Summary
Quantitative studies were made of the distribution of labeled intracortical axons after focal injections of horseradish peroxidase (HRP) into mouse barrel cortex, in vitro. The pattern of labeled fibers was compared to that of labeled cell bodies with respect to the barrel map in layer IV. We analyzed 4 cortices with injections in supragranular layers and centered above a single barrel row. Computer microscope/image analysis routines were used to collect the data and to perform various statistical analyses on them. The distributions of both labeled cells and fibers in layer IV and in the infragranular layers show strong connectional tendencies between barrels representing a whisker row. This result is consistent with single unit recordings from barrel cortex. Fiber labeling is more widespread than cell body labeling in layer IV. In addition, the fibers show a directional bias into the adjacent anterior barrel row (e.g., C → D, D → E). In earlier 2-deoxyglucose (2-DG) studies of behaving animals, the anterior barrel rows were more heavily labeled; inter-row projections are therefore predominantly from less active to more active barrel columns. These data show that labeled fiber distribution differs from the distribution pattern of labeled cell bodies. The findings indicate that integration of information between whisker rows within barrel cortex involves asymmetrical connections within layer IV and infragranular layers.
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References
Adams JC (1977) Technical considerations on the use of HRP as a neuronal marker. Neuroscience 2:141–145
Adams JC (1981) Heavy metal intensification of DAB-based HRP reaction product. J Histochem Cytochem 29:775
Akers RA, Killackey HP (1978) Organization of corticocortical connections in the parietal cortex of the rat. J Comp Neurol 181:513–538
Armstrong-James M, Fox K (1987) Spatiotemporal convergence and divergence in the rat S1 “barrel” cortex. J Comp Neurol 263:265–281
Bernardo KL, McCasland JS, Woolsey TA, Strominger RN (1990) Local intraand interlaminar connections in mouse barrel cortex. J Comp Neurol 291:231–255
Bernardo KL, Ma PK, Woolsey TA (1986) In vitro labeling of axonal projections in the mammalian central nervous system. J Neurosci Meth 16:89–101
Bernardo KL, Woolsey TA (1987) Axonal trajectories between mouse somatosensory thalamus and cortex. J Comp Neurol 258:542–564
Burkhalter A, Bernardo KL (1989) Organization of corticocortical connections in human visual cortex. Proc Natl Acad Sci USA 86:1071–1075
Durham D, Woolsey TA (1978) Acute whisker removal reduces neuronal activity in barrels of mouse Sml cortex. J Comp Neurol 178:629–644
Durham D, Woolsey TA (1985) Functional organization in cortical barrels of normal and vibrissae-damaged mice: a (3H) 2-deoxyglucose study. J Comp Neurol 235:97–110
Harris RM, Woolsey TA (1983) Computer-assisted analyses of barrel neuron axons and their putative synaptic contacts. J Comp Neurol 220:63–79
Hoogland PV, Welker E, Van der Loos H (1987) Organization of the projections from barrel cortex to thalamus in mice studied with Phaseolus vulgarisleucoagglutinin and HRP. Exp Brain Res 68:73–87
Kyriazi HT, Simons DJ (1989) Computer simulations of information processing in a barrel of rat somatosensory cortex. Soc Neurosci Abstr 15:313
Lapenko TK, Podladchikova ON (1983) Intracortical connections between neuron groups in the somatosensory cortex studied by the retrograde horseradish peroxidase transport method in rats. Neurophysiology 15:16–20
McCasland JS, Woolsey TA (1988a) A new high resolution 2-deoxyglucose method featuring double labeling and automated data collection. J Comp Neurol 278:543–554
McCasland JS, Woolsey TA (1988b) High resolution 2-deoxyglucose mapping of functional cortical columns in mouse barrel cortex. J Comp Neurol 278:555–569
McCasland JS, Woolsey TA (1988c) High resolution scanning and analysis from microscope slides. Soc Neurosci Abstr 14:549
Pearson JC, Finkel LH, Edelman GM (1987) Plasticity in the organization of adult cerebral cortical maps: a computer simulation based on neuronal group selection. J Neurosci 7:4209–4223
Picker S, Pieper CF, Goldring S (1981) Glial membrane potentials and their relationship to (K+)0 in man and guinea pig. J Neurosurg 55:347–363
Ryugo R, Killackey HP (1975) Corticocortical connections of the barrel field of rat somatosensory cortex. Soc Neurosci Abstr 5:126
Simons DJ (1978) Response properties of vibrissa units in rat SI somatosensory neocortex. J Neurophysiol 41:798–820
Simons DJ, Carvell GE (1989) Thalamocortical response transformation in the rat vibrissa/barrel system. J Neurophysiol 61:311–330
Simons DJ, Durham D, Woolsey TA (1984) Functional organization of mouse and rat SmI barrel cortex following vibrissal damage on different postnatal days. Somatosens Res 1:207–245
Simons DJ, Woolsey TA (1979) Functional organization in mouse barrel cortex. Brain Res 165:327–332
Strominger RN, Woolsey TA (1987) Templates for locating the whisker area in fresh flattened mouse and rat cortex. J Neurosci Meth 22:113–118
Welker C, Woolsey TA (1974) Structure of layer IV in the somatosensory neocortex of the rat: description and comparison with the mouse. J Comp Neurol 158:437–454
Welker E, Hoogland PV, Van der Loos H (1988) Organization of feedback and feedforward projections of the barrel cortex: a PHA-L study in the mouse. Exp Brain Res 73:411–435
Woolsey TA, Van der Loos H (1970) The structural organization of layer IV in the somatosensory region (SI) of mouse cerebral cortex. Brain Res 17:205–242
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Bernardo, K.L., McCasland, J.S. & Woolsey, T.A. Local axonal trajectories in mouse barrel cortex. Exp Brain Res 82, 247–253 (1990). https://doi.org/10.1007/BF00231244
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DOI: https://doi.org/10.1007/BF00231244