0 A-Ink Period Covered: June 15, 1966 to October 15, 1966 1. Experiiiiental Followin- is a brief synopsis of activities under tl-iis contract performed during the 0 first four months. Details will appear in the s2ix-month report. 1. Animal experiments involved electrical stimulation of the plantar nerve ;In cats, while recording skin potential responses and conductance responses from the foot pad. Response at-nplitude @vas found to be stro-,igly potentiated by increasing periods of rest between test series. This effect appears to be due to the state of resting hydration. It affect2s both potential response and conductance response and conductance response and may accounc for a 100 per cent difference in response amplitude. 2. Microelectrode studies were extended to observation of potential response from sweat gland pores and from epidermal sites along with simultaneous recordings from large sites witli conventional electrodes. The epidermal sites C.'ave primarily positive responses a2t the same time as 'the sweat pore and the gross site was producing ne,-j-ative responses. This finding was consistant wit:ti t-ie -hypothesis that C) the positive responses are of epidermal origin and reflect a different type of biological adaptation than does te sweat gland activation. 3. Further experiments were carried out on the nail bed -,o determine whether 2these alleo-ed epidermal responses Nvere in fact only artifacts of nearby skin activity due to volume conduction. Strong positive potential responses were found to be easily el-'minated by puncture of the epidermis with the microelectrode used for the recording. Negative responses, if present, could not be so elii@inated. The possibility that the weak negative responses are of vascular origin is beinc, examined. This2 effect would corlfound the interpretation of negative waves from the sweat gland at normal skin sites. 4. Experiments to inveptigate the temperature effect on amplitude of the positive skin potential response have ber;n initiated. There is a potentiation of the positive wave with increasing room temperat,,ire (these induced temperature chanaes are not local as in previous experiments) indicating that the e2pidermal component (if this is the origin of the posi-tive wave) possibly serves a thermoregulatory function and is indicative of a covert preparation for motor activity. The negative wave, presumed to be of sweat gland origin, is not potentiated by increasing room temDera-,ure. Appro,ved for Relezsa 0 Date 2 7, 2 This is not surprisin- if tllc-.se sweat glaii:Js are noii-tliermoregulatory as 43 claimed by Kuno and others. 5. A model, xelating potent@l,-l responses to conductance responses, has been developed, and --s serviny as a2 gruide to the direction of experiment@ition and interpretation of results. This rnodel, attributin- nec,,ative waves and the long lasting component of the conductance response to sweat -land activity and positive waves and the fast-recovering component of the conductance response to epidermal activity points to metliods for their separation. One mettiod involves analysis of the 2recovery slope of the skin resistance response. The other entails the use of high frequency impedance measurements in conjunction with copventional D.C. measurements of skin resistance. These measurements are now under test. 11. Research facilities and perso el procured under this contract has been delivered and is in operation. The laboratory for the animal work and microelectrode wor2k has been renovated and is also in operation. All @person-net en,-,aged in the research activities under this contract have been recruited and trained where necessary.