Neuronal metabolism in learning and memory: The anticipatory activity perspective.

Current research on the molecular mechanisms of learning and memory is based on the "stimulus-response" paradigm, in which the neural circuits connecting environmental events with behavioral responses are strengthened. By contrast, cognitive and systems neuroscience emphasize the intrinsic activity of the brain that integrates information, establishes anticipatory actions, executes adaptive actions, and assesses the outcome via regulatory feedback mechanisms. We believe that the difference in the perspectives of systems and molecular studies is a major roadblock to further progress toward understanding the mechanisms of learning and memory. Here, we briefly overview the current studies in molecular mechanisms of learning and memory and propose that studying the predictive properties of neuronal metabolism will significantly advance our knowledge of how intrinsic, predictive activity of neurons shapes a new learning event. We further suggest that predictive metabolic changes in the brain may also take place in non-neuronal cells, including those of peripheral tissues. Finally, we present a path forward toward more in-depth studies of the role of cell metabolism in learning and memory.

Analytic and Holistic Thinkers: Differences in the Dynamics of Heart Rate Complexity When Solving a Cognitive Task in Field-Dependent and Field-Independent Conditions.

Analytic and holistic thinking styles are known to be associated with individual differences in various aspects of behavior and brain activity. In this study, we tested a hypothesis that differences in thinking styles may also be manifested at the level of neuro-visceral coordination. Heart rate variability (HRV) was compared between analytic and holistic thinkers at rest, during a simple motor choice reaction time task and when solving cognitive choice reaction time tasks in conditions with varying instructions contrasting the role of the field when evaluating objects. Participants (N = 52) with analytic and holistic thinking styles were equally successful at solving the cognitive tasks but response times were longer in the analytic group, compared to the holistic group. Heart rate complexity, as measured by sample entropy, was higher in the analytic group during the cognitive tasks but did not differ from the holistic group at rest or during the simple motor task. Analytic participants had longer response times and higher heart rate complexity when evaluating objects in relation to the field than when evaluating objects irrespective to the field. No difference in response times or heart rate complexity between tasks was observed in the holistic group. Our findings demonstrate that differences in individual behavior, including those related to holistic and analytic thinking styles, can be reflected not only in brain activity, as shown previously using fMRI and EEG methods, but also at the level of neuro-visceral coordination, as manifested in heart rate complexity.

Complexity of heart rate variability during moral judgement of actions and omissions.

Recent research strongly supports the idea that cardiac activity is involved in the organisation of behaviour, including social behaviour and social cognition. The aim of this work was to explore the complexity of heart rate variability, as measured by permutation entropy, while individuals were making moral judgements about harmful actions and omissions. Participants (N = 58, 50% women, age 21-52 years old) were presented with a set of moral dilemmas describing situations when sacrificing one person resulted in saving five other people. In line with previous studies, our participants consistently judged harmful actions as less permissible than equivalently harmful omissions (phenomenon known as the "omission bias"). Importantly, the response times were significantly longer and permutation entropy of the heart rate was higher when participants were evaluating harmful omissions, as compared to harmful actions. These results may be viewed as a psychophysiological manifestation of differences in causal attribution between actions and omissions. We discuss the obtained results from the positions of the system-evolutionary theory and propose that heart rate variability reflects complexity of the dynamics of neurovisceral activity within the organism-environment interactions, including their social aspects. This complexity can be described in terms of entropy and our work demonstrates the potential of permutation entropy as a tool of analyzing heart rate variability in relation to current behaviour and observed cognitive processes.

A drama movie activates brains of holistic and analytical thinkers differentially.

People socialized in different cultures differ in their thinking styles. Eastern-culture people view objects more holistically by taking context into account, whereas Western-culture people view objects more analytically by focusing on them at the expense of context. Here we studied whether participants, who have different thinking styles but live within the same culture, exhibit differential brain activity when viewing a drama movie. A total of 26 Finnish participants, who were divided into holistic and analytical thinkers based on self-report questionnaire scores, watched a shortened drama movie during functional magnetic resonance imaging. We compared intersubject correlation (ISC) of brain hemodynamic activity of holistic vs analytical participants across the movie viewings. Holistic thinkers showed significant ISC in more extensive cortical areas than analytical thinkers, suggesting that they perceived the movie in a more similar fashion. Significantly higher ISC was observed in holistic thinkers in occipital, prefrontal and temporal cortices. In analytical thinkers, significant ISC was observed in right-hemisphere fusiform gyrus, temporoparietal junction and frontal cortex. Since these results were obtained in participants with similar cultural background, they are less prone to confounds by other possible cultural differences. Overall, our results show how brain activity in holistic vs analytical participants differs when viewing the same drama movie.

Neuronal Bases of Systemic Organization of Behavior.

Despite the years of studies in the field of systems neuroscience, functions of neural circuits and behavior-related systems are still not entirely clear. The systems description of brain activity has recently been associated with cognitive concepts, e.g. a cognitive map, reconstructed via place-cell activity analysis and the like, and a cognitive schema, modeled in consolidation research. The issue we find of importance is that a cognitive unit reconstructed in neuroscience research is mainly formulated in terms of environment. In other words, the individual experience is considered as a model or reflection of the outside world and usually lacks a biological meaning, such as describing a given part of the world for the individual. In this chapter, we present the idea of a cognitive component that serves as a model of behavioral interaction with environment, rather than a model of the environment itself. This intangible difference entails the need in substantial revision of several well-known phenomena, including the long-term potentiation.The principal questions developed here are how the cognitive units appear and change upon learning and performance, and how the links between them create the whole structure of individual experience. We argue that a clear distinction between processes that provide the emergence of new components and those underlying the retrieval and/or changes in the existing ones is necessary in learning and memory research. We then describe a view on learning and corresponding neuronal activity analysis that may help set this distinction.

Activity during Learning and the Nonlinear Differentiation of Experience.

Walter Freeman's work emphasises the role of individual activity and intentionality as opposed to the traditional stimulus-reaction view and the machine metaphor. The results of our computer modeling studies suggest the nonlinear dynamics of experience emerging from perception-action cycles. We consider the perception-action cycle as a behavioral continuum of anticipated outcomes of actions. Neuroscientific research shows that each behavioral act is based on the activity of behaviorally specialized neurons distributed across the brain. Active learning during individual development leads to an increasing differentiation of the structure of individual experience through the formation of such groups of behaviorally specialized neurons. We consider the differentiation of individual experience as a nonlinear process which is implemented at different levels, and argue that consciousness and emotion can be described as dynamic characteristics prominent at the most and least differentiated systemic levels, correspondingly.

Sociocultural Influences on Moral Judgments: East-West, Male-Female, and Young-Old.

Gender, age, and culturally specific beliefs are often considered relevant to observed variation in social interactions. At present, however, the scientific literature is mixed with respect to the significance of these factors in guiding moral judgments. In this study, we explore the role of each of these factors in moral judgment by presenting the results of a web-based study of Eastern (i.e., Russia) and Western (i.e., USA, UK, Canada) subjects, male and female, and young and old. Participants (n = 659) responded to hypothetical moral scenarios describing situations where sacrificing one life resulted in saving five others. Though men and women from both types of cultures judged (1) harms caused by action as less permissible than harms caused by omission, (2) means-based harms as less permissible than side-effects, and (3) harms caused by contact as less permissible than by non-contact, men in both cultures delivered more utilitarian judgments (save the five, sacrifice one) than women. Moreover, men from Western cultures were more utilitarian than Russian men, with no differences observed for women. In both cultures, older participants delivered less utilitarian judgments than younger participants. These results suggest that certain core principles may mediate moral judgments across different societies, implying some degree of universality, while also allowing a limited range of variation due to sociocultural factors.

Mental Reactivation and Pleasantness Judgment of Experience Related to Vision, Hearing, Skin Sensations, Taste and Olfaction.

Language acquisition is based on our knowledge about the world and forms through multiple sensory-motor interactions with the environment. We link the properties of individual experience formed at different stages of ontogeny with the phased development of sensory modalities and with the acquisition of words describing the appropriate forms of sensitivity. To test whether early-formed experience related to skin sensations, olfaction and taste differs from later-formed experience related to vision and hearing, we asked Russian-speaking participants to categorize or to assess the pleasantness of experience mentally reactivated by sense-related adjectives found in common dictionaries. It was found that categorizing adjectives in relation to vision, hearing and skin sensations took longer than categorizing adjectives in relation to olfaction and taste. In addition, experience described by adjectives predominantly related to vision, hearing and skin sensations took more time for the pleasantness judgment and generated less intense emotions than that described by adjectives predominantly related to olfaction and taste. Interestingly the dynamics of skin resistance corresponded to the intensity and pleasantness of reported emotions. We also found that sense-related experience described by early-acquired adjectives took less time for the pleasantness judgment and generated more intense and more positive emotions than that described by later-acquired adjectives. Correlations were found between the time of the pleasantness judgment of experience, intensity and pleasantness of reported emotions, age of acquisition, frequency, imageability and length of sense-related adjectives. All in all these findings support the hypothesis that early-formed experience is less differentiated than later-formed experience.

Expression of c-Fos in the rat retrosplenial cortex during instrumental re-learning of appetitive bar-pressing depends on the number of stages of previous training.

Learning is known to be accompanied by induction of c-Fos expression in cortical neurons. However, not all neurons are involved in this process. What the c-Fos expression pattern depends on is still unknown. In the present work we studied whether and to what degree previous animal experience about Task 1 (the first phase of an instrumental learning) influenced neuronal c-Fos expression in the retrosplenial cortex during acquisition of Task 2 (the second phase of an instrumental learning). Animals were progressively shaped across days to bar-press for food at the left side of the experimental chamber (Task 1). This appetitive bar-pressing behavior was shaped by nine stages ("9 stages" group), five stages ("5 stages" group) or one intermediate stage ("1 stage" group). After all animals acquired the first skill and practiced it for five days, the bar and feeder on the left, familiar side of the chamber were inactivated, and the animals were allowed to learn a similar instrumental task at the opposite side of the chamber using another pair of a bar and a feeder (Task 2). The highest number of c-Fos positive neurons was found in the retrosplenial cortex of "1 stage" animals as compared to the other groups. The number of c-Fos positive neurons in "5 stages" group animals was significantly lower than in "1 stage" animals and significantly higher than in "9 stages" animals. The number of c-Fos positive neurons in the cortex of "9 stages" animals was significantly higher than in home caged control animals. At the same time, there were no significant differences between groups in such behavioral variables as the number of entrees into the feeder or bar zones during Task 2 learning. Our results suggest that c-Fos expression in the retrosplenial cortex during Task 2 acquisition was influenced by the previous learning history.

Effect of emotional context in auditory-cortex processing.

We examined how emotional context influences processing of emotionally neutral acoustic stimuli in the human auditory cortex. Nine subjects performed a simple discrimination task. In the positive-emotional trials correct performance was awarded with money, whereas in the negative-emotional trials, correct performance resulted in avoidance of the loss of money. Auditory stimuli were identical in both trial types. An event-related brain potential (ERP) N100 deflection, generated in the auditory cortex, was significantly larger in the negative as compared to the positive-emotional trials. This result demonstrates that emotional context influences early sensory-specific cortical processing. In addition, we found some evidence in favor of assumption that processing of positive visual feedback was faster in negative-emotional trials. This was reflected in the tendency for the latency of visual ERPs to be shorter in the latter case. We suggest that our results indicate that the systemic organization at all stages of deployment of behavior depends on emotional context. Dynamics of learning the discrimination task was also dependent on emotional context.

Emotion and consciousness: ends of a continuum.

We suggest a united concept of consciousness and emotion, based on the systemic cognitive neuroscience perspective regarding organisms as active and goal-directed. We criticize the idea that consciousness and emotion are psychological phenomena having quite different neurophysiological mechanisms. We argue that both characterize a unified systemic organization of behavior, but at different levels. All systems act to achieve intended behavioral results in interaction with their environment. Differentiation of this interaction increases during individual development. Any behavioral act is a simultaneous realization of systems ranking from the least to the most differentiated. We argue that consciousness and emotion are dynamic systemic characteristics that are prominent at the most and least differentiated systemic levels, correspondingly. These levels are created during development. Our theory is based on both theoretical and empirical research and provides a solid framework for experimental work.