Experimental Brain Research

, Volume 112, Issue 3, pp 420–430 | Cite as

Reorganization in the auditory cortex of the rat induced by intracortical microstimulation: a multiple single-unit study

  • Pedro E. Maldonado
  • George L. Gerstein
Research Article


Many manipulations are able to change or perturb various aspects of single neuron properties and interneuronal relationships. Changes of cerebral cortex organization have been observed in different cortical areas and at different time scales in relation to peripheral stimulation, peripheral damage, associative learning, and electrical stimulation. Here we describe studies on separable multineuron recordings in the rat's auditory cortex under two different anesthetics. Acoustic stimuli were used as a normal, physiological input, and weak electrical intracortical microstimulation (ICMS) as a perturbation that forces a rapid cortical reorganization. ICMS induced fast changes in the cortical map and in the receptive field properties of cells at the electrically stimulated and adjacent electrodes. In effect there was an enlargement of the cortical domain tuned to the acoustic frequency that had been represented at the stimulating electrode. ICMS also incremented afterdischarge responses; these consisted of an initial response to the auditory stimulus followed by less intense repetitive activity that was stimulus-time locked and had a period of 8–12 Hz, similar to that of the spontaneous synchronous activity. Cortical activity under ketamine differed from that under pentobarbital sodium, although in both situations we observed that cortical neurons were highly synchronous.

Key words

Plasticity Auditory cortex Neuronal assemblies Microstimulation Cortical maps Rat 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Abeles M, Goldstein MH (1977) Multispike train analysis. Proc IEEE 65:762–773Google Scholar
  2. Albers GW, Goldberg MP, Choi DW (1989) N-methyl-d-aspartate antagonists: ready for clinical trial in brain ischemia? Ann Neurol 25:398–403Google Scholar
  3. Altman IA, Bekhterev NN, Kotelenko LM, Kudriavtseva IN (1980) Afterdischarges of cat medial geniculate body neurons. Fiziol Zh SSSR 66(1):80–88Google Scholar
  4. Bakin JS, Weinberger NM (1990) Classical conditioning induces CS-specific receptive field plasticity in the auditory cortex of the guinea pig. Brain Res. 536:271–286Google Scholar
  5. Bedenbaugh P (1993) ICMS-induced plasticity in the rat somatosensory cortex and theoretical investigations of information flow through neurons. Ph.D. Dissertation Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USAGoogle Scholar
  6. Calford MB, Tweedale R (1988) Immediate and chronic changes in responses of somatosensory cortex in adult flying-fox after digit amputation. Nature 332(6163):446–448Google Scholar
  7. Carla V, Moroni F (1992) General anesthetics inhibit the responses induced by glutamate receptor agonist in the mouse cortex. Neurosci Lett 146:21–24Google Scholar
  8. Chino YM, Smith EL III, Kaas JH, Sasaki Y, Cheng h (1995) Receptive field properties of deafferentated visual cortical neurons after topographic map reorganization in adults cats. J Neuroscience 15:2417–2433Google Scholar
  9. Clark SA, Allard T, Jenkins WM, Merzenich MM (1988) Receptive fields in the body-surface map on adult cortex defined by temporally correlated inputs. Nature 332:444–445Google Scholar
  10. Crawford JM (1970) Anesthetics agents and the chemical sensitivity of cortical neurons. Neuropharmacology 9:31–46Google Scholar
  11. Eggermont J (1992) Stimulus induced and spontaneous rhythmic firing of single units in cat primary visual cortex. Hear Res 61:1–11Google Scholar
  12. Hammer RP, Herkenham M (1983) Altered metabolic activity in the cerebral cortex of rats exposed to ketamine. J Comp Neurol 220:396–404Google Scholar
  13. Harrison RV, Nagasawa A, Smith DW, Stanton S, Mount RJ (1991) Reorganization of auditory cortex after neonatal high frequency cochlear hearing loss. Hearing Res 54(1):11–19Google Scholar
  14. Hebb DO (1949) The organization of behavior. A neuropsychological theory. Wiley, New YorkGoogle Scholar
  15. Hubel D, Wiesel T, LeVay S (1977) Plasticity of ocular dominance columns in monkey striate cortex. Philos Trans R Soc Lond Biol 278:377–409Google Scholar
  16. Jenkins WM, Merzenich MM (1987) Reorganization of neocortical representations after brain injury: a neurophysiological model of the bases of recovery from stroke. Prog Brain Res 71:249–266Google Scholar
  17. Jenkins WM, Merzenich MM, Recanzone G (1990) Neocortical representational dynamics in adult primates: implications for neurophysiology. Neuropsychologia 28(6):573–584Google Scholar
  18. Kaas JH, Krubitzer LA, Chino YM, Langston AL, Polley E, Blair N (1990) Reorganization of retinocortical maps in adult mammals after lesions of the retina. Science 248:229–231Google Scholar
  19. Kelly JB (1990) Rat auditory cortex. In: Kolb B, Tees R (eds) The cerebral cortex of the rat. MIT Press, Cambridge, MA, pp 381–405Google Scholar
  20. Maldonado PE, Gerstein GL (1996) Neuronal assembly dynamics in the rat auditory cortex during reorganization induced by intracortical microstimulation. Exp Brain Res 112:431–441Google Scholar
  21. Merzenich MM, Kaas JH, Waal J, Nelson JM, Sur M, Felleman M (1983) Topographic reorganization of somatosensory cortical areas 3b and 1 in adult monkeys following restricted deafferentation. Neuroscience 8(1):33–55CrossRefPubMedGoogle Scholar
  22. Merzenich MM, Nelson RJ, Stryker MS, Cynader MS, Schopmann MS, Zook JM (1984) Somatosensory cortical map changes following digit amputation in adult monkeys. J Comp Neurol 224:591–605Google Scholar
  23. Patel IM, Chapin JK (1990) Ketamine effects on somatosensory cortical single neurons and on behavior in rats. Anesth Analg 70(6):635–644Google Scholar
  24. Pettet MW, Gilbert CD (1992) Dynamic changes in receptive-field size in the primary visual cortex. Proc Natl Acad Sci USA 89:8366–8370Google Scholar
  25. Rajan R, Irvine DR, Wise LZ, Heil P (1993) Effect of unilateral partial cochlear lesions in adult cats on the representation of lesioned and unlesioned cochleas in primary auditory cortex. J Comp Neurol 338(1):17–49Google Scholar
  26. Rauschecker JP, Hahn S (1987) Ketamine-xylazine anesthesia blocks consolidation of ocular dominance changes in kitten visual cortex. Nature 326:183–185Google Scholar
  27. Recanzone GH, Merzenich MM, Dinse HR (1992) Expansion of the cortical representation of a specific skin field in primary somatosensory cortex by intracortical microstimulation. Cereb Cortex 2:181–196Google Scholar
  28. Ribaupierre F, Goldstein MH, Yeni-Komshian G (1972) Intracellular study of the cat's primary auditory cortex. Brain Res 48:185–204Google Scholar
  29. Richards CD (1978) The action of anesthetics on synaptic transmission. Gen Pharmacol 9:287–293Google Scholar
  30. Robertson D, Irvine D (1989) Plasticity of frequency organization in auditory cortex of guinea pig with partial unilateral deafness. J Comp Neurol 282:456–471Google Scholar
  31. Sally SL, Kelly JB (1988) Organization of the auditory cortex in the albino rat: sound frequency. J Neurophysiol 59:1627–1638Google Scholar
  32. Stryker MP, Jenkins WM, Merzenich MM (1987) Anesthetic state does not affect the map of the hand representation within area 3b somatosensory cortex in owl monkey. J Comp Neurol 258:297–303Google Scholar
  33. Wang Z, Ryan A, Woolf NK (1897) Pentobarbital and ketamine alter the pattern of 2-deoxyglucose uptake in the central auditory system of the gerbil. Hear Res 27:145–155Google Scholar

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • Pedro E. Maldonado
    • 1
  • George L. Gerstein
    • 1
  1. 1.Department of NeuroscienceSchool of Medicine, University of PennsylvaniaPhiladelphiaUSA

Personalised recommendations