Chris Frith, Consciousness Researcher - Abstracts

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Alfredo Pereira Jr (group admin)

Date:

25 August 2007

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1: Curr Biol. 2007 Aug 21;17(16):R724-32.

Social cognition in humans.

Frith CD, Frith U.

Welcome Trust Centre for Neuroimaging at University College London, UK; Center
for Functionally Integrative Neuroscience, Aarhus University, Denmark.

We review a diversity of studies of human social interaction and highlight the
importance of social signals. We also discuss recent findings from social
cognitive neuroscience that explore the brain basis of the capacity for
processing social signals. These signals enable us to learn about the world from
others, to learn about other people, and to create a shared social world. Social
signals can be processed automatically by the receiver and may be unconsciously
emitted by the sender. These signals are non-verbal and are responsible for
social learning in the first year of life. Social signals can also be processed
consciously and this allows automatic processing to be modulated and overruled.
Evidence for this higher-level social processing is abundant from about 18 months
of age in humans, while evidence is sparse for non-human animals. We suggest that
deliberate social signalling requires reflective awareness of ourselves and
awareness of the effect of the signals on others. Similarly, the appropriate
reception of such signals depends on the ability to take another person’s point
of view. This ability is critical to reputation management, as this depends on
monitoring how our own actions are perceived by others. We speculate that the
development of these high level social signalling systems goes hand in hand with
the development of consciousness.

PMID: 17714666 [PubMed – in process]

2: Conscious Cogn. 2002 Dec;11(4):481-7.

Attention to action and awareness of other minds.

Frith C.

Wellcome Department of Imaging Neuroscience, Institute of Neurology, University
College London, 12 Queen Square, London WC1N 3BG, UK. cfrith@fil.ion.ucl.ac.uk

We have only limited awareness of the system by which we control our actions and
this limited awareness does not seem to be concerned with the control of action.
Awareness of choosing one action rather than another comes after the choice has
been made, while awareness of initiating an action occurs before the movement has
begun. These temporal differences bind together in consciousness the intention to
act and the consequences of the action. This creates our sense of agency.
Activity in the anterior cingulate cortex and medial prefrontal cortex is
associated with awareness of our own actions and also occurs when we think about
the actions of others. I propose that the mechanism underlying awareness of how
our own intentions lead to actions can also be used to represent the intentions
that underlie the actions of others. This common system enables us to communicate
mental states and thereby share our experiences. Copyright 2002 Elsevier Science
(USA)

PMID: 12470618 [PubMed – indexed for MEDLINE]

3: Trends Cogn Sci. 1999 Mar;3(3):105-114.

The neural correlates of conscious experience: an experimental framework.

Frith C, Perry R, Lumer E.

Wellcome Department of Cognitive Neurology, Institute of Neurology, 12 Queen
Square, London, UK WC1N 3BG.

Demonstrating that neural activity ‘represents’ physical properties of the world
such as the orientation of a line in the receptive field of a nerve cell is a
standard procedure in neuroscience. However, not all such neural activity will be
associated with the mental representations that form the contents of
consciousness. In some cases, such as when patients with blindsight correctly
‘guess’ the location of a stimulus, neural activity is associated with physical
stimulation and with appropriate behaviour, but not with awareness. To identify
the neural correlates of conscious experience we need to identify patterns of
neural activity that are specifically associated with awareness. Experiments
aimed at making such identifications require that subjects report some aspect of
their conscious experience either verbally or through some pre-arranged
non-verbal report while neural activity is measured. If there is some
characteristic neural signature of consciousness, then this should be
distinguishable from the kinds of neural activity associated with stimulation
and/or behaviour in the absence of awareness. It remains to be seen whether the
neural signature of consciousness relates to the location of the neural activity,
the temporal properties of the neural activity or the form of the interaction
between activity in different brain regions.

PMID: 10322462 [PubMed – as supplied by publisher]

4: Philos Trans R Soc Lond B Biol Sci. 1996 Oct 29;351(1346):1505-12.

The role of the prefrontal cortex in self-consciousness: the case of auditory
hallucinations.

Frith C.

Wellcome Department of Cognitive Neurology, Institute of Neurology, London, U.K.

Many patients with schizophrenia report hallucinations in which they hear voices
talking to them or about them. Behavioural and physiological studies show that
this experience is associated with processes occurring in auditory language
systems associated with both the production and the reception of speech. I
propose that hallucinations are experienced because patients have difficulty in
distinguishing sensations caused by their own actions from those that arise from
external influences. This distinction can be made by predicting the sensations
that will result from executive commands (forward modelling). If the predicted
sensation matches the actual sensation then no outside influences have occurred
and perception of change can be ‘cancelled’. At the physiological level this
mechanism depends upon interactions between the prefrontal areas where the
executive commands originate and posterior brain regions concerned with the
resultant sensations. Evidence from functional brain imaging confirms that
interactions between prefrontal (executive) areas and auditory association areas
are abnormal in schizophrenia. However, this account needs to be extended before
we can understand why patients experience the voices as emanating, not just from
an external source, but from agents who are trying to influence their behaviour.
Recent imaging studies suggest that medial prefrontal cortex is engaged when we
think about other people, but the precise nature of the interaction of this brain
area with other regions remains to be established.

Publication Types: Review

PMID: 8941962 [PubMed – indexed for MEDLINE]

5: Brain Res Cogn Brain Res. 1996 Dec;5(1-2):175-81.

The role of the prefrontal cortex in higher cognitive functions.

Frith C, Dolan R.

Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK.

The higher cognitive functions, working memory, mental imagery and willed action,
are all intimately associated with consciousness. The common process underlying
all these functions is that information is “held in mind” for a period of time.
This information, which may be about stimuli or responses, can be derived from
the past or generated for the future. Brain imaging studies show that “holding
something in mind” is associated with activity in an extended system which
involves both prefrontal cortex and more posterior areas whose location is
determined by the nature of the information being held in mind. Automatic actions
and perceptions which do not involve consciousness are associated with activity
in the relevant posterior areas, but not in the prefrontal cortex. These studies
demonstrate that activity occurs in the same posterior area whether the
associated information comes from the outside world or is internally generated.
This raises the problem of how we know whether our experience derives from mental
imagery or from something happening in the outside world. There is evidence that
patients with schizophrenia have precisely this problem since they perceive their
own thoughts and even sub-vocal speech as coming from outside (hallucinations).
Recent brain imaging studies suggest that there is a disconnection between
prefrontal and posterior areas in these patients which could explain their
characteristic misperceptions.

Publication Types: Review

PMID: 9049084 [PubMed – indexed for MEDLINE]

6: Nature. 1995 Aug 31;376(6543):778-81.

Modulation of conscious experience by peripheral sensory stimuli.

Bottini G, Paulesu E, Sterzi R, Warburton E, Wise RJ, Vallar G, Frackowiak RS,
Frith CD.

Wellcome Department of Cognitive Neurology, Institute of Neurology, Hammersmith
Hospital, London, UK.

Lack of awareness of touch associated with brain damage may transiently recover
after stimulation of the vestibular system. We used positron emission tomographic
regional cerebral blood flow measurements to study the neurophysiological effect
of vestibular stimulation on touch imperception in a subject with a right brain
lesion. We tested the hypothesis that the vestibular system aids conscious
tactile perception by introducing a bias in the neural system subserving body
representation. We show that in normal subjects touch and vestibular signals
share projections to the putamen, insula, somatosensory area II, premotor cortex
and supramarginal gyrus. In our patient a subset of these regions (right putamen
and insula) was spared by the lesion and was maximally active when touch and
vestibular stimulations were combined. These results support the suggestion that
our phenomenological consciousness is associated with activation in circumscribed
brain areas specific to the particular sensation of which we are aware.

Publication Types: Case Reports Research Support, Non-U.S. Gov’t

PMID: 7651537 [PubMed – indexed for MEDLINE]

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