Bernard Baars, Consciousness Researcher - Abstracts

Posted by:

Alfredo Pereira Jr (group admin)

Date:

25 August 2007

Comments:

7 comments

1: Prog Brain Res. 2005;150:45-53.

Global workspace theory of consciousness: toward a cognitive neuroscience of
human experience.

Baars BJ.

The Neurosciences Institute, 10640 John Jay Hopkins Dv., San Diego, CA 92121,
USA. baars@nsi.edu

Global workspace (GW) theory emerged from the cognitive architecture tradition in
cognitive science. Newell and co-workers were the first to show the utility of a
GW or “blackboard” architecture in a distributed set of knowledge sources, which
could cooperatively solve problems that no single constituent could solve alone.
The empirical connection with conscious cognition was made by Baars (1988, 2002).
GW theory generates explicit predictions for conscious aspects of perception,
emotion, motivation, learning, working memory, voluntary control, and self
systems in the brain. It has similarities to biological theories such as Neural
Darwinism and dynamical theories of brain functioning. Functional brain imaging
now shows that conscious cognition is distinctively associated with wide spread
of cortical activity, notably toward frontoparietal and medial temporal regions.
Unconscious comparison conditions tend to activate only local regions, such as
visual projection areas. Frontoparietal hypometabolism is also implicated in
unconscious states, including deep sleep, coma, vegetative states, epileptic loss
of consciousness, and general anesthesia. These findings are consistent with the
GW hypothesis, which is now favored by a number of scientists and philosophers.

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

PMID: 16186014 [PubMed – indexed for MEDLINE]

2: Conscious Cogn. 2005 Mar;14(1):169-87.

Identifying hallmarks of consciousness in non-mammalian species.

Edelman DB, Baars BJ, Seth AK.

The Neurosciences Institute, 10640 John Jay Hopkins Drive, San Diego, CA 92121,
USA. dedelman@nsi.edu

Most early studies of consciousness have focused on human subjects. This is
understandable, given that humans are capable of reporting accurately the events
they experience through language or by way of other kinds of voluntary response.
As researchers turn their attention to other animals, “accurate report”
methodologies become increasingly difficult to apply. Alternative strategies for
amassing evidence for consciousness in non-human species include searching for
evolutionary homologies in anatomical substrates and measurement of physiological
correlates of conscious states. In addition, creative means must be developed for
eliciting behaviors consistent with consciousness. In this paper, we explore
whether necessary conditions for consciousness can be established for species as
disparate as birds and cephalopods. We conclude that a strong case can be made
for avian species and that the case for cephalopods remains open. Nonetheless, a
consistent effort should yield new means for interpreting animal behavior.

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

PMID: 15766896 [PubMed – indexed for MEDLINE]

3: Conscious Cogn. 2005 Mar;14(1):140-68.

Neural Darwinism and consciousness.

Seth AK, Baars BJ.

The Neurosciences Institute, 10640 John Jay Hopkins Drive, San Diego, CA 92121,
USA. seth@nsi.edu

Neural Darwinism (ND) is a large scale selectionist theory of brain development
and function that has been hypothesized to relate to consciousness. According to
ND, consciousness is entailed by reentrant interactions among neuronal
populations in the thalamocortical system (the ‘dynamic core’). These
interactions, which permit high-order discriminations among possible core states,
confer selective advantages on organisms possessing them by linking current
perceptual events to a past history of value-dependent learning. Here, we assess
the consistency of ND with 16 widely recognized properties of consciousness, both
physiological (for example, consciousness is associated with widespread,
relatively fast, low amplitude interactions in the thalamocortical system), and
phenomenal (for example, consciousness involves the existence of a private flow
of events available only to the experiencing subject). While no theory accounts
fully for all of these properties at present, we find that ND and its recent
extensions fare well.

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

PMID: 15766895 [PubMed – indexed for MEDLINE]

4: Conscious Cogn. 2005 Mar;14(1):119-39.

Criteria for consciousness in humans and other mammals.

Seth AK, Baars BJ, Edelman DB.

The Neurosciences Institute, 10640 John Jay Hopkins Drive, San Diego, CA 92121,
USA. seth@nsi.edu

The standard behavioral index for human consciousness is the ability to report
events with accuracy. While this method is routinely used for scientific and
medical applications in humans, it is not easy to generalize to other species.
Brain evidence may lend itself more easily to comparative testing. Human
consciousness involves widespread, relatively fast low-amplitude interactions in
the thalamocortical core of the brain, driven by current tasks and conditions.
These features have also been found in other mammals, which suggests that
consciousness is a major biological adaptation in mammals. We suggest more than a
dozen additional properties of human consciousness that may be used to test
comparative predictions. Such homologies are necessarily more remote in
non-mammals, which do not share the thalamocortical complex. However, as we learn
more we may be able to make “deeper” predictions that apply to some birds,
reptiles, large-brained invertebrates, and perhaps other species.

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

PMID: 15766894 [PubMed – indexed for MEDLINE]

5: Conscious Cogn. 2005 Mar;14(1):7-21.

Subjective experience is probably not limited to humans: the evidence from
neurobiology and behavior.

Baars BJ.

The Neurosciences Institute, San Diego, CA, USA. bbaars@comcast.net

In humans, conscious perception and cognition depends upon the thalamocortical
(T-C) complex, which supports perception, explicit cognition, memory, language,
planning, and strategic control. When parts of the T-C system are damaged or
stimulated, corresponding effects are found on conscious contents and state, as
assessed by reliable reports. In contrast, large regions like cerebellum and
basal ganglia can be damaged without affecting conscious cognition directly.
Functional brain recordings also show robust activity differences in cortex
between experimentally matched conscious and unconscious events. This basic
anatomy and physiology is highly conserved in mammals and perhaps ancestral
reptiles. While language is absent in other species, homologies in perception,
memory, and motor cortex suggest that consciousness of one kind or another may be
biologically fundamental and phylogenetically ancient. In humans we infer
subjective experiences from behavioral and brain evidence. This evidence is quite
similar in other mammals and perhaps some non-mammalian species. On the weight of
the biological evidence, therefore, subjectivity may be conserved in species with
human-like brains and behavior.

PMID: 15766888 [PubMed – indexed for MEDLINE]

6: Trends Neurosci. 2003 Dec;26(12):671-5.

Brain, conscious experience and the observing self.

Baars BJ, Ramsoy TZ, Laureys S.

The Neurosciences Institute, San Diego, CA 92121, USA. baars@nsi.edu

Conscious perception, like the sight of a coffee cup, seems to involve the brain
identifying a stimulus. But conscious input activates more brain regions than are
needed to identify coffee cups and faces. It spreads beyond sensory cortex to
frontoparietal association areas, which do not serve stimulus identification as
such. What is the role of those regions? Parietal cortex support the ‘first
person perspective’ on the visual world, unconsciously framing the visual object
stream. Some prefrontal areas select and interpret conscious events for executive
control. Such functions can be viewed as properties of the subject, rather than
the object, of experience – the ‘observing self’ that appears to be needed to
maintain the conscious state.

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

PMID: 14624851 [PubMed – indexed for MEDLINE]

7: Trends Cogn Sci. 2003 Apr;7(4):166-172.

How conscious experience and working memory interact.

Baars BJ, Franklin S.

The Neurosciences Institute, San Diego, 92121, California, USA

Active components of classical working memory are conscious, but traditional
theory does not account for this fact. Global Workspace theory suggests that
consciousness is needed to recruit unconscious specialized networks that carry
out detailed working memory functions. The IDA model provides a fine-grained
analysis of this process, specifically of two classical working-memory tasks,
verbal rehearsal and the utilization of a visual image. In the process, new light
is shed on the interactions between conscious and unconscious aspects of working
memory.

PMID: 12691765 [PubMed – as supplied by publisher]

8: Neural Netw. 1997 Oct 1;10(7):1195-1206.

A Neural Global Workspace Model for Conscious Attention.

Cho SB, Baars BJ, Newman J.

Department of Computer Science, Yonsei University, Seoul, South Korea

Considerable progress is being made in interdisciplinary efforts to develop a
general theory of the neural correlates of consciousness. Developments of Baars’
Global Workspace theory over the past decade are examples of this progress.
Integrating experimental data and models from cognitive psychology, AI and
neuroscience, we present a neurocognitive model in which consciousness is defined
as a global integration and dissemination system – nested in a large-scale,
distributed array of specialized bioprocessors – which controls the allocation of
the processing resources of the central nervous system. It is posited that this
global control is effected via cortical ‘gating’ of a strategic thalamic nucleus.
The basic circuitry of this neural system is reasonably well understood, and can
be modeled, to a first approximation, employing neural network principles.

PMID: 12662511 [PubMed – as supplied by publisher]

9: Trends Cogn Sci. 2002 Jan 1;6(1):47-52.

The conscious access hypothesis: origins and recent evidence.

Baars BJ.

The Neurosciences Institute, 10640 John Jay Hopkins Drive, 92121, San Diego,
California, USA

Consciousness might help to mobilize and integrate brain functions that are
otherwise separate and independent. Evidence for this ‘conscious access
hypothesis’ was described almost two decades ago, in a framework called global
workspace theory. The theory had little impact at first, for three reasons:
because consciousness was controversial; the evidence, though extensive, was
indirect; and integrative theory was unfashionable. Recent neuroimaging evidence
appears broadly to support the hypothesis, which has implications for perception,
learning, working memory, voluntary control, attention and self systems in the
brain.

PMID: 11849615 [PubMed – as supplied by publisher]

10: J Gen Psychol. 1999 Jul;126(3):224-33.

Attention versus consciousness in the visual brain: differences in conception,
phenomenology, behavior, neuroanatomy, and physiology.

Baars BJ.

Wright Institute, USA. baars@cogsci.berkeley.edu

A common confound between consciousness and attention makes it difficult to think
clearly about recent advances in the understanding of the visual brain. Visual
consciousness involves phenomenal experience of the visual world, but visual
attention is more plausibly treated as a function that selects and maintains the
selection of potential conscious contents, often unconsciously. In the same
sense, eye movements select conscious visual events, which are not the same as
conscious visual experience. According to common sense, visual experience is
consciousness, and selective processes are labeled as attention. The distinction
is reflected in very different behavioral measures and in very different brain
anatomy and physiology. Visual consciousness tends to be associated with the
“what” stream of visual feature neurons in the ventral temporal lobe. In
contrast, attentional selection and maintenance are mediated by other brain
regions, ranging from superior colliculi to thalamus, prefrontal cortex, and
anterior cingulate. The author applied the common-sense distinction between
attention and consciousness to the theoretical positions of M. I. Posner (1992,
1994) and D. LaBerge (1997, 1998) to show how it helps to clarify the evidence.
He concluded that clarity of thought is served by calling a thing by its proper
name.

PMID: 10443028 [PubMed – indexed for MEDLINE]

Please note only group admins can post notices. Group members can post comments.