Additional Science Notes
The "About Pages".
These pages are intended to serve as a bridge between the website and the blog. I will post links here that I think
will be more useful towards the course material and I have moved some of the links that are less directly-related to the
current material to the blog.
The blog is intended as a place for interesting links, pod-casts, and other notables that have to do with neuroscience
and physiology. It is also a place to record longer answers to some of the questions posed by email.
Nifty Site of the Week
There are several great sites to help you get familiar with the geography of the brain. This
site has a massive collection of brain imagery from blockfaces (slices of brain in natural colour) to MRI to Nissl staining (just the cell bodies are stain). These can really help to orient you to where you are in the brain.
Also:
The Digital Anatomist Project has line drawings and movies and most importantly, quizzes to help you understand the structure of the brain.
We started the course with a tidbit about perception and how your mind often lies to you when interpreting information. This is a great link that one of you sent to me. Watch this video and count the passes of the basketball.
This is really just an article at CNN, but it mentions dopaminergic pathways and cocaine, two of my favourite subjects. It is a short read that describes the regions of the brain that are active when one is having 'loving thoughts' invoked by pictures of the subject's sweetheart.
Find a great Nernst/GHK equation simulator here.
For a more mundane version, here is a local site page.
Nifty article of the week
We have begun cover synapses and will be discussing concepts involving synapses such as learning and memory. The molecular and cellular basis of these concepts is believed to be Long Term Potentiation (LTP) and depression (LTD). This is a
student-submitted article on LTP that is a very nice quick read.
Time published an
entire issue on the brain at the end of January. This is a great gentle read to get you in the mood for neuronerdiness.
This is a short
article on the nature of consciousness. There is a discussion of the difficulty in defining just what it means to be cognizant and how what we perceive as a vegetative state phenotypically, can have all the hallmarks of an "awake" patient when monitored with fMRI machines.
This is a very
nice read about Eric Kandel of Columbia University. He is often considered something of a god in neuroscience circles. I tried to kiss his feet once, but he just threw down some coins and complained that the police do nothing about the bums.
Nifty Podcast of the Week
July 15th. There is a very cool podcast from Australia to covers the last frontier of privacy: your thoughts.
This ~30 minute long podcast discusses "mind reading" and the power of brain scans to detect lies and psychoses. It does this in light of what sort of evidence can be presented in a court of law.
Subscribe to Science Friday Podcasts and listen to popular descriptions of ongoiong Neuroscience research.
This particular hour has a nice description of consolidation of memories in the hippocampus during sleep. They recorded a rat brain "replaying" its wanderings through a maze in reverse order.
ScienceFriday December 22 2006
Other neuroscience podcasts:
TWIS: This Week in Science– Neuroscience.
Brain Sites:
Brain Facts and Figures |
Action Potentials |
Neuroscience Tutorials |
Mind and Brain Portal |
Wikibooks: neuroscience |
Textbooks online: Purves Neuroscience
Neurons
The primary function of neurons is the transmission of information from one point to another. In general, the neuron is composed of three regions: the soma, or cell body, with extensions called dendrites that increase the surface area and also allow for interactions with distant neurons; the synaptic bouton, which is the part of the cell which transmits a signal onto its target; and lastly, the axon. This last segment is the often long projection from the cell body to the target cells. This may extend from the toe of a vertebrate organism to the spine – some 12 feet in a giraffe. The signal that indelibly is carried down the axon is called an action potential. Links: wikipedia- Neuron | Pretty pictures of neurons.
Action Potentials
Axons are the primary communication conduits between a neuron's soma/dendrites receiving stimuli and the synapses on target cells. While pre- and post-synaptic membranes are sites for signal modulation, integration, and discrimination, axons are rather simple wires. The primary signal is a current that propogates the length of the axon, which may be some 12 feet long in some animals. This current relies on the influx of sodium through voltage-gated channels that are inactivating. But it also relies on the fact that the axon is 'insulated' with Schwann cells. These cells provide a coating to the axon which inhibits the capacitance that would occur in an exposed membrane. This capacitance does two things: (1) It "holds" some ions along the membrane as they are attracted to opposite charges on the other side of the membrane. This prevents them from moving down the axon, which is a way of weakening the signal. (2) It is the flow (or current) of ions towards the membrane that sets them moving in a direction other than down the axon. This means that a current due to capacitance (a capacitance current, duh) is 'distracting' ions from being involved in transmitting a signal down the axon. So the capacitance current, and capacitance itself, both inhibit or resist the axonal current. Myelination by Schwann cells increases membrane resistance. This means the capacitance is not likely to occur since the opposite charges are too far apart for them to detect each other. If they cannot see each other, the ions inside continue to flow down the axon. This means they are resisted from travelling to the membrane. So myelination provides membrane resistance against the capacitance current, which promotes the signal current down the axon.
Links: wikipedia- Action Patential |
The original paper that describes the axon potential in the giant squd axon.
