Relationship of blood flow and metabolism to acoustic processing centers of the dolphin brain.
Odontocete brain tissues associated with auditory processing are hypertrophied and modified relative to their terrestrial counterparts. The relationship between the functional demand on these tissues and metabolic substrate requirements is unknown. Using positron emission tomography (PET), relative cerebral blood flow was measured in a bottlenose dolphin. Approximately 60 mCi (13)NH(3) was administered to the dolphin via a catheter inserted into the hepatic vein and threaded proximate to the vena cava. Radiolabel initially appeared as distributed focal points in the cerebellum. Increasing scan time resulted in an increase in the number of focal regions and in the diffusivity of label activity throughout the brain. The time course and spatial distribution of radiolabel was consistent with a cerebral blood supply dominated by the spinal meningeal arteries. Blood flow was predominantly observed in the cerebellum and neocortex, particularly the auditory and visual cortex. Differential brain glucose uptake, previously measured in a separate dolphin, showed good agreement with the differential supply of blood to brain tissues. Rates of blood supply and glucose uptake in the auditory cortex, inferior colliculus, and cerebellum are consistent with a high metabolic demand of tissues which are important to the integration of auditory and other sensory inputs.
Houser
Dorian S
DS
National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, California 92106, USA. dorian.houser@nmmfoundation.org
Moore
Patrick W
PW
Johnson
Shawn
S
Lutmerding
Betsy
B
Branstetter
Brian
B
Ridgway
Sam H
SH
Trickey
Jennifer
J
Finneran
James J
JJ
Jensen
Eric
E
Hoh
Carl
C
D000818:Animals; D001303:Auditory Cortex / Q000098:blood supply / Q000378:metabolism; D001307:Auditory Perception; D050681:Bottle-Nosed Dolphin / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism*; D001931:Brain Mapping / Q000379:methods; D002531:Cerebellum / Q000098:blood supply / Q000378:metabolism; D002560:Cerebrovascular Circulation; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism*; D008297:Male; D009590:Nitrogen Radioisotopes / Q000008:administration & dosage; D049268:Positron-Emission Tomography; D000644:Quaternary Ammonium Compounds / Q000008:administration & dosage; D013997:Time Factors; D014793:Visual Cortex / Q000098:blood supply / Q000378:metabolism
D009590:Nitrogen Radioisotopes; D000644:Quaternary Ammonium Compounds; D005947:Glucose