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Superior olive complex, anatomy and function

Superior olive complex, anatomy and function

The superior olive or olive complex It is a set of oval-shaped nuclei, similar to that of an olive, found in the lower part of the Brain stem. These structures are very important to maintain auditory function, forming part of the ascending and descending pathways of the Auditive System.

In addition, the superior olive complex is related to decusant trapezoidal body, the cross between the axons of the contralateral neurons of the two cochlear subnuclei. The neurons of the superior olive complex, for the most part, are placed dorsally to the axons of the trapezoidal body's neurons. In addition, some olive neurons are embedded in this structure.

Content

  • 1 Anatomy and location of the superior olive complex
  • 2 Functions of the superior olive complex
  • 3 Lower olive complex

Anatomy and location of the superior olive complex

The superior olive complex is located in the Brain stem and extends from the marrow Rostral halfway east. This set of nuclei receives its projections especially from the anterior ventral cochlear nucleus through the trapezoidal body and the posterior ventral nucleus through the intermediate acoustic stria. Thus, the superior olive complex is thus connected to the cochlea, a fundamental piece for the hearing of humans and animals that is in the inner ear and appears as a spiral-shaped tube, responsible for sending the vibrations of sounds to the rest of the brain thanks to the gliad cells that it has inside, specifically in the organ of Corti.

The superior olive complex is divided into the following main nuclei:

  • Upper medial olive
  • Upper side olive
  • Medial core of the trapezoidal body

Functions of the superior olive complex

As we have mentioned, the superior olive complex has different functions in relation to hearing. These functions are very demarcated in each core of the structure:

The upper medial olive, One of the nuclei found in the upper olive complex and containing approximately 15,000 neurons, is responsible for measuring the different intensities of the sounds that arrive between the ears, being its very important function to classify the sounds of high frequency. Its main function is to detect the signals of interaural time differences.

In addition, the upper lateral olive seems to be related to the measurement of the difference in the intensities of the sounds between the two ears. This is also essential to evaluate high frequency sounds.

Likewise, the superior olive medial they have an important function when classifying the angle from which the sound comes, whose source can be located to the right or to the left. This horizontal sound information is therefore processed by the upper olive complex, although not the vertical information, in which it is decided whether a sound comes from a source located higher or lower than the listener. This process is carried out instead by the lower colliculus.

Moreover, the upper side olive It has functions very similar to the upper medial olive. However, it receives excitatory glutamatergic entrances of the ipsilateral cochlear nucleus and inhibitors of the medial nucleus of the trapezoidal body that manage to sharpen the intensity for the location of the sound source. In addition, this structure projects to the central nucleus of the lower follicle and to the lateral lemnisk.

The medial core of the trapezoidal body It is composed of neurons that transmit the neurotransmitter glycine and whose function is developed in the ascending auditory pathway. Its functions are essential to locate the sound and encode the temporal characteristics of complex sounds. This nucleus has been found in humans in very recent times, since before it was only contemplated in other animals, however, recent studies have proven the existence of this core essential for these functions

Lower Olive Complex

In addition to the upper olive complex, there is a lower olive complex or lower olive core that is related to the cerebellum and is placed between the lateral spinal cord and the pyramid of the spinal bulb. The lower olive grove, in turn, is composed of the primary olive kernel, which forms its largest structure; the accessory medial olive nucleus resting between the first nucleus and the bulbar pyramid and the dorsal accessory olive nucleus, which appears as a curved blade behind the primary nucleus. The main function of this complex is involved in motor activity and learning of cerebellar structure.

Links of interest

//www.ncbi.nlm.nih.gov/pubmed/25873865

//radiopaedia.org/articles/superior-olivary-nucleus