Some Neuronal Response Patterns in the Cochlear Nucleus of Kangaroo Rat

1967 ◽  
Vol 41 (6) ◽  
pp. 1585-1585
Author(s):  
Allen L. Rupert ◽  
George Moushegian
1964 ◽  
Vol 27 (6) ◽  
pp. 1174-1191 ◽  
Author(s):  
George Moushegian ◽  
Allen Rupert ◽  
Milton A. Whitcomb

1976 ◽  
Vol 39 (1) ◽  
pp. 179-194 ◽  
Author(s):  
R. Britt ◽  
A. Starr

Responses of 99 cochlear nucleus cells and 24 cochlear nerve fibers were studied with FM signals; 14 cochlear nerve fibers and 57 cochlear nucleus cells were studied at four rates of modulation and several signal intensities. Classification of FM response patterns as symmetrical, asymmetrical, or unidirectional was based on the calculation of a symmetry factor (S), which compared the number of discharges evoked by the ascending and by the descending phases of the FM sweep. Certain FM response patterns could not adequately be described by the symmetry factor along and variables of modulation rate and signal intensity had significant influence. A correspondence was found between the four response classes evoked by a steady-frequency tone burst (primarylike, buildup, onset, and pause) and the FM response pattern. Cochlear nerve fibers showed symmetrical response patterns to FM stimulation. Primarylike units were similar to eighth nerve fibers and generally showed symmetrical FM responses. Occasional eighth nerve fibers and primarylike cells developed asymmetry at the fastest rate of modulation (50 sps). Buildup units showed a variety of response patterns to FM signals. Onset units generally showed asymmetrical response patterns with the greater response occurring to the ascending than to the descending phase of the FM sweep. Pause units showed a characteristic inhibition of activity at 5 sps (rate-dependent inhibition). Of the 57 cochlear nuclear cells studied in response to FM signals, 16 were symmetrical, another 16 were symmetrical except at the fastest modulation rate, 12 were asymmetrical, 3 were unidirectional, and 10 showed complex responses to certain signal rates or intensities. It is clear the the cat cochlear with its complex cytoarchitecture is involved in the recoding of acoustic information. Some units in cochlear nucleus demonstrate differential responses to the direction and to the rate of frequency movement. Other cochlear nucleus cells respond as eighth nerve fibers and may serve as simple "relays" in transmitting information from the cochlea to higher auditory centers.


1977 ◽  
Vol 86 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Allen L. Rupert ◽  
Donald M. Caspary ◽  
George Moushegian

Most studies in auditory neurophysiology have utilized tonal stimuli to determine the coding properties of neurons in the cochlear nuclei. In this investigation of the kangaroo rat, cochlear nuclei, neuronal responses to vowel sounds, as well as tones, were studied. The vowel sounds, each about 40 msec in duration were: [a], [i], [I], [ε], [o], [u], [Formula: see text] [æ], and [ṛ]. Five were linked together to form a 200 msec stimulus and various combinations of five vowel sounds provided us with 18 different stimuli. The results show that neurons in the cochlear nuclei are remarkably sensitive and selective to vowel sounds. Furthermore, the responses of these neurons to pure tones do not provide a complete basis to predict the types of responses to the vowel sounds. More significant is the finding that the neural discharge rate and pattern of discharge to a particular vowel may depend on where the vowel appears in the stimulus and what other vowel precedes it. This vowel positional effect is not the same for every neuron. We have called this phenomenon a neural “set.”


2018 ◽  
Author(s):  
Raphael Wallroth ◽  
Kathrin Ohla

The categorization of food via sensing nutrients or toxins is crucial to the survival of any organism. On ingestion, rapid responses within the gustatory system are required to identify the oral stimulus to guide immediate behaviour (swallowing or expulsion). The way in which the human brain accomplishes this task has so far remained unclear. Using multivariate analysis of 64-channel scalp EEG recordings obtained from 16 volunteers during tasting salty, sweet, sour, or bitter solutions, we found that activity in the delta-frequency range (1-4 Hz; delta power and phase) has information about taste identity in the human brain, with discriminable response patterns at the single-trial level within 130 ms of tasting. Importantly, the latencies of these response patterns predicted the point in time at which participants indicated detection of a taste by pressing a button. Furthermore, taste pattern discrimination was independent of motor-related activation and other taste features such as intensity and valence. On comparison with our previous findings from a passive (delayed) taste-discrimination task (Crouzet et al., 2015), taste-specific neural representations emerged earlier during this active (speeded) taste-detection task, suggesting a goal-dependent flexibility in gustatory response coding. Together, these findings provide the first evidence of a role of delta activity in taste-information coding in humans. Crucially, these neuronal response patterns can be linked to the speed of simple gustatory perceptual decisions, a vital performance index of nutrient sensing.


1991 ◽  
Vol 65 (3) ◽  
pp. 606-629 ◽  
Author(s):  
M. I. Banks ◽  
M. B. Sachs

1. We investigate the discharge patterns of chopper units in the anteroventral cochlear nucleus (AVCN) by developing an equivalent cylinder compartmental model of AVCN stellate cells, which are the sources of the chopper response pattern. The model consists of a passive dendritic tree connected to somatic and axonal compartments with voltage-sensitive channels. Synaptic inputs to the model are simulated auditory nerve fiber responses to best-frequency tones. 2. We adjust the anatomic and electrical parameters of the model to agree with available intracellular data from stellate cells in the AVCN of the mouse and the cat and compare the response of the model to injected current with responses recorded in vitro. The model shows approximately linear current-voltage characteristics for small hyperpolarizing currents. The model's input resistance and the time course of its response to hyperpolarizing current applied at the soma are comparable with those measured from stellate cells in vitro. In response to sustained depolarizing current, the model fires repetitively with nearly perfect regularity, a property also observed in vitro. 3. Auditory nerve inputs to the cell are modeled as deadtime-modified Poisson processes with a multiexponential adaptation in the Poisson rate. We are able to adjust the number, rate, and location of excitatory and inhibitory inputs to the model and succeed in simulating chopper response patterns seen in vivo. 4. Chopper units exhibit a variety of regularity and adaptation patterns in response to tone stimuli. Physiological data from brain slice experiments and experiments in vivo imply that this heterogeneity is primarily due to differences in input configurations. By systematically varying the number and position of excitatory and inhibitory inputs, we can simulate a range of chopper response patterns. 5. We quantify the regularity of the model's response using the coefficient of variation (CV) of the interspike interval. We find that the CV decreases, i.e., the regularity increases, as the number of converging inputs or their distance from the soma increases. The regularity of the output is more sensitive to the number of converging inputs than to their location on the dendritic tree. The statistics of the first spike latency (FSL) are also sensitive to the configuration of excitatory inputs. The mean and minimum FSL are more sensitive to the electrotonic distance of the inputs from the soma than to the number of inputs, whereas the standard deviation of the FSL is highly dependent on the number of converging inputs and is nearly independent of their location.(ABSTRACT TRUNCATED AT 400 WORDS)


2008 ◽  
Vol 99 (3) ◽  
pp. 1077-1095 ◽  
Author(s):  
Yan Gai ◽  
Laurel H. Carney

Anatomical and physiological studies have shown that anteroventral cochlear nucleus (AVCN) neurons receive glycinergic and GABAergic inhibitory inputs. In this study, changes in the temporal responses of AVCN neurons to pure tones and complex sounds after blocking inhibition were analyzed. Blocking inhibition influenced the temporal responses of each type of AVCN neuron. Choppers showed more chopping peaks and shortened chopping cycles after blocking inhibition. Sustained and slowly adapting choppers showed increased regularity throughout the response duration after blocking inhibition, whereas most transient choppers showed increased regularity in the early part of the response. Diverse changes in temporal response patterns were observed in neurons with primary-like and unusual responses, with several neurons showing a large decrease in the first-spike latency after blocking inhibition. This result disagreed with previous findings that onset responses are less affected than sustained responses by manipulating inhibition. Although blocking inhibition had a greater effect on spontaneous activity than that on tone-evoked activity, the change in spontaneous activity was less significant because of larger variability. In addition, for relatively high level masker noises, blocking inhibition had similar effects on responses to noise-alone and noise-plus-tone stimuli, in contrast with previous studies with low-level background noise. In general, inhibition had an enhancing effect on temporal contrast only for responses to amplitude-modulated tones, for which envelope synchrony was enhanced. Results of this study contribute new information about the characteristics, functional roles, and possible sources of inhibitory inputs received by AVCN neurons.


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