Generative models, brain function and neuroimaging

The representational capacity and inherent function of any neuron, neuronal population or cortical area in the brain is dynamic and context-sensitive. Functional integration, or interactions among brain systems, that employ driving (bottom up) and backward (top-down) connections, mediate this adaptive and contextual specialisation. A critical consequence is that neuronal responses, in any given cortical area, can represent different things at different times. This can have fundamental implications for the design of brain imaging experiments and the interpretation of their results. Our arguments are developed under generative models of brain function, where higher-level systems provide a prediction of the inputs to lower-level regions. Conflict between the two is resolved by changes in the higher-level representations, which are driven by the ensuing error in lower regions, until the mismatch is "cancelled". From this perspective the specialisation of any region is determined both by bottom-up driving inputs and by top-down predictions. Specialisation is therefore not an intrinsic property of any region but depends on both forward and backward connections with other areas. Because the latter have access to the context in which the inputs are generated they are in a position to modulate the selectivity or specialisation of lower areas. The implications for classical models (e.g., classical receptive fields in electrophysiology, classical specialisation in neuroimaging and connectionism in cognitive models) are severe and suggest these models may provide incomplete accounts of real brain architectures. Here we focus on the implications for cognitive neuroscience in the context of neuroimaging.     

Intelligence is differentially related to neural effort in the task-positive and the task-negative brain network

Previous studies on individual differences in intelligence and brain activation during cognitive processing focused on brain regions where activation increases with task demands (task-positive network, TPN). Our study additionally considers brain regions where activation decreases with task demands (task-negative network, TNN) and compares effects of intelligence on neural effort in the TPN and the TNN. In a sample of 52 healthy subjects, functional magnetic resonance imaging was used to determine changes in neural effort associated with the processing of a working memory task. The task comprised three conditions of increasing difficulty: (a) maintenance, (b) manipulation, and (c) updating of a four-letter memory set. Neural effort was defined as signal increase in the TPN and signal decrease in the TNN, respectively. In both functional networks, TPN and TNN, neural effort increased with task difficulty. However, intelligence, as assessed with Raven's Matrices, was differentially associated with neural effort in the TPN and TNN. In the TPN, we observed a positive association, while we observed a negative association in the TNN. In terms of neural efficiency (i.e., task performance in relation to neural effort expended on task processing), more intelligent subjects (as compared to less intelligent subjects) displayed lower neural efficiency in the TPN, while they displayed higher neural efficiency in the TNN. The results illustrate the importance of differentiating between TPN and TNN when interpreting correlations between intelligence and fMRI measures of brain activation. Importantly, this implies the risk of misinterpreting whole brain correlations when ignoring the functional differences between TPN and TNN.     

Christfried Jakob's late views (1930-1949) on the psychogenetic function of the cerebral cortex and its localization: culmination of the neurophilosophical thought of a keen brain observer

This article follows the culmination of the scientific thought of the neurobiologist Christfried Jakob (1866-1956) during the later part of his career, based on publications from 1930 to 1949, when he was between 64 and 83 years of age. Jakob emphasized the necessity of bridging philosophy to the biological sciences, neurobiology in particular. Thus, we consider him as one of the early protagonists in the emergence of neurophilosophy in the 20th century. The topics that occupied his mind were the foundations for a future philosophy of the brain, and the 'neurobiogenetic', 'neurodynamic', and 'neuropsychogenetic' problems in relation to how consciousness emerges. Jakob's views have many elements in common with great thinkers of philosophy and psychology, including Immanuel Kant, William James, Edmund Husserl, Henri Bergson, Jean Piaget and Willard Quine. A common denominator can also be discerned between Jakob's dynamic approach and certain aspects of cybernetics and neurophenomenology. Jakob propounded the interdisciplinarity of sciences as an indispensable tool for ultimately solving the enigma of consciousness.     

Do the wrong thing: How toddlers tell a joke from a mistake

We investigated whether 19–36-month-olds (1) differentiate mistakes from jokes, and (2) understand humorous intentions. The experimenter demonstrated unambiguous jokes accompanied by laughter, unambiguous mistakes accompanied by the experimenter saying, “Woops!”, and ambiguous actions that could either be a mistake or a joke, accompanied by either laughter or, “Woops!” Toddlers were asked to try. Nineteen- to 36-month-olds differentiated jokes and mistakes by copying unambiguous jokes and correcting unambiguous mistakes. Only 25–36-month-olds differentiated mistakes and humorous intentions by copying ambiguous actions marked by laughter, and correcting those marked by, “Woops!” Understanding humorous intentions precedes understanding intentions behind pretense, lying, and false beliefs, thus may be a first step in understanding that others can intend to do the wrong thing.     

Functional role theories of representation and content explanation: with a case study from spatial cognition

The aim of this paper is to show that the widespread opinion, according to which functional role theories of representation fail to account for content explanations of human and animal behaviour, cannot be confirmed with respect to each type of functional role theory. Functional resemblance theories (as referred to by O’Brien and Opie in Representation in mind, Elsevier, 2004) allow for content explanations of successfully performed cognitive abilities as much as for explanations of systematic errors resulting from misrepresentation. How functional roles do their explanatory work in actual scientific research examples is shown by a detailed exploration of model assumptions about homing performances based on path integration mechanisms in humans and animals.

Translating Evidence to Practice: Two Stories from the Field

Translating research evidence into daily practice is a challenging process at the organizational level. Conceptual models about this process point to the importance of resources for change and environmental influences as two key factors that need to be addressed in translation efforts. Two organizational case studies focused on improving care for adults with depression are described that illustrate lessons about translating evidence to practice that may be helpful to others.     

Children's knowledge of the earth: a new methodological and statistical approach

In the field of children’s knowledge of the earth, much debate has concerned the question of whether children’s naive knowledge—that is, their knowledge before they acquire the standard scientific theory—is coherent (i.e., theory-like) or fragmented. We conducted two studies with large samples (N = 328 and N = 381) using a new paper-and-pencil test, denoted the EARTH (EArth Representation Test for cHildren), to discriminate between these two alternatives. We performed latent class analyses on the responses to the EARTH to test mental models associated with these alternatives. The naive mental models, as formulated by Vosniadou and Brewer, were not supported by the results. The results indicated that children’s knowledge of the earth becomes more consistent as children grow older. These findings support the view that children’s naive knowledge is fragmented.     

Mental Models: An Alternative Evaluation of a Sensemaking Approach to Ethics Instruction

In spite of the wide variety of approaches to ethics training it is still debatable which approach has the highest potential to enhance professionals' integrity. The current effort assesses a novel curriculum that focuses on metacognitive reasoning strategies researchers use when making sense of day-to-day professional practices that have ethical implications. The evaluated trainings effectiveness was assessed by examining five key sensemaking processes, such as framing, emotion regulation, forecasting, self-reflection, and information integration that experts and novices apply in ethical decision-making. Mental models of trained and untrained graduate students, as well as faculty, working in the field of physical sciences were compared using a think-aloud protocol 6 months following the ethics training. Evaluation and comparison of the mental models of participants provided further validation evidence for sensemaking training. Specifically, it was found that trained students applied metacognitive reasoning strategies learned during training in their ethical decision-making that resulted in complex mental models focused on the objective assessment of the situation. Mental models of faculty and untrained students were externally-driven with a heavy focus on autobiographical processes. The study shows that sensemaking training has a potential to induce shifts in researchers' mental models by making them more cognitively complex via the use of metacognitive reasoning strategies. Furthermore, field experts may benefit from sensemaking training to improve their ethical decision-making framework in highly complex, novel, and ambiguous situations.     

How semantic memory structure and intelligence contribute to creative thought: a network science approach

The associative theory of creativity states that creativity is associated with differences in the structure of semantic memory, whereas the executive theory of creativity emphasises the role of top-down control for creative thought. For a powerful test of these accounts, individual semantic memory structure was modelled with a novel method based on semantic relatedness judgements and different criteria for network filtering were compared. The executive account was supported by a correlation between creative ability and broad retrieval ability. The associative account was independently supported, when network filtering was based on a relatedness threshold, but not when it was based on a fixed edge number or on the analysis of weighted networks. In the former case, creative ability was associated with shorter average path lengths and higher clustering of the network, suggesting that the semantic networks of creative people show higher small-worldness.     

Syntactic processing in the human brain: what we know, what we don't know, and a suggestion for how to proceed

For every claim in the neuroimaging literature about a particular brain region supporting syntactic processing, there exist other claims implicating the target region in different linguistic processes, and, in many cases, in non-linguistic cognitive processes (e.g., Blumstein, 2009). We argue that traditional group analysis methods in neuroimaging may obscure functional specificity because of inter-subject anatomical variability (Fedorenko & Kanwisher, 2009). In Fedorenko, Hsieh, Nieto-Castanon, Whitfield-Gabrieli, and Kanwisher (2010) we presented a functional localizer that allows quick and reliable identification of key language-sensitive regions in each individual brain. This approach enables pooling data from corresponding functional regions across subjects rather than from the same locations in stereotaxic space that may differ functionally due to inter-subject anatomical variability. In the current paper we demonstrate that the individual-subjects functional localization approach is superior to the traditional methods in its ability to distinguish among conditions in a brain region’s response. This ability is at the core of all neuroimaging research and is critical for answering questions of functional specialization (e.g., does a brain region specialize for processing syntactic aspects of the linguistic signal), which is in turn essential for making inferences about the precise computations conducted in each brain region. Based on our results, we argue that supplementing existing methods with an individual-subjects functional localization approach may lead to a clearer picture of the neural basis of syntactic processing, as it has in some other domains, such as high-level vision (e.g., Kanwisher, 2010) and social cognition (e.g., Saxe & Kanwisher, 2003).     

On the language specificity of basic number processing: transcoding in a language with inversion and its relation to working memory capacity

Transcoding Arabic numbers from and into verbal number words is one of the most basic number processing tasks commonly used to index the verbal representation of numbers. The inversion property, which is an important feature of some number word systems (e.g., German einundzwanzig [one and twenty]), might represent a major difficulty in transcoding and a challenge to current transcoding models. The mastery of inversion, and of transcoding in general, might be related to nonnumerical factors such as working memory resources given that different elements and their sequence need to be memorized and manipulated. In this study, transcoding skills and different working memory components in Austrian (German-speaking) 7-year-olds were assessed. We observed that inversion poses a major problem in transcoding for German-speaking children. In addition, different components of working memory skills were differentially correlated with particular transcoding error types. We discuss how current transcoding models could account for these results and how they might need to be adapted to accommodate inversion properties and their relation to different working memory components.     

A lateralization of function approach to sex differences in spatial ability: a reexamination

The current study assessed the lateralization of function hypothesis (Rilea, S. L., Roskos-Ewoldsen, B., & Boles, D. (2004). Sex differences in spatial ability: A lateralization of function approach. Brain and Cognition, 56, 332–343) which suggested that it was the interaction of brain organization and the type of spatial task that led to sex differences in spatial ability. A second purpose was to evaluate explanations for their unexpected findings on the mental rotation task. In Experiment 1, participants completed the Water Level, Paper Folding, and mental rotation tasks (using an object-based or self-based perspective), presented bilaterally. Sex differences were only observed on the Water Level Task; a right hemisphere advantage was observed on Water Level and mental rotation tasks. In Experiment 2, a human stick figure or a polygon was mentally rotated. Men outperformed women when rotating polygons, but not when rotating stick figures. Men demonstrated a right hemisphere advantage when rotating polygons; women showed no hemisphere differences for either stimulus. Thus, hemisphere processing, task complexity, and stimulus type may influence performance for men and women across different spatial measures.     

Relation of depression to perceived social support: results from a randomized adolescent depression prevention trial

Theorists posit that certain behaviors exhibited by depressed individuals (e.g., negative self-statements, dependency, reassurance seeking, inappropriate or premature disclosures, passivity, social withdrawal) reduce social support, yet there have been few experimental tests of this hypothesis. Using data from a randomized depression prevention trial (N = 253) involving adolescents (M age = 15.5, SD = 1.2), we tested whether a cognitive behavioral group intervention that significantly reduced depressive symptoms relative to bibliotherapy and educational brochure control conditions through 2-year follow-up produced improvements in perceived parental and friend social support and whether change in depressive symptoms mediated the effect on change in social support. Cognitive behavioral group participants showed significantly greater increases in perceived friend social support through 1-year follow-up relative to bibliotherapy and brochure controls, but there were no significant effects for perceived parental support. Further, change in depressive symptoms appeared to mediate the effects of the intervention on change in perceived friend support. Results provide experimental support for the theory that depressive symptoms are inversely related to perceived social support, but imply that this effect may be specific to friend vs. parental support for adolescents.     

How to turn a hawk into a dove and vice versa: Interactions between emotions and goals in a give-some dilemma game

The present study investigated emotional influences on behavior in a one-shot, simultaneous, give-some dilemma game. In accordance with functional perspectives on the role of discrete emotions, we found fear to reduce, and guilt to increase levels of cooperation. Moreover, we showed individual differences in the effect of induced emotional states. Specifically, results indicated that inducing fear reduced cooperation only for individuals with a pro-social value orientation, and that guilt induction increased cooperation only for individuals with a pro-self value orientation. We also established that both social value orientations could be adequately described in terms of differences in chronically accessible goals (as assessed by value-importance ratings). These results, therefore, seem to support our hypothesis that individual differences in the behavioral consequences of induced emotional states are related to variation in chronic accessibility of general goals associated with a particular emotional state.     

How to tell a wife from a hat: Affective feedback in perceptual categorization

How do people understand that their perception is correct? In line with the recurring idea of perception as prediction, the affective feedback account of hypotheses testing suggests that correct perceptual predictions are reinforced with positive affect. In four experiments, we tested whether correct categorization of a degraded image will lead to more positive liking ratings. The obtained findings supported the proposed approach: subjects liked the images they were able to perceive correctly more than others. Importantly, these findings were independent of the initial affective valence of stimuli. A further investigation demonstrated that this effect exists only when answers are at least moderately confident. The obtained findings add to the growing amount of literature on the role of affect in basic cognitive processing.     

Predicting brain organization from dichotic listening performance: Cortical and subcortical functional asymmetries contribute to perceptual asymmetries

The patterns of perceptual asymmetry elicited by dichotic speech and complex pitch stimuli were evaluated in a group of 28 normal, right-handed subjects. As in previous studies, between 70 and 75% of the subjects showed a right-ear advantage for speech and left-ear advantage for pitch. However, less than half of the subjects (46%) showed the expected pattern on both tests. It is argued that the assumption of symmetrical, contralateral auditory pathway superiority during dichotic stimulation is only appropriate in roughly half of the dextral population. In the remaining half, significant subcortical asymmetries and/or a lack of contralateral advantage appear to be present. The assessment of complementary cortical functions should provide a way to reduce the confounding of cortical and subcortical contributions to auditory perceptual asymmetries, and thus provide a more accurate behavioral index of brain organization.     

Neural computation as a tool to differentiate perceptual from emotional processes: The case of anger superiority effect

Research findings in social and cognitive psychology imply that it is easier to detect angry faces than happy faces in a crowd of neutral faces [Hansen, C. H., & Hansen, R. D. (1988). Finding the face in the crowd – An anger superiority effect. Journal of Personality and Social Psychology, 54(6), 917–924]. This phenomenon has been held to have evolved over phylogenetic development because it was adaptive to quickly and accurately detect a potential threat in the environment. However, across recent studies, a controversy has emerged about the underlying perceptual versus emotional factors responsible for this so-called anger superiority effect [Juth, P., Lundqvist, D., Karlsson, A., & Ohman, A. (2005). Looking for foes and friends: Perceptual and emotional factors when finding a face in the crowd. Emotion, 5(4), 379–395; Purcell, D. G., Stewart, A. L., & Skov, R. B. (1996). It takes a confounded face to pop out of a crowd. Perception, 25(9), 1091–1108]. To tease apart emotional and perceptual processes, we used neural network analyzes of human faces in two different simulations. Results show that a perceptual bias is probably acting against faster and more accurate identification of anger faces compared to happy faces at a purely perceptual level. We suggest that a parsimonious hypothesis related to the simple perceptual properties of the stimuli might explain these behavioral results without reference to evolutionary processes. We discuss the importance of statistical or connectionist analysis for empirical studies that seek to isolate perceptual from emotional factors, but also learned vs. innate factors in the processing of facial expression of emotion.     

Neuronal correlates of decisions to speak and act: Spontaneous emergence and dynamic topographies in a computational model of frontal and temporal areas

The neural mechanisms underlying the spontaneous, stimulus-independent emergence of intentions and decisions to act are poorly understood. Using a neurobiologically realistic model of frontal and temporal areas of the brain, we simulated the learning of perception–action circuits for speech and hand-related actions and subsequently observed their spontaneous behaviour. Noise-driven accumulation of reverberant activity in these circuits leads to their spontaneous ignition and partial-to-full activation, which we interpret, respectively, as model correlates of action intention emergence and action decision-and-execution. Importantly, activity emerged first in higher-association prefrontal and temporal cortices, subsequently spreading to secondary and finally primary sensorimotor model-areas, hence reproducing the dynamics of cortical correlates of voluntary action revealed by readiness-potential and verb-generation experiments. This model for the first time explains the cortical origins and topography of endogenous action decisions, and the natural emergence of functional specialisation in the cortex, as mechanistic consequences of neurobiological principles, anatomical structure and sensorimotor experience.     

Cultural chameleons and iconoclasts: Assimilation and reactance to cultural cues in biculturals’ expressed personalities as a function of identity conflict

Bicultural individuals vary in the degree to which their two cultural identities are integrated versus conflicting—Bicultural Identity Integration (BII). Past research on attribution biases finds that BII influences the way that biculturals shift in response to cultural primes: integrated biculturals shift assimilatively, whereas conflicted biculturals shift contrastively. Proposing that this reflects assimilation versus reactance responses, we tested whether it extends to shifts in self-perceived personality. In two experiments with Asian-American participants, we found that BII influences the direction of cultural priming effects (assimilation versus contrast) on the personality dimensions of need for uniqueness (Experiment 1) and extraversion (Experiment 2). As hypothesized, high BIIs shifted in a culturally assimilative direction, perceiving the self as more uniqueness-seeking and extraverted following American versus Asian priming, whereas low BIIs shifted in the reverse direction. Implications for research on bicultural identity, priming, personality, organizational and consumer behavior are discussed.