Neurosensory development of the four brainstem-projecting sensory systems and their integration in the telencephalon

Abstract

Somatosensory, taste, vestibular, and auditory information is first processed in the brainstem. From the brainstem, the respective information is relayed to specific regions within the cortex, where these inputs are further processed and integrated with other sensory systems to provide a comprehensive sensory experience. We provide the organization, genetics, and various neuronal connections of four sensory systems: trigeminal, taste, vestibular, and auditory systems. The development of trigeminal fibers is comparable to many sensory systems, for they project mostly contralaterally from the brainstem or spinal cord to the telencephalon. Taste bud information is primarily projected ipsilaterally through the thalamus to reach the insula. The vestibular fibers develop bilateral connections that eventually reach multiple areas of the cortex to provide a complex map. The auditory fibers project in a tonotopic contour to the auditory cortex. The spatial and tonotopic organization of trigeminal and auditory neuron projections are distinct from the taste and vestibular systems. The individual sensory projections within the cortex provide multi-sensory integration in the telencephalon that depends on context-dependent tertiary connections to integrate other cortical sensory systems across the four modalities.

Volitional mental absorption in meditation: Toward a scientific understanding of advanced concentrative absorption meditation and the case of jhana

“…The brainstem, and more specifically, the ascending reticular activating system (ARAS), connects to the cortex through the thalamus [ 56 ] and plays a critical role in regulating consciousness, wakefulness, and arousal [ [57] , [58] , [59] , [60] , [61] ]. One of the key functions of the brainstem [ 62 , 63 ] and thalamus [ [64] , [65] , [66] , [67] ] is to process and filter incoming sensory information, allowing important sensory information to pass through to maintain coherent perception of the world. Decreased brainstem activity during deeper ACAM-J is suggestive of reduction in sensory processing [ 62 , 63 ] and regulation of emotion and arousal [ [68] , [69] , [70] , [71] ].…”

“…One of the key functions of the brainstem [ 62 , 63 ] and thalamus [ [64] , [65] , [66] , [67] ] is to process and filter incoming sensory information, allowing important sensory information to pass through to maintain coherent perception of the world. Decreased brainstem activity during deeper ACAM-J is suggestive of reduction in sensory processing [ 62 , 63 ] and regulation of emotion and arousal [ [68] , [69] , [70] , [71] ]. The dynamic changes in thalamic activity may also be related to alterations in sensory-gating to Refs.…”

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“…Foxg1 , Phox2a and Phox2b are expressed in the placodes during delamination [ 128 ], followed by the set of genes Coe1 , Drg11 and Dcx , which are only activated after the migrating cells have left the placode [ 128 , 192 ]. Once the final position is reached (facial, glossopharyngeal, vagus ganglion), the neurons grow a single process that branches to innervate the targeted taste bud cells and sends the proximal innervation to reach distinct areas of the hindbrain to reach out the solitary tract [ 16 , 127 , 195 ].…”

The Development of Speaking and Singing in Infants May Play a Role in Genomics and Dementia in Humans

“…In addition to the direct input from the A1, higher-level connections between various brain regions influence and combine auditory sensations with inputs from other sensory systems. The auditory system is interconnected with the visual, somatosensory, taste, and vestibular systems, facilitating multisensory integration and enabling complex information processing [ 87 ].…”