Question

The passage below is adapted from an essay on the history of neuroscience.

Paragraph 1 (lines 1–12)
For nearly a century, a central dogma of neuroscience held that the mature adult brain was entirely incapable of generating new neurons. According to this view, humans are born with a finite number of brain cells, and any subsequent cognitive decline or brain injury is irreversible because the brain lacks the capacity to replenish its neural stock. This belief was largely established by Santiago Ramón y Cajal, the father of modern neuroscience, who famously declared that in adult brains, "the nerve paths are something fixed, ended, immutable; nothing may be regenerated." This dogma dictated the direction of research and medical treatment for decades, discouraging scientists from looking for signs of new cell growth in adult mammals.

Paragraph 2 (lines 13–27)
However, this scientific consensus began to fracture in the 1960s when researcher Joseph Altman utilized autoradiography to detect dividing cells in the brains of adult rats. Altman’s findings suggested that new neurons were indeed being formed in the hippocampus—a region crucial for learning and memory. Despite the evidence, Altman’s work was widely dismissed or ignored by a scientific community deeply wedded to the established belief of an immutable adult brain. It was not until the late 1990s, when Elizabeth Gould and her colleagues demonstrated neurogenesis in adult primates, and subsequent studies confirmed it in humans, that the scientific community finally accepted adult neurogenesis as a biological reality. This paradigm shift has since revolutionized our understanding of brain plasticity and opened new avenues for treating neurodegenerative diseases.

Which of the following statements best captures the main point of Paragraph 2 (lines 13–27)?