Download Does History Repeat Itself? The case of cortical columns

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
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)
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)
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. 2nd
edition, 1943
Phrenology
Gall and
Spurzheim’s 1810
drawing of skull
with areas
marked for
correspondence
with different
mental faculties.
Nineteenth century phrenology
Architectonics
Korbinian
Brodmann’s map of
architectonic areas
on A the lateral
surface and B the
medial surface of
the human brain.
Brodmann, 1908
‘…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
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
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
Para-sagittal section of the post-central
gyrus of Macaque
Central sulcus
to the right
between areas
3 and 4
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
‘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
Ocular dominance columns
The white
patches represent
radioactive
accumulations in
the striate cortex
from the injected
left eye
Hubel and Wiesel,
1977
Orientation columns
These are in the
striate cortex of
Macaque by the 2deoxyglucose
method
From Hubel, Wiesel
and Stryker, 1977
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
Hubel and Wiesel’s ‘ice-tray’
model of the striate cortex
Orientation
‘hypercolumns’ consist of
18 discrete 50μm columns
each 10o 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
Ice-tray model popularised
• From Hubel
Eye, Brain
and Vision,
1988, p.131
Kanizsa’s triangle
‘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
‘…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
Spandrel
‘Spandrels’ are a
necessary but
structurally
unimportant outcome
of building with
arches. Gothic
architects often filled
these spaces with
elaborate decoration
Spandrel in St Mark’s Basilica, Venice
(c.1050 AD)
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
‘History repeats itself because no one was
listening the first time’
Anonymous