By Gary W. Harding
This site is dedicated to the memory and legacy of our mentor, colleague, and friend Arnold L. Towe (1927-2002). Arnie's legacy is composed of three elements: First, the data that were collected (much of which is posted here); Second, the published analyses of these data (noted below in References); and Third, the training of many graduate students, post-doctoral fellows and colleagues who went on to their own successful careers (their names are listed below in connection with the individual data sets).
Arnie and his students, post-docs, and colleagues collected a large quantity of data on single-neuron behavior and evoked extracellular field potentials in the somatosensory-motor system of the CNS. These experiments were conducted in the Department of Physiology and Biophysics, University of Washington School of Medicine over a period of 30 years (1953-1983). Seventy five % of the single-neuron data characterize, in detail, the behavior of single neurons under a condition where the sensory integration channels were not only wide open, but the sensitivity of these channels was enhanced so that sensory interactions could be explicitly seen. About five % were collected under a condition where all sensory integration channels were closed. The remaining 20 % were collected in awake animals where the state of alertness was manipulated to shift the level of sensory integration.
The single-neuron data have been (and more will be) posted here as a resource for others who are interested in modeling the dynamic behavior of neuronal circuits. There will (eventually) be data from 17,500 neurons in the sensorimotor cortex of the cat, 1,600 from the VPL nucleus of the thalamus, and 3,200 from the cuneate nucleus. Another 2,000 neurons sampled in the cuneate nucleus of the monkey are also posted. A link to and a brief description of how some of these data were used to model neuronal circuit behavior can be found below under '(Cat) Cerebral Cortex'.
There exist small somatosensory-motor single-neuron data sets from other species (e.g., Squirrel Monkey, Slow Loris, Raccoon, Ferret, Opossum, Wood Chuck, Wood Rat, Laboratory Rat, Lizard) and other CNS systems (e.g., cat cerebellum, spinal cord to the cat's tail) which will not likely find a home here.
Much of these data have been published over the years as individual studies, but a substantial amount has not appeared in peer-reviewed journals (see References below and those with the individual data sets). If you choose to use these data, it is strongly recommend that copies of these references be acquired to provide guidance for the proper handling and pitfalls which might lead to misinterpretation. If the data you are interested in is not yet posted, please E-mail hardingg@ent.wustl.edu. Interest will dictate which data set gets posted next. Also, it is intended that a list of users will be kept so that notice of corrections, revisions and additions can be sent. If you are not on the list, check the version number and date below for updates.
In experiments on sensory integration such as those recounted here, the state of the system is critically important. To quote Arnie: "The nature of the sample and the conclusions that can be drawn from it depend strongly on the method by which the neurons were found and how broadly they were tested; nothing can be said about the sensitivity of a neuron to any untested input."
System state was involved in the methods by which these neurons were found. Suppose that there were tools which could be used to manipulate system state in anesthetized animals. A useful tool would be one that shuts down sensory integration, leaving just the on-focus somatotopic mapping of the periphery upon the elements of the system. Another helpful tool would be one that opens up the sensory integration channels and enhances their sensitivity, so that usually subthreshold interactions can be seen. Tools with such properties were used in these studies, the first being a barbiturate anesthetic (Pentobarbital) and the second being the anesthetic alpha-Chloralose. Further discussion of these state setting drugs
The general paradigm for the acute experiments was to: 1) anesthetize the animal and expose the tissue to be examined; 2) deliver an electrical hunting-stimulus (a brief pulse at low current, most often to the central foot pad); 3) isolate responding single neurons extracellularly with a microelectrode; 4) manipulate the location, frequency and intensity of electrical stimulation and record the responses; and 5) determine the sensory modality and map the peripheral receptive field using natural stimulation.
In awake animals, the paradigm was to: 1) Anesthetize the animal and surgically install a recording chamber on the skull; 2) in repeated sessions with the animal awake but dozing, isolate neurons extracellularly with a microelectrode using natural stimulation (e.g., tapping, hair bending, squeezing, bending joints); 3) determine the sensory modality and map the peripheral receptive field; 4) shift the animals state of alertness and remap the peripheral receptive field; 5) allow the animal to return to the dozing state and map the peripheral receptive field again.
The details for the methods used are described briefly with each data set and more detail can be found in the specific references cited with the data sets.
Although these data were collected before the advent of rules and regulations on the humane care and use of laboratory animals and IACUC committees, all experiments were conducted according to present day standards; first, because this was the right thing to do and second, because pain and distress would have interfered with the system states that we were investigating.
Cerebral Cortex
VPL Nucleus of the Thalamus
Cuneate Nucleus
Present version 2.1; last updated 14 February 2003
This work was supported by grants from the National Institutes of Health (NIH), National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) NS00396 and NS05136 and numerous NIH training grants.
The untimely deaths at the height of their careers of two contributors to this work, Russell W. Morse and Fred A. Harris, saddens the rest of us still.
Adkins, R. J., R. W. Morse and A. L. Towe. 1966. Control of somatosensory input by cerebral cortex. Science 153:1020-1022.
Baker, M. A. 1971. Spontaneous and evoked activity of neurons in the somatosensory thalamus of the waking cat. J. Physiol. 217:359-379.
Baker, M. A., C. F. Tyner, and A. L. Towe. 1971. Observations on single neurons in the sigmoid gyri of awake, nonparalyzed cats. Exp. Neurol. 32:388-403.
Blum, P., M. B. Bromberg and D. Whitehorn. 1975 Population analysis of single units in the cuneate nucleus of the cat. Exp. Neurol. 48:57-78.
Bromberg, M. B., P. Blum and D. Whitehorn. 1975. Quantitative characteristics of inhibition in the cuneate nucleus of the cat. Exp. Neurol. 48:37-56.
Bromberg, M. B., J. A. Burnham and A. L. Towe. 1981. Doubly projecting neurons of the dorsal column nuclei. Neurosci. Lett. 25:215-220.
Chen, Z. and A. L. Towe. 1985. Influence of molecular layer on pyramidal tract neurons. Exp. Neurol. 88:215-228.
Chen, Z., G. W. Harding and A. L. Towe. 1983. Effect of strychnine on the cutaneous responsiveness of wide-field cerebral neurons after depression by pentobarbital. Exp. Neurol. 81:770-775.
Doetsch, G. S. and A. L. Towe. 1976. Response properties of distinct neuronal subsets in hindlimb sensorimotor cerebral cortex of the domestic cat. Exp. Neurol. 53:520-547.
Doetsch, G. S. and A. L. Towe. 1976. Population response patterns of distinct neuronal subsets in the hindlimb sensorimotor cerebral cortex of the domestic cat. Exp. Neurol 53:548-566.
Ennever. J. A. and A. L. Towe. 1974. Response of somatosensory cerebral neurons to stimulation of dorsal and dorsolateral spinal funiculi. Exp. Neurol. 43:124-142.
Gehary, Y. and A. L. Towe. 1993. Effect of optic nerve stimulation on neurons in pericruciate cortex of cats. Exp. Brain Res. 94:272-278.
Harding, G. W. and A. L. Towe. 1976. An on-line real-time laboratory for single neuron studies. Comput. Biomed. Res. 9:471-501.
Harding, G. W., R. M. Stogsdill and A. L. Towe. 1979. Relative effects of pentobarbital and chloralose on the responsiveness of neurons in sensorimotor cerebral cortex of the domestic cat. Neuroscience 4:369-378.
Harris, F. A. 1978a. Functional subsets of neurons in somatosensory thalamus of the cat. Exp. Neurol. 58:149-170.
Harris, F. A. 1978b. Regional variations of somatosensory input convergence in nucleus VPL of cat thalamus. Exp. Neurol. 58:171-189.
Harris, F. A. 1980. Wide-field neurons in somatosensory thalamus of domestic cats under barbiturate anesthesia. Exp. Neurol. 68:27-49.
Harris, F. A. and A. L. Towe. 1976. Effects of topical bicuculline on primary evoked responses in pericruciate and precoronal cortex of the domestic cat. Exp. Neurol. 52:227-241.
Harris, F. A. and A. L. Towe. 1978. Effects of topical application of diphenylhydantoin on gross evoked responses and single-neuron activity in pericruciate and precoronal cerebral cortex of the domestic cat. Exp. Neurol. 62:521-538.
Harris, F., S. J. Jabbur, R. W. Morse and A. L. Towe. 1965. Influence of the cerebral cortex on the cuneate nucleus of the monkey. Nature 208: 1215-1216.
Harrison T. A. and A. L. Towe. 1986. Antidromic response to medulary pyramid stimulation in rats and its relation to that in cats. Brain Behav. Evol. 29:143-161.
Jabbur, S. J., M. A. Baker and A. L. Towe. 1972. Wide-field neurons in thalamic nucleus ventralis posterolateralis of the cat. Exp. Neurol. 36:213-238:
Jabbur, S. J. and A. L. Towe. 1961. Cortical excitation of neurons in dorsal column of cat, including an analysis of pathways. J: Neurophysiol. 24:499-509.
Kennedy, T. T. and A. L. Towe. 1962. Identification of a fast lamnisco-cortical system in the cat. J. Physiol. (London) 160:535-547.
Kennedy, T. T., R. J. Grimm and A. L. Towe. 1966. The role of cerebral cortex in evoked somatosensory activity in cat cerebellum. Exp. Neurol. 14: 13-32.
Mann, M. D. 1979. Sets of neurons in somatic cerebral cortex of the cat and their ontogeny. Brain Res. Rev. 1:3-45.
Mann, M. D., W. S. Holt and A. L. Towe. 1977. Afferent modulation of the excitability of pyramidal tract fibers. Exp. Neurol. 55:414-435.
Mann, M. D., and A. L. Towe. 1974. Effect of strychnine on single neurons of the pericruciate cerebral cortex. Exp. Neurol. 42:388-411.
Morse, R. W. and R. A. Vargo. 1970. Functional neuronal subsets in the forepaw focus of somatosensory area II of the cat. Exp. Neurol. 27:125-138.
Morse, R. W., R. J. Adkins and A. L. Towe. 1965. Population and modality characteristics of neurons in the coronal region of somatosensory area I of the cat. Exp. Neurol. 11:419-440.
Nyquist, J. K. and A. L. Towe. 1970. Neuronal activity evoked in cat precruciate cerebral cortex by cutaneous stimulation. Exp. Neurol. 29:494-512.
Patton, H. D., A. L. Towe, and T. T. Kennedy. 1962. Activation of pyramidal tract neurons by ipsilateral cutaneous stimuli. J. Neurophysiol. 25:501-514.
Satterthwaite, W. R. 1976. Feline pericruciate cerebral neurons activated by electrical stimulation of the ventral medulla. PhD Dissertation, University of Washington. 251pp.
Satterthwaite, W. R., J. A. Burnham, and A. L. Towe. 1978. Wide-field conditioning effects on small-field neurons in the posterior sigmoid gyrus of domestic cats. Exp. Neurol. 60:603-613.
Slimp, J. C. and A. L. Towe. 1977. Characteristics of somatic receptive fields of neurons in postcruciate cerebral cortex in awake-restrained and two anesthetic conditions in the same cat. Neurosci. Abs. 2:492.
Slimp, J. C. and A. L. Towe. 1980. Effects of pudendal nerve stimulation on neurons in pericruciate cerebral cortex of male domestic cats. Exp. Neurol. 67:181-204
Slimp, J. C. and A. L. Towe. 1990. Spatial distribution of modalities and receptive fields in sensorimotor cortex of awake cats. Exp. Neurol. 107:78-96.
Surmeier, D. J. 1983. Physiological properties of neurons in the cuneate nucleus of the cat: A study using white noise and spike train analysis. PhD Dissertation, University of Washington. 401pp.
Surmeier, D. J. and A. L. Towe. 1987. Properties of proprioceptive neurons in the cuneate nucleus of the cat. J. Neurophysiol. 57: 938-961.
Surmeier, D. J. and A. L. Towe. 1987. Intrinsic features contributing to spike train patterning in proprioceptive cuneate neurons. J. Neurophysiol. 57: 962-976.
Talbott, R. E., A. L. Towe and T. T. Kennedy. 1967. Physiological and histological classification of cerebellar neurons in chloralose-anesthetzed cats. Exp. Neurol. 19: 46-64.
Towe, A. L. 1965. Neuron population analysis in the cerebral cortex, pp. 143-156. In P. W. Nye (ed.). "Proceedings, Symposium on Information Processing in Sight -Sensory systems'". California Institute of Technology, Pasadena, California.
Towe, A. L. 1966. On the nature of the primary evoked response. Exp. Neurol. 15:113-139.
Towe, A. L. 1968. Neuronal population behavior in the somatosensory systems. pp. 552--574. In D. R.- Kenshalo (ed.) "The Skin Senses". Thomas, Springfield, Illinois.
Towe, A. L. 1975. Notes on the hypothesis of columnar organization in somatosensory cerebral cortex. Brain Behav. Evol. 11:16-47.
Towe, A. L. and G. W. Harding. 1970. Extracellular microelectrode sampling bias. Exp. Neurol. 29:366-381.
Towe, A. L. and T. A. Harrison. 1993. Cerebral response to pyramidal tract stimulation in wood rats and its relation to laboratory rats. Exp. Brain Res. 97: 311-316.
Towe, A. L. and S. J. Jabbur. 1961. Cortical inhibition of neurons in dorsal column nuclei of cat. J. Neurophysiol. 24:488-498
Towe, A. L. and T. T. Kennedy. 1961. Response of cortical neurons to variation of stimulus intensity and locus. Exp. Neurol. 3:570-587.
Towe, A. L. and R. W. Morse. 1962. Dependence of the response characteristics of somatosensory neurons on the form of their afferent input. Exp. Neurol. 6:407-425.
Towe, A. L., M. D. Mann, and G. W. Harding. 1981. On the currents that flow during the strychnine spike. Elecroenceph. clin. Neurophysiol. 51:306-327.
Towe, A. L., H. D. Patton, and T. T. Kennedy. 1963. Properties of the pyramidal system in the cat. Exp. Neurol. 8:220-238.
Towe, A. L., H. D. Patton, and T. T. Kennedy. 1964. Response properties of neurons in the pericruciate cortex of the cat following electrical stimulation of the appendages. Exp. Neurol. 10:325-344.
Towe, A. L. and J. C. Slimp. 1977. Organization of postcruciate neurons with respect to somatic modality and receptive field in a awake-restrained cat. Neurosci. Abs. 3:493.
Towe, A. L., C. F. Tyner, and J. K. Nyquist. 1976. Facilitatory an inhibitory modulation of wide-field neuron activity in postcruciate cerebral cortex of the domestic cat. Exp. Neurol. 50:734-756.
Towe, A. L., D. Whitehorn, and J. K. Nyquist. 1968. Differential activity among wide-field neurons of the cat postcruciate cerebral cortex. Exp. Neurol. 20:497-521.
Tyner, C. F. 1975. The naming of neurons: Application of taxonomic theory to the study of cellular populations. Brain Behav. Evol. 12:75-96.
Tyner, C. F. 1979. Splanchnic nerve activation of single cells in the cat's postcruciate motorsensory cortex. Exp. Neurol. 63:76-93.
Tyner, C. F. and M. G. Miller. 1977. Selective inhibition of some wide-field sensorimotor cortex neurons by high intensity skin stimuli. Neurosci. Abs. 3:72.
Tyner, C. F. and A. L. Towe. 1970. Interhemispheric influences on sensorimotor neurons. Exp. Neurol. 28:88-105.
Videen, T. 0. 1981. Visual input to small-field and wide-field neurons in the postcruciate cortex of domestic cat. Exp. Neurol. 71:341-355.
Weinberg, R. J. 1983. Transmission failure in cat cuneate nucleus during repetitive stimulation of peripheral nerves. PhD Dissertation, University of Washington. 275pp.
Whitehorn, D. and A. L. Towe. 1968. Postsynaptic potential patterns evoked upon cells in sensorimotor cortex of cat by stimulation at the periphery. Exp. Neurol. 22:222-242.
Zimmerman. I. D. 1968. A triple representation of the body surface in the sensorimotor cortex of the squirrel monkey. Exp. Neurol. 20:415-431.