Professor Sir Gabriel Horn MD ScD FRS - Neural Mechanisms of Learning and Memory
Senior Research Scientist, Sub-Department of Animal Behaviour, Department of Zoology.
Chair, Cambridge University Government Policy Programme

+44 (0)1223 741813
gh105@cam.ac.uk

Research Interests
Neural mechanisms of attention, learning and memory. The current, major focus of research is to analyse neural mechanisms of memory through a study of imprinting in the domestic chick. The young of many species, when exposed to a conspicuous object (an imprinting stimulus), rapidly learn the object's characteristics and subsequently narrow their social preferences to it. This learning process is called imprinting, the study of which has yielded important insights into the nature of learning and memory. A part of the chick forebrain (the IMHV [IMM]) has been identified that is critical for imprinting. The available evidence indicates that the IMHV (IMM) is a site of memory for features of the imprinting stimulus. Currently, learning-specific changes in the IMHV are being studied using behavioural, biochemical, electrophysiological and immunocytochemical techniques.

Selected Publications

1. Horn, G. (1952) The neurological basis of thought. Mermaid 18: 17-25 (special collections@bham.ac.uk_20100401_091829.pdf).
2. Horn, G. (1960) Electrical activity of the cerebral cortex of the unaneasthetized cat during attentive behaviour. Brain 83: 57-67.
3. Horn,G. (1962) Some neural correlates of perception. In: Viewpoints in Biology 1, pp242-285. Eds. J.D. Carthy and C.L. Duddington. Butterworths, London.
4. Horn, G. (1965) Physiological and psychological aspects of selective perception. In: Advances in the Study of Animal Behavior 1, pp155-215. Eds. D.S. Lehrman, R.A. Hinde and E. Shaw. Academic Press, New York.
5. Griffith, J.S. & Horn, G. (1963) Functional coupling between cells in the visual cortex of the unrestrained cat. Nature 199: 893-895.
   
6. Horn, G. & Hill, R.M. (1964) Habituation of the response to sensory stimuli of neurones in the brain stem of rabbits. Nature 202: 296-298.
   
7. Horn, G. & Hill, R.M. (1966) Responsiveness to sensory stimulation of units in the superior colliculus and subjacent tectotegmental regions of the rabbit. Exp. Neurol. 14: 199-223.
8. Horn, G. (1967) Neuronal mechanisms of habituation. Nature 215: 707-711.
9. Horn, G. and Fraser Rowell, C.H. (1968) Medium and long term changes in the behaviour of visual neurones in the tritocerebrum of locusts. J. Exp. Biol. 49: 143-169.
10. Fraser Rowell, C.H. & Horn, G. (1968) Dishabituation and arousal in the response of single nerve cells in an insect brain. J. Exp. Biol. 49: 171-184.
11. Horn, G. & Wright, M.J. (1970) Characteristics of transmission failure in the squid stellate ganglion: a study of a simple habituating system. J. Exp. Biol. 52: 217-231.
12. Horn, G. & Hill, R.M. (1969) Modifications of receptive fields in cells of the visual cortex occurring spontaneously and associated with bodily tilt. Nature 221: 186-188.
13. Bateson, P.P.G., Horn, G. & Rose, S.P.R. (1969) Effects of an imprinting procedure on regional incorporation of tritiated lysine into protein of chick brain. Nature 223: 534-535.
14. Horn, G., Horn, A.L.D., Bateson, P.P.G. & Rose S.P.R. (1971) Effects of imprinting on uracil incorporation into brain RNA in the "split-brain" chick. Nature 229: 131-132.
15. Horn, G., Rose, S.P.R. & Bateson, P.P.G (1973) Experience and plasticity in the central nervous system. Science 181: 506-514.
16. Horn, G., McCabe B.J. & Bateson, P.P.G. (1979) An autoradiographic study of the chick brain after imprinting. Brain Res. 168: 361-373.
17. Horn, G. & McCabe B.J. (1984) Predisposition and preferences. Effects on imprinting of lesions to the chick brain. Anim. Behav. 32: 288-292.
18. Horn, G. (1985) Memory, imprinting and the brain. Clarendon Press, Oxford.
19. Johnson, M.H., Bolhuis, J.J. & Horn, G. (1985) Interaction between acquired preferences and developing predispositions during imprinting. Anim. Behav. 33: 10001006.
20. Johnson, M.H., Bolhuis, J.J. & Horn, G. (1992) Predispositions and learning: behavioural dissociations in the chick. Anim. Behav. 44: 943-948.
21. Johnson, M.H., Davies, D.C. & Horn, G. (1989) A sensitive period for the development of a predisposition in dark-reared chicks. Anim. Behav. 37: 1044-1046.
22. Johnson, J.H. & Horn, G. (1987) The role of a restricted region of the chick forebrain in the recognition of individual conspecifics. Behav. Brain Res. 23: 269-275.
23. Horn, G. (1988) What can the bird brain tell us about thought without language? In: Thought Without Language, pp279-304. Ed. L. Weiskrantz. Clarendon Press, Oxford.
24. Horn, G. & McCabe B.J. (1985) Changes in the structure of synapses associated with learning. J. Neurosci. 5: 3161-3168.
25. McCabe, B.J. & Horn, G. (1988) Learning and memory: regional changes in N-methyl-D-aspartate receptors in the chick brain after imprinting. Proc. Natl. Acad. Sci. USA 85: 2849-2853.
26. McCabe, B.J. & Horn, G. (1994) Learning-related changes in Fos-like immunoreactivity in the chick forebrain after imprinitng. Proc. Natl. Acad. Sci. USA 91: 11417-11421.
27. Solomonia, R.O., McCabe, B.J. and Horn, G. (1998). Neural cell adhesion molecules, learning and memory in the domestic chick. Behav. Neurosci. 112: 646-655.
28. Nicol. A.U., Born, M.W. & Horn, G. (1998) Neural encoding of subject-object-distance in a visual recognition system. Eur. J. Neurosci. 10: 34-44.
29. Horn, G, Nicol, A.U. and Brown, M.W. (2001). Tracking memory's trace. Proc. Natl. Acad. Sci. USA 98: 5282-5287.
30. Horn, G. (2004).Pathways of the past; the imprint of memory. Nature Rev. Neurosci. 5: 108-120.
31. Jackson, C., McCabe, B.J., Nicol, A.U., Grout, A.S., Brown, M.W. and Horn, G. (2008). Dynamics of a memory trace: effects of sleep on consolidation. Current Biology 18: 393-40
32. Nicol, A. & Horn, G. (2009) Competing changes in evoked activity in a polysensory brain region during imprinting in domestic chicks. Proc. Physiol. Soc. 17: C17.
33. Horn, G. Barnes, J., Brownsword, R., Deakin, J.F.W., Gilmore, I., Hickman, M., Iversen, L., Robbins, T., Taylor, E. & Wolff, J. (2008) Brain Sciences, addiction and drugs, pp214. Academy of Medical Sciences. London.
34. Solomonia, R.O. Kunelauri, N., Mikautadze, E., Apkhazav, D., McCabe, B.J. and Horn, G. (2011) Mitochondrial proteins, learning and memory: biochemical specialization of a memory system. Neuroscience 194: 112-123.
    
    

Collaborations
Prof. Johan Bolhuis (University of Utrecht)
Prof. Malcolm Brown (University of Bristol)
Prof. Mark Darlison (Nottingham Trent University)
Dr. Brian McCabe University of Cambridge
Dr. Tony Jackson (University of Cambridge)
Prof. Revaz Solomonia (Georgian Academy of Sciences, Tbilisi, Georgia)
Dr. Keith Kendrick (Babraham Institute)