Bilingualism: consequences for mind and brain

Building on earlier evidence showing a beneficial effect of bilingualism on children's cognitive development, we review recent studies using both behavioral and neuroimaging methods to examine the effects of bilingualism on cognition in adulthood and explore possible mechanisms for these effects. This research shows that bilingualism has a somewhat muted effect in adulthood but a larger role in older age, protecting against cognitive decline, a concept known as 'cognitive reserve'. We discuss recent evidence that bilingualism is associated with a delay in the onset of symptoms of dementia. Cognitive reserve is a crucial research area in the context of an aging population; the possibility that bilingualism contributes to cognitive reserve is therefore of growing importance as populations become increasingly diverse.     

The dreaming brain/mind, consciousness and psychosis

Several independent lines of research in neurobiology seem to support the phenomenologically-grounded view of the dreaming brain/mind as a useful model for psychosis. Hallucinatory phenomena and thought disorders found in psychosis share several peculiarities with dreaming, where internally generated, vivid sensorimotor imagery along with often heightened and incongruous emotion are paired with a decrease in ego functions which ultimately leads to a severe impairment in reality testing. Contemporary conceptualizations of severe mental disorders view psychosis as one psychopathological dimension that may be found across several diagnostic categories. Some experimental data have shown cognitive bizarreness to be equally elevated in dreams and in the waking cognition of acutely psychotic subjects and in patients treated with pro-dopaminergic drugs, independent of the underlying disorder. Further studies into the neurofunctional underpinnings of both conditions will help to clarify the use and validity of this model.     

The mind considered as a system of meaning structures II. Concepts and representations

The theory of the mind considered as a system of meaning structures, which was sketched in an earlier paper (Lundh, 1981), is developed further in this paper. Whereas the earlier paper remained at a prelinguistic, sensorimotor level of functioning, the present paper extends the theory to conceptual thinking. Three main distinctions are drawn: between 1) mental representations and symbols, 2) sensorimotor intelligence and conceptual intelligence, and 3) habitual inferences and cognitive operations. Sensorimotor development consists in the development of mental representations, which the child, however, does not yet have any conscious access to. It is argued that sensorimotor structures are transformed into conceptual and propositional structures to the extent that the child becomes able not only to act, but also to think in terms of these structures—the latter is equated with the development of a kind of conscious access to already existent mental representations.     

Decoding semantic representations in mind and brain

A key goal for cognitive neuroscience is to understand the neurocognitive systems that support semantic memory. Recent multivariate analyses of neuroimaging data have contributed greatly to this effort, but the rapid development of these novel approaches has made it difficult to track the diversity of findings and to understand how and why they sometimes lead to contradictory conclusions. We address this challenge by reviewing cognitive theories of semantic representation and their neural instantiation. We then consider contemporary approaches to neural decoding and assess which types of representation each can possibly detect. The analysis suggests why the results are heterogeneous and identifies crucial links between cognitive theory, data collection, and analysis that can help to better connect neuroimaging to mechanistic theories of semantic cognition.     

We are what we eat: How food is represented in our mind/brain

Despite the essential role of food in our lives, we have little understanding of the way our knowledge about food is organized in the brain. At birth, human infants exhibit very few food preferences, and do not yet know much about what is edible and what is not. A multisensory learning development will eventually turn young infants into omnivore adults, for whom deciding what to eat becomes an effortful task. Recognizing food constitutes an essential step in this decisional process. In this paper we examine how concepts about food are represented in the human brain. More specifically, we first analyze how brain-damaged patients recognize natural and manufactured food, and then examine these patterns in the light of the sensory-functional hypothesis and the domain-specific hypothesis. Secondly, we discuss how concepts of food are represented depending on whether we embrace the embodied view or the disembodied view. We conclude that research on food recognition and on the organization of knowledge about food must also take into account some aspects specific to food category, the relevance of which has not been sufficiently recognized and investigated to date.     

Imaging brain in search of mind

The fourth annual fMRI Experience was held at the National Institutes of Health (NIH), in Bethesda, Maryland, USA, on 3-14 May 2002. The conference was organized jointly by research fellows at the NIH and Institute of Psychiatry (IoP) in London, and benefited from financial support from the National Institute of Mental Health (NIMH) Intramural Research Program, the NIMH Division of Intramural Training, and the Guarantors of Brain in association with the IoP.     

New visions of the aging mind and brain

Cognitive aging is widely viewed as a process of progressive mental loss. Compelling new evidence from functional neuroimaging urges a reconsideration of this pessimistic view. In the domains of working memory and episodic memory, older adults recruit different brain regions from those recruited by younger adults when performing the same tasks. Specifically, older adults show prominent changes in the recruitment of prefrontal regions, and a conspicuous increase in the extent to which activation patterns are bilateral. These results are stimulating new hypotheses about the mechanisms underlying age-related cognitive declines and the potential for compensation. By suggesting a life-long potential for reorganization and plasticity, these discoveries might revise long-held views of functional localization.     

Language and spatial frames of reference in mind and brain

Some language communities routinely use allocentric reference directions (e.g. 'uphill-downhill') where speakers of European languages would use egocentric references ('left-right'). Previous experiments have suggested that the different language groups use different reference frames in non-linguistic tasks involving the recreation of oriented arrays. However, a recent paper argues that manipulating test conditions produces similar effects in monolingual English speakers, and in animals.     

Event valence and estimates of own, average person's, and randomly chosen person's risk

People typically believe they have a lower likelihood of experiencing negative events and a greater likelihood of experiencing positive events than does the average person. This effect is greater for negative than positive events. It has been proposed that this is a by-product of a tendency for estimates of the average person's likelihood to increase with the size of the group concerned. If so, event valence should affect estimates of the average person's likelihood, but not estimates of one's own likelihood or estimates of the likelihood of a person selected at random. These predictions were tested for a single event using a student sample (N = 113). Results were not in accord with the proposal. An explanation in terms of motivational processes is offered instead.     

Inhibitory control in mind and brain: an interactive race model of countermanding saccades

The stop-signal task has been used to study normal cognitive control and clinical dysfunction. Its utility is derived from a race model that accounts for performance and provides an estimate of the time it takes to stop a movement. This model posits a race between go and stop processes with stochastically independent finish times. However, neurophysiological studies demonstrate that the neural correlates of the go and stop processes produce movements through a network of interacting neurons. The juxtaposition of the computational model with the neural data exposes a paradox-how can a network of interacting units produce behavior that appears to be the outcome of an independent race? The authors report how a simple, competitive network can solve this paradox and provide an account of what is measured by stop-signal reaction time.