Does History Repeat Itself? The case of cortical columns. Those who fail to learn the lessons of history are condemned to repeat it George Santayana

Transcription

1 Does History Repeat Itself? The case of cortical columns Those who fail to learn the lessons of history are condemned to repeat it George Santayana

2 Stripe of Gennari Gennari says that he first saw his line in 1776 and the illustration in his 1782 book shows it labelled hhhh and (in fig.2) ddd. From De peculiari structura (Parma, 1782)

3 Drawing of Golgi-stained short axon neurons (motor cortex): Cajal, 1911 Cajal s drawings emphasise the great variety of neurons in the cerebral cortex (in this case the human cerebral cortex)

4 Lorente de No s intracortical chains of neurons Lorente de No s illustration of his elementary unit of cortical activity. Fig.74 in Fulton: Physiology of the Nervous System. 2 nd edition, 1943

5 Phrenology Gall and Spurzheim s 1810 drawing of skull with areas marked for correspondence with different mental faculties.

6 Nineteenth century phrenology

7 Architectonics Korbinian Brodmann s map of architectonic areas on A the lateral surface and B the medial surface of the human brain. Brodmann, 1908

8 while it is more useful (and probably more correct anatomically) to retain the concept of a field as used by older workers..it should nevertheless be recognised that a field thus conceived displays consistent changes in structural detail which must be considered.architectonic characteristics which vary systematically should be designated gradients of a field Rose, 1949, Proceedings of Royal Society

9 Auditory cortex of cat A I Auditory area 1 A II Auditory area 2 Ep posterior ectosylvian area ss suprasylvian fringe From Rose and Woolsey, 1949

10 Somaesthetic cortex of Macaque (Post-central gyrus) Diagram ro show the three areas of the somaesthetic cortex. CS = central sulcus PCS = post-central sulcus Numbers without arrows show the cytoarchitectonic areas

11 Para-sagittal section of the post-central gyrus of Macaque Central sulcus to the right between areas 3 and 4

12 Mountcastle s micro-electrode penetrations Microelectrode tracks in areas 1,2, and 3 of Macaque somatosensory cortex. Horizontal dashes indicate single units CS = central sulcus Mountcastle, 1959

13 Along any given electrode penetration only one submodality is encountered. indicating vertical organisation of columns of cortical cells for topography and submodality Powell and Mountcastle, 1955, American Journal of Physiology

14 Ocular dominance columns The white patches represent radioactive accumulations in the striate cortex from the injected left eye Hubel and Wiesel, 1977

15 Orientation columns These are in the striate cortex of Macaque by the 2- deoxyglucose method From Hubel, Wiesel and Stryker, 1977

16 Cortical column - Szentagothai Inhibitory cells are shown in black on the left and excitatory cells in outline on the right. The two flat cylinders are the termination domains of specific afferents. From Szentagothai, 1979, p.408

17 Hubel and Wiesel s ice-tray model of the striate cortex Orientation hypercolumns consist of 18 discrete 50μm columns each 10 o different. Ocular dominance hypercolumns consist of a single R eye and a single L eye about 500μm wide. Two hypercolumns together constitute an elementary unit. Hubel, Wiesel, LeVay, 1976

18 Ice-tray model popularised From Hubel Eye, Brain and Vision, 1988, p.131

19 Kanizsa s triangle

20 Ontogenetic column The progeny of progenitor cells in the ventricular zone (VZ) migrate along radial glia to form vertical minicolumns in the cortical plate (CP) From Horton and Adams, 2005

21 should not be interpreted to mean that only this pattern of functional organisation exists, for cortical cells must certainly be grouped into various patterns subserving higher orders of cortical functioning, patterns of activity about which at present nothing is known Powell and Mountcastle, 1959, Johns Hopkins Bull., p.160

22 Spandrel Spandrels are a necessary but structurally unimportant outcome of building with arches. Gothic architects often filled these spaces with elaborate decoration

23 Spandrel in St Mark s Basilica, Venice (c.1050 AD)

24 Electronmicrograph of cortex On the left of the micrograph is a dendrite of a pyramidal cell and on the right is the intricate neuropil. The arrowheads show the position of synapses

25 History repeats itself because no one was listening the first time Anonymous