The smart gut: Tracking affective associative learning with measures of “liking”, facial electromyography, and preferential looking

We demonstrate here that initially neutral items can acquire specific value based on their associated outcomes, and that responses of physiological systems to such previously meaningless stimuli can rapidly reflect this associative history. Each participant participated in an associative learning task in which four neutral abstract pictures were each repeatedly paired with one of four foods that varied in valence and magnitude. Over the course of learning, participants’ “liking” ratings of and preferences for each picture came to reflect the value of the food with which it was paired. The abstract pictures also elicited physiological responses characteristic of the foods with which they were paired, including changes in facial electromyography (EMG) and preferential looking. A logistic modeling procedure showed that learning parameters, such as the rate at which participants learned the values associated with the pictures, were similar across food outcomes of different value.     

A neural model of hippocampal–striatal interactions in associative learning and transfer generalization in various neurological and psychiatric patients

Building on our previous neurocomputational models of basal ganglia and hippocampal region function (and their modulation by dopamine and acetylcholine, respectively), we show here how an integration of these models can inform our understanding of the interaction between the basal ganglia and hippocampal region in associative learning and transfer generalization across various patient populations. As a common test bed for exploring interactions between these brain regions and neuromodulators, we focus on the acquired equivalence task, an associative learning paradigm in which stimuli that have been associated with the same outcome acquire a functional similarity such that subsequent generalization between these stimuli increases. This task has been used to test cognitive dysfunction in various patient populations with damages to the hippocampal region and basal ganglia, including studies of patients with Parkinson’s disease (PD), schizophrenia, basal forebrain amnesia, and hippocampal atrophy. Simulation results show that damage to the hippocampal region—as in patients with hippocampal atrophy (HA), hypoxia, mild Alzheimer’s (AD), or schizophrenia—leads to intact associative learning but impaired transfer generalization performance. Moreover, the model demonstrates how PD and anterior communicating artery (ACoA) aneurysm—two very different brain disorders that affect different neural mechanisms—can have similar effects on acquired equivalence performance. In particular, the model shows that simulating a loss of dopamine function in the basal ganglia module (as in PD) leads to slow acquisition learning but intact transfer generalization. Similarly, the model shows that simulating the loss of acetylcholine in the hippocampal region (as in ACoA aneurysm) also results in slower acquisition learning. We argue from this that changes in associative learning of stimulus–action pathways (in the basal ganglia) or changes in the learning of stimulus representations (in the hippocampal region) can have similar functional effects.     

Direct Associations or Internal Transformations? Exploring the Mechanisms Underlying Sequential Learning Behavior

We evaluate two broad classes of cognitive mechanisms that might support the learning of sequential patterns. According to the first, learning is based on the gradual accumulation of direct associations between events based on simple conditioning principles. The other view describes learning as the process of inducing the transformational structure that defines the material. Each of these learning mechanisms predicts differences in the rate of acquisition for differently organized sequences. Across a set of empirical studies, we compare the predictions of each class of model with the behavior of human subjects. We find that learning mechanisms based on transformations of an internal state, such as recurrent network architectures (e.g., Elman, 1990), have difficulty accounting for the pattern of human results relative to a simpler (but more limited) learning mechanism based on learning direct associations. Our results suggest new constraints on the cognitive mechanisms supporting sequential learning behavior.     

Integrating the most unintuitive empirical observations of 2007 in the domain of personality and social psychology into a unified framework

Two obstacles impede the development of productive theories in personality, social, and organizational psychology. First, the distinct frameworks are seldom integrated; the various theories sometimes yield incompatible implications. Second, because many findings in these fields seem intuitive, these observations do not augment the validity of these theories. To override these issues, this paper integrates the 70 most unintuitive findings of 2007 into a unified framework, derived from personality systems interaction theory. Specifically, 10 participants extracted the most unintuitive observations from 17 scholarly journals. These findings were reconciled within a single framework that generates 41 testable propositions. The framework assumes that an associative self system, underpinned by a vast network of schemas, governs behavior as well as enhances intuition, engagement, creativity, and cooperation. When individuals experience a threat, this system is inhibited, unless the requisite defense mechanisms to accommodate potential hazards have been developed. Furthermore, individuals attempt to distance themselves from unassailable threats, which activate an analytical system that formulates plans that could accommodate future contingencies. These plans are retained in memory or executed if individuals have acquired sufficient confidence.     

Reducing mind to molecular pathways: explicating the reductionism implicit in current cellular and molecular neuroscience

As opposed to the dismissive attitude toward reductionism that is popular in current philosophy of mind, a “ruthless reductionism” is alive and thriving in “molecular and cellular cognition”—a field of research within cellular and molecular neuroscience, the current mainstream of the discipline. Basic experimental practices and emerging results from this field imply that two common assertions by philosophers and cognitive scientists are false: (1) that we do not know much about how the brain works, and (2) that lower-level neuroscience cannot explain cognition and complex behavior directly. These experimental practices involve intervening directly with molecular components of sub-cellular and gene expression pathways in neurons and then measuring specific behaviors. These behaviors are tracked using tests that are widely accepted by experimental psychologists to study the psychological phenomenon at issue (e.g., memory, attention, and perception). Here I illustrate these practices and their importance for explanation and reduction in current mainstream neuroscience by describing recent work on social recognition memory in mammals.     

Simple Co‐Occurrence Statistics Reproducibly Predict Association Ratings

What determines human ratings of association? We planned this paper as a test for association strength (AS) that is derived from the log likelihood that two words co‐occur significantly more often together in sentences than is expected from their single word frequencies. We also investigated the moderately correlated interactions of word frequency, emotional valence, arousal, and imageability of both words (r's ≤ .3). In three studies, linear mixed effects models revealed that AS and valence reproducibly account for variance in the human ratings. To understand further correlated predictors, we conducted a hierarchical cluster analysis and examined the predictors of four clusters in competitive analyses: Only AS and word2vec skip‐gram cosine distances reproducibly accounted for variance in all three studies. The other predictors of the first cluster (number of common associates, (positive) point‐wise mutual information, and word2vec CBOW cosine) did not reproducibly explain further variance. The same was true for the second cluster (word frequency and arousal); the third cluster (emotional valence and imageability); and the fourth cluster (consisting of joint frequency only). Finally, we discuss emotional valence as an important dimension of semantic space. Our results suggest that a simple definition of syntagmatic word contiguity (AS) and a paradigmatic measure of semantic similarity (skip‐gram cosine) provide the most general performance‐independent explanation of association ratings.     

转基因小鼠在学习记忆研究中的应用

综述了国内外运用转基因小鼠研究学习记忆的主要成果;分析探讨了某些基因表达的蛋白质,如NMDA受体,nociceptin受体,非受体酪氨酸激酸,Ca^2 和钙调素依赖性激酶,蛋白激酶A,蛋白激酶C,与cAMP反应成分结合的蛋白质,神经细胞粘附分子,神经生长因子等在学习记忆过程中的作用机制;初步探讨了学习记忆与LTP的关系。     

杏仁体与情绪及感觉功能的关系

近来研究表明杏仁体与感觉、情绪和记忆关系密切。对恐惧条件反射的研究发现杏仁体是情绪活动的关键性结构;导致恐惧条件反射的细胞及分子机制研究征实杏仁体具有情绪学习与记忆机能;杏仁体在向中感觉信息的筛选和凋制中具有显著作用和重要意义。本文将综述这方面的进展。     

Inference making and linking both require thinking: Spontaneous trait inference and spontaneous trait transference both rely on working memory capacity

Past research suggests that spontaneous trait inference (STI) and spontaneous trait transference (STT) may reflect different cognitive processes, the former being inferential and the latter associational. The present research was designed to explore whether either or both of these processes involve thinking that occupies cognitive capacity. Four studies suggest that reductions in available cognitive capacity reduce both STI and STT effects, both on measures of savings in relearning (which reflect the strength of trait associations with a person) and on trait ratings measures (which reflect the strength of trait inferences made about a person). Similar results were obtained using an individual difference measure of cognitive capacity. Although these results suggest that STI and STT are similar, in that both exhibit interference from reductions in cognitive capacity, other results, such as halo effects in trait ratings, support previous assertions that their underlying processes are distinct.