TABLE 1.
Analytical techniques used in piglet developmental neuroscience
| Technique | Definition | Dietary sensitivity (reference) |
| MRI | ||
| Voxel-based morphometry | Comparison of gray or white matter tissue volumes on a voxel-by-voxel basis between treatment groups. Reported as edge-connected voxel clusters, which may span multiple brain regions. | Milk protein concentrate (enriched with phospholipids and gangliosides) (61) |
| Milk fat globule membrane and lactoferrin (67) | ||
| Iron deficiency (69) | ||
| Small for gestational age (90) | ||
| Volumetric analysis | Defines absolute (cubic millimeter) or relative (percentage total brain volume) volumes for distinct brain regions, which are then compared between treatment groups. Includes both gray and white matter in individual brain regions. | Milk protein concentrate (enriched with phospholipids and gangliosides) (61) |
| Milk fat globule membrane and lactoferrin (67) | ||
| Perinatal choline deficiency (74) | ||
| Small for gestational age (90) | ||
| Diffusion tensor imaging | Characterizes microscopic water movement within the brain, which can help to infer structural changes, such as myelination, fiber coherence, and changes in neuron size. Reported as axial diffusivity (movement parallel to magnetization gradient), radial diffusivity (movement perpendicular to magnetization gradient), mean diffusivity (overall water movement), and fractional anisotropy (measure of rate and direction of water movement) for distinct brain regions. | α-Lipoic acid (66) |
| Milk fat globule membrane and lactoferrin (67) | ||
| Iron deficiency (69) | ||
| Perinatal choline deficiency (74) | ||
| Small for gestational age (90) | ||
| Tract-based spatial statistics | Characterizes diffusion tensor measures along predefined white matter tracts. | α-Lipoic acid (66) |
| Magnetic resonance spectroscopy | Quantifies neurometabolites (parts per million) within a specified voxel. | Iron deficiency (69) |
| Perinatal choline deficiency (74) | ||
| Behavioral techniques | ||
| Home cage | Used to assess daily bouts of activity and rest. May be useful in characterizing repetitive behaviors. | Preterm piglet (80) |
| Open field | Assessment for anxiety-like behavior in which measures exploration and vocalization are observed. | Cholesterol (47) |
| Spatial T-maze | Assessment of discrimination and spatial learning and memory in which piglets use visual cues to learn the location of a food reward. | Milk protein concentrate (enriched with phospholipids and gangliosides) (61) |
| Iron deficiency (68) | ||
| Small for gestational age (90) | ||
| 8-arm radial maze | Assessment of discrimination and spatial learning and memory in which piglets use visual cues to learn the location of a food reward. | Sialic acid (51) |
| Cognitive hole-board | Assessment of spatial learning and memory in which habituation, reference memory, search strategies, exploration, and anxiety-related behaviors can be assessed. | Iron deficiency (70) |
| Molecular assessments | ||
| Gene, mRNA, and protein expression | Allows for characterizations in transcription and translation from dietary treatment | Sialic acid (51, 52) |
| Lactoferrin (54, 56) | ||
| Iron deficiency (68) | ||
| Betaine (76) | ||
| Protein deficiency (88) | ||
| Fatty acid profiling | Used to quantify changes in fatty acid composition within the brain. | Various fatty acid supplementations (29–39) |
| Histologic staining | Allows for visual characterization of structural changes in distinct brain regions. | Lactoferrin (56) |
| Iron deficiency (69, 70) | ||
| Stable-isotope labeling | Characterizes accretion of labeled dietary compounds in brain tissue. | Gangliosides and phospholipids (62) |
| DHA (94) |