Brain stem

An evolutionary older, more ‘primitive’ part of the lower central mammalian brain responsible for organizing fundamental emotions related to fear, hunger, sex, protective drives and temperature control, emotionality, arousal, sleep, heart and breathing rates, water retention, blood pressure and volume, as well as possibly the ratio of carbon dioxide to oxygen.  Among other functions, it …

Brain sparing

A notion derived from animal studies, which claims that when the developing organism is subjected to perinatal insults such as hypoxia, then the supply of oxygen and nutrients is preferentially directed to the brain at the expense of other vital organs like the kidneys and liver.  Recent research, including that with preterm infants suffering from …

Brain derived neurotrophic factor (BDNF)

In contrast to nerve growth factor (NGF), BDNF is mainly, though not exclusively, localized in the central nervous system.  It supports the survival of primary sensory neurons originating from the neural crest and ectodermal placodes that are not responsive to NGF. See Axonal retraction, Ectoderm, Embryogenesis, Nerve growth factor (NGF), Neural crest, Placode

Brain (or encephalon)

0.056 Representative pregnancy durations (days), neonatal and adult brain and body weights (grams), and advancement factors for three of the great apes and humans. Data based on Sacher, G.A., & Staffeldt, E.F. (1974). Relation of gestation time to brain weight for placental animals: implications for the theory of vertebrate growth. American Naturalist, 108, 593-615. See …

Brain (neuro-) imaging

Identified by two broad categories: structural and functional imaging.  Structural imaging evolved from radiographic techniques for imaging the brain through non-invasive techniques such computerised axial tomography (CAT) to two-dimensional structural magnetic resonance imaging (sMRI).  Functional imaging, which began with xenon gas inhalation, really started to develop with the discovery of radioligands that remained in the …

Boutons

Terminal bulbs (presynaptic terminals) at the end of a axon (see figure below) or varicosities along the course of axons.  Occurring in both the central and peripheral nervous systems, they release neurotransmitters across the synaptic cleft that bind to receptors on the postsynaptic cell (neurone or muscle) leading it to respond with depolarization. Synaptic bouton …

Bourbaki

Collectivepseudonym of a group of mainly French mathematicians who, particularly in thefirst half of the 20th century, sought to redefine the fundamentals ofmathematics on a formal basis.  Their emphasis on structure as a basic featureof mathematics was an important source of inspiration and partial disagreementfor Piaget.  The historical Nicholas Bourbaki was a 19th century French …