Understanding neurons 3


So far, I described communication between neurons in an intuitive manner.  You touch an object, a signal sweeps across the neuron's axon, and neurotransmitters are released into the synapse. The idea that something can move from one location to another (a car, a train, a wave moving toward the shore) is familiar.  So it's intuitive to imagine neuronal signals carrying touch information from the hand to the brain.

Regardless of whether the neuron is carrying a signal about something you touched, heard, smelled, or thought, the signal could not possibly move along the axon if the entire neuron were not bathed in fluid. That's because the signal involves a substance moving in and out of the neuron, and the fluid allows things to flow in and out.  This is where neural communication becomes a little less intuitive.

The neuron is surrounded by fluid that contains sodium, abbreviated Na+.  Neural communication begins when gates within the wall of the neuron open, allowing sodium to flow in.

Understanding neurons 2


Neurons in the hand communicate tactile (and pain) information to other neurons, and neurons in the brain receive these signals and turn them into the conscious sensation of touch (or pain).

But what does it mean to say that one neuron 'communicates' with another?  The neurons don't speak in words. 

Understanding neurons


For people interested in understanding how the brain gives rise to vision, memory, pleasure, pain, and other mental phenomena, it's worthwhile to start by understanding what it means for a neuron to become activated and to communicate with other neurons.

When you touch something with your finger, the touch sensation is not occurring in the finger but in your brain.  At the moment of touch, neurons in your fingers send 'signals' to the spinal cord, and neurons in the spinal cord send signals to particular areas of the brain that give rise to the touch sensation. 

Differences between countries


After so many years visiting Spain, it's become second nature to me to make mental comparisons of U.S. and Spanish culture. There are differences in terms of politics, eating, ways of living, and so on.  Sometimes it's the small differences that make a big impression on you.   For instance, when you ask for coffee with milk in Spain, they give you heated milk which makes the coffee taste better (but don't go by me).

Sometimes comparisons between countries are complicated by variations that exist within a country.   For instance, in Madrid during the summer, when the temperature is sometimes in the 90s,