Different Behavioral Experiences Produce Distinctive Parallel Changes in, and Correlate With, Frontal Cortex and Hippocampal Global Post-translational Histone Levels.

While it is clear that behavioral experience modulates epigenetic profiles, it is less evident how the nature of that experience influences outcomes and whether epigenetic/genetic biomarkers could be extracted to classify different types of behavioral experience. To begin to address this question, male and female mice were subjected to either a Fixed Interval (FI) schedule of food reward, or a single episode of forced swim followed by restraint stress, or no explicit behavioral experience after which global expression levels of two activating (H3K9ac and H3K4me3) and two repressive (H3K9me2 and H3k27me3) post-translational histone modifications (PTHMs), were measured in hippocampus (HIPP) and frontal cortex (FC). The specific nature of the behavioral experience differentiated profiles of PTHMs in a sex- and brain region-dependent manner, with all 4 PTHMs changing in parallel in response to different behavioral experiences. These different behavioral experiences also modified the pattern of correlations of PTHMs both within and across FC and HIPP. Unexpectedly, highly robust correlations were found between global PTHM levels and behavioral performances, suggesting that global PTHMs may provide a higher-order pattern recognition function. Further efforts are needed to determine the generality of such findings and what characteristics of behavioral experience are critical for modulating PTHM responses

Signal and Schedule Functions when Pausing is the Operant

Pausing, like other operants, is affected by the schedule of reinforcement for alternative responses and the antecedent discriminative stimuli that set the occasion for it to be reinforced. The effects of both of these variables on pausing were further investigated in three experiments in which key pecking by pigeons was reinforced concurrently according to, respectively, a variable-interval schedule, a differential-reinforcement-of-low-rate schedule, and a fixed-ratio schedule. The antecedent discriminative stimulus control of pausing was investigated by comparing unsignaled, briefly signaled, and fully signaled pausing contingencies in each experiment. Pigeons\u27 time allocation to pausing in both full-and brief- signal conditions with each key-peck reinforcement schedule was lower than unsignaled-baseline and control conditions, demonstrating discriminative control of pausing. Although there were no systematic differences between the brief- and full-signal conditions, how pauses of the required duration were assimilated depended on the schedule of reinforcement for pecking. The current experiments replicated prior findings with a variable-interval schedule, and extended them by showing pauses were assimilated in those pauses already maintained under a differential-reinforcement-of-low-rate schedule in Experiment 2, and into the postreinforcement pause under a fixed-ratio schedule in Experiment 3. Together, these results demonstrate the antecedent and consequent control of pausing under several schedules of reinforcement for pecking, under which characteristically different peck-pause interactions emerge

Post-reinforcement pause in grocery shopping: comparing interpurchase times across products and consumers

Purchase probability as a function of interpurchase time was examined through comparison of findings from laboratory experiments on reinforcement schedules and from marketing investigations of consumers’ interpurchase time. Panel data, based on a sample of 80 consumers who purchased nine supermarket food products during 16 weeks, were used. For each product category, interpurchase time was similar for each shopping occasion and cumulative purchase probability increased as a Gamma function of the time since the last purchase. A comparison of interpurchase times across products and consumers showed that average interpurchase time differed across four subsets of products and across seven groups of consumers, with a significant interaction effect. Interpurchase times tended to be longer after larger purchases, as would be predicted from laboratory results. A correlation between individual interpurchase time and number of products bought on each shopping occasion indicated that consumers who shop more frequently buy larger numbers of products per occasion. These results have several managerial implications and demonstrate the usefulness of a behavior-analytic framework in the interpretation of consumer behavior

The Fixed-Interval Presentation of a Small Fixed Ratio

In mixed fixed-ratio schedules, reinforcement is delivered according to two or more fixed-ratio components, which may be programmed in simple alternation or according to a random sequence. If the components simply alternate, the behavior is similar to that obtained in a multiple schedule. Pauses are long before long fixed ratios and short before short fixed ratios. If a random sequence is used, responding is characterized by short pauses after reinforcement independent of the size of the ratio and primes occur at the beginning of many of the fixed ratios. The purpose of the present study was to investigate the possibility of other patterns of responding being controlled by component sequences ether than simple or random alternation in mixed fixed-ratio schedules. Two pigeons were trained to key peck on a fixed-ratio 100 (FR 100) schedule. Following this training, the schedule was based on a superimposed fixed-interval contingency which specified that an FR 10 would occur after the completion of the first FR 100 following a fixed period, timed from the last FR 10. Thus, the schedule was a mixed FR 100 FR 10 with FR 10 frequency controlled by the superimposed fixed-interval contingency. The value of the FI was varied for both birds. To control for the possibility that the pattern of responding was related to priming, two additional pigeons were trained to respond on comparable multiple schedules in which primes were absent. The mixed schedule shortened the pre-FR 100 pause. Analysis of the sequence of pauses following an FR 10 showed that the pause following an FR 10 was long relative to other pauses in the sequence which were short and approximately equal to the pre-FR 10 pause. Primes, a run of approximately ten responses at the beginning of a ratio followed by a pause, were relatively infrequent in the first FR 100 after an FR 10, but were more frequent in other positions in the sequence. In the multiple schedule, all pre-FR 100 pauses were long and approximately ·equal in length, but the pre-FR 10 pauses were short. These results demonstrate that the pattern of responding obtained in the mixed schedule was related to priming. First, short pauses preceded FR 100s which contained primes in the mixed schedule. Primes did not occur in the multiple schedule, and the pre-FR 100 pauses were long. Second, primes were frequent only in those ordinal positions in the mixed schedule which were preceded by short pauses. Third, short pauses and primes developed simultaneously. These three effects suggest a new account of priming as a unit of behavior. This unit consists of a short pause followed by a run of ten responses. This run of ten responses is intermittently reinforced by food delivery when the FR 10 occurs. The pause after this run, which occurs if the schedule is FR 100, is caused by the S-delta condition produced by the information that the schedule is not FR 10. The pattern of responding in the mixed schedule was also related to the sequential nature of the schedule. Since FR 100s always followed FR 10s, FR 10s were followed by long pauses and few primes. FR 100s, on the other hand, were occasionally followed by FR 10s. Thus, the completion of an FR 100 was a discriminative stimulus for FR 10-like behavior