Semir Zeki

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Semir Zeki (2016) Profesor Semir Zeki.jpg
Semir Zeki (2016)

Semir Zeki FMedSci FRS (born 8 November 1940) [1] is a British and French neurobiologist who has specialised in studying the primate visual brain and more recently the neural correlates of affective states, such as the experience of love, desire and beauty that are generated by sensory inputs within the field of neuroesthetics. He was educated at University College London (UCL) where he was Henry Head Research Fellow of the Royal Society before being appointed Professor of Neurobiology. Since 2008 he has been Professor of Neuroesthetics at UCL.

Contents

Early work

Zeki's early work was mainly anatomical in nature and consisted in charting visual areas in the primate (monkey) brain by studying their connections, leading him to define several visual areas lying anterior to the primary visual cortex (area V1) of the brain. [2] [3] This was followed by recording from single cells in these areas, which led him to the view (a) that there is a functional specialisation in the visual cortex, with different visual areas undertaking different visual tasks, such as the processing of colour, motion and form [4] and (b) that the visual brain processes these different attributes in parallel. [5]

Time at University College London

He later showed, using brain imaging techniques, that the same principles apply to the organisation of the human visual brain. [6] In recent work he has shown that parallel processing appears to extend beyond the mere processing of visual signals to their grouping in parietal cortex. [7] His work on colour vision was influenced by the work and methods of Edwin H. Land, whose techniques he employed in his physiological and brain imaging experiments, [8] and which led him to the view that colour is constructed by the brain and that a specialised visual area, area V4, is critical to this process. [9]

These findings raised the question of how the signals processed in these separate visual areas are integrated to give a unified picture of the visual world. In psychophysical experiments undertaken with colleagues, he showed that we perceive, and become aware of, different visual attributes at different times, with colour preceding motion by about 80 ms and form (orientation) by about 40 ms, [10] leading to the view that there is a temporal asynchrony in vision which is the result of different processing speeds for different attributes. This in turn led him to suggest that visual consciousness is not unified; rather there are many visual micro-consciousness which are distributed in time and space, [11] and that activity in each visual area can acquire a conscious correlate without the necessity of reporting to another cortical area, though acknowledging that there must be other enabling systems, possibly located in the reticular formation. [12] Thus, functional specialisation manifests itself in the temporal sequence with which we see different attributes such as colour

More recently he has also studied the brain reaction to affective states generated by sensory inputs, such as the experience of love [13] and hate. [14] His studies of the experience of visual [15] and musical beauty has led him to suggest that a specific part of the emotional brain, field A1 of the medial orbito-frontal cortex, is critical for such experiences. [16]

Public engagement

He has lectured widely across the world, giving over 60 named lectures, including the Ferrier Lecture (Royal Society 1995); The Philip Bard Lecture (Johns Hopkins University, 1992); The Woodhull Lecture (Royal Institution, London, 1995); The Humphry Davy Lecture (Académie des Sciences, Paris, 1996); The Grass Foundation Forbes Lectures (Marine Biological Laboratory, Woods Hole, USA 1997; Carl Gustave Bernhard Lecture (Royal Swedish Academy of Science, Stockholm, 1996; and the Tizard Lecture (Westminster School, London, 2004) among others.

He has published three books, A Vision of the Brain (Blackwell, Oxford 1993 – translated into Japanese and Spanish), Inner Vision: an exploration of art and the brain (OUP, 1999); Splendors and Miseries of the Brain (Wiley-Blackwell, Oxford 2009) and co-authored La Quête de l'essentiel, Les Belles Lettres, Archimbaud, Paris, 1995 (with Balthus, Count Klossowski de Rola) and La bella e la bestia, 2011, Laterza, Italy (with Ludovica Lumer).

He held an exhibition of his own art work at the Pecci Museum of Contemporary Art in Milan in 2011 (Bianco su bianco: oltre Malevich).

Posts, honours and awards

He was Editor of the Philosophical Transactions of the Royal Society (B) from 1997 to 2004.

He has been a Trustee of Fight for Sight, a Guarantor of the neurological journal Brain, a member and then Chairman of the Wellcome Trust Vision Panel and a member of the National Science Council of France (1998–2002).

He has been a Visiting Fellow or Professor at St Andrews University; Ludwig-Maxilmilians University, Munich; Duke University, USA, University of California (Berkeley), among other institutions. He has conducted a number of public dialogues with writers, artists and art historians, including Dame Antonia Byatt, Balthus, Hans Belting, Peter Sellars, Michelangelo Pistoletto and Tetsuo Miyajima.

He is a Fellow of the Royal Society (1990), Member of the Academia Europaea (1991), Member of the European Academy of Sciences and Arts (Salzburg) (1993), Foreign Member of the American Philosophical Society (1998), [17] Founding Fellow of the Academy of Medical Sciences (1998), Fellow of University College London (2000) and Honorary Member of the Physiological Society (2013).

D.Sc. (honoris causa) from Aston University, University of Aberdeen, Aristotle University of Thessaloniki and an MD (honoris causa) from the National and Kapodistrian University of Athens.

Prizes include The Golden Brain Award (1985), Prix Science pour l'art (1991), Rank Prize in Opto-Electronics (1992) (jointly with A. Movshon and T. Adelson), Zotterman Prize (1993); Koetser Foundation Prize (1997), Award in Electronic Imaging (2002); King Faisal International Prize in Biology (2004), Erasmus Medal (Academia Europaea, 2008), Aristotle Gold Medal (2011), Rome Prize (Atena Onlus) (2012) and the BMI-Kaloy Prize (Kaloy Foundation) 2015. He received the 38th TS Srinivasan Endowment Oration Award 2018, during the TS Srinivasa NIMHANS Conclave. [18] The conclave coincides with the 11th International Congress of the International Neuropsychiatric Association.

Scientific achievements

Zeki's scientific achievements include:

Related Research Articles

<span class="mw-page-title-main">Visual cortex</span> Region of the brain that processes visual information

The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 (V1), Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5.

Blindsight is the ability of people who are cortically blind to respond to visual stimuli that they do not consciously see due to lesions in the primary visual cortex, also known as the striate cortex or Brodmann Area 17. The term was coined by Lawrence Weiskrantz and his colleagues in a paper published in a 1974 issue of Brain. A previous paper studying the discriminatory capacity of a cortically blind patient was published in Nature in 1973. The assumed existence of blindsight is controversial, with some arguing that it is merely degraded conscious vision.

<span class="mw-page-title-main">Color constancy</span> How humans perceive color

Color constancy is an example of subjective constancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions. A green apple for instance looks green to us at midday, when the main illumination is white sunlight, and also at sunset, when the main illumination is red. This helps us identify objects.

<span class="mw-page-title-main">Color vision</span> Ability to perceive differences in light frequency

Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different frequencies independently of light intensity. Color perception is a part of the larger visual system and is mediated by a complex process between neurons that begins with differential stimulation of different types of photoreceptors by light entering the eye. Those photoreceptors then emit outputs that are propagated through many layers of neurons and then ultimately to the brain. Color vision is found in many animals and is mediated by similar underlying mechanisms with common types of biological molecules and a complex history of evolution in different animal taxa. In primates, color vision may have evolved under selective pressure for a variety of visual tasks including the foraging for nutritious young leaves, ripe fruit, and flowers, as well as detecting predator camouflage and emotional states in other primates.

The consciousness and binding problem is the problem of how objects, background and abstract or emotional features are combined into a single experience.

<span class="mw-page-title-main">Neuroesthetics</span> Sub-discipline of empirical aesthetics

Neuroesthetics is a relatively recent sub-discipline of applied aesthetics. Empirical aesthetics takes a scientific approach to the study of aesthetic experience of art, music, or any object that can give rise to aesthetic judgments. Neuroesthetics is a term coined by Semir Zeki in 1999 and received its formal definition in 2002 as the scientific study of the neural bases for the contemplation and creation of a work of art. Neuroesthetics uses neuroscience to explain and understand the aesthetic experiences at the neurological level. The topic attracts scholars from many disciplines including neuroscientists, art historians, artists, art therapists and psychologists.

Multisensory integration, also known as multimodal integration, is the study of how information from the different sensory modalities may be integrated by the nervous system. A coherent representation of objects combining modalities enables animals to have meaningful perceptual experiences. Indeed, multisensory integration is central to adaptive behavior because it allows animals to perceive a world of coherent perceptual entities. Multisensory integration also deals with how different sensory modalities interact with one another and alter each other's processing.

Akinetopsia, also known as cerebral akinetopsia or motion blindness, is a term introduced by Semir Zeki to describe an extremely rare neuropsychological disorder, having only been documented in a handful of medical cases, in which a patient cannot perceive motion in their visual field, despite being able to see stationary objects without issue. The syndrome is the result of damage to area V5, whose cells are specialized to detect directional visual motion. There are varying degrees of akinetopsia: from seeing motion as frames of a cinema reel to an inability to discriminate any motion. There is currently no effective treatment or cure for akinetopsia.

<span class="mw-page-title-main">Cerebral achromatopsia</span> Medical condition

Cerebral achromatopsia is a type of color-blindness caused by damage to the cerebral cortex of the brain, rather than abnormalities in the cells of the eye's retina. It is often confused with congenital achromatopsia but underlying physiological deficits of the disorders are completely distinct. A similar, but distinct, deficit called color agnosia exists in which a person has intact color perception but has deficits in color recognition, such as knowing which color they are looking at.

<span class="mw-page-title-main">Filling-in</span>

In vision, filling-in phenomena are those responsible for the completion of missing information across the physiological blind spot, and across natural and artificial scotomata. There is also evidence for similar mechanisms of completion in normal visual analysis. Classical demonstrations of perceptual filling-in involve filling in at the blind spot in monocular vision, and images stabilized on the retina either by means of special lenses, or under certain conditions of steady fixation. For example, naturally in monocular vision at the physiological blind spot, the percept is not a hole in the visual field, but the content is “filled-in” based on information from the surrounding visual field. When a textured stimulus is presented centered on but extending beyond the region of the blind spot, a continuous texture is perceived. This partially inferred percept is paradoxically considered more reliable than a percept based on external input..

<span class="mw-page-title-main">Colour centre</span> Brain region responsible for colour processing

The colour centre is a region in the brain primarily responsible for visual perception and cortical processing of colour signals received by the eye, which ultimately results in colour vision. The colour centre in humans is thought to be located in the ventral occipital lobe as part of the visual system, in addition to other areas responsible for recognizing and processing specific visual stimuli, such as faces, words, and objects. Many functional magnetic resonance imaging (fMRI) studies in both humans and macaque monkeys have shown colour stimuli to activate multiple areas in the brain, including the fusiform gyrus and the lingual gyrus. These areas, as well as others identified as having a role in colour vision processing, are collectively labelled visual area 4 (V4). The exact mechanisms, location, and function of V4 are still being investigated.

In neuroscience the bridge locus for a particular sensory percept is a hypothetical set of neurons whose activity is the basis of that sensory percept. The term was introduced by D.N. Teller and E.Y. Pugh Jr. in 1983, and has been sparingly used. Activity in the bridge locus neurons is postulated to be necessary and sufficient for sensory perception: if the bridge locus neurons are not active, then the sensory perception does not occur, regardless of the actual sensory input. Conversely if the bridge locus neurons are active, then sensory perception occurs, regardless of the actual sensory input. It is the highest neural level of a sensory perception. So, for example, retinal neurons are not considered a bridge locus for visual perception because stimulating visual cortex can give rise to visual percepts.

In cognitive neuroscience, visual modularity is an organizational concept concerning how vision works. The way in which the primate visual system operates is currently under intense scientific scrutiny. One dominant thesis is that different properties of the visual world require different computational solutions which are implemented in anatomically/functionally distinct regions that operate independently – that is, in a modular fashion.

Neuroarthistory is a term coined by Professor John Onians, an art historian at the University of East Anglia in 2005. Neuroarthistory is an approach that concerns the neurological study of artists, both living and dead.

<span class="mw-page-title-main">Neural correlates of consciousness</span> Neuronal events sufficient for a specific conscious percept

The neural correlates of consciousness (NCC) refer to the relationships between mental states and neural states and constitute the minimal set of neuronal events and mechanisms sufficient for a specific conscious percept. Neuroscientists use empirical approaches to discover neural correlates of subjective phenomena; that is, neural changes which necessarily and regularly correlate with a specific experience. The set should be minimal because, under the materialist assumption that the brain is sufficient to give rise to any given conscious experience, the question is which of its components are necessary to produce it.

<span class="mw-page-title-main">Mathematical beauty</span> Aesthetic value of mathematics

Mathematical beauty is the aesthetic pleasure derived from the abstractness, purity, simplicity, depth or orderliness of mathematics. Mathematicians may express this pleasure by describing mathematics as beautiful or describe mathematics as an art form, or, at a minimum, as a creative activity.

<span class="mw-page-title-main">Otto Detlev Creutzfeldt</span>

Otto Detlev Creutzfeldt was a German physiologist and neurologist. He was the son of Hans Gerhard Creutzfeldt and the younger brother of Werner Creutzfeldt, a professor of internal medicine.

<span class="mw-page-title-main">Functional specialization (brain)</span> Neuroscientific theory that different regions of the brain are specialized for different functions

In neuroscience, functional specialization is a theory which suggests that different areas in the brain are specialized for different functions.

Joseph Anthony Movshon is an American neuroscientist. He has made contributions to the understanding of the brain mechanisms that represent the form and motion of objects, and the way these mechanisms contribute to perceptual judgments and visually guided movement. He is a founding co-editor of the Annual Review of Vision Science.

Perceptual asynchrony refers to the phenomenon of two simultaneously presented attributes of the visual world being perceived by humans asynchronously instead of simultaneously.

References

  1. Profile of Semir Zeki
  2. Zeki, SM (1969) Representation of central visual fields in prestriate cortex of monkey. Brain Res. 14:271–291
  3. Zeki, SM (1971). Cortical projections from two prestriate areas in the monkey. Brain Res. 34:19–35.
  4. Zeki, SM (1978). Functional specialisation in the visual cortex of the rhesus monkey. Nature 274:423–428.
  5. Zeki, SM (1976). The functional organization of projections from striate to prestriate visual cortex in the rhesus monkey. Cold Spring Harb. Symp. Quant. Biol. 40, 591–600.
  6. Zeki, S. et al. (1991). A direct demonstration of functional specialization in human visual cortex. J. Neurosci. 11:641–649.
  7. Zeki, S. and Stutters, J. (2013). Functional specialization and generalization for grouping of stimuli based on colour and motion. Neuroimage 73: 156–166.
  8. Zeki, S. (1980). The representation of colours in the cerebral cortex. Nature 284, 412–418
  9. Zeki, S. (1984). The construction of colours by the cerebral cortex. Proc. Roy. Inst. Gt. Britain 56:231–257
  10. Moutoussis, K and Zeki, S (1997). A direct demonstration of perceptual asynchrony in vision. Proc. R. Soc. Lond. B. 265:393–399
  11. Zeki, S. (2003). The disunity of consciousness. Trends in Cogn. Neurosci. 7:214–218.
  12. Zeki, S and ffytch, DH (1998). The Riddoch syndrome: insights into the neurobiology of conscious vision. Brain 121:25–45
  13. 1 2 Bartels, A and Zeki, S (2004). The neural correlates of maternal and romantic love. NeuroImage 21:1155–66
  14. 1 2 Zeki, S. and Romaya, J (2008). Neural correlates of hate. PLOS ONE 3 (10) Article e3556
  15. 1 2 Kawabata, H and Zeki, S (2004). Neural correlates of beauty. J Neurophysiol. 91:1699-705 (2004)
  16. Ishizu, T and Zeki, S. (2011). Toward a brain-based theory of beauty. PLoS One 6 (7) e21852
  17. "APS Member History". search.amphilsoc.org. Retrieved 6 December 2021.
  18. "Brain can perceive beauty even in mathematical formulae". The Hindu. 19 February 2018. ISSN   0971-751X . Retrieved 23 March 2018.