regarding ltp; what is the earlier learning theory?
The number of neurons in the adult brain (roughly 100 billion) did not increase significantly with age, memories were generally not the result of new neuron production, memories could form in the absence of new neurons.
Long-term potentiation
At the end of the 19th century, scientists generally recognized that the number of neurons in the adult brain (roughly 100 billion) did not increase significantly with age, giving neurobiologists good reason to believe that memories were generally not the result of new neuron production. With this realization came the need to explain how memories could form in the absence of new neurons.

The Spanish neuroanatomist Santiago Ramón y Cajal was among the first to suggest a mechanism of learning that did not require the formation of new neurons. In his 1894 Croonian Lecture, he proposed that memories might instead be formed by strengthening the connections between existing neurons to improve the effectiveness of their communication. Hebbian theory, introduced by Donald Hebb in 1949, echoed Ramón y Cajal's ideas, further proposing that cells may grow new connections or undergo metabolic and synaptic changes that enhance their ability to communicate and create a neural network of experiences
what is the best description for long-term potentiation (ltp) In neuroscience, long-term potentiation (LTP) is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. what is mean by the first mentioned science? It is the scientific study of the nervous system.
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Long-term potentiation [SEP] Early theories of learning
At the end of the 19th century, scientists generally recognized that the number of neurons in the adult brain (roughly 100 billion) did not increase significantly with age, giving neurobiologists good reason to believe that memories were generally not the result of new neuron production. With this realization came the need to explain how memories could form in the absence of new neurons. The Spanish neuroanatomist Santiago Ramón y Cajal was among the first to suggest a mechanism of learning that did not require the formation of new neurons. In his 1894 Croonian Lecture, he proposed that memories might instead be formed by strengthening the connections between existing neurons to improve the effectiveness of their communication.