Multiple Brain Samples Research Articles

Precise Mapping of Single Neurons by Calibrated 3D Reconstruction of Brain Slices Reveals Topographic Projection in Mouse Visual Cortex

Recent breakthroughs in neuroanatomical tracing methods have helped unravel complicated neural connectivity in whole-brain tissue at single-cell resolution. However, in most cases, analysis of brain images remains dependent on highly subjective and sample-specific manual processing, preventing precise comparison across sample animals. In the present study, we introduce AMaSiNe, software for automated mapping of single neurons in the standard mouse brain atlas with annotated regions. AMaSiNe automatically calibrates misaligned and deformed slice samples to locate labeled neuronal positions from multiple brain samples into the standardized 3D Allen Mouse Brain Reference Atlas. We exploit the high fidelity and reliability of AMaSiNe to investigate the topographic structures of feedforward projections from the lateral geniculate nucleus to the primary visual area by reconstructing rabies-virus-injected brain slices in 3D space. Our results demonstrate that distinct organization of neural projections can be precisely mapped using AMaSiNe.

Decreased 16:0/20:4-phosphatidylinositol level in the post-mortem prefrontal cortex of elderly patients with schizophrenia

The etiology of schizophrenia includes phospholipid abnormalities. Phospholipids are bioactive substances essential for brain function. To analyze differences in the quantity and types of phospholipids present in the brain tissue of patients with schizophrenia, we performed a global analysis of phospholipids in multiple brain samples using liquid chromatography electrospray ionization mass/mass spectrometry (LC-ESI/MS/MS) and imaging mass spectrometry (IMS). We found significantly decreased 16:0/20:4-phosphatidylinositol (PI) levels in the prefrontal cortex (PFC) in the brains from patients with schizophrenia in the LC-ESI/MS/MS, and that the 16:0/20:4-PI in grey matter was most prominently diminished according to the IMS experiments. Previous reports investigating PI pathology of schizophrenia did not identify differences in the sn-1 and sn-2 fatty acyl chains. This study is the first to clear the fatty acid composition of PI in brains from patients with schizophrenia. Alteration in the characteristic fatty acid composition of PI may also affect neuronal function, and could play a role in the etiology of schizophrenia. Although further studies are necessary to understand the role of reduced 16:0/20:4-PI levels within the prefrontal cortex in the etiology of schizophrenia, our results provide insight into the development of a novel therapy for the clinical treatment of schizophrenia.

An improved approach to align and embed multiple brain samples in a gelatin-based matrix for simultaneous histological processing

BackgroundPreparation and processing of free-floating histological sections involve a series of steps. The amount of labor, particularly sectioning and mounting, quickly multiplies as the number of samples increases. Embedding tissue samples in a flexible matrix allows simultaneous handling of multiple samples and preserves the integrity of the tissue during histological processing. However, aligning multiple asymmetrical samples, for example small-animal brains, in a particular orientation requires skillful arrangement and securing of the samples by pinning onto a solid surface. Consequently, costly technical services offered by contract research organizations are often sought. New methodAn improved approach to align and embed multiple whole or half rodent brain samples into a gelatin-based matrix is described. Using a template specifically designed to form arrayed mouse brain-shaped cavities, a ⿿receiving matrix⿿ is prepared. Inserting brain samples directly into the cavities allows the samples to be effortlessly positioned into a uniform orientation and embedded in a block of matrix. ResultsMultiple mouse brains were arrayed in a uniform orientation in a gelatin matrix block with ease using the receiving matrix. The gelatin-embedded brains were simultaneously sectioned and stained, and effortlessly mounted onto glass slides. Comparison with existing methodsThe improved approach allowed multiple whole or half mouse brains to be easily arrayed without pinning the samples onto a solid surface and prevented damages or shifting of the samples during embedding. ConclusionsThe new approach to array multiple brain samples provides a simple way to prepare gelatin-embedded whole or half brain arrays of commercial quality.

Quantitative dot-immunoblot assay to measure protein in multiple brain samples.

Quantitative dot-immunoblot assay to measure protein in multiple brain samples.

Cerebral effects of isovolemic hemodilution with crystalloid or colloid solutions

The cerebral effects of iv fluids have not been well defined, particularly the differences between crystalloids and colloids. We thus evaluated the effects of lactated Ringer's (LR) and 6% hetastarch (HES) solutions on brain edema, intracranial pressure (ICP), and cerebral blood flow (CBF) in anesthetized rabbits, using a model of isovolemic hemodilution (IVHD). In this model, arterial blood was removed at a rate of approximately 2 ml/min for one hour and replaced simultaneously with LR or HES in amounts needed to maintain arterial BP and CVP; Hct decreased from approximately 40% to approximately 19%. Thirty-six animals were divided into three groups (n = 12 each): a) IVHD with LR, b) IVHD with HES, and c) maintenance LR without hemodilution. To permit the examination of both acute and delayed fluid effects, each group was further divided into two subgroups (n = 6 each): one in which animals were sacrificed immediately on completion of the one-hour IVHD period (early), and one in which animals were sacrificed 4 h later (late). After sacrifice, brain and skeletal muscle water contents (% H2O) were determined, and the specific gravity (SpGr) of multiple brain samples was measured. Much larger volumes of LR were required to maintain normovolemia as compared with HES, (e.g., totals 203 +/- 68 vs. 76 +/- 18 ml/kg, respectively in late animals) and those given LR had larger increases in body weight and muscle % H2O.(ABSTRACT TRUNCATED AT 250 WORDS)