sentences:  The second generation of HTM learning algorithms, often referred to as cortical learning algorithms (CLA), was drastically different from zeta 1.It relies on a data structure called sparse distributed representations (that is, a data structure whose elements are binary, 1 or 0, and whose number of 1 bits is small compared to the number of 0 bits) to represent the brain activity and a more biologically-realistic neuron model (often also referred to as cell, in the context of the HTM theory).There are two core components in this HTM theory