Functional localization of brainstem and cervical spinal cord nuclei in humans with fMRI.
OBJECTIVE
To our knowledge, no published functional map of the human lower brainstem exists. Our purpose was to use 1.5-T functional MR imaging (fMRI) to visualize the location of cranial nerve (CN) nuclei and other pontine, bulbar, and cervical spinal cord nuclei by using specific sensory stimulation or motor performance.


METHODS
We localized nuclei by using cross-correlation analysis of regional blood oxygen level-dependent (BOLD) signal intensity during specific motor and sensory procedures based on known functions of specific nuclei. Statistical parametric mapping (SPM) analysis was used for comparison. Head, cardiac, and respiratory motion artifact correction was applied. Histologic atlases aided localization.


RESULTS
We obtained evidence of localization of the following nuclei by using tests, as follows: main trigeminal sensory (CN V), brushing the face; abducens (CN VI), left-right eye movement; facial (CN VII), smiling and lip puckering; hypoglossal (CN XII), pushing the tongue against the hard palate; nucleus ambiguus, swallowing; nucleus tractus solitarii (NTS), tasting a sweet-sour-salty-bitter mixture; nucleus cuneatus, finger tapping; and cervical spinal cord levels C1-C3, tongue movement to activate the strap muscles. Activation of cortical motor and sensory areas and somatosensory thalamus corresponded with the tasks and sites of brainstem activation. Head movement was minimal, typically less than 1 mm in all three axes.


CONCLUSIONS
With 1.5-T fMRI, the CN nuclei of the pons and medulla, and other nuclei of the lower brainstem and cervical spinal cord, can be localized in awake humans with specific sensory stimulation or motor performance.
Komisaruk
Barry R
BR
Department of Psychology, Rutgers, The State University of New Jersey, Newark 07102, USA.
Mosier
Kristine M
KM
Liu
Wen-Ching
WC
Criminale
Cecily
C
Zaborszky
Laszlo
L
Whipple
Beverly
B
Kalnin
Andrew
A
D000010:Abducens Nerve / Q000033:anatomy & histology / Q000502:physiology; D000328:Adult; D001931:Brain Mapping; D001933:Brain Stem / Q000502:physiology*; D003391:Cranial Nerves / Q000502:physiology*; D005154:Facial Nerve / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000033:anatomy & histology / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009068:Movement; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation; D012016:Reference Values; D013116:Spinal Cord / Q000502:physiology*; D014276:Trigeminal Nerve / Q000033:anatomy & histology / Q000502:physiology
D010100:Oxygen