CEREBRAL PATHWAYS

ASSOCIATION FIBRES

COMMISSURAL FIBRES
(connect corresponding regions of both hemispheres)

corpus callosum - the largest commissure with rich connections for both motor and sensory regions of head, trunc and proximal patrs of limbs (! do not connect corresponding motor and sensory areas for hand, foot a periphral section of the eye field !)
commissura anterior - pars anterior (connects the olfactory areas - paleocortex)

- pars posterior (connects the whole temporal lobe cortex -! but the auditory areas !)

commissura fornicis /Lyra Davidis/ - connnects gyri parahippocampales and dentati of both hemispheres

commissura habenularum - connects habenulae
commissura posterior - connects nuclei of n. III., IV., VI. and nuclei interstitiales /Cajali/, gives off fibres joining the fasciculus longitudinalis medialis which help the synkinesis of eyes and head

PROJECTION FIBRES
(interconnect various levels of CNS one another)

dorsal column-medial lemniscus pathway - 3-neurons tract mediating proprioception /position sense and kinaesthesia from joints, muscles and tendons/, exteroceptive infotmation /touch-pressure and vibration sensation/

spinothalamic tract - 3-neuron tract mediating exteroceptive information /pain and temperature perception, coarse touch-pressure/

Descendent /efferent, motor/

tractus tectospinalis - motor synkinesis of head and neck
tractus rubrospinalis - excitation of flexors, inhibition of extensors
tractus reticulospinalis - excitation of gama-neurons, excitation or inhibiton of flexors and extensors
tractus vestibulospinalis - excitation of extensors (= antigravitational muscles)

fasciculus longitudinalis medialis - non-crosses pathway containig fibres from nuclei of n. III., IV., VI., colliculus superior, nucleus interstitialis Cajal and nuclei vestibulares descends through the brain stem to cervical part of medulla spinalis, its aim is the synkinesis of eyes, head and neck
fasciculus longitudinalis dorsalis /Schützi/ - it passes from the medial part of hypothalamus along the median line to parasympathetic nuclei of cranial nerves