Editing Human brain (section)

===Sensory===
[[File:1604 Types of Cortical Areas-02.jpg|thumb|upright=1.3|Cortical areas]]
[[File:Gray722.png|thumb|upright=0.9|Routing of neural signals from the two eyes to the brain]]
The [[sensory nervous system]] is involved with the reception and processing of [[sense|sensory information]]. This information is received through the cranial nerves, through tracts in the spinal cord, and directly at centres of the brain exposed to the blood.<ref name="Hellier">{{cite book |author=Hellier, J. |title=The Brain, the Nervous System, and Their Diseases [3 volumes] |publisher=[[ABC-CLIO]] |year=2014 |pages=300–303 |isbn=978-1-61069-338-7 |url=https://books.google.com/books?id=SDi2BQAAQBAJ&pg=PA300}}</ref> The brain also receives and interprets information from the [[special sense]]s of [[visual perception|vision]], [[Olfaction|smell]], [[hearing]], and [[taste]]. [[Sensory-motor coupling|Mixed motor and sensory signals]] are also integrated.<ref name="Hellier"/>

From the skin, the brain receives information about [[touch|fine touch]], [[pressure]], [[pain]], [[vibration]] and [[temperature]]. From the joints, the brain receives information about [[proprioception|joint position]].{{sfn|Guyton & Hall|2011|pp=571–576}} The [[sensory cortex]] is found just near the motor cortex, and, like the motor cortex, has areas related to sensation from different body parts. Sensation collected by a [[sensory receptor]] on the skin is changed to a nerve signal, that is passed up a series of neurons through tracts in the spinal cord. The [[dorsal column–medial lemniscus pathway]] contains information about fine touch, vibration and position of joints. The pathway fibres travel up the back part of the spinal cord to the back part of the medulla, where they connect with [[dorsal column–medial lemniscus pathway#Second-order neurons|second-order neurons]] that immediately [[Decussation|send fibres across the midline]]. These fibres then travel upwards into the [[ventrobasal complex]] in the thalamus where they connect with [[dorsal column–medial lemniscus pathway#Third-order neurons|third-order neurons]] which send fibres up to the sensory cortex.{{sfn|Guyton & Hall|2011|pp=571–576}} The [[spinothalamic tract]] carries information about pain, temperature, and gross touch. The pathway fibres travel up the spinal cord and connect with second-order neurons in the [[reticular formation]] of the brainstem for pain and temperature, and also terminate at the ventrobasal complex of the thalamus for gross touch.{{sfn|Guyton & Hall|2011|pp=573–574}}

[[Visual perception|Vision]] is generated by light that hits the [[retina]] of the eye. [[Photoreceptor cell|Photoreceptors]] in the retina [[visual phototransduction|transduce]] the sensory stimulus of [[light]] into an electrical [[action potential|nerve signal]] that is sent to the [[visual cortex]] in the occipital lobe. The arrangements of the eyes' optics cause light from the left [[visual field]] to be received by the rightmost portion of each retina, and vice versa. This arrangement ultimately means that a portion of each retina is processed by each hemisphere of the cortex, such that both the right and left visual cortex process information from both eyes. Visual signals leave the retinas through the [[optic nerves]]. Optic nerve fibres from the retinas' nasal halves [[Optic chiasm|cross to the opposite sides]] joining the fibres from the temporal halves of the opposite retinas, which do not cross, forming the [[optic tracts]]. The optic tract fibres reach the brain at the [[lateral geniculate nucleus]], and travel through the [[optic radiation]] to reach the visual cortex.{{sfn|Guyton & Hall|2011|pp=623-631}}

[[Hearing]] and [[Equilibrioception|balance]] are both generated in the [[inner ear]]. Sound results in vibrations of the [[ossicles]] which continue finally to [[Hair cell|the hearing organ]], and change in balance results in movement of [[Vestibular system|liquids within the inner ear]]. This creates a nerve signal that passes through the [[vestibulocochlear nerve]]. From here, it passes through to the [[cochlear nuclei]], the [[superior olivary nucleus]], the [[medial geniculate nucleus]], and finally the [[auditory radiation]] to the [[auditory cortex]].{{sfn|Guyton & Hall|2011|pp=739–740}}

The sense of [[Olfaction|smell]] is generated by [[Olfactory receptor neuron|receptor cells]] in the [[olfactory epithelium|epithelium]] of the [[olfactory mucosa]] in the [[nasal cavity]]. This information passes via the [[olfactory nerve]] which goes into the skull through [[cribiform plate|a relatively permeable part]]. This nerve transmits to the neural circuitry of the [[olfactory bulb]] from where information is passed to the [[olfactory system|olfactory cortex]].{{sfn|Pocock|2006|pp=138–139}}{{sfn|Squire|2013|pp=525–526}}
[[Taste]] is generated from [[Taste receptor|receptors on the tongue]] and passed along the [[Facial nerve|facial]] and [[glossopharyngeal nerve]]s into the [[solitary nucleus]] in the brainstem. Some taste information is also passed from the pharynx into this area via the [[vagus nerve]]. Information is then passed from here through the thalamus into the [[gustatory cortex]].{{sfn|Guyton & Hall|2011|pp=647–648}}