Adult neurogenesisAdult neurogenesis is the process in which neurons are generated from neural stem cells in the adult. This process differs from prenatal neurogenesis. In most mammals, new neurons are born throughout adulthood in two regions of the brain: The subgranular zone (SGZ), part of the dentate gyrus of the hippocampus, where neural stem cells give birth to granule cells (implicated in memory formation and learning). The subventricular zone (SVZ) of the lateral ventricles, which can be divided into three microdomains: lateral, dorsal and medial.
NeurogenesisNeurogenesis is the process by which nervous system cells, the neurons, are produced by neural stem cells (NSCs). It occurs in all species of animals except the porifera (sponges) and placozoans. Types of NSCs include neuroepithelial cells (NECs), radial glial cells (RGCs), basal progenitors (BPs), intermediate neuronal precursors (INPs), subventricular zone astrocytes, and subgranular zone radial astrocytes, among others.
T cellT cells are one of the important types of white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells.
Hemolytic disease of the newbornHemolytic disease of the newborn, also known as hemolytic disease of the fetus and newborn, HDN, HDFN, or erythroblastosis foetalis, is an alloimmune condition that develops in a fetus at or around birth, when the IgG molecules (one of the five main types of antibodies) produced by the mother pass through the placenta. Among these antibodies are some which attack antigens on the red blood cells in the fetal circulation, breaking down and destroying the cells. The fetus can develop reticulocytosis and anemia.
B cellB cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell.
Dendritic cellA dendritic cell (DC) is an antigen-presenting cell (also known as an accessory cell) of the mammalian immune system. A DC's main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and adaptive immune systems. Dendritic cells are present in tissues that are in contact with the body's external environment, such as the skin (where there is a specialized dendritic cell type called the Langerhans cell), and the inner lining of the nose, lungs, stomach and intestines.
T helper cellThe T helper cells (Th cells), also known as CD4+ cells or CD4-positive cells, are a type of T cell that play an important role in the adaptive immune system. They aid the activity of other immune cells by releasing cytokines. They are considered essential in B cell antibody class switching, breaking cross-tolerance in dendritic cells, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages and neutrophils.
Nucleated red blood cellA nucleated red blood cell (NRBC), also known by several other names, is a red blood cell that contains a cell nucleus. Almost all vertebrate organisms have hemoglobin-containing cells in their blood, and with the exception of mammals, all of these red blood cells are nucleated. In mammals, NRBCs occur in normal development as precursors to mature red blood cells in erythropoiesis, the process by which the body produces red blood cells. NRBCs are normally found in the bone marrow of humans of all ages and in the blood of fetuses and newborn infants.
Antigen-presenting cellAn antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). APCs process antigens and present them to T-cells. Almost all cell types can present antigens in some way. They are found in a variety of tissue types.
HaematopoiesisHaematopoiesis (hɪˌmætəpɔɪˈiːsɪs,_ˌhiːmətoʊ-,_ˌhɛmə-, from Greek αἷμα, 'blood' and ποιεῖν 'to make'; also hematopoiesis in American English; sometimes also h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult human, roughly ten billion () to a hundred billion () new blood cells are produced per day, in order to maintain steady state levels in the peripheral circulation.
Naive T cellIn immunology, a naive T cell (Th0 cell) is a T cell that has differentiated in the thymus, and successfully undergone the positive and negative processes of central selection in the thymus. Among these are the naive forms of helper T cells (CD4+) and cytotoxic T cells (CD8+). Any naive T cell is considered immature and, unlike activated or memory T cells, has not encountered its cognate antigen within the periphery. After this encounter, the naive T cell is considered a mature T cell.
Medium spiny neuronMedium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), are a special type of GABAergic inhibitory cell representing 95% of neurons within the human striatum, a basal ganglia structure. Medium spiny neurons have two primary phenotypes (characteristic types): D1-type MSNs of the direct pathway and D2-type MSNs of the indirect pathway. Most striatal MSNs contain only D1-type or D2-type dopamine receptors, but a subpopulation of MSNs exhibit both phenotypes.
Reelin'Reelin', encoded by the RELN gene, is a large secreted extracellular matrix glycoprotein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this important role in early development, reelin continues to work in the adult brain. It modulates synaptic plasticity by enhancing the induction and maintenance of long-term potentiation.
HippocampusThe hippocampus (via Latin from Greek ἱππόκαμπος, 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex in humans, as well as primates.
Bone marrowBone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. Bone marrow comprises approximately 5% of total body mass in healthy adult humans, such that a man weighing 73 kg (161 lbs) will have around 3.
Subgranular zoneThe subgranular zone (SGZ) is a brain region in the hippocampus where adult neurogenesis occurs. The other major site of adult neurogenesis is the subventricular zone (SVZ) in the brain. The subgranular zone is a narrow layer of cells located between the granule cell layer and hilus of the dentate gyrus. This layer is characterized by several types of cells, the most prominent type being neural stem cells (NSCs) in various stages of development.
Ventral tegmental areaThe ventral tegmental area (VTA) (tegmentum is Latin for covering), also known as the ventral tegmental area of Tsai, or simply ventral tegmentum, is a group of neurons located close to the midline on the floor of the midbrain. The VTA is the origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system and other dopamine pathways; it is widely implicated in the drug and natural reward circuitry of the brain.
Γ-Aminobutyric acidγ-Aminobutyric acid (gamma-aminobutyric acid) ˈɡæmə_əˈmiːnoʊbjuːˈtɪrᵻk_ˈæsᵻd, or GABA ˈɡæbə, is the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system. GABA is sold as a dietary supplement in many countries. It has been traditionally thought that exogenous GABA (i.e. taken as a supplement) does not cross the blood–brain barrier, but data obtained from more recent research in rats describes the notion as being unclear.
LymphopoiesisLymphopoiesis (lĭm'fō-poi-ē'sĭs) (or lymphocytopoiesis) is the generation of lymphocytes, one of the five types of white blood cells (WBCs). It is more formally known as lymphoid hematopoiesis. Disruption in lymphopoiesis can lead to a number of lymphoproliferative disorders, such as lymphomas and lymphoid leukemias. Lymphocytes are of the lymphoid (rather than the myeloid or erythroid) lineage of blood cells.
StriatumThe striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutamatergic and dopaminergic inputs from different sources; and serves as the primary input to the rest of the basal ganglia. Functionally, the striatum coordinates multiple aspects of cognition, including both motor and action planning, decision-making, motivation, reinforcement, and reward perception.
