Metamemory Experiments in Neurological Populations: A Review

Metamemory refers to knowledge about one's memory capabilities and strategies that can aid memory, as well as the processes involved in memory self-monitoring. Although metamemory has been studied in cognitive psychology for several decades, there have been fewer studies investigating the neuropsychology of metamemory. In recent years, a growing number of studies of neurological patient groups have been conducted in order to investigate the neural correlates of metamemory. In this review, we examine the neuropsychological evidence that the frontal lobes are critically involved in monitoring and control processes, which are the central components of metamemory. The following conclusions are drawn from this literature: (1) There is a strong correlation between indices of frontal lobe function or structural integrity and metamemory accuracy (2) The combination of frontal lobe dysfunction and poor memory severely impairs metamemorial processes (3) Metamemory tasks vary in subject performance levels, and quite likely, in the underlying processes these different tasks measure, and (4) Metamemory, as measured by experimental tasks, may dissociate from basic memory retrieval processes and from global judgments of memory.     

Understanding Motor Awareness Through Normal and Pathological Behavior

ABSTRACT— Data on patients with localized brain damage and on neurologically intact subjects show that normal motor control depends on the functionality of a chain of neurobiological events. These events, through the activation of internal representations of the desired, predicted, and actual condition of one's body with respect to the external world, contribute to the construction of conscious knowledge of voluntary actions and to self-awareness.     

Unawareness of Deficits in Alzheimer's Disease and Other Dementias: Operational Definitions and Empirical Findings

Individuals with dementia frequently demonstrate decreased awareness of their cognitive difficulties. Empirical research examining this phenomenon has addressed a number of aspects of unawareness in Alzheimer's disease and other dementias, including occurrence in various disorders; possible neuroanatomical substrates; relationship to general cognitive functioning, executive functioning, and psychiatric symptomatology; and progression over time and across cognitive domains. Limitations of the current research literature are discussed, particularly issues surrounding operational definitions of unawareness and the current limited understanding of the role of the frontal lobes. A number of conclusions regarding unawareness that appear to be supported by the current body of empirical research and possible future directions are discussed.     

Singularity and consciousness: A neuropsychological contribution

In common sense experience based on introspection, consciousness is singular. There is only one ‘me’ and that is the one that is conscious. This means that ‘singularity’ is a defining aspect of ‘consciousness’. However, the three main theories of consciousness, Integrated Information, Global Workspace and Recurrent Processing theory, are generally not very clear on this issue. These theories have traditionally relied heavily on neuropsychological observations and have interpreted various disorders, such as anosognosia, neglect and split-brain as impairments in conscious awareness without any reference to ‘the singularity’. In this review, we will re-examine the theoretical implications of these impairments in conscious awareness and propose a new way how to conceptualize consciousness of singularity. We will argue that the subjective feeling of singularity can coexist with several disunified conscious experiences. Singularity awareness may only come into existence due to environmental response constraints. That is, perceptual, language, memory, attentional and motor processes may largely proceed unintegrated in parallel, whereas a sense of unity only arises when organisms need to respond coherently constrained by the affordances of the environment. Next, we examine from this perspective psychiatric disorders and psycho-active drugs. Finally, we present a first attempt to test this hypothesis with a resting state imaging experiment in a split-brain patient. The results suggest that there is substantial coherence of activation across the two hemispheres. These data show that a complete lesioning of the corpus callosum does not, in general, alter the resting state networks of the brain. Thus, we propose that we have separate systems in the brain that generate distributed conscious. The sense of singularity, the experience of a ‘Me-ness’, emerges in the interaction between the world and response-planning systems, and this leads to coherent activation in the different functional networks across the cortex.