Experimental Brain Research

, Volume 82, Issue 2, pp 247–253

Local axonal trajectories in mouse barrel cortex

  • K. L. Bernardo
  • J. S. McCasland
  • T. A. Woolsey


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.

Key words

Cortical connections Cortical columns Barrel cortex Somatosensory system Computer microscope Mice 


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  1. Adams JC (1977) Technical considerations on the use of HRP as a neuronal marker. Neuroscience 2:141–145Google Scholar
  2. Adams JC (1981) Heavy metal intensification of DAB-based HRP reaction product. J Histochem Cytochem 29:775Google Scholar
  3. Akers RA, Killackey HP (1978) Organization of corticocortical connections in the parietal cortex of the rat. J Comp Neurol 181:513–538Google Scholar
  4. Armstrong-James M, Fox K (1987) Spatiotemporal convergence and divergence in the rat S1 “barrel” cortex. J Comp Neurol 263:265–281Google Scholar
  5. Bernardo KL, McCasland JS, Woolsey TA, Strominger RN (1990) Local intraand interlaminar connections in mouse barrel cortex. J Comp Neurol 291:231–255Google Scholar
  6. Bernardo KL, Ma PK, Woolsey TA (1986) In vitro labeling of axonal projections in the mammalian central nervous system. J Neurosci Meth 16:89–101Google Scholar
  7. Bernardo KL, Woolsey TA (1987) Axonal trajectories between mouse somatosensory thalamus and cortex. J Comp Neurol 258:542–564Google Scholar
  8. Burkhalter A, Bernardo KL (1989) Organization of corticocortical connections in human visual cortex. Proc Natl Acad Sci USA 86:1071–1075Google Scholar
  9. Durham D, Woolsey TA (1978) Acute whisker removal reduces neuronal activity in barrels of mouse Sml cortex. J Comp Neurol 178:629–644Google Scholar
  10. Durham D, Woolsey TA (1985) Functional organization in cortical barrels of normal and vibrissae-damaged mice: a (3H) 2-deoxyglucose study. J Comp Neurol 235:97–110Google Scholar
  11. Harris RM, Woolsey TA (1983) Computer-assisted analyses of barrel neuron axons and their putative synaptic contacts. J Comp Neurol 220:63–79Google Scholar
  12. 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 68:73–87Google Scholar
  13. Kyriazi HT, Simons DJ (1989) Computer simulations of information processing in a barrel of rat somatosensory cortex. Soc Neurosci Abstr 15:313Google Scholar
  14. 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 15:16–20Google Scholar
  15. McCasland JS, Woolsey TA (1988a) A new high resolution 2-deoxyglucose method featuring double labeling and automated data collection. J Comp Neurol 278:543–554Google Scholar
  16. McCasland JS, Woolsey TA (1988b) High resolution 2-deoxyglucose mapping of functional cortical columns in mouse barrel cortex. J Comp Neurol 278:555–569Google Scholar
  17. McCasland JS, Woolsey TA (1988c) High resolution scanning and analysis from microscope slides. Soc Neurosci Abstr 14:549Google Scholar
  18. 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 7:4209–4223Google Scholar
  19. Picker S, Pieper CF, Goldring S (1981) Glial membrane potentials and their relationship to (K+)0 in man and guinea pig. J Neurosurg 55:347–363Google Scholar
  20. Ryugo R, Killackey HP (1975) Corticocortical connections of the barrel field of rat somatosensory cortex. Soc Neurosci Abstr 5:126Google Scholar
  21. Simons DJ (1978) Response properties of vibrissa units in rat SI somatosensory neocortex. J Neurophysiol 41:798–820Google Scholar
  22. Simons DJ, Carvell GE (1989) Thalamocortical response transformation in the rat vibrissa/barrel system. J Neurophysiol 61:311–330Google Scholar
  23. 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 1:207–245Google Scholar
  24. Simons DJ, Woolsey TA (1979) Functional organization in mouse barrel cortex. Brain Res 165:327–332Google Scholar
  25. Strominger RN, Woolsey TA (1987) Templates for locating the whisker area in fresh flattened mouse and rat cortex. J Neurosci Meth 22:113–118Google Scholar
  26. 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 158:437–454Google Scholar
  27. 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 73:411–435Google Scholar
  28. Woolsey TA, Van der Loos H (1970) The structural organization of layer IV in the somatosensory region (SI) of mouse cerebral cortex. Brain Res 17:205–242Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • K. L. Bernardo
    • 1
    • 2
  • J. S. McCasland
    • 1
    • 2
  • T. A. Woolsey
    • 1
    • 2
  1. 1.Department of Neurology and Neurological Surgery, James L. O'Leary Division of Experimental Neurology and Neurological SurgeryWashington University School of MedicineSt. LouisUSA
  2. 2.McDonnell Center for Studies of Higher Brain Function, Washington University School of MedicineSt. LouisUSA
  3. 3.Department of Neurological SurgeryWashington University School of MedicineSt. LouisUSA

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