PSYCHOLOGY Chapter 3 Biopsychology: Neurons and Brain Structures
Learning Objectives
- Understand the structure and functioning of neurons, including neuronal communication.
- Define neurotransmitters and know the main neurotransmitters involved in behavior and mental processes.
- Understand the structure of the nervous system, including the main branches of the central and peripheral systems.
- List and describe the main parts of the brain, especially the component structures of the hindbrain and the forebrain (including the components of the limbic system and of the cerebral cortex).
Cells of the Nervous System
- Neurons – the basic units of the nervous system that communicate with each other.
- Figure 3.8 indicates a prototypical neuron.
Electrical Properties of Neurons
- Resting potential.
- Action potential.
Neuronal Communication (Through Neurotransmitters)
- Presynaptic neuron (A).
- Postsynaptic neuron (B).
- Axon.
- Action potential.
- Neurotransmitters.
- Synapse.
- Receptors for neurotransmitters.
- Process overview: An action potential travels to the synaptic terminal, triggering release of neurotransmitters into the synapse, which then bind to receptors on the postsynaptic neuron to propagate the signal.
Neurotransmitters
- Neurotransmitter – chemical messenger of the nervous system.
- Different neurons release different types of neurotransmitters.
- Psychotropic medication – drugs that treat psychiatric symptoms by restoring neurotransmitter balance.
- Agonist strengthens, Antagonist weakens the activity of a neurotransmitter.
- Acetylcholine – muscle action and memory
- Beta-endorphin – pain reduction, pleasure
- Dopamine – mood, reward, schizophrenia, movement
- Norepinephrine – alertness
- Serotonin – mood, sleep, appetite
- GABA – anxiety reduction
The Nervous System
- Central nervous system (CNS): Brain and Spinal cord.
- Peripheral nervous system (PNS).
- Somatic nervous system.
- Autonomic nervous system with its Sympathetic and Parasympathetic divisions.
The Autonomic Nervous System
- Parasympathetic Nervous System:
- Constricts pupil
- Stimulates salivation
- Slows heart rate
- Constricts bronchi
- Stimulates digestion
- Causes bladder to contract
- Sympathetic Nervous System:
- Dilates pupil
- Inhibits salivation
- Increases heart rate
- Dilates bronchi
- Inhibits digestion
- Inhibits contraction of bladder
The Hindbrain
- Medulla – automated processes like breathing, blood pressure, and heart rate (survival functions).
- Pons – regulating brain activity during sleep.
- Cerebellum – balance, coordination, movement, and processing some types of memory.
- All three comprise the brain stem.
Forebrain Structures: Thalamus and Limbic System
- Thalamus – sensory relay.
- Amygdala – emotion and linking emotion to memories.
- Hippocampus – learning and memory.
- Hypothalamus – homeostatic processes including body temperature, appetite, sleep, and blood pressure.
Forebrain Structures: Cerebral Cortex
- Cerebral cortex – surface of the brain, highest mental capabilities.
- It consists of two hemispheres, each broken up into four lobes.
- Occipital lobe – vision.
- Split-brain research.
Connections to Real-World Relevance
- Neurotransmitters influence mood, cognition, and behavior; imbalances are linked to psychiatric symptoms and treated with psychotropic medications.
- The autonomic nervous system governs stress responses and everyday bodily regulation (digestion, heart rate, pupil dilation).
- The hindbrain supports vital regulatory functions and motor coordination; the cerebellum also contributes to memory processing for some tasks.
- The limbic system links emotion and memory, affecting learning and behavior.
- The cerebral cortex enables complex thought, perception, language, and conscious experience; lateralization and split-brain findings inform our understanding of hemispheric specialization.
- No numerical values, equations, or statistical references are provided in this transcript.