Laminar specificity of functional MRI onset times during somatosensory stimulation in rat

AUTOR(ES)

Silva, Afonso C.

FONTE

National Academy of Sciences

RESUMO

The blood oxygenation level-dependent (BOLD) response to somatosensory stimulation was measured in α-chloralose-anesthetized rats. BOLD fMRI was obtained at 40-ms temporal resolution and spatial resolution of 200 × 200 × 2,000 μm3 by using a gated activation paradigm in an 11.7 T MRI. Results show a consistent heterogeneity of fMRI onset times and amplitudes. The earliest onset time (0.59 ± 0.17 s, n = 9) corresponded anatomically to layer IV, with superficial and deeper layers starting significantly later (1.27 ± 0.43 s in layers I–III, and 1.11 ± 0.45 s in layer VI). The amplitude of BOLD signal changes also varied with the cortical depth from the pial surface. Changes in the supragranular layers (8.3%) were 44% bigger than changes in the intermediate layers (5.5%), located only ≈700 μm below, and 144% larger than the bottom layer (3.5%), located ≈1.4 mm below the pial surface. The data presented demonstrate that BOLD signal changes have distinct amplitude and temporal characteristics, which vary spatially across cortical layers.

Documentos Relacionados

• Dynamic mapping at the laminar level of odor-elicited responses in rat olfactory bulb by functional MRI
• Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects.
• Aβ1–40-related reduction in functional hyperemia in mouse neocortex during somatosensory activation
• Assessment and discrimination of odor stimuli in rat olfactory bulb by dynamic functional MRI
• Clinical onset and MRI features of Krabbe's disease in adolescence.