Neuroscience of Brain, Behavior, and Disorders — Structure, Neurotransmitters, and Neurological Diseases | Chapter 49 of Campbell Biology

The brain is the seat of thought, behavior, and emotion—its complex circuits underpinning everything from memory and learning to movement and mood. Chapter 49 of Campbell Biology explores the fascinating world of neuroscience, examining how neurons communicate, how the brain is organized, and what happens when neural circuits go awry. This chapter connects brain anatomy with physiology and behavior, highlighting both normal brain function and the basis of neurological and psychiatric disorders.

Watch the podcast summary below for a comprehensive overview, then read on for an in-depth look at neural networks, the biology of behavior, and the mechanisms of brain disorders.

Introduction: Structure and Organization of the Nervous System

The nervous system is divided into the central nervous system (CNS)—the brain and spinal cord—and the peripheral nervous system (PNS), which carries signals to and from the rest of the body. Glial cells support, insulate, and protect neurons, playing essential roles in neural function.

Brain Anatomy and Cognitive Functions

• Cerebrum: Responsible for higher cognitive functions—learning, memory, language, and perception.
• Cerebral Cortex: The outer layer of the cerebrum, involved in voluntary movement and sensory processing.
• Brainstem and Cerebellum: Control vital functions, coordination, and motor learning.
• Limbic System: Includes the amygdala and hippocampus, regulating emotions and memory formation.
• Prefrontal Cortex: Critical for decision-making, planning, and personality.
• Thalamus: Relay station for sensory information heading to the cortex.

Neural Communication, Synaptic Plasticity, and Memory

• Neurons and Synapses: Neurons transmit information via neurotransmitters across synapses to coordinate thoughts, movement, and homeostasis.
• Synaptic Plasticity: The ability of synapses to strengthen or weaken in response to activity, crucial for learning and memory.
• Neuroplasticity: The brain's capacity to reorganize itself by forming new connections after learning or injury.
• Synaptic Pruning: The elimination of excess synapses to refine neural circuits during development and learning.

Behavior, Emotions, and Brain Regions

• Amygdala: Involved in processing emotions, especially fear and aggression.
• Limbic System: Coordinates emotional responses and memory storage.
• Prefrontal Cortex: Integrates emotion and rational thought, guiding decision-making and personality.
• Reflexes: Simple, involuntary responses mediated by the spinal cord.

Neurological and Psychiatric Disorders

• Schizophrenia: A disorder involving disorganized thinking, hallucinations, and disrupted dopamine pathways.
• Depression: Linked to neurotransmitter imbalances and changes in brain circuitry.
• Drug Addiction: Involves maladaptive changes in dopamine signaling and reward circuits.
• Alzheimer’s Disease: Characterized by memory loss and cognitive decline due to amyloid plaques and neurofibrillary tangles.
• Parkinson’s Disease: Motor control problems resulting from loss of dopamine-producing neurons.

Key Glossary Terms

• Afferent Neurons: Sensory neurons carrying signals to the CNS
• Amygdala: Emotion and memory processing center
• Cerebellum: Coordination and motor learning
• Cerebrum: Higher cognitive functions
• Cerebral Cortex: Sensory and voluntary control
• Limbic System: Emotions, memory, and motivation
• Neurotransmitter: Chemical messengers in synapses
• Prefrontal Cortex: Decision-making and personality
• Reflex: Rapid, involuntary response
• Synaptic Pruning: Elimination of excess synapses
• Neuronal Plasticity/Neuroplasticity: Adaptation and new connections in the brain
• Synapse: Neuron-to-neuron communication site
• Glial Cells (Glia): Neuron support and protection
• Thalamus: Sensory relay in the brain
• Wernicke's Area: Language comprehension region
• Parkinson's Disease: Motor disorder from dopamine loss
• Schizophrenia: Disorder with hallucinations and thought disturbances
• Dopamine: Neurotransmitter for reward and motivation
• Alzheimer’s Disease: Neurodegenerative memory disorder

Conclusion: The Dynamic Brain—From Circuits to Disorders

The nervous system enables perception, thought, movement, and emotion—while its dysfunction leads to a range of neurological and psychiatric disorders. Advances in neuroscience continue to illuminate how the brain’s structure and chemistry shape who we are and how we behave.

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