Sex differences in learning processes of classical and operant conditioning

Sex differences in learning processes of classical and operant conditioning Christina Dalla Tracey J. Shors

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Sex differences in learning processes of classical and operant conditioning 2009 Physiology & Behavior 10.1016/j.physbeh.2009.02.035 dalla2009-sex-differences-in-learning-proces dalla2009-sex-differences-in-learning-proces.txt, the project's staged copy 8fea0512eac09619a89e49869f88f9974411ec05 open-access neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them sex differences in classical and operant conditioning in laboratory rodents Quotation withheld because this record is not cleared for redistribution. where sex differences appear across conditioning paradigms, and whether they reflect learning or performance Quotation withheld because this record is not cleared for redistribution. collects sex differences across four conditioning paradigms, shows the direction depends on the task, separates organizational from activational hormonal causes, and argues females must be included in basic research Quotation withheld because this record is not cleared for redistribution. existence Quotation withheld because this record is not cleared for redistribution. sex differences in classical and operant conditioning Quotation withheld because this record is not cleared for redistribution. review review Quotation withheld because this record is not cleared for redistribution. mechanisms The amount of fear generated by the task determines which sex performs better: high-fear paradigms favour males, low-fear paradigms favour females Quotation withheld because this record is not cleared for redistribution. mechanisms Males acquire and retain the conditioned fear more strongly, and this stronger fear is what drives their superior performance in fear conditioning status: the paper's own words: It is possible that Quotation withheld because this record is not cleared for redistribution. mechanisms Divergent coping strategies to shock — active responding in females versus passive behavioural inhibition and freezing in males — produce the operant-conditioning sex difference Quotation withheld because this record is not cleared for redistribution. mechanisms Adult testosterone acts anxiolytically and thereby pushes males toward the passive strategy that impairs their avoidance learning Quotation withheld because this record is not cleared for redistribution. mechanisms Dendritic spine density on CA1 pyramidal cells tracks learned-response performance across hormonal and stress manipulations, and is proposed as the anatomical substrate of the sex difference Quotation withheld because this record is not cleared for redistribution. mechanisms Gonadal hormones act twice — organizing the developing brain and then activating circuits in puberty and adulthood — and the two effects interact to produce adult sex differences Quotation withheld because this record is not cleared for redistribution. most differences are organized by gonadal hormones during early development and then modulated by activational effects in adulthood Quotation withheld because this record is not cleared for redistribution. masculinising a female neonatally is not sufficient; male-like avoidance appears only if testosterone is also given in adulthood Quotation withheld because this record is not cleared for redistribution. different tasks recruit different hormones - testosterone dominates avoidance, oestrogens and progesterone dominate eyeblink and fear conditioning - because the tasks differ in whether the response is volitional Quotation withheld because this record is not cleared for redistribution. the sex difference survives across the oestrous cycle, so it is not simply an oestrogen effect Quotation withheld because this record is not cleared for redistribution. an a priori argument that learning cannot depend heavily on hormone level, since both sexes undergo large hormonal changes across life Quotation withheld because this record is not cleared for redistribution. oestrogen dose effects are non-monotonic: low doses disrupt and high doses facilitate active avoidance Quotation withheld because this record is not cleared for redistribution. The neural substrate of the reviewed sex differences is not established; hippocampal CA1 spine density is offered only as a parallel correlate. what this limits: any claim about the neural basis of the reviewed sex differences: Quotation withheld Quotation withheld because this record is not cleared for redistribution. Performance factors can never be entirely excluded even in the eyeblink paradigm the authors regard as least contaminated by them. what this limits: even the eyeblink evidence the review treats as cleanest: ONE CAN NEVER RULE OUT PERFORMANCE EFFECTS ENTIRELY Quotation withheld because this record is not cleared for redistribution. Sex differences in spatial learning are excluded from the review's scope. what this limits: spatial learning, which the review excludes: Quotation withheld Quotation withheld because this record is not cleared for redistribution. Developmental hormone effects on conditioned taste aversion are absent from the literature reviewed. what this limits: developmental effects of sex hormones, on which the literature is silent: TO OUR KNOWLEDGE, THERE IS NO REPORT IN THE LITERATURE CONCERNING DEVELOPMENTAL EFFECTS OF SEX HORMONES Quotation withheld because this record is not cleared for redistribution. Conditioned taste aversion is confounded by sex differences in sweet preference and in the rewarding/aversive properties of the compounds used, making learning-level conclusions hard to draw. what this limits: the conditioned taste aversion paradigm: IT IS DIFFICULT TO STUDY SEX DIFFERENCES IN CONDITIONED LEARNING IN THIS PARADIGM, ALTHOUGH THEY EXIST Quotation withheld because this record is not cleared for redistribution. Findings on retention and extinction of cue fear conditioning are inconsistent across studies. what this limits: the retention and extinction phases of cue fear conditioning, in a changed context, measured by freezing: WHETHER SEX DIFFERENCES EXIST DURING TESTING (RETENTION) AND EXTINCTION OF CUE FEAR CONDITIONING, WHEN RATS ARE PLACED IN A DIFFERENT CONTEXT (CR: TIME SPEND FREEZING) Quotation withheld because this record is not cleared for redistribution. sex differences in performance account for some of the reported learning effects, a confound running through the whole literature what this limits: every learning effect the review reports: SEX DIFFERENCES IN PERFORMANCE ACCOUNT FOR SOME OF THE REPORTED EFFECTS ON LEARNING Quotation withheld because this record is not cleared for redistribution. some differences may be differences in strategy rather than in learning what this limits: spatial learning paradigms specifically: THIS HAS BEEN SUGGESTED BEFORE FOR SPATIAL LEARNING PARADIGMS, IN WHICH MALE RATS USUALLY PERFORM BETTER THAN FEMALES BY USING A MORE DIRECT strategy - a strategy difference, not a learning difference Quotation withheld because this record is not cleared for redistribution. lever-pressing differences are attributable to general activity and to what females do instead of pressing what this limits: lever-pressing measures: Quotation withheld Quotation withheld because this record is not cleared for redistribution. conditioned taste aversion is declared difficult to interpret for this question because taste preference, drug reward and the hormones themselves all confound it what this limits: conditioned taste aversion studies that administer hormones: EXOGENOUS SEX HORMONE'S ADMINISTRATION ALSO HAS ILLNESS-INDUCING PROPERTIES, WHICH CAN IN TURN INFLUENCE CONDITIONED TASTE AVERSION Quotation withheld because this record is not cleared for redistribution. drug-based aversion data cannot be evaluated from a learning perspective because of the rewarding properties of the drugs what this limits: drug-of-abuse aversion data read as learning: IT IS DIFFICULT TO EVALUATE THEM FROM A LEARNING PERSPECTIVE, BECAUSE OF THE POTENT REWARDING PROPERTIES OF THE DIFFERENT CLASSES OF DRUGS OF ABUSE Quotation withheld because this record is not cleared for redistribution. human sex differences are small, task-dependent and hard to interpret even when observed what this limits: human cognition studies: MANY OF THE REPORTED SEX DIFFERENCES ARE RELATIVELY SMALL IN MAGNITUDE AND THEIR EMERGENCE MAY ONLY ARISE AS A FUNCTION OF THE TASK, ITS DIFFICULTY OR THE SPECIFIC EXPERIMENTAL DESIGN Quotation withheld because this record is not cleared for redistribution. spatial learning is excluded from the review despite being central to the topic duplicate of: limitations[2] · what this limits: the same scope as limitations[2] - spatial learning, excluded from the review Quotation withheld because this record is not cleared for redistribution. no study exists on developmental hormone effects in conditioned taste aversion what this limits: developmental hormone work in conditioned taste aversion: THERE IS NO REPORT IN THE LITERATURE CONCERNING DEVELOPMENTAL EFFECTS OF SEX HORMONES, and SUCH STUDIES WOULD BE DIFFICULT TO DO, ALTHOUGH NOT IMPOSSIBLE Quotation withheld because this record is not cleared for redistribution. the verbal-versus-spatial pattern of human sex differences, used to motivate the rodent work Quotation withheld because this record is not cleared for redistribution. the sex-skewed prevalence of specific disorders, used as the applied justification for the whole review Quotation withheld because this record is not cleared for redistribution. a sex difference in this literature is a difference in measured PERFORMANCE, and the review's central caution is that performance and learning are not the same thing Quotation withheld because this record is not cleared for redistribution. organizational versus activational is the distinction between hormones building the difference during development and hormones modulating it in adulthood - and the two can be separated experimentally by when the manipulation is done Quotation withheld because this record is not cleared for redistribution. the DIRECTION of the sex difference is not a property of sex but of the task: females lead in eyeblink, fear-potentiated startle and active avoidance, males in fear conditioning, simple lever-pressing and taste aversion Quotation withheld because this record is not cleared for redistribution. difficulty flips the direction within one paradigm - males lead on simple lever-pressing, females on the harder low-rate variant Quotation withheld because this record is not cleared for redistribution. claim_type: critique a second reading DIFFERING from the recorded value. Recorded: existence — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. method: narrative review across eyeblink conditioning, fear conditioning, active avoidance and conditioned taste aversion, with hormonal manipulation studies a second reading DIFFERING from the recorded value. Recorded: review — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. phenomenon: sex differences in associative learning a second reading DIFFERING from the recorded value. Recorded: sex differences in classical and operant conditioning — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. critiques → the practice of excluding females from basic research, and the assumption that their behaviour is like males but more variable Quotation withheld because this record is not cleared for redistribution. contradicts → the assumption that females are the more variable sex, citing human data showing the opposite Quotation withheld because this record is not cleared for redistribution. qualifies → reported sex differences in learning, by attributing some to performance and some to strategy Quotation withheld because this record is not cleared for redistribution. supports → the case for including sex as a variable when animal models are applied to sex-differentiated disorders Quotation withheld because this record is not cleared for redistribution. organizational —contrasted-with→ activational organizational activational strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. trace conditioning —contrasted-with→ delay conditioning trace conditioning delay conditioning differs in: THE AXIS IS THE TRACE INTERVAL, AND IT IS GIVEN AS A NUMBER. 'This task depends on the hippocampus and requires multiple trials to learn because Quotation withheld.' The two procedures are identical except for a gap, and the sentence states the gap AS THE CAUSE of both the hippocampal dependence and the slower learning - so the axis is not a description of the difference, it is the explanation of the consequences. · strength of the relation: 1 · note: separated by whether the hippocampus is required, which is what makes the pair diagnostic Quotation withheld because this record is not cleared for redistribution. learned helplessness —operationalised-as→ active avoidance learned helplessness active avoidance strength of the relation: 0.9 Quotation withheld because this record is not cleared for redistribution. p-value p-value Quotation withheld because this record is not cleared for redistribution. statistical significance test statistical significance test Quotation withheld because this record is not cleared for redistribution. Female rats emit more conditioned eyeblink responses than males in both the hippocampus-dependent trace version and the hippocampus-independent delay version of the task. Quotation withheld because this record is not cleared for redistribution. The direction of the sex difference reverses in fear conditioning: males acquire and express conditioned fear better than females. Quotation withheld because this record is not cleared for redistribution. In the harder two-way active avoidance task most females learn to escape in the first trials, while males need more. Quotation withheld because this record is not cleared for redistribution. Removing the ovaries in adulthood abolishes the female advantage in eyeblink conditioning, showing the effect depends on circulating ovarian hormones. Quotation withheld because this record is not cleared for redistribution. The sex difference in learning emerges after puberty, with none before or during puberty. Quotation withheld because this record is not cleared for redistribution. Testosterone given to females on the day of birth reduces their adult classical conditioning. Quotation withheld because this record is not cleared for redistribution. In conditioned taste aversion females extinguish sooner, drinking the sweet solution again sooner and in greater amounts. Quotation withheld because this record is not cleared for redistribution. After uncontrollable stress, male rats fail to learn to escape shock in active avoidance and become helpless. Quotation withheld because this record is not cleared for redistribution. Because females learn trace eyeblink conditioning better, more of the newly born hippocampal cells survive in females than in males. Quotation withheld because this record is not cleared for redistribution. Castrating adult males facilitates their operant conditioning. Quotation withheld because this record is not cleared for redistribution. females outperform males in eyeblink conditioning, fear-potentiated startle and most operant tasks Quotation withheld because this record is not cleared for redistribution. males outperform females in classical fear conditioning, some lever-pressing tasks and taste aversion Quotation withheld because this record is not cleared for redistribution. the direction reverses with task difficulty within lever-pressing Quotation withheld because this record is not cleared for redistribution. the eyeblink difference persists in diestrus, so it is not solely an oestrogen effect Quotation withheld because this record is not cleared for redistribution. females retain the conditioned response better weeks later, which argues the difference is learning and not performance Quotation withheld because this record is not cleared for redistribution. no sex difference exists in spontaneous blinking, in response to the noise alone, or in the unconditioned response Quotation withheld because this record is not cleared for redistribution. males exposed to uncontrollable stress become helpless while females do not Quotation withheld because this record is not cleared for redistribution. the helplessness difference survives gonadectomy and neonatal masculinisation, unlike the other effects Quotation withheld because this record is not cleared for redistribution. oestrogen effects on avoidance are non-monotonic - low doses disrupt, high doses facilitate Quotation withheld because this record is not cleared for redistribution. physiological oestrogen replacement does not restore the eyeblink advantage; only non-physiological doses do Quotation withheld because this record is not cleared for redistribution. classical eyeblink conditioning paradigm classical eyeblink conditioning paradigm Quotation withheld because this record is not cleared for redistribution. trace conditioning trace conditioning Quotation withheld because this record is not cleared for redistribution. delay conditioning delay conditioning Quotation withheld because this record is not cleared for redistribution. conditioned taste aversion conditioned taste aversion Quotation withheld because this record is not cleared for redistribution. fear-potentiated startle paradigm fear-potentiated startle paradigm Quotation withheld because this record is not cleared for redistribution. light-enhanced startle paradigm light-enhanced startle paradigm Quotation withheld because this record is not cleared for redistribution. one-way avoidance task (FR1) one-way avoidance task (FR1) Quotation withheld because this record is not cleared for redistribution. two-way avoidance task (FR2) two-way avoidance task (FR2) Quotation withheld because this record is not cleared for redistribution. organizational and activational effects organizational and activational effects Quotation withheld because this record is not cleared for redistribution. eyeblink response eyeblink response Quotation withheld because this record is not cleared for redistribution. escape latencies escape latencies Quotation withheld because this record is not cleared for redistribution. Density of dendritic spines Density of dendritic spines Quotation withheld because this record is not cleared for redistribution. sex sex Quotation withheld because this record is not cleared for redistribution. phase of the estrous cycle phase of the estrous cycle Quotation withheld because this record is not cleared for redistribution. 500 ms — length of the temporal gap between CS and US that makes eyeblink conditioning hippocampus-dependent Quotation withheld because this record is not cleared for redistribution. 800 trials — total trace eyeblink conditioning trials given, spread over four days at 200 per day Quotation withheld because this record is not cleared for redistribution. 34% / 17% — increase in the density of new hippocampal cells caused by training, in females versus males Quotation withheld because this record is not cleared for redistribution. 60% — the responding rate used as the learning criterion that more females than males reach Quotation withheld because this record is not cleared for redistribution. 1 mA — intensity of the footshock the rats learn to avoid in the one-way avoidance task Quotation withheld because this record is not cleared for redistribution. 30 trials — amount of avoidance training after which some male rats still have not learned to escape Quotation withheld because this record is not cleared for redistribution. EVIDENCE CORRECTED (RE-GROUNDED - THE POINTER WAS WRONG, NOT THE CLAIM) · 800 trials over 4 days, 200 per day — the eyeblink training protocol EVIDENCE CORRECTED: RE-GROUNDED - THE POINTER WAS WRONG, NOT THE CLAIM. The old evidence was verbatim, anchored and correctly cut, and it contained NONE of this claim's numbers (200, 800). The paper states the claim in one sentence elsewhere and the tagger did not use it. the project, 2026-08-23: 'WE HAVE SPENT THE DAY VERIFYING THAT QUOTES ARE REAL AND NONE OF IT ASKS WHETHER THEY ARE RELEVANT.' Confirmed by reading the claim, the old span and the candidate together; the candidate carries every number AND the claim's own content words. Quotation withheld because this record is not cleared for redistribution. 500 ms trace interval — the gap that makes the task hippocampus-dependent Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1016/j.physbeh.2009.02.035.