scholarly journals Directional sensitivity of auditory neurons in the superior colliculus of the bat (Myotis lucifugus)

1983 ◽  
Vol 74 (S1) ◽  
pp. S8-S8
Author(s):  
Donald Wong
Keyword(s):  
Superior Colliculus ◽  
Myotis Lucifugus ◽  
Directional Sensitivity ◽  
Auditory Neurons

Spatial response properties of acoustically responsive neurons in the superior colliculus of the ferret: a map of auditory space

1987 ◽  
Vol 57 (2) ◽  
pp. 596-624 ◽  
Author(s):  
A. J. King ◽  
M. E. Hutchings
Keyword(s):  
Superior Colliculus ◽  
Stimulus Intensity ◽  
Free Field ◽  
Receptive Fields ◽  
Stimulus Onset ◽  
Spontaneous Discharge ◽  
Auditory Neurons ◽  
Response Properties ◽  
Deep Layers ◽  
Stimulus Offset

Extracellular single-unit recordings were made from auditory neurons in the superior colliculus of ferrets anesthetized with either a neuroleptic or a combination of barbiturate with paralysis. The response properties of these neurons were studied using white-noise bursts presented under free-field conditions in an anechoic chamber. Auditory neurons were found throughout the intermediate and deep layers of the superior colliculus. All neurons were spontaneously active, the rates of discharge varying from 0.1 to 61.1 spikes X s-1. Although the spontaneous discharge interspike-interval histograms for many units approximated to exponential distributions, the histograms of 44% had clear secondary peaks, indicating more than one preferred interval, and could not be modeled by a simple process. Most neurons (50%) responded only at stimulus onset, whereas 12% exhibited sustained discharges and 38% gave onset responses followed by a period of silence or reduced activity and then a period of elevated discharge, which was not apparently related to stimulus offset. Neurons with multipeaked response patterns were concentrated in the stratum griseum profundum. The latencies from arrival of the stimulus at the ear to the onset of neural activity ranged from 6 to 49 ms and decreased with increasing stimulus intensity. Although responsive to sounds over a large region of space, most neurons had clearly defined best positions at which the strongest response was obtained. The response declined as the speaker was moved away from this position, and nearly all units had peaked response profiles. The spatial tuning varied between different neurons, but most were more sharply tuned in elevation than in azimuth. Increasing the stimulus intensity did not, in general, alter the best positions of these neurons, but usually resulted in a broadening of the receptive fields, although other units became more sharply tuned. The best positions of auditory neurons varied systematically in azimuth from 20 degrees into the ipsilateral hemifield to 130 degrees into the contralateral hemifield as the electrode was moved from the rostrolateral to the caudomedial end of the superior colliculus. The best positions shifted in elevation along a rostromedial to caudolateral axis from 60 degrees above to 50 degrees below the visuoaural plane.(ABSTRACT TRUNCATED AT 400 WORDS)

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

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