Table 1. Median values and ranges for ratios of mean unit activity durmg three behavioral
conditions to mean unit activity during sleep with slow waves for 52 electrodes.
N, number;
Md, median.
Location
N
Paradoxical sleep
rats (8).
A group of 12 animals was observed,
Md
Range
Md
Range
providing a total of 52 unit recordings.
11
3.52
0.95- 5.17
2.06
0.83- 4.81
2.84
0.89- 9.28
Electrodes were aimed at the following
Lateral preoptic
Anterior thalamus
9
7
1.79
1.49
.49- 3.15
.T3- 3.46
1.31
1.48
.92- 1.76
94- 3.40
1.57
2.45
1.11- 2.44
0.75- 3.30
pothalamus, reticular ormation, ventra
tegmentum. anterior thalamus, dorsal
0.87- 1.26
0.99
34 1.26
9 2.80
6 194
Parietal cortex
4
Dorsal hippocampus
1.42
6 0.62
Total
52.
1.93
Range
BarP
food
ari Tess,fooe’
Lateral hypothalamus
Reticular formation
Ventral tegmentum
Md
k
Quiet awake
waves to paradoxical sleep in our animals was similar to that reported in
.97-20.50
63 2.75
1.51
1.37
.88- 2.09
1.23
34 0.87
1.03
.34-20.50
1.37
.79- 4.25
.55— 3.41
LOI- 1.26
.55- 4.81
1.53
1.13
.95-16.25
.32- 6.20
1.21
.98— 1.53
1.58
.32-16.25
areas: lateral preoptic area, lateral hythal
‘cular f
ti
tral
.
n
;
hippocampus, and parietal cortex.
The number of 2-second samples
varied from 350 to 2000. Because rates
of response per 2-second period were
greatly different from unit to unit, absolute response rates were not used in
comparisons but were converted to
Anterior Thalamus''}
Hypothalamus: 2
Cortex 3
‘|
ratios of a baseline average response
rate obtained during sleep with slow
waves. The analyses of results were.
Reticular Formation 4
I
Reticular Formation 5
!
Anterior Thalamus, 6
based on these ratios. The medians and
ranges of the ratios were tabulated for
each of the stereotaxically defined brain
Ventral Tegmentum 7
imacr:
Clock - 10 min.) 8
Gate %
'
Water Behavior 10
Posterlor Hypothalamus 11
'
|
AVA
|
|
1
SLEEP WITH SLOW WAVES] paRapoxicat’ steep
Movement 12
|
areas (Table 1).
:
In total neuronal activity, paradoxical
sleep surpassed the quiet awakestate
|
GuLET AWAKE
|
s
| ;
|
Food Bahavior 3B
Complete Trial - or - Reinforcement 14
Fig. 1.
I
Sample records of one complete sample interval for the four conditions
which were observed. Analog channels are EEG tracings (3, 7, 11) and movement (12);
digital channels indicate the readout of unit counters (1, 2, 4, 5, 6) and the state
of the behavior sampling system (8, 9, 10, 13, 14).
(P<.05), and the latter surpassed quiet
sleep (P<.05}. The motivated awake
condition was highly variable, falling
above the quiet awake state and below
paradoxical sleep in mean value but
statistically not differing from either.
The pattern of changes in rate of
firing from normal to paradoxical sleep
was highly differentiated by brain locus.
The hypothalamus and reticular areas
showed the highest increments: both
changes
were
Statistically
significant.
The median response rate in hypothala-
Hypothalamus
Hippocampus
ad
ee
ee
mus was more than 350 percent of the
normal sleep rate, and that in reticular
formation was more than 250 percent.
The thalamic, preoptic, tegmental, and
cortical groups had median increments
ranging from 42 to 94 percent; each of
the latter three groups was significant-
mee
a
—
ly below the hypothalamus in the size
of the increments. Histological material
showed that the highly augmented cases
of hypothalamus occurred in the lateral
part, in or near the medial forebrain
bundle. The involvement of the medial
forebrain bundle was also indicated by
the characteristic recordings which
usually had a small ratio of signal to
Fig. 2. Samples of neuronal activity in lateral hypothalamus and dorsal hippocampus
the background, making units difficult
to distinguish from one another (Fig. 2,
left-hand column). The units of hippocampus showed a consistent decrease
in rate of firing during paradoxical
sleep. In fact, a decrease was observed
in the rate of every hippocampal unit.
The hippocampus as an area was significantly different from all the others,
the two recording points.
decrement (Fig. 3). The hippocampal
during normal sleep and paradoxical sleep. Histological sections show the location of
1336
being the only case to show a consistent
SCIENCE, VOL. 158