Activity and excitability to electrical current of cortical auditory receptive neurons of awake cats as affected by stimulus association

1976 ◽  
Vol 39 (5) ◽  
pp. 1045-1061 ◽  
Author(s):  
C. D. Woody ◽  
J. D. Knispel ◽  
T. J. Crow ◽  
P. A. Black-Cleworth
Keyword(s):  
Auditory Stimulus ◽  
Conditioned Reflex ◽  
Unit Activity ◽  
Temporal Order ◽  
Electrical Current ◽  
Spike Discharge ◽  
Suprasylvian Cortex ◽  
Evoked Activity ◽  
Awake Cats

1. Unit activity and excitability were studied at the midlateral and suprasylvian cortex of naive, blink-conditioned and "randomization" cats. The latter received the same CS and US as did the conditioned animals, but in random temporal order and with random intertrial intervals with mean comparable to that used for conditioning. The randomization group failed to develop a blink CR. 2. With conditioning, spontaneous and evoked unit discharges were increased above levels found in naive animals. Correspondingly, levels of extracellularly injected current required to elicit a spike discharge were lower in conditioned than in naive animals. In addition, in the conditioned animals, the degree of enhancement of evoked activity and excitability was found to be greatest in the units that responded to the CS, as opposed to units that responded to another auditory stimulus of equal intensity but of no special behavioral significance vis-a-vis the conditioned reflex. 3...

Sensitivity of Auditory Cortical Neurons to the Locations of Leading and Lagging Sounds

2005 ◽  
Vol 94 (2) ◽  
pp. 979-989 ◽  
Author(s):  
Brian J. Mickey ◽  
John C. Middlebrooks
Keyword(s):  
Unit Activity ◽  
Cortical Neurons ◽  
Precedence Effect ◽  
Related Information ◽  
Sound Levels ◽  
Transmission Of Information ◽  
Discrete Responses ◽  
Temporal Firing ◽  
Spike Patterns ◽  
Awake Cats

We recorded unit activity in the auditory cortex (fields A1, A2, and PAF) of anesthetized cats while presenting paired clicks with variable locations and interstimulus delays (ISDs). In human listeners, such sounds elicit the precedence effect, in which localization of the lagging sound is impaired at ISDs ≲10 ms. In the present study, neurons typically responded to the leading stimulus with a brief burst of spikes, followed by suppression lasting 100–200 ms. At an ISD of 20 ms, at which listeners report a distinct lagging sound, only 12% of units showed discrete lagging responses. Long-lasting suppression was found in all sampled cortical fields, for all leading and lagging locations, and at all sound levels. Recordings from awake cats confirmed this long-lasting suppression in the absence of anesthesia, although recovery from suppression was faster in the awake state. Despite the lack of discrete lagging responses at delays of 1–20 ms, the spike patterns of 40% of units varied systematically with ISD, suggesting that many neurons represent lagging sounds implicitly in their temporal firing patterns rather than explicitly in discrete responses. We estimated the amount of location-related information transmitted by spike patterns at delays of 1–16 ms under conditions in which we varied only the leading location or only the lagging location. Consistent with human psychophysical results, transmission of information about the leading location was high at all ISDs. Unlike listeners, however, transmission of information about the lagging location remained low, even at ISDs of 12–16 ms.

scholarly journals Very early EEG responses to a meaningful auditory stimulus in the frontal lobes: an intracerebral study in humans

2010 ◽  
pp. 1019-1027
Author(s):  
M Kukleta ◽  
B Turak ◽  
J Louvel
Keyword(s):  
Auditory Stimulus ◽  
Auditory Evoked Potentials ◽  
Precentral Gyrus ◽  
Onset Latency ◽  
Negative Wave ◽  
Depth Electrodes ◽  
Nucleus Caudatus ◽  
Epileptic Patients ◽  
Evoked Activity ◽  
Local Generation

Frontal auditory evoked potentials (FAEPs) obtained as a response to the warning auditory stimulus of a contingent negative variation task from depth electrodes were investigated. The second, imperative stimulus was visual. Thirteen epileptic patients participated in the study. Records from 20 electrodes of 10 patients exhibited signs of local generation. They were localized in the motor cortices (7 cases), in the superior, medial, and inferior frontal gyri (7 cases), in the cingulate gyrus (5 cases), and in the nucleus caudatus (1 case). A typical FAEP from these generators consisted of three components: (i) first negative wave peaking at 99±13 ms; (ii) positive wave peaking at 181±21 ms; (iii) second negative wave peaking at 324±63 ms. In 11 generators no evoked activity to visual stimulus was observed; in the remaining 9 generators both auditory and visual stimuli evoked a response. FAEPs with very early onsets (onset latency below 20 ms) were found in three sites in the precentral gyrus.

Olivocochlear Bundle Activity Recorded in Awake Cats

1979 ◽  
Vol 87 (4) ◽  
pp. 463-471
Author(s):  
William F. Banks ◽  
James C. Saunders ◽  
Louis D. Lowry
Keyword(s):  
Stainless Steel ◽  
Auditory System ◽  
Unit Activity ◽  
Fourth Ventricle ◽  
Acoustic Stimulation ◽  
Behavioral Activity ◽  
Olivocochlear Bundle ◽  
Efferent Pathway ◽  
Decerebrate Cats ◽  
Awake Cats

Multi-unit activity was recorded in awake cats from the crossed olivocochlear bundle (COCB). Miniature stainless steel concentric electrodes were chronically implanted onto the floor of the fourth ventricle of six animals. There was no activity at the electrode tip in anesthetized animals, while in awake cats a great deal of unit activity could be seen. A correlation between COCB activity and ongoing behavioral activity such as scratching, grooming, yawning, vocalizing, or orientation could not be established. It was found, however, that the multi-unit responses in the COCB statistically increased their firing rate during acoustic stimulation, and a 500-Hz tone was found to be most effective. The electrode locations were histologically confirmed. The present results are similar to other data that describe unit activity in the olivocochlear bundle of decerebrate cats. The capacity to record from this fiber tract in awake animals, however, provides a new tool for studying the peripheral efferent pathway of the auditory system.

The 5-HT1A receptor antagonist p-MPPI blocks 5-HT1A autoreceptors and increases dorsal raphe unit activity in awake cats

1998 ◽  
Vol 356 (2-3) ◽  
pp. 167-178 ◽  
Author(s):  
Bjørn Bjorvatn ◽  
Casimir A. Fornal ◽  
Francisco J. Martı́n ◽  
Christine W. Metzler ◽  
Barry L. Jacobs
Keyword(s):  
Receptor Antagonist ◽  
Unit Activity ◽  
Dorsal Raphe ◽  
Awake Cats ◽  
Dorsal Raphé

Spinal pathways mediating tonic, coeruleospinal, and raphe-spinal descending inhibition in the rat

1987 ◽  
Vol 58 (1) ◽  
pp. 138-159 ◽  
Author(s):  
S. L. Jones ◽  
G. F. Gebhart
Keyword(s):  
Spontaneous Activity ◽  
Dorsal Horn ◽  
Unit Activity ◽  
Tail Flick ◽  
Descending Inhibition ◽  
Nociceptive Transmission ◽  
Dorsal Horn Neurons ◽  
C Fibers ◽  
Electrophysiological Studies ◽  
Evoked Activity

1. The contribution of midline medullary bulbospinal neurons to descending inhibition from the locus coeruleus (LC) and the funicular trajectories of coeruleo- and raphe-spinal fibers mediating inhibition of spinal nociceptive transmission were examined in different experiments. Extracellular recordings of lumbar dorsal horn neurons were made in deeply pentobarbital-anesthetized, paralyzed rats. All units studied responded to electrical stimulation of the ipsilateral tibial nerve at intensities supramaximal to activate A-alpha-delta- and C-fibers and to mechanical and heat (50 degrees C) stimuli of the glabrous skin of the ipsilateral hind foot. Parallel studies were done in lightly pentobarbital-anesthetized rats utilizing the nociceptive tail-flick (TF) reflex. 2. To examine the contribution of bulbospinal neurons in the nucleus raphe magnus (NRM) to descending coeruleospinal inhibition, lidocaine microinjections were made into the NRM to produce a time-limited, reversible block. Lidocaine microinjections into the NRM effectively blocked NRM stimulation-produced inhibition of the TF reflex (prelidocaine stimulation thresholds were increased two to three times), but did not affect stimulation-produced inhibition from the LC. 3. In parallel electrophysiological studies, stimulation in the NRM inhibited heat-evoked dorsal horn unit activity to 31% of control, whereas stimulation in the LC/SC inhibited heat-evoked activity of the same units to 30% of control. Following NRM lidocaine microinjections, stimulation at the same intensity in the NRM no longer inhibited heat-evoked activity (93% of control), confirming the efficacy of the lidocaine block. LC stimulation-produced inhibition, however, was not affected by blockage of the NRM; heat-evoked unit activity was inhibited by LC stimulation to 39% of control. 4. The effects of ipsilateral and bilateral ventrolateral funiculus (VLF) lidocaine microinjections on spontaneous and heat-evoked unit activity were examined in other experiments. Spontaneous activity increased following ipsilateral VLF lidocaine microinjections for 13/18 units; decreases and no change in spontaneous activity were observed for three and two units, respectively. Heat-evoked unit activity was increased significantly following ipsilateral VLF lidocaine microinjections.(ABSTRACT TRUNCATED AT 400 WORDS)

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