rate. The results showed that SD rats and the two sublines developed similar CTA for novel sugar and significantly stronger appetitive memory after long-term sugar exposure. However, after 14 days of sugar exposure, HY and LY sublines were unable to develop latent inhibition of CTA after two acquisition trials and had a slower aversive memory extinction rate than outbreed rats. Thus, the inability of the HY and LY sublines to develop latent inhibition of CTA after long-term sugar exposure could be related to the time/context processes involved in long-term appetitive re-learning, and in the strong inbreeding that characterizes the behavioral traits of these sublines, suggesting that inbreeding affects associative learning, particularly after long-term exposure to sweet stimuli which reflects high familiarization.

Beyond Freezing: Temporal Expectancy of an Aversive Event Engages the Amygdalo-Prefronto-Dorsostriatal Network.

During Pavlovian aversive conditioning, a neutral conditioned stimulus (CS) becomes predictive of the time of arrival of an aversive unconditioned stimulus (US). Using a paradigm where animals had to discriminate between a CS+ (associated with a footshock) and a CS- (never associated with a footshock), we show that, early in training, dynamics of neuronal oscillations in an amygdalo-prefronto-striatal network are modified during the CS+ in a manner related to the CS-US time interval (30 or 10 s). This is the case despite a generalized high level of freezing to both CS+ and CS-. The local field potential oscillatory power was decreased between 12 and 30 Hz in the dorsomedial striatum (DMS) and increased between 55 and 95 Hz in the prelimbic cortex (PL), while the coherence between DMS, PL, and the basolateral amygdala was increased in the 3-6 Hz frequency range up to the expected time of US arrival only for the CS+ and not for the CS-. Changing the CS-US interval from 30 to 10 s shifted these changes in activity toward the newly learned duration. The results suggest a functional role of the amygdalo-prefronto-dorsostriatal network in encoding temporal information of Pavlovian associations independently of the behavioral output.

Using aversive conditioning with near-real-time feedback to shape eye movements during naturalistic viewing.

Strategically shaping patterns of eye movements through training has manifold promising applications, with the potential to improve the speed and efficiency of visual search, improve the ability of humans to extract information from complex displays, and help correct disordered eye movement patterns. However, training how a person moves their eyes when viewing an image or scene is notoriously difficult, with typical approaches relying on explicit instruction and strategy, which have notable limitations. The present study introduces a novel approach to eye movement training using aversive conditioning with near-real-time feedback. Participants viewed indoor scenes (eight scenes presented over 48 trials) with the goal of remembering those scenes for a later memory test. During viewing, saccades meeting specific amplitude and direction criteria probabilistically triggered an aversive electric shock, which was felt within 50 ms after the eliciting eye movement, allowing for a close temporal coupling between an oculomotor behavior and the feedback intended to shape it. Results demonstrate a bias against performing an initial saccade in the direction paired with shock (Experiment 1) or generally of the amplitude paired with shock (Experiment 2), an effect that operates without apparent awareness of the relationship between shocks and saccades, persists into extinction, and generalizes to the viewing of novel images. The present study serves as a proof of concept concerning the implementation of near-real-time feedback in eye movement training.

Effects of caloric or non-caloric sweetener long-term consumption on taste preferences and new aversive learning.

Food palatability and caloric content are crucial factors in guiding diet choice and amount consumed; as a result, sweet caloric tastes are associated with a positive hedonic value. Recent evidence in rodents indicates that consumption of artificial (non-caloric) sweeteners, in which sweet taste is dissociated from normal caloric consequences, could induce changes in energy and body weight regulation, suggesting that sweeteners not only modify intake and appetitive behavior, but could also change taste-learning processes. Particularly, there are different properties in some artificial sweeteners, like saccharin, that might differ from sugar in the reward responses that, after long-term consumption, could also be associated with the inability to learn new negative consequences related to the same taste. Thus, the main goal of this study was to determine, in adult rats, the effects of long-term consumption (14 days) of sugar or saccharin, on taste preference, on new aversive learning, i.e. latent inhibition (LI) of conditioned taste aversion (CTA), and appetitive taste re-learning after aversive taste associations. The results showed that 14 days' exposure to sugar, but not to saccharin, induced a significant increment in the LI of CTA and that taste preference is rapidly recovered during the next 3 days (e.g. CTA extinctions), indicating that long-term sugar consumption significantly accelerates aversive memory extinction during appetitive re-learning of a specific sweet taste; furthermore, high familiarization to sugar, but not to saccharin, promotes appetitive learning for the same taste. Overall, the results indicate that long-term consumption of sugar, but not saccharin, produces changes in appetitive re-learning and suggests that long-term sugar consumption could trigger escalating consumption due to the inability to learn new negative consequences associated with the same taste.

Assessment of lethal and sublethal effects of imidacloprid, ethion, and glyphosate on aversive conditioning, motility, and lifespan in honey bees (Apis mellifera L.).

Honeybees (Apis mellifera) play an important role in agriculture worldwide. Several factors including agrochemicals can affect honey bee health including habitat fragmentation, pesticide application, and pests. The growing human population and subsequent increasing crop production have led to widespread use of agrochemicals and there is growing concern that pollinators are being negatively impacted by these pesticides. The present study compares acute exposure to imidacloprid (0.2 and 0.4 mgL-1), ethion (80 and 106.7 mgL-1) or glyphosate (0.12 and 0.24 mgL-1) on aversive learning and movement, to chronic exposure at these and higher concentrations on movement, circadian rhythms, and survival in honey bee foragers. For acute learning studies, a blue/yellow shuttle box experiment was conducted; we observed honey bee choice following aversive and neutral stimuli. In learning studies, control bees spent >50% of the time on yellow which is not consistent with previous color bias literature in the subspecies or region of the study. The learning apparatus was also used to estimate mobility effects within 20 min of exposure. Chronic exposure (up to 2 weeks) with the above metrics was recorded by an automated monitoring system. In chronic exposure experiments, RoundUp®, was also tested to compare to its active ingredient, glyphosate. We found that imidacloprid and ethion have negative impacts on aversive learning and movement following a single-dose and that chronic exposure effects were dose-dependent for these two insecticides. In contrast, glyphosate had no effect on learning and less of an effect on movement; RoundUp® showed dose-dependent results on circadian rhythmicity. Overall, the results suggest that short-term exposure to imidacloprid and ethion adversely affect honey bee foragers and chronic exposure to glyphosate may affect pollination success.

Aversive Imagery Causes De Novo Fear Conditioning.

In classical fear conditioning, neutral conditioned stimuli that have been paired with aversive physical unconditioned stimuli eventually trigger fear responses. Here, we tested whether aversive mental images systematically paired with a conditioned stimulus also cause de novo fear learning in the absence of any external aversive stimulation. In two experiments (N = 45 and N = 41), participants were first trained to produce aversive, neutral, or no imagery in response to three different visual-imagery cues. In a subsequent imagery-based differential-conditioning paradigm, each of the three cues systematically coterminated with one of three different neutral faces. Although the face that was paired with the aversive-imagery cue was never paired with aversive external stimuli or threat-related instructions, participants rated it as more arousing, unpleasant, and threatening and displayed relative fear bradycardia and fear-potentiated startle. These results could be relevant for the development of fear and related disorders without trauma.

Aversive learning of odor-heat associations in ants.

Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general.

Developmental differences in aversive conditioning, extinction, and reinstatement: A study with children, adolescents, and adults.

This study investigated developmental differences in aversive conditioning, extinction, and reinstatement (i.e., the recovery of conditioned aversive associations following reexposure to the unconditioned stimulus [US] post-extinction). This study examined these mechanisms in children (Mage=8.8years), adolescents (Mage=16.1years), and adults (Mage=32.3years) using differential aversive conditioning with a geometric shape conditional stimulus (CS+) paired with an aversive sound US and another shape (CS-) presented alone. Following an extinction phase in which both CSs were presented alone, half of the participants in each age group received three US exposures (reinstatement condition) and the other half did not (control condition), followed by all participants completing an extinction retest phase on the same day. Findings indicated (a) significant differences in generalizing aversive expectancies to safe stimuli during conditioning and extinction that persisted during retest in children relative to adults and adolescents, (b) significantly less positive CS reevaluations during extinction that persisted during retest in adolescents relative to adults and children, and (c) reinstatement of US expectancies to the CS+ relative to the CS- in all age groups. Results suggest important differences in stimulus safety learning in children and stimulus valence reevaluation in adolescents relative to adults.

Counterintuitive effects of negative social feedback on attention.

Which stimuli we pay attention to is strongly influenced by learning. Stimuli previously associated with reward outcomes, such as money and food, and stimuli previously associated with aversive outcomes, such as monetary loss and electric shock, automatically capture attention. Social reward (happy expressions) can bias attention towards associated stimuli, but the role of negative social feedback in biasing attentional selection remains unexplored. On the one hand, negative social feedback often serves to discourage particular behaviours. If attentional selection can be curbed much like any other behavioural preference, we might expect stimuli associated with negative social feedback to be more readily ignored. On the other hand, if negative social feedback influences attention in the same way that other aversive outcomes do, such feedback might ironically bias attention towards the stimuli it is intended to discourage selection of. In the present study, participants first completed a training phase in which colour targets were associated with negative social feedback. Then, in a subsequent test phase, these same colour stimuli served as task-irrelevant distractors during a visual search task. The results strongly support the latter interpretation in that stimuli previously associated with negative social feedback impaired search performance.

A developmental analysis of threat/safety learning and extinction recall during middle childhood.

The current study examined developmental changes in fear learning and generalization in 54 healthy 5-10-year old children using a novel fear conditioning paradigm. In this task, the conditioned stimuli (CS+/CS-) were two blue and yellow colored cartoon bells, and the unconditioned stimulus was an unpleasant loud alarm sound presented with a red cartoon bell. Physiological and subjective data were acquired. Three weeks after conditioning, 48 of these participants viewed the CS-, CS+, and morphed images resembling the CS+. Participants made threat-safety discriminations while appraising threat and remembering the CS+. Although no age-related differences in fear learning emerged, patterns of generalization were qualified by child age. Older children demonstrated better discrimination between the CS+ and CS morphs than younger age groups and also reported more fear to stimuli resembling the CS+ than younger children. Clinical implications and future directions are discussed.

Olfactory aversive conditioning during sleep reduces cigarette-smoking behavior.

Recent findings suggest that novel associations can be learned during sleep. However, whether associative learning during sleep can alter later waking behavior and whether such behavioral changes last for minutes, hours, or days remain unknown. We tested the hypothesis that olfactory aversive conditioning during sleep will alter cigarette-smoking behavior during ensuing wakefulness. A total of 66 human subjects wishing to quit smoking participated in the study (23 females; mean age, 28.7 ± 5.2 years). Subjects completed a daily smoking diary detailing the number of cigarettes smoked during 7 d before and following a 1 d or night protocol of conditioning between cigarette odor and profoundly unpleasant odors. We observed significant reductions in the number of cigarettes smoked following olfactory aversive conditioning during stage 2 and rapid eye movement (REM) sleep but not following aversive conditioning during wakefulness (p < 0.05). Moreover, the reduction in smoking following aversive conditioning during stage 2 (34.4 ± 30.1%) was greater and longer lasting compared with the reduction following aversive conditioning during REM (11.9 ± 19.2%, p < 0.05). Finally, the reduction in smoking following aversive conditioning during sleep was significantly greater than in two separate control sleep experiments that tested aversive odors alone and the effects of cigarette odors and aversive odors without pairing. To conclude, a single night of olfactory aversive conditioning during sleep significantly reduced cigarette-smoking behavior in a sleep stage-dependent manner, and this effect persisted for several days.

Cognitive emotion regulation enhances aversive prediction error activity while reducing emotional responses.

Cognitive emotion regulation is a powerful way of modulating emotional responses. However, despite the vital role of emotions in learning, it is unknown whether the effect of cognitive emotion regulation also extends to the modulation of learning. Computational models indicate prediction error activity, typically observed in the striatum and ventral tegmental area, as a critical neural mechanism involved in associative learning. We used model-based fMRI during aversive conditioning with and without cognitive emotion regulation to test the hypothesis that emotion regulation would affect prediction error-related neural activity in the striatum and ventral tegmental area, reflecting an emotion regulation-related modulation of learning. Our results show that cognitive emotion regulation reduced emotion-related brain activity, but increased prediction error-related activity in a network involving ventral tegmental area, hippocampus, insula and ventral striatum. While the reduction of response activity was related to behavioral measures of emotion regulation success, the enhancement of prediction error-related neural activity was related to learning performance. Furthermore, functional connectivity between the ventral tegmental area and ventrolateral prefrontal cortex, an area involved in regulation, was specifically increased during emotion regulation and likewise related to learning performance. Our data, therefore, provide first-time evidence that beyond reducing emotional responses, cognitive emotion regulation affects learning by enhancing prediction error-related activity, potentially via tegmental dopaminergic pathways.

Prenatal ethanol increases ethanol intake throughout adolescence, alters ethanol-mediated aversive learning, and affects µ but not δ or κ opioid receptor mRNA expression.

Animal models of prenatal ethanol exposure (PEE) have indicated a facilitatory effect of PEE on adolescent ethanol intake, but few studies have assessed the effects of moderate PEE throughout adolescence. The mechanisms underlying this facilitatory effect remain largely unknown. In the present study, we analysed ethanol intake in male and female Wistar rats with or without PEE (2.0 g/kg, gestational days 17-20) from postnatal days 37 to 62. The results revealed greater ethanol consumption in PEE rats than in controls, which persisted throughout adolescence. By the end of testing, ethanol ingestion in PEE rats was nearly 6.0 g/kg. PEE was associated with insensitivity to ethanol-induced aversion. PEE and control rats were further analysed for levels of µ, δ and κ opioid receptor mRNA in the infralimbic cortex, nucleus accumbens shell, and ventral tegmental area. Similar levels of mRNA were observed across most areas and opioid receptors, but µ receptor mRNA in the ventral tegmental area was significantly increased by PEE. Unlike previous studies that assessed the effects of PEE on ethanol intake close to birth, or in only a few sessions during adolescence, the present study observed a facilitatory effect of PEE that lasted throughout adolescence. PEE was associated with insensitivity to the aversive effect of ethanol, and increased levels of µ opioid receptor transcripts. PEE is a prominent vulnerability factor that probably favors the engagement of adolescents in risky trajectories of ethanol use.

Enhancement of Odor Sensitivity Following Repeated Odor and Visual Fear Conditioning.

Odor detection sensitivity can be rapidly altered by fear conditioning; whether this effect is augmented over time is not known. The present study aimed to test whether repeated conditioning sessions induce changes in odor detection threshold as well as in conditioned responses and whether olfactory stimuli evoke stronger conditioned responses than visual stimuli. The repeated conditioning group participated in repeated sessions over 2 weeks whereas the single conditioning group participated in 1 conditioning session; both groups were presented with visual and olfactory stimuli, were paired with an electric shock (CS+) and 2 matched control stimuli not paired with shock (CS-) while olfactory detection threshold and skin conductance responses (SCRs) were measured before and after the last session. We found increased sensitivity for the CS+ odor in the repeated but not in the single conditioning group, consistent with changes in olfactory sensitivity following repeated aversive learning and of a similar magnitude to what has previously been demonstrated in the periphery. SCR to the visual and olfactory CS+ were similar between groups, indicating that sensory thresholds can change without corresponding change in conditioned responses. In conclusion, repeated conditioning increases detection sensitivity and reduces conditioned responses, suggesting that segregated processes influence perception and conditioned responses.

Extinction of aversive classically conditioned human sexual response.

INTRODUCTION: Research has shown that acquired subjective likes and dislikes are quite resistant to extinction. Moreover, studies on female sexual response demonstrated that diminished genital arousal and positive affect toward erotic stimuli due to aversive classical conditioning did not extinguish during an extinction phase. Possible resistance to extinction of aversive conditioned sexual responses may have important clinical implications. However, resistance to extinction of aversive conditioned human sexual response has not been studied using extensive extinction trials. AIM: This article aims to study resistance to extinction of aversive conditioned sexual responses in sexually functional men and women. METHODS: A differential conditioning experiment was conducted, with two erotic pictures as conditioned stimulus (CSs) and a painful stimulus as unconditioned stimuli (USs). Only one CS (the CS+) was followed by the US during the acquisition phase. Conditioned responses were assessed during the extinction phase. MAIN OUTCOME MEASURE: Penile circumference and vaginal pulse amplitude were assessed, and ratings of affective value and subjective sexual arousal were obtained. Also, a stimulus response compatibility task was included to assess automatic approach and avoidance tendencies. RESULTS: Men and women rated the CS+ more negative as compared with the CS-. During the first trials of the extinction phase, vaginal pulse amplitude was lower in response to the CS+ than in response to the CS-, and on the first extinction trial women rated the CS+ as less sexually arousing. Intriguingly, men did not demonstrate attenuated genital and subjective sexual response. CONCLUSIONS: Aversive conditioning, by means of painful stimuli, only affects sexual responses in women, whereas it does not in men. Although conditioned sexual likes and dislikes are relatively persistent, conditioned affect eventually does extinguish.