Did we find a copycat? Do as I Do in a domestic cat (Felis catus).

This study shows evidence of a domestic cat (Felis catus) being able to successfully learn to reproduce human-demonstrated actions based on the Do as I Do paradigm. The subject was trained to reproduce a small set of familiar actions on command "Do it!" before the study began. To test feature-contingent behavioural similarity and control for stimulus enhancement, our test consisted of a modified version of the two-action procedure, combined with the Do as I Do paradigm. Instead of showing two different actions on an object to different subjects, we applied a within-subject design and showed the two actions to the same subject in separate trials. We show evidence that a well-socialized companion cat was able to reproduce actions demonstrated by a human model by reproducing two different actions that were demonstrated on the same object. Our experiment provides the first evidence that the Do as I Do paradigm can be applied to cats, suggesting that the ability to recognize behavioural similarity may fall within the range of the socio-cognitive skills of this species. The ability of reproducing the actions of a heterospecific human model in well-socialized cats may pave the way for future studies addressing cats' imitative skills.

Social influence on the expression of robbing and bartering behaviours in Balinese long-tailed macaques.

Animals use social information, available from conspecifics, to learn and express novel and adaptive behaviours. Amongst social learning mechanisms, response facilitation occurs when observing a demonstrator performing a behaviour temporarily increases the probability that the observer will perform the same behaviour shortly after. We studied "robbing and bartering" (RB), two behaviours routinely displayed by free-ranging long-tailed macaques (Macaca fascicularis) at Uluwatu Temple, Bali, Indonesia. When robbing, a monkey steals an inedible object from a visitor and may use this object as a token by exchanging it for food with the temple staff (bartering). We tested whether the expression of RB-related behaviours could be explained by response facilitation and was influenced by model-based biases (i.e. dominance rank, age, experience and success of the demonstrator). We compared video-recorded focal samples of 44 witness individuals (WF) immediately after they observed an RB-related event performed by group members, and matched-control focal samples (MCF) of the same focal subjects, located at similar distance from former demonstrators (N = 43 subjects), but in the absence of any RB-related demonstrations. We found that the synchronized expression of robbing and bartering could be explained by response facilitation. Both behaviours occurred significantly more often during WF than during MCF. Following a contagion-like effect, the rate of robbing behaviour displayed by the witness increased with the cumulative rate of robbing behaviour performed by demonstrators, but this effect was not found for the bartering behaviour. The expression of RB was not influenced by model-based biases. Our results support the cultural nature of the RB practice in the Uluwatu macaques.

Response Facilitation Induced by Insulin-like Growth Factor-I in the Primary Somatosensory Cortex of Mice Was Reduced in Aging.

Aging is accompanied by a decline in cognition that can be due to a lower IGF-I level. We studied response facilitation induced in primary somatosensory (S1) cortical neurons by repetitive stimulation of whiskers in young and old mice. Layer 2/3 and 5/6 neurons were extracellularly recorded in young (≤ 6 months of age) and old (≥ 20 month of age) anesthetized mice. IGF-I injection in S1 cortex (10 nM; 0.2 µL) increased whisker responses in young and old animals. A stimulation train at 8 Hz induced a long-lasting response facilitation in only layer 2/3 neurons of young animals. However, all cortical neurons from young and old animals showed long-lasting response facilitation when IGF-I was applied in the S1 cortex. The reduction in response facilitation in old animals can be due to a reduction in the IGF-I receptors as was indicated by the immunohistochemistry study. Furthermore, a reduction in the performance of a whisker discrimination task was observed in old animals. In conclusion, our findings indicate that there is a reduction in the synaptic plasticity of S1 neurons during aging that can be recovered by IGF-I. Therefore, it opens the possibility of use IGF-I as a therapeutic tool to ameliorate the effects of heathy aging.

Proactive motor control within and between hands: Effects of age, motor set, and cue type.

Several studies have reported that proactive motor control in a cued four-finger choice reaction task proceeds more efficiently with a 2-hands motor set (two fingers on each hand) than with a 1-hand motor set (four fingers on one hand). According to the Grouping Model, this is because the 2-hands motor set recruits distinct left and right hand representations located in separate cerebral hemispheres, whereas the 1-hand motor set recruits partially overlapping neural areas grouped together in one hemisphere. The latter neural organization increases neuromotor noise, thereby complicating proactive motor selection. The present study examined the effect of older age on the 2-hands motor selection advantage. A group of young and a group of older adults performed two proactive motor tasks-the procue task and the anticue task-with two motor sets: a 2-hands and 1-hand set. Predictive cues preceded the target signal at five different time intervals (100-850 ms), allowing advance selection of 2 out of 4 fingers. Older adults showed longer reaction times and smaller cueing benefits compared to younger adults. Overall, cueing benefits were greater, and accrued faster, with the 2-hands than with the 1-hand motor set, reflecting the beneficial impact of the neuroanatomical hand distinction. Importantly, the 2-hands advantage was substantially greater in the older age group, suggesting that the hand distinction might abate age-related neural dedifferentiation. These findings highlight the impact of cortical representational distinctiveness in proactive motor control, especially in older age.

Both facilitatory and inhibitory impairments underlie age-related differences of proactive cognitive control across the adult lifespan.

We investigated two components of proactive cognitive control, response facilitation and response inhibition, in an adult lifespan sample (N=544, age range=18-91years) by administering two response-preparation tasks: a procue task, primarily involving facilitation, and an anticue task, involving both facilitation and inhibition. Cues in both tasks corresponded with the index and middle fingers of either the left or right hand. After a random preparation interval (PI) of 100-850ms following the onset of the cue signal, a single-target stimulus indicated the required response. Where procues were spatially aligned with the two fingers of the responding hand, anticues consistently indicated the two fingers of the opposite hand, requiring a remapping of cue location and response hand. This remapping requires inhibition to suppress the automatic activation of the ipsilateral responses. Previous research revealed typical reaction time (RT) profiles for procues and anticues as a function of PI. Whereas procues generate RT benefits (relative to a neutral-cue condition) already at short PIs, which increase with longer PIs, anticues generate RT costs at short PIs and RT benefits at longer PIs. Our results showed that, in the anticue task, older participants needed more preparation time to turn RT costs into RT benefits than younger participants, revealing an age-related deficit of response inhibition. Moreover, in both tasks, older participants were less able to increase RT benefits with longer PIs, revealing a deficit of response facilitation. We conclude that both facilitatory and inhibitory impairments contribute to age-related deficiencies in proactive cognitive control.

Facilitation of responses by task-irrelevant complex deviant stimuli.

Novel stimuli reliably attract attention, suggesting that novelty may disrupt performance when it is task-irrelevant. However, under certain circumstances novel stimuli can also elicit a general alerting response having beneficial effects on performance. In a series of experiments we investigated whether different aspects of novelty--stimulus novelty, contextual novelty, surprise, deviance, and relative complexity--lead to distraction or facilitation. We used a version of the visual oddball paradigm in which participants responded to an occasional auditory target. Participants responded faster to this auditory target when it occurred during the presentation of novel visual stimuli than of standard stimuli, especially at SOAs of 0 and 200 ms (Experiment 1). Facilitation was absent for both infrequent simple deviants and frequent complex images (Experiment 2). However, repeated complex deviant images did facilitate responses to the auditory target at the 200 ms SOA (Experiment 3). These findings suggest that task-irrelevant deviant visual stimuli can facilitate responses to an unrelated auditory target in a short 0-200 millisecond time-window after presentation. This only occurs when the deviant stimuli are complex relative to standard stimuli. We link our findings to the novelty P3, which is generated under the same circumstances, and to the adaptive gain theory of the locus coeruleus-norepinephrine system (Aston-Jones and Cohen, 2005), which may explain the timing of the effects.

When given the opportunity, chimpanzees maximize personal gain rather than "level the playing field".

We provided chimpanzees (Pan troglodytes) with the ability to improve the quality of food rewards they received in a dyadic test of inequity. We were interested to see if this provision influenced their responses and, if so, whether it was mediated by a social partner's outcomes. We tested eight dyads using an exchange paradigm in which, depending on the condition, the chimpanzees were rewarded with either high-value (a grape) or low-value (a piece of celery) food rewards for each completed exchange. We included four conditions. In the first, "Different" condition, the subject received different, less-preferred, rewards than their partner for each exchange made (a test of inequity). In the "Unavailable" condition, high-value rewards were shown, but not given, to both chimpanzees prior to each exchange and the chimpanzees were rewarded equally with low-value rewards (a test of individual contrast). The final two conditions created equity. In these High-value and Low-value "Same" conditions both chimpanzees received the same food rewards for each exchange. Within each condition, the chimpanzees first completed ten trials in the Baseline Phase, in which the experimenter determined the rewards they received, and then ten trials in the Test Phase. In the Test Phase, the chimpanzees could exchange tokens through the aperture of a small wooden picture frame hung on their cage mesh in order to receive the high-value reward. Thus, in the Test Phase, the chimpanzees were provided with an opportunity to improve the quality of the rewards they received, either absolutely or relative to what their partner received. The chimpanzees responded in a targeted manner; in the Test Phase they attempted to maximize their returns in all conditions in which they had received low-value rewards during the Baseline Phase. Thus, the chimpanzees were apparently motivated to increase their reward regardless of their partners', but they only used the mechanism provided when it afforded the opportunity for them to increase their rewards. We also found evidence that the chimpanzees' responses were enhanced by social facilitation. Specifically, the chimpanzees were more likely to exchange their tokens through the frame when their test partner also did so, even in circumstances in which their reward value could not be improved. Our paradigm provided the chimpanzees with the possibility to improve the quality of rewards they received in the Test Phase. We found that refusals - to exchange tokens or to eat rewards - decreased significantly in the Test Phase compared to the Baseline Phase, where no such opportunity for improvement of outcomes existed. Thus, the chimpanzees participated more when they could improve the rewards they received.