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 …
Category Archives: Uncategorized
Bridge law (or principle)
Also known as reduction function, it is a law (or set of laws) connecting the predicates of the reduced theory (the theory to be reduced) with the predicates of the reducing theory (the theory to which the first is reduced). First introduced by Ernest Nagel (1901-1985) as a means of integrating different levels of organization …
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 damage studies
Used to help determine the functions of parts of the brain; a person with damage to a specific brain area often shows deficits in specific abilities (e.g., damage to the hippocampus leads to deficits in memory). One of the salient features of such studies in recent times has been an interest the neuroprotective factors of …
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 …
Brachial plexus
A group of nerves formed from vertebral levels C4-T1 in the spinal cord that are responsible for innervating most of the structures in the upper limb (see figure below). The majority of brachial plexus injuries occur during delivery through the birth canal. Most newborns with such injuries are larger than average at birth, although the …
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 …
Botulinus (or botulinum or botox)
Toxin injections made from a chemical produced by bacteria that temporarily paralyse muscle by acting on nerve impulse transmission. They produce reduction of hypertonicity by reversible denervation. Although this toxin exerts this effect on most nerve cells, it acts preferentially on cholinergic nerve endings. Dose-response experiments indicate that the vertebrate neuromuscular junction is the site …