Brain Anatomy, Neurotransmitters, and Perception Explained

Posted on Oct 7, 2026 in Psychology

Brain Anatomy and Regions

  • Frontal Lobe / Prefrontal Cortex: Directs higher-order thinking, executive functions, planning, and impulse control. Damage results in poor judgment, impulsivity, and personality changes.
  • Occipital Lobe: Dedicated to visual processing and vision.
  • Parietal Lobe: Integrates sensory input and spatial awareness. Damage can lead to tactile agnosia (inability to identify objects by touch) or misjudging space.
  • Temporal Lobe: Manages hearing, memory, language comprehension, and object recognition.
  • Cerebellum: Coordinates voluntary movement, posture, and physical balance.
  • Brain Stem: Controls automatic, life-sustaining functions such as breathing and heart rate.
  • Corpus Callosum: Nerve bridge enabling communication between the left and right hemispheres.
  • Hippocampus: Essential for encoding and forming new long-term memories.
  • Amygdala: Handles emotional processing, fear responses, and threat detection.
  • Thalamus: Serves as the central relay station routing sensory signals to the cortex.
  • Cingulate Cortex: Regulates emotions and connects behavioral actions to motivation.
  • Modern System View: Brain functions emerge from interconnected networks rather than single, isolated areas.

Nervous System and Chemical Messengers

  • Dopamine: Drives motivation, reward pathways, and feelings of accomplishment.
  • Acetylcholine: Triggers voluntary muscle contractions.
  • Serotonin: Regulates mood, emotional well-being, and anxiety reduction.
  • Glutamate: Primary neurotransmitter for learning and memory consolidation.
  • Endorphins: Relieves physical pain and boosts positive feelings.
  • Oxytocin: Promotes social bonding, trust, and interpersonal attachment.
  • Norepinephrine / Noradrenaline: Fuels the fight-or-flight response, boosting alertness and heart rate.
  • GABA: Primary inhibitory neurotransmitter; calms neural overactivity to reduce anxiety.
  • Somatic Nervous System: Governs conscious, voluntary muscle movements.
  • Autonomic Nervous System: Regulates involuntary body functions (heartbeat, digestion).
    • Sympathetic: Accelerates fight-or-flight reactions (sweating, dilated pupils, high heart rate).
    • Parasympathetic: Rest-and-digest response (slows heart rate, stimulates digestion).
  • Sensory vs. Motor Divisions: Sensory pathways carry input from the body to the brain; motor pathways carry commands from the brain to muscles.

Perception, Stress, and Memory Concepts

  • Vision and Depth:
    • The blind spot occurs where the optic nerve exits the retina because it lacks photoreceptors.
    • The lens projects an inverted (upside-down) 2D image onto the retina; the brain merges projections from both eyes to generate 3D depth perception.
    • Stratton’s experiment proved sensory adaptation allows the brain to normalize inverted vision over time.
  • Sensory Thresholds:
    • Absolute Threshold: The minimum stimulus intensity detectable at least 50% of the time.
    • Subliminal Stimuli: Messages delivered below conscious awareness thresholds.
  • Stress Mechanics:
    • Amygdala Hijack: The amygdala triggers an immediate flood of cortisol and adrenaline before rational prefrontal thinking can occur.
    • Brain Glucose: Protects neural tissue from stress-hormone damage and electrical storms; fruit sugars and raw honey restore it most effectively.
  • Sensory Memories:
    • Somatic Memory: Bodily sensations tied to past emotional trauma that can be triggered by sensory cues (smells, music).
    • Phantom Limb: Sensations of an amputated limb that often retain pre-amputation feelings like wearing a ring, joint pain, or limb positions.