Browsing by Subject "Association Learning"

Now showing 1 - 8 of 8
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    A comparison of dimensional models of emotion: evidence from emotions, prototypical events, autobiographical memories, and words.
    (Memory, 2009-11) Rubin, David C; Talarico, Jennifer M
    The intensity and valence of 30 emotion terms, 30 events typical of those emotions, and 30 autobiographical memories cued by those emotions were each rated by different groups of 40 undergraduates. A vector model gave a consistently better account of the data than a circumplex model, both overall and in the absence of high-intensity, neutral valence stimuli. The Positive Activation - Negative Activation (PANA) model could be tested at high levels of activation, where it is identical to the vector model. The results replicated when ratings of arousal were used instead of ratings of intensity for the events and autobiographical memories. A reanalysis of word norms gave further support for the vector and PANA models by demonstrating that neutral valence, high-arousal ratings resulted from the averaging of individual positive and negative valence ratings. Thus, compared to a circumplex model, vector and PANA models provided overall better fits.
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    Attractor Dynamics in Networks with Learning Rules Inferred from In Vivo Data.
    (Neuron, 2018-07) Pereira, Ulises; Brunel, Nicolas
    The attractor neural network scenario is a popular scenario for memory storage in the association cortex, but there is still a large gap between models based on this scenario and experimental data. We study a recurrent network model in which both learning rules and distribution of stored patterns are inferred from distributions of visual responses for novel and familiar images in the inferior temporal cortex (ITC). Unlike classical attractor neural network models, our model exhibits graded activity in retrieval states, with distributions of firing rates that are close to lognormal. Inferred learning rules are close to maximizing the number of stored patterns within a family of unsupervised Hebbian learning rules, suggesting that learning rules in ITC are optimized to store a large number of attractor states. Finally, we show that there exist two types of retrieval states: one in which firing rates are constant in time and another in which firing rates fluctuate chaotically.
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    Emotional intensity predicts autobiographical memory experience.
    (Mem Cognit, 2004-10) Talarico, Jennifer M; LaBar, Kevin S; Rubin, David C
    College students generated autobiographical memories from distinct emotional categories that varied in valence (positive vs. negative) and intensity (high vs. low). They then rated various perceptual, cognitive, and emotional properties for each memory. The distribution of these emotional memories favored a vector model over a circumplex model. For memories of all specific emotions, intensity accounted for significantly more variance in autobiographical memory characteristics than did valence or age of the memory. In two additional experiments, we examined multiple memories of emotions of high intensity and positive or negative valence and of positive valence and high or low intensity. Intensity was a more consistent predictor of autobiographical memory properties than was valence or the age of the memory in these experiments as well. The general effects of emotion on autobiographical memory properties are due primarily to intensity differences in emotional experience, not to benefits or detriments associated with a specific valence.
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    Sensory information and associative cues used in food detection by wild vervet monkeys.
    (Anim Cogn, 2014-05) Teichroeb, Julie A; Chapman, Colin A
    Understanding animals' spatial perception is a critical step toward discerning their cognitive processes. The spatial sense is multimodal and based on both the external world and mental representations of that world. Navigation in each species depends upon its evolutionary history, physiology, and ecological niche. We carried out foraging experiments on wild vervet monkeys (Chlorocebus pygerythrus) at Lake Nabugabo, Uganda, to determine the types of cues used to detect food and whether associative cues could be used to find hidden food. Our first and second set of experiments differentiated between vervets' use of global spatial cues (including the arrangement of feeding platforms within the surrounding vegetation) and/or local layout cues (the position of platforms relative to one another), relative to the use of goal-object cues on each platform. Our third experiment provided an associative cue to the presence of food with global spatial, local layout, and goal-object cues disguised. Vervets located food above chance levels when goal-object cues and associative cues were present, and visual signals were the predominant goal-object cues that they attended to. With similar sample sizes and methods as previous studies on New World monkeys, vervets were not able to locate food using only global spatial cues and local layout cues, unlike all five species of platyrrhines thus far tested. Relative to these platyrrhines, the spatial location of food may need to stay the same for a longer time period before vervets encode this information, and goal-object cues may be more salient for them in small-scale space.
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    The frequency of voluntary and involuntary autobiographical memories across the life span.
    (Mem Cognit, 2009-07) Rubin, David C; Berntsen, Dorthe
    In the present study, ratings of the memory of an important event from the previous week on the frequency of voluntary and involuntary retrieval, belief in its accuracy, visual imagery, auditory imagery, setting, emotional intensity, valence, narrative coherence, and centrality to the life story were obtained from 988 adults whose ages ranged from 15 to over 90. Another 992 adults provided the same ratings for a memory from their confirmation day, when they were at about age 14. The frequencies of involuntary and voluntary retrieval were similar. Both frequencies were predicted by emotional intensity and centrality to the life story. The results from the present study-which is the first to measure the frequency of voluntary and involuntary retrieval for the same events-are counter to both cognitive and clinical theories, which consistently claim that involuntary memories are infrequent as compared with voluntary memories. Age and gender differences are noted.
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    The neural basis of involuntary episodic memories.
    (J Cogn Neurosci, 2014-10) Hall, Shana A; Rubin, David C; Miles, Amanda; Davis, Simon W; Wing, Erik A; Cabeza, Roberto; Berntsen, Dorthe
    Voluntary episodic memories require an intentional memory search, whereas involuntary episodic memories come to mind spontaneously without conscious effort. Cognitive neuroscience has largely focused on voluntary memory, leaving the neural mechanisms of involuntary memory largely unknown. We hypothesized that, because the main difference between voluntary and involuntary memory is the controlled retrieval processes required by the former, there would be greater frontal activity for voluntary than involuntary memories. Conversely, we predicted that other components of the episodic retrieval network would be similarly engaged in the two types of memory. During encoding, all participants heard sounds, half paired with pictures of complex scenes and half presented alone. During retrieval, paired and unpaired sounds were presented, panned to the left or to the right. Participants in the involuntary group were instructed to indicate the spatial location of the sound, whereas participants in the voluntary group were asked to additionally recall the pictures that had been paired with the sounds. All participants reported the incidence of their memories in a postscan session. Consistent with our predictions, voluntary memories elicited greater activity in dorsal frontal regions than involuntary memories, whereas other components of the retrieval network, including medial-temporal, ventral occipitotemporal, and ventral parietal regions were similarly engaged by both types of memories. These results clarify the distinct role of dorsal frontal and ventral occipitotemporal regions in predicting strategic retrieval and recalled information, respectively, and suggest that, although there are neural differences in retrieval, involuntary memories share neural components with established voluntary memory systems.
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    The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving.
    (Cereb Cortex, 2008-01) Daselaar, Sander M; Rice, Heather J; Greenberg, Daniel L; Cabeza, Roberto; LaBar, Kevin S; Rubin, David C
    We sought to map the time course of autobiographical memory retrieval, including brain regions that mediate phenomenological experiences of reliving and emotional intensity. Participants recalled personal memories to auditory word cues during event-related functional magnetic resonance imaging (fMRI). Participants pressed a button when a memory was accessed, maintained and elaborated the memory, and then gave subjective ratings of emotion and reliving. A novel fMRI approach based on timing differences capitalized on the protracted reconstructive process of autobiographical memory to segregate brain areas contributing to initial access and later elaboration and maintenance of episodic memories. The initial period engaged hippocampal, retrosplenial, and medial and right prefrontal activity, whereas the later period recruited visual, precuneus, and left prefrontal activity. Emotional intensity ratings were correlated with activity in several regions, including the amygdala and the hippocampus during the initial period. Reliving ratings were correlated with activity in visual cortex and ventromedial and inferior prefrontal regions during the later period. Frontopolar cortex was the only brain region sensitive to emotional intensity across both periods. Results were confirmed by time-locked averages of the fMRI signal. The findings indicate dynamic recruitment of emotion-, memory-, and sensory-related brain regions during remembering and their dissociable contributions to phenomenological features of the memories.
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    Watch me grow: a garden-based pilot intervention to increase vegetable and fruit intake in preschoolers.
    (BMC Public Health, 2013-04-18) Namenek Brouwer, Rebecca J; Benjamin Neelon, Sara E
    BACKGROUND: Americans, including children, consume fewer fruit and vegetable servings than is recommended. Given that young children spend large amounts of time in child care centers, this may be an ideal venue for increasing consumption of and enthusiasm for fruits and vegetables. This pilot study aimed to assess the feasibility of a gardening intervention to promote vegetable and fruit intake among preschoolers. METHODS: We enrolled two intervention centers and two control centers. The intervention included a fruit and vegetable garden, monthly curriculum, gardening support, and technical assistance. We measured mean (SD) servings of fruits and vegetables served to and consumed by three children per center before and after the intervention. RESULTS: Post intervention, intervention and control centers served fewer vegetables (mean (standard deviation) difference of -0.18 (0.63) in intervention, -0.37 (0.36) in control), but intervention children consumed more than control children (+0.25 (1.11) vs. -0.18 (0.52). The number of fruits served decreased in all centers (intervention -0.62 (0.58) vs. control -0.10 (0.52)) but consumption was higher in controls (intervention -0.32 (0.58) vs. control 0.15 (0.26)). CONCLUSIONS: The garden-based feasibility study shows promise, but additional testing is needed to assess its ability to increase vegetable and fruit intake in children.