Journal of neurophysiology
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1. Intracellular and extracellular recordings were made from rat olfactory bulb mitral and tufted cells during odor stimulation and during electrical stimulation of the olfactory nerve. Neurons were identified by horseradish peroxidase injections and/or antidromic activation. ⋯ However, there were several clear exceptions. In five cells, a prominent hyperpolarization, seen in the first sniff of a series of 10 consecutive sniffs, was associated with pauses in spike activity. In the following
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1. This study was devoted to the neuronal processes underlying the construction of the motor program. Two monkeys were trained in a choice reaction time task to perform precise wrist flexion and extension movements of small and large extent. ⋯ Two hundred and seven neurons whose activity changes were related to movement direction and/or movement extent have been selected for the further study. They were classified into three main groups: 1) execution-related neurons (49 in MI, 27 in PM), 2) preparation- and execution-related neurons (48 in MI, 54 in PM), and 3) preparation-related neurons (8 in MI, 21 in PM). 4. Directionally selective, execution-related neurons were found to be more frequently located within MI (81/105, 77.1%) than within PM (55/102, 53.9%), whereas directionally selective, preparation-related neurons appeared to be more frequently located within PM (47/102, 46.1%) than within MI (24/105, 22.9%).(ABSTRACT TRUNCATED AT 400 WORDS)
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1. In anesthetized rats, recordings were made within the medullary subnucleus reticularis dorsalis (SRD) from neurons that exhibited convergence of nociceptive inputs from the entire body. Neurons with total nociceptive convergence (TNC) responded to suprathreshold percutaneous electrical stimuli (2-ms duration) with an early and a late peak due to activation of A delta- and C-fibers, respectively, no matter which part of the body was stimulated. ⋯ When mechanical stimuli were applied, a linear relationship was found between the logarithm of the strength of the mechanical stimulus and the neuronal discharges, in the 5.3- to 7.4-N/cm2 range. With thermal stimulation, TNC neurons linearly increased their discharges in the 44-52 degrees C range. When increasing amounts of the tail were immersed in a 50 degrees C waterbath, TNC neurons increased their discharges within a restricted range of tail surface areas (0.9-5.7 cm2); further increases in the stimulated surface size were not followed by increases in firing rate.(ABSTRACT TRUNCATED AT 400 WORDS)
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1. Temporal properties of single- and multiple-unit responses were investigated in the inferior colliculus (IC) of the barbiturate-anesthetized cat. Approximately 95% of recording sites were located in the central nucleus of the inferior colliculus (ICC). ⋯ The onset response latency of a given unit or unit cluster was significantly correlated with the period of the BMF and the period of the CF (P less than 0.05). 5."Intrinsic oscillations" of short duration, i.e., regularly timed discharges of units in response to stimuli without a corresponding temporal structure, were frequently observed in the ICC. Oscillation intervals were commonly found to be integer multiples of 0.4 ms. Changes of stimulus frequency or intensity had only minor influences on these intrinsic oscillations.(ABSTRACT TRUNCATED AT 400 WORDS)
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Comparative Study
Response properties of cochlear efferent neurons: monaural vs. binaural stimulation and the effects of noise.
1. Discharge properties of olivocochlear efferent neurons were measured in anesthetized cats. Previous studies of these neurons concentrated on monaural stimulation with tones and found sound-evoked discharge rates rarely exceeded 60 spikes/s (16, 20). ⋯ In general, the weaker the response to monaural stimuli, the stronger the binaural facilitation. 6. The facilitatory effects of stimulation with continuous noise could outlast the stimulus. Persistent increases in efferent sensitivity were documented following 10-min exposures to broadband noise at 85-115 dB SPL.