| 1. |
- Jansson, T, et al.
(author)
-
Automated correction of linear deformation due to sectioning in serial micrographs.
- 1995
-
In: Journal of microscopy. - 0022-2720. ; 177:Pt 2, s. 119-27
-
Journal article (peer-reviewed)abstract
- This paper describes an objective and automatic method for detection and correction of sectioning deformations in digitized micrographs, as well as an evaluation of the method applied to light and electron microscopic images of semi-thin and ultra-thin serial sections from brain cortex. The detection is based on matching of image subregions and the deformation model is bi-linear, i.e. two first-order polynomials are used for modelling compression/expansion in perpendicular directions. The procedure is applicable to prealigned serial two-dimensional sections and is primarily aimed at three-dimensional reconstruction of tissue samples consisting of a large number of cells with random distribution and morphology.
|
|
| 2. |
- Skoglund, Thomas, 1969, et al.
(author)
-
A method for 3D reconstruction of neuronal processes using semithin serial sections displayed as a cinematographic sequence.
- 1995
-
In: Journal of neuroscience methods. - 0165-0270. ; 61:1-2, s. 105-11
-
Journal article (peer-reviewed)abstract
- In order to study the organization and distribution of dendrites and axons in the cerebral cortex, we have developed a computer-assisted method for 3D reconstruction of neuronal processes based on serial light microscopic images displayed as a continuous sequence. A series of tangential sections (0.65 micron thick) through rat parietal cortex was aligned, digitized into the computer and then used to build a sequence (stack) of images which was stored to a digital real-time video disk. Apical dendrites located in dendritic bundles in laminae III and IV were traced through the sequence. Two tracing modes were tested: (1) cinematographic mode, in which the image stack was displayed continuously and automatically by the computer at various preset speeds (max. speed: 25 images/s) and (2) stepping mode, in which the interval between each image was varied manually according to the choice of the operator. Coordinates were stored in a database and used to build a 3D reconstruction where apical dendrites were displayed as wires or tubes. Tracing in cinematographic mode was about 3 times faster than tracing in stepping mode. We believe that the former mode exploits the built in 'filtering' capacity of the visual system to perform temporal averaging.
|
|
| 3. |
- Skoglund, Thomas, 1969, et al.
(author)
-
Aspects of the quantitative analysis of neurons in the cerebral cortex.
- 1996
-
In: Journal of neuroscience methods. - 0165-0270. ; 70:2, s. 201-10
-
Journal article (peer-reviewed)abstract
- We address three problems concerning the quantitative analysis of nerve cell distribution in the cerebral cortex: (i) preparatory tissue deformation (shrinkage); (ii) difficulties in differentiating between small neurons and astroglia; and (iii) the bias introduced by the counting method. We found that staining with Richardson's solution led to no shrinkage in Vibratome-cut sections of aldehyde-fixed rat brains, but did result in staining of the neurons and left the glial cells unstained. This was in striking contrast to Nissl staining which introduced a linear shrinkage of 20-30% and stained all kinds of cortical cells indiscriminately. A computer-based unbiased counting method was implemented by taking advantage of the stereological procedure referred to as the 'optical disector' (Gundersen, H.J.G. (1986) Stereology of arbitrary particles, J. Microsc., 143: 3-45).
|
|
| 4. |
- Skoglund, Thomas, 1969, et al.
(author)
-
Heterogeneity in the columnar number of neurons in different neocortical areas in the rat.
- 1996
-
In: Neuroscience letters. - 0304-3940. ; 208:2, s. 97-100
-
Journal article (peer-reviewed)abstract
- We have investigated the number of neurons in three neocortical areas of the rat brain. Our results challenge the uniformity concept proposed by Rockel et al. [Brain, 103 (1980) 221-244]. Area Fr1, HL and Oc2 (primary motor, primary somatosensory and secondary visual cortex) from Sprague-Dawley rats were examined. The brains were glutaraldehyde fixed, sectioned in 50 mu m thick sagittal slices and stained in Richardson's solution. The counting was carried out using a computerized system based on the optical disector. The cortical thickness was measured to be 1.9 mm, 1.9 mm, and 1.4 mm in area Fr1, HL, and Oc2, respectively. The number of neurons under 1 mm2 cortical surface was calculated to be 91 100 in Fr1, 133 500 in HL and 106 100 in Oc2. The number of neurons in a volume of tissue 30 x 25 mu m through the depth of the cortex was calculated to be 68 in Fr1, 100 in HL and 80 in Oc2. The density of neurons was calculated to be 48 500 neurons/mm3 in Fr1, 69 400 neurons/mm3 in HL and 76,900 neurons/mm3 in Oc2. There were significant (P < 0.01) differences between all areas regarding both the number of neurons under a certain area of surface as well as the neuron density. The results indicate that there is no basic uniformity in the number of neurons under a certain area of cortical surface.
|
|
| 5. |
- Skoglund, Thomas, 1969, et al.
(author)
-
The existence of a layer IV in the rat motor cortex.
- 1997
-
In: Cerebral cortex (New York, N.Y. : 1991). - 1047-3211. ; 7:2, s. 178-80
-
Journal article (peer-reviewed)abstract
- We have reconstructed the laminar pattern of rat primary motor cortex (Fr1) using a computerized analysis system based on the so-called 'optical dissector'. Data were visualized on a graphics terminal. In contrast to current views, which state that there is no prominent layer IV in the motor cortex of the rat, our method of analysis revealed a genuine layer IV consisting of densely packed small neurons.
|
|
