John G. Taylor

Does the corollary discharge of attention exist

We discuss experimental support for the existence of a corollary discharge signal of attention movement control and its formulation in terms of the corollary discharge of attention model of attention movement (CODAM). The data is from fMRI, MEG and EEG activity observed about 200 ms after stimulus onset in various attention paradigms and in which the activity is mainly sited in parietal and extra-striate visual areas. Moreover the data arises from neural activity observed before report of a subjects experience occurs. The overall experimental support for the existence of a copy of the attention movement control signal generates, it is suggested, a viable route to explore the relation between this signal and human consciousness, as concluded in the paper.

The Story of Consciousness

We look out into the Universe to attempt to understand its nature. In the process we have discovered strange and disturbing objects like black holes, surrounded by an event horizon to shield us from their impossibly bizarre centre, where matter magically disappears. Our search in the heavens also involves a search for ourselves, and how we fit into this bizarre material universe we are discovering. So at the same time we are searching the heavens for ourselves and our own souls (whatever they are), thereby hoping to make sense of our inner black holes. For we have something equivalent to those exotic black hole entities at the centres of our being – they are our central core of experience. We try to find a place to stay equably outside the event horizon (the region around the centre of a black hole from which there is no escape if once entered) of our inner central black-hole-like attractor. For some people it is hard, with them falling ever faster to their inevitable end. But for all of us, however hard we struggle we must eventually turn to look at our own minds, and especially that central inner black hole that seems empty and which we try forever to escape. It is our core ‘I’, sometimes called our soul. What is this ‘I’ to which we must face up in order to make our lives complete?

Does ‘I’ Really Exist?

We are concerned here with a particular component of consciousness, its phenomenal aspect. This was already discussed in the previous two chapters (although mainly in Chap. 7), assuming it existed. The problem we now have to face is: does ‘I’ really exist or not?

The Control Nature of Attention

We analyze in this chapter the manner in which attention acts as a controller in the brain. We hope thereby to be able to begin a more complete probe of attention and so try to uncover in what manner consciousness itself might be hidden in the interstices of some part of the attention control system.

Understanding Consciousness and Emotions

There have been many attempts to understand the emotions. In particular there has been a strong thrust towards what has been termed ‘affective computing’, where human emotion is monitored by a computer, or emotional responses to human activity are attempted to be incorporated in a computer system, an avatar or a robot. But in order to achieve ‘affective computing’ it is necessary to know what is being computed. That is, in order to compute with what would pass for human emotions, it is necessary to have a computational basis for the emotions themselves. What does it mean quantitatively if a human is sad or angry? How is this affective state computed in their brain? How are emotions ‘felt’ in the consciousness system? It is these questions, on the very core of the computational nature of the human emotions, which is addressed in this chapter. A proposal will be made as to this computational basis based on the well established approach to emotions as arising from an appraisal of a given situation or event by a specific human being. Finally how emotions can become conscious will be discussed at the end of the chapter.

Understanding the Mental Disease of Schizophrenia

There are numerous mental diseases that yet require deep investigation in terms of the alteration of the mental state of the patient due to the disease onset. Of course there are other aspects of mental diseases which obviously urgently need exploration, such as cause, cure, etc. However it is only appropriate to consider the alteration of the patient’s mental state in this book. And of all the mental diseases it is schizophrenia which is most relevant in looking for the mental disease with greatest effect on the subject’s mental state. Numerous researchers have pointed out over the last decades that there is a loss of the sense of the inner self in schizophrenia. In particular the illuminating paper of Sass and Parnas (Schizophr Bull 29(3):427–444, 2003) gives an underpinning explanation of the disease along these lines in each of its three manifestations, with positive, negative or disordered symptoms (see also Cermolacce M, Naudin J, Parnas J, Conscious Cogn 16:703–714, 2007; Parnas J, Handest P, Saebye D, Jansson L, Acta Psychiatrica Scandinavica 108:126–133, 2003; Parnas J, Handest P, Jannsson L, Saebye D, Psychopathology 38(5):259–267, 2005; Sass L, Parnas J, Explaining schizophrenia: the relevance of phenomenology. In: Chung MC, Fulford KMW, Graham G (eds) Reconceiving Schizophrenia. Oxford University Press, Oxford, pp 63–95, 2007; Sass L, Madness and modernism. Harvard University Press, Cambridge, MA, 1992). The crucial component of the analysis of these researchers is that of various disturbances in ipseity (the ongoing sense of ‘being there’ accompanying all conscious experience) that can occur for a sufferer, giving a framework with which to understand the disease. Such analyses of schizophrenia in terms of distortions of the self go back much earlier (Berze J, Die Primare Insuffizienz der Psychishcen Aktivitat: Ihr Wesen, ihre Erscheinungen and ihre Bedeutung als Grundstorungen der Dementia Praecox und des hypophrenen Uberhaupt. F Deutke, Leipzig, 1914; Minkowski E, La schizophrenia. Psychopathologie des shizoides et des schizophrenes. Payot, Paris, 1927; Blankenburg W. First steps toward a psychopathology of “common sense (trans: Mishara A). Philos Psychiatry Psychol 8:303–315, 2001; Kimura B, Ecrits de Psychopathologie Phenomenologique. Trans Boderlique. P.U.F, Paris France, 1992; Sass LA, Philos Psychiatry Psychol 8:251–270, 2001). However the more recent work has become more precise and embracing in terms of seeing most forms of schizophrenia as arising from such distortions. It also provides new ways of looking at and diagnosing the disease.

Solving the Mind-Body Problem

The mind is composed of mental fragments – sensations, feelings, thoughts, imaginations, all flowing now in an ordered sequence, now in a chaotic fashion. There are also non-conscious components involved in early brain processing of stimuli (as in lower level processing in vision, such as in V1) or in emotions not yet in consciousness (as discussed in Chap. 14). On the other hand the body is constructed to obey the underlying laws of physics, and its components obey the well-enumerated laws of physiology. It is these characteristic differences – between mind and body – that leads to the Mind-Body problem.

The Owner, The Inner Self and CODAM

The functioning of the pre-reflective or inner self is considered in more detail in this chapter in terms of its possible creation through the CODAM model of attention presented in the previous chapter. In contradiction to the view of Western phenomenology, that the inner self appears to serve no specific purpose except that of providing the further ownership of experience, it is proposed here that the inner self acts rather as a call centre, enabling connections to be made between distant and functionally different components of brain processing thereby making such interactions more efficient. It achieves these functions by monitoring and speeding up ongoing calls or those calls about to be set up so that incorrect call routing is avoided and call switching occurs as fast as possible.

The Full CODAM Model

The CODAM network was designed in the late 1990s (Taylor JG. Race for consciousness. Bradford Book, Cambridge, MA, 1999; Taylor JG. Soc Neurosci Abstr 26:2231#839.3, 2000) so as to bring attention into the modern engineering control domain by updating it beyond ballistic control by the introduction of further components, such as by the presence of a predictor or forward model and of an error corrector. It also possesses a working memory module to hold the amplified input representing the attended stimulus so as to allow it to be available for general report around the brain for further processing. Such a process of singling out a stimulus for further work is the essence of attention acting as a filter. In a complex environment, with many distracters, such a filtering action is crucial to simplify the ‘world in the head’ so allowing it to be used in an efficient manner at a higher level. Thus attention can be seen as a way to achieve simplified conscious report, without having to go through a possibly long list of external but unimportant stimuli for any task at hand.

Attention Versus Consciousness: Fused or Independent?

The American neuroscientist Christof Koch, working with his group at Caltech, has spearheaded the important thesis that consciousness and attention are not as closely fused as is almost universally claimed. The usual statement is that attention to a stimulus in the external world is necessary for consciousness of that stimulus to arise in a subject. More may be needed for that consciousness to arise, but at least attention must be directed to that stimulus in order for there to be any chance of consciousness of the stimulus. This implies that consciousness is to be searched for in the interstices of attention. Koch claims that this is not the case. In particular he and his colleague Tsuchiya (Koch C, Tsuchiya N, Trends Cogn Sci 11(1):16–22, 2007) wrote that consciousness could arise in a subject without them paying attention to the relevant stimulus. This claim was based on several subtle experiments, which clearly we need to analyze in some detail in order to investigate this important claim.