Exploring Behavioral Neuroscience

Rebecca Joan Neisler
May 27, 2024
4 min read

Updated: Oct 21

Behavioral neuroscience is the scientific attempt to explain why we do what we do—how perception, movement, sleep, sex, emotion, learning, and language all emerge from the firing of billions of microscopic cells. It’s the study of behavior reduced to its biological machinery, tracing every thought and twitch back to the electric murmurs of the nervous system.

At its core, behavioral neuroscience asks one hauntingly simple question: “How is this creature constructed to be able to do that?” Answering that means peering under the hood at the machinery itself—neurons, glia, proteins, enzymes, brain regions, spinal cord, and the sprawling peripheral nervous system. Together, they form the living circuitry behind every act of consciousness.

Structures — cells

Proteins, Receptors, Enzymes

Brain Regions

Spinal Cord

Peripheral Nervous System

Why Neuroscience Matters

The importance of neuroscience isn’t abstract—it’s personal. Millions of people live with neurological and psychiatric disorders, and understanding the brain is our best hope for relief. The field draws together a wildly interdisciplinary crowd: psychologists, biologists, engineers, physicians, and dreamers alike, all trying to decode the same tangled signal.

Behavioral neuroscience isn’t just about fixing broken brains—it’s also about understanding healthy ones. Sometimes basic science drives medical discovery; other times, treatments for disease reveal something profound about how the brain normally works. It’s a reciprocal loop: healing informs knowing, and knowing informs healing.

The Five Major Viewpoints of Behavioral Neuroscience

To grasp behavior, neuroscientists often rotate the same problem through five complementary lenses:

Description—What does the behavior look like?
Evolution—How did it arise and adapt across species? (Comparative neuroscience.)
Development—How does it unfold across an organism’s life span (ontogeny)?
Mechanism—What neural machinery produces it? (Physiology.)
Application—How can understanding it improve lives?

These perspectives are like five dimensions of the same puzzle. Evolutionary comparisons, for instance, reveal both difference and continuity. Some bats navigate by sonar, others by sight—divergent solutions to the same ecological problem. Meanwhile, sex hormones appear across all mammals, a sign of deep ancestral continuity. Evolution conserves what works.

Ontogeny—the study of development—adds another layer. As brains mature, circuits shift. Monkeys gradually improve their memory over years, implying that neural systems for recall take time to wire up. Rodents can learn before they can remember long-term, showing that learning and memory aren’t the same trick performed at different speeds—they’re separate processes, with distinct neural roots.

By exploring these viewpoints, we start to see how behavior, biology, and time sculpt one another.

From Heart to Head

Early humans got it wrong in a poetic way. Ancient Egyptians, and later Aristotle, thought the heart was the seat of mind and soul. When Pharaoh Tutankhamun was mummified around 1300 BCE, his brain was literally scooped out—discarded as useless tissue. The Hebrew Bible echoes this view: “Teach us… that we may gain a heart of wisdom” (Psalm 90:12). The brain was barely a footnote.

Herophilus (350 BCE), dissecting cadavers in ancient Greece, began connecting nerves to specific body regions—a revolutionary insight. Later, Galen observed gladiators with head injuries and realized brain damage changed behavior. The brain was finally earning respect.

Renaissance Reawakening

Fast forward to Leonardo da Vinci, who treated anatomy like art and revelation. He poured wax into brain ventricles, then peeled away tissue to reveal the internal geometry—effectively performing the first 3D brain imaging, Renaissance-style. His cross-sections mapped nerves, ventricles, and brain surfaces with obsessive precision. Anatomy, once mystical, was now observable.

The Mind-Body Problem

At the root of neuroscience lies a philosophical hangover: What’s the relationship between the mind and the brain?

Enter René Descartes (17th century), who saw animals as biological machines running reflex programs but insisted humans had a soul—a separate, immaterial “thinking substance” that communicated with the body through the pineal gland. (He chose the pineal because it’s single, like consciousness. He was wrong about it being uniquely human.)

This view, called dualism, let early scientists study anatomy without angering the church—the soul remained untouched. But modern neuroscience rejects dualism. We’ve found no ghost in the machine, only the machine itself.

The alternative, monism, claims the universe is made of one kind of stuff. Most neuroscientists are materialists: everything mental arises from the physical. Thoughts, feelings, even the sense of self—all emerge from matter in motion.

If you guessed that 99% of neuroscientists are materialists, you’re right.

Consciousness—our awareness of existence—is still the unsolved frontier. We know it depends on brain activity: deep structures regulate arousal, cortical regions weave experience. Yet how subjective awareness arises from matter remains a profound mystery. Neuroscience can explain how we think—not yet why it feels like something to think.

Close, but Not Quite: Phrenology

By the late 1600s, Thomas Willis had convinced the Western world that the brain controlled behavior. Two centuries later, phrenology tried to push this idea too far—claiming you could read personality by feeling the bumps on someone’s skull.

It was nonsense, of course, but it introduced one enduring idea: localization—that different parts of the brain might handle different functions. While phrenology died, localization survived, refined by real data.

Localization Wins: Broca and Beyond

French neurologist Paul Broca made localization respectable. When his patient “Tan” lost the ability to speak, Broca discovered a lesion in the left frontal lobe—now Broca’s area. Suddenly, function could be mapped to structure.

Then came the golden age: William James’s Principles of Psychology framed behavior as brain function; Ivan Pavlov uncovered conditioning; Karl Lashley searched (unsuccessfully) for the physical trace of memory—the “engram.” Donald Hebb later proposed how memory might actually work: neurons that “fire together, wire together.” Hebbian plasticity became the modern basis for learning theory and artificial neural networks.

Meanwhile, the question of brain size and intelligence kept resurfacing. Francis Galton sought a link between skull size and intellect (spoiler: poor methods, bad data). Modern MRI studies show a modest but real correlation—around r = 0.38 after adjusting for body size. So, yes, bigger brains tend to have more processing capacity, but wiring efficiency matters more than raw volume.

The Living Frontier

From Aristotle’s misplaced heart to Hebb’s synapses, neuroscience has evolved from guesswork to precision mapping. Today, it’s booming: over 25,000 neuroscientists attend the Society for Neuroscience’s annual meeting, and tens of thousands of studies are published each year.

We’re still chasing the same old question—what makes consciousness emerge from meat—but with better tools, sharper questions, and far less superstition. Neuroscience, at its best, isn’t just about studying the brain. It’s about studying ourselves—the universe’s most self-reflective organ trying to understand its own construction.