Question #18: Modeling differential equations in neurochemistry

Modeling is at the crux of what makes science iterative. Andrews and Arkin’s 2006 review (here) explains many of the major equations in modeling the reactions of chemical species in cells. The most common model is the kinetic ordinary differential equation (ODE). It assumes that 1) concentrations of molecules are continuous (even though individual molecules [...]

Read Full Post »

Question #17: Biological and physical basis of fMRI

Functional magnetic resonance imaging is pretty technical stuff. As the Neuroskeptic aptly puts it, “when you do an fMRI scan you’re using a superconducting magnet to image human neural activity by measuring the quantum spin properties of protons. It doesn’t get much more technical.” The technique for measuring neural activity has become a household name [...]

Read Full Post »

Question #16: Three applications of the local field potential

The local field potential (LFP) is extracted by placing a extracellular microelectrode in the middle of a group of neurons without being too close to any particular cell. When ion channels open and close, charged molecules diffuse around. This changes the electrical potential of the medium surrounding the cells, which the electrode detects and transduces. [...]

Read Full Post »

Question #15: The neurogenetics of interspecies brain size variance

Neural tissue is nearly an order of magnitude more energetically taxing than other tissue types, so evolutionarily, larger brains would only evolve if they endowed a selective advantage large enough to compensate for the high energy cost. On the molecular level, increases in brain size could be accounted for by various gene duplications and divergences. [...]

Read Full Post »

Question #14: Three lesion studies on orbitalfrontal cortex function

The frontal lobe is predictably divided from the temporal lobe by the central sulcus. However, the morphology of the central sulcus varies between subjects, due in part to handedness and aging. The frontal lobes have traditionally been associated with executive functions. The prefrontal cortex is a part of the frontal lobe. Specifically, it contains the [...]

Read Full Post »

Question #13: Two applications of transgenic animals and knock-out mice

Here’s a quick rundown of transgenic animals: By deleting a particular gene or a particular promoter or some aspect of the genetic code, researchers can determine the role of that particular gene. Transgenic knock-outs can be for one or both of the gene alleles at a given locus. These days the name of the game [...]

Read Full Post »

Question #12: Two types of central pattern generators

Central pattern generators (CPGs) are networks of neurons that endogenously produce rhythmic output, typically used in motor control. Scott Hooper’s accepted definition of CPGs is that they must have rhythms in which: “(1) two or more processes that interact such that each process sequentially increases and decreases, and (2) that, as a result of this [...]

Read Full Post »

Question #11: Where does the plasticity of the vestibular ocular reflex occur?

One of the main roles of the semicircular canal system is to maintain the location of eye focus despite any head movements. The three pairs eye muscles are matched by the three planes of the semicircular canals, and each plane of the canals have direct control over one of these muscle pairs–either the medial and [...]

Read Full Post »

Question #10: Three findings from the crustacean stomatogastric nervous system

The crustacean stomatogastric nervous system has some particularly attractive features as a model system for neuroscience. Both their 14-cell pyloric network and 11-cell gastric mill network are anatomically separated from the rest of the nervous system and produce distinct motor patterns, allowing researchers to study the properties of each network individually. Here are three of [...]

Read Full Post »

Question #9: Variation of neural processing in sensory systems

The fact that so many sensory systems eventually project to the cerebral cortex indicates that there are likely similarities in their processing. Evolutionarily, it’s plausible that most neural sensory systems diverged from one common system that involved early analogue of the cortex. Within mammals, there is a large amount of variation in the number of [...]

Read Full Post »