Drosophila Conditioned Courtship: Two Ways of Testing Memory

In Drosophila, courtship reduction in male flies that have previous experience of courting a mated female is a result of the counterconditioning of an attractive unconditioned stimulus (US)—the aphrodisiac—which becomes an aversive conditioned stimulus (CS) after being paired with an aversive US—the antiaphrodisiac. In a retention test with a virgin female lacking the antiaphrodisiac, males retain a lower level of courtship for 3 hr after training. However, a measure of courtship suppression, the learning index (LI), decreases significantly after only 1 hr. In contrast, in the retraining test with a mated female, the LI shows no decrease for 8 hr but falls below significance 16 hr after training. These results are discussed in terms of the transfer of training. Nonspecific transfer and nonassociative behavioral modifications play little, if any, role in the transfer of training. The retraining test is recommended as a new protocol for studying conditioned courtship. According to the model proposed here, in tests with a virgin female, the duration of memory retention is limited by the retention of the direct association between the CS and the aversive motivational system or by the retention of an internal representation of the US. In retraining tests, the CS–US association seems to be the only factor involved in transfer 3 or more hours after training.     

Courtship learning in Drosophila melanogaster: Diverse plasticity of a reproductive behavior

Mechanisms for identifying appropriate mating partners are critical for species propagation. In many species, the male uses multiple sensory modalities to search for females and to subsequently determine if they are fit and receptive. Males can also use the information they acquire in this process to change their courtship behavior and reduce courtship of classes of targets that are inappropriate or unreceptive. In Drosophila, courtship plasticity, in the form of both nonassociative and associative learning, has been documented—the type of learning depending on the nature of the trainer. The conditions in which the male is presented with the training target can profoundly alter the cues that he finds salient and the longevity of the memory that he forms. With the exception of habituation and sensitization, these types of plasticity have an operant component in that the male must be courting to respond to the behavior-altering cues. Courtship plasticity is therefore a complex and rich range of behaviors rather than a single entity. Our understanding of these plastic behaviors has been enhanced by recent advances in our understanding of the circuitry underlying courtship itself and the identification of chemical cues that drive and modify the behavior. Courtship learning is providing a window into how animals can use a variety of sensory inputs to modulate a decision making process at many levels.When confronted with a potential mate, Drosophila melanogaster males perform a stereotyped courtship ritual. This behavior serves at least two obvious functions for the male. The first is to prime conspecific females for copulation. During courtship, the female is assessing the male''s suitability, and if the song he sings (Burnet et al. 1971; von Schilcher 1976a) and pheromones he emits (Grillet et al. 2006; Kurtovic et al. 2007) are correct for her species and of sufficient quality, her willingness to copulate is increased. She will slow her locomotion, present her abdomen to the male, and then spread her wings and genital plates to allow him to mount (Lasbleiz et al. 2006). A second function of courtship is that it allows a male to accumulate information about the target courtship object to assess its suitability and receptiveness. The male uses auditory, mechanosensory, visual, and chemosensory signals from the target to make this assessment (for review, see Villella and Hall 2008; Ejima and Griffith 2009).Since D. melanogaster males will avidly initiate courtship of a wide variety of inappropriate and/or unreceptive targets, including immature males, sexually immature virgin females, mated females, and heterospecific females, the information obtained during courtship is critical to deciding whether to increase the intensity of his effort or terminate pursuit of the target. In the last several years, courtship has become a favored model for those researchers interested in how the nervous system specifies “innate” behaviors. While it is true that a male does not have to be instructed to produce adequate courtship (Hall 1994; Clyne and Miesenbock 2008), this apparently stereotyped behavior is far from static: It can be modified in a dizzying number of ways by experience. In this paper, we will discuss how information gathered during courtship can allow males to learn about specific types of courtship objects and broadly modify future behavioral responses to a particular class of target.     

Conditioning of the microcirculation in the rat

The serotonin-catecholamine balancing mechanism maintains normal vascular tonus and permeability of the microcirculation. Serotonin provokes local vasodilatation and increases capillary permeability in the skin of rats. Released or injected catecholamines inhibit the serotonin-induced peripheral hemodynamic alterations. Following eleotroconvulsive treatment (ECT) (US), there is a catecholamine release and the microcirculatory response to serotonin does not occur. When the administration of a visual stimulus (in six consecutive occasions) proceedingly coincided with the administration of the ECT, it was noted that the light became an effective stimulus for this system. Light alone is an indifferent stimulus to catecholamine release. Thus, the inhibition of the serotonin-induced vasodilatation by ECT (via catecholamine release) became conditioned to the visual-conditional stimulus. Since the net effect of extrinsic serotonin depends on free catecholamines at the vascular bed, the intensity of the serotonin-induced vascular response reflects alterations in the chemical balancing mechanism. This mechanism can be conditioned with the present technique. The result indicates that there is central nervous system mediation.     

Courtship in the personals column: The influence of gender and sexual orientation

Eight hundred personal advertisements were analyzed, representing an equal sampling of male and female homosexual and heterosexual advertisers on the East and West Coast of the United States. In general, men were more concerned with physical characteristics, while women stressed psychological factors. Homosexuals were more concerned with sexuality, while heterosexuals specified a broader range of characteristics. Significant interactions between gender and sexual orientation point to the importance of sex-role expectations in the heterosexual context and suggest substantial differences between males and females who choose homosexuality.     

Issues of Reliability in Measuring Intimate Partner Violence during Courtship

The current paper focuses on problems in conceptualizing and establishing reliability when using self-administered measures of intimate partner violence to assess dating violence. Establishing reliability is an important step in the development of dating violence assessment instruments. However, the nature of dating violence can make it difficult to establish reliability. Most notably, measures of intimate partner violence in courtship yield data that are positively skewed, with almost no one reporting high levels of violence. This could have implications for the calculation of several forms of reliability that assume normality (e.g., Pearson correlations, intraclass correlations). In addition, there are other characteristics of dating violence that could impact reliability. For example, partner violence perpetrators do not necessarily use multiple acts (internal consistency reliability) or repeat specific acts (test-retest reliability). And, gender differences in the perception of partner violence may influence intra-couple reliability in heterosexual couples. Finally, statistical interdependence within couples makes current intra-couple reliability assessment suspect. Research is reviewed and recommendations are made concerning the establishment of test-retest reliability, intra-couple reliability, and internal consistency reliability for measures of dating violence.     

Conditioning the cardiorespiratory dynamics of locomotion in dogs

In 17 dogs blood pressure in the carotid artery, heart rate, pneumogram and actogram of the hind leg were recorded during rest and during locomotion on a treadmill. The increases in cardiorespiratory dynamics which occurred during locomotion were then conditioned. The conditional stimulus was represented by the noise and vibration of the treadmill. It was determined that conditional changes in cardiorespiratory dynamics can be formed quickly on the basis of locomotion. Qualitatively the changes were the same as the unconditional changes, and their magnitude was 60 to 70 per cent that of the unconditional changes. Conditional increase in cardiorespiratory dynamics was most intensive in the first 30 seconds from the onset of the conditional stimulus. In acute extinction of these conditional changes, movements of the extremities were inhibited first, followed by inhibition of increased blood pressure, then inhibition of increased heart rate, and last, inhibition of increased respiratory rate. In another series of experiments on five dogs cardiorespiratory responses were conditioned to a sudden change from moderate locomotion (50 m per min) to rapid locomotion (200 m per min). Increased cardiorespiratory dynamics could be conditioned easily. Increased circulation of blood and increased respiratory rate on exposure to conditional stimuli signalling muscular exertion can be considered an important preparation of the organism for actual muscular activity. This preparation also takes place in natural life conditions.     

Conditioning and the Coordination of Movements

(Krech, D., and Crutchfield, R. S. Theory and Problems of Social Psychology. New York: McGraw-Hill, 1948. Pp. 639.) Reviewed by Gwynne Nettler     

Conditioning in the prediction of therapeutic outcome in depressions

Predictions of clinical responsiveness to tricyclic anti-depressants were studied in 25 depressed patients. A well-preserved external inhibition at the commencement of treatment was found to be the best single indicator of therapeutic success.     

Ontogenetic Changes in the Neural Mechanisms of Eyeblink Conditioning

The rodent eyeblink conditioning paradigm is an ideal model system for examining the relationship between neural maturation and the ontogeny of associative learning. Elucidation of the neural mechanisms underlying the ontogeny of learning is tractable using eyeblink conditioning because the necessary neural circuitry (cerebellum and interconnected brainstem nuclei) underlying the acquisition and retention of the conditioned response (CR) has been identified in adult organisms. Moreover, the cerebellum exhibits substantial postnatal anatomical and physiological maturation in rats. The eyeblink CR emerges developmentally between postnatal day (PND) 17 and 24 in rats. A series of experiments found that the ontogenetic emergence of eyeblink conditioning is related to the development of associative learning and not related to changes in performance. More recent studies have examined the relationship between the development of eyeblink conditioning and the physiological maturation of the cerebellum, a brain structure that is necessary for eyeblink conditioning in adult organisms. Disrupting cerebellar development with lesions or antimitotic treatments impairs the ontogeny of eyeblink conditioning. Studies of the development of physiological processes within the cerebellum have revealed striking ontogenetic changes in stimulus-elicited and learning-related neuronal activity. Neurons in the interpositus nucleus and Purkinje cells in the cortex exhibit developmental increases in neuronal discharges following the unconditioned stimulus (US) and in neuronal discharges that model the amplitude and time-course of the eyeblink CR. The developmental changes in CR-related neuronal activity in the cerebellum suggest that the ontogeny of eyeblink conditioning depends on the development of mechanisms that establish cerebellar plasticity. Learning and the induction of neural plasticity depend on the magnitude of the US input to the cerebellum. The role of developmental changes in the efficacy of the US pathway has been investigated by monitoring neuronal activity in the inferior olive and with stimulation techniques. The results of these experiments indicate that the development of the conditioned eyeblink response may depend on dynamic interactions between multiple developmental processes within the eyeblink neural circuitry.     

Conditioning preparation for the nictitating membrane of the pigeon

A procedure is described for restraining the pigeon while recording movement of the nictitating membrane. The preparation provides a means of studying classical conditioning that combines the rich sensory capacities of the pigeon with the control achieved in nictitating membrane conditioning of the rabbit.     

Differential Conditioning Based on a Difference in the Predictability of Reinforcement

A Pavlovian procedure containing a set of several alternative reliable trial stimuli and a set of several alternative unreliable trial stimuli was used to determine if reliability of outcome, per se, would differentially condition additional trial stimuli that either preceded or followed those original trial stimuli in a serial conditioning paradigm. The reinforcing effectiveness of the antecedent stimuli themselves was later tested in a higher-order conditioning design. It was found that different rates could be established to the different antecedent stimuli in the absence of a difference in the probability of reinforcement. Further, stimuli paired with those antecedent stimuli in the higher-order conditioning test also exhibited a difference in rate. It was concluded that a combination of a stimulus that is always followed by food and another that is never followed by food are, in net, a more effective reinforcer than a common stimulus that has the same overall probability of reinforcement but which is followed by both outcomes.     

Scopolamine Selectively Disrupts the Acquisition of Contextual Fear Conditioning in Rats

Muscarinic cholinergic antagonism produces learning and memory deficits in a variety of hippocampal-dependent tasks. Hippocampal lesions produce both acquisition deficits and retrograde amnesia for contextual fear conditioning, but do not impact fear conditioning to discrete cues. In order to examine the effects of muscarinic antagonism in this paradigm, rats were given scopolamine (1 mg/kg) either before or for 3 days after a Pavlovian fear-conditioning session in which tones were paired with aversive footshocks. Fear to the context and the tone was assessed by measuring freezing in separate tests. It was found that pretraining, but not posttraining, scopolamine severely impaired contextual fear conditioning; tone conditioning was not affected under either condition (cf., Young, Bohenek, & Fanselow,Neurobiology of Learning and Memory,63,174–180, 1995).     

Evolution, Traits, and the Stages of Human Courtship: Qualifying the Parental Investment Model

ABSTRACT Individual differences are explicitly connected to social interaction in Darwin's notion of sexual selection Traits that increase the probability of successful reproduction will tend to increase in frequency This process operates partly through differential choice, by one sex, of certain traits in the other According to the parental investment model, females frequently have more stringent criteria for the traits they will accept in a mate because they have a relatively larger investment in each offspring Because human mating arrangements often involve a substantial commitment of resources by the male, it is necessary to invoke a distinction between the selectivity involved during casual mating opportunities and the selectivity exercised when choosing a long-term partner Ninety-three undergraduate men and women rated their minimum criteria on 24 partner characteristics at four levels of commitment In line with an unqualified parental investment model, females were more selective overall, particularly on status-linked variables In line with a qualified parental investment model, males' trait preferences depended upon the anticipated investment in the relationship Males had lower requirements for a sexual partner than did females, but were nearly as selective as females when considenng requirements for a long-term partner     

The Role of Mediated Conditioning in Acquired Equivalence

In Experiment 1 rats received initial training in which delivery of a sucrose pellet was signalled by an auditory cue. This cue was then paired with shock in a second phase of training. In a test the rats showed an unwillingness to perform an instrumental response that yielded the sucrose pellet. This was interpreted as indicating that the associatively activated representation of the pellet had acquired aversive properties during the shock-reinforced stage of training. Experiment 2 replicated this mediated conditioning effect making use of a Phase 1 training procedure, modelled on that used by Honey and Hall (1989) to demonstrate acquired equivalence of cues, in which two auditory cues were each used to signal sucrose pellets. A further test revealed that this training resulted in enhanced generalization between these two cues. It was argued that this effect is mediated by the conditioned aversive properties of the common associate of the two auditory cues.     

Conditioning across the duration of a backward conditioned stimulus

Five conditioned suppression experiments examined the extent to which an appetitively motivated lever-press response can be punished by different components of a backward conditioned stimulus (CS). Using a 0-s unconditioned stimulus (US)-CS interval, Experiments 1 and 2 showed that the initial 3 s of a normally 30-s backward CS served as a more effective punisher than the CS as a whole. Experiment 3 found no such effect if the US-CS interval were 3 s rather than 0 s. Experiments 4A and 4B found that if the US-CS interval were 0 s, the initial part of the backward CS acquired excitatory properties although the CS as a whole passed a summation test for conditioned inhibition. By contrast, the 3-s US-CS interval supported inhibitory conditioning across the whole duration of the backward CS. Taken together, these findings support a modified version of Wagner's sometimes opponent process model, which suggests that different components of a backward CS become either excitatory or inhibitory depending on the components' temporal proximity to the US.