brain stem and limbic system

Brainstem - older

• Oldest and innermost part of the brain.

• Begins where spinal cord swells into medulla:

  • Controls heartbeat and breathing.

• Pons (above medulla):

  • Coordinates purposeful movement.

• Crossover point: most nerves from each brain side connect to the opposite body side.

What are the four key areas of the brain and what are they known for?

1. Brainstem - regulating life functions like breathing, heart rate, blood pressure

2. Cerebellum - balance, motor function, speech production, learning in classically conditioned responses

3. Cerebral - largest part, higher brain function like thought and action, divided into lobes

4. Limbic - emotional brain, memory and emotion

Cognitive task

You have to think about it, but the brain adapts to minimize energy expended

Associative task

Chunking together a series of movements or behaviors, the task becomes automatic —> habit

Thalamus - older

• Egg-shaped sensory control center.

• Routes info for all senses except smell to higher brain regions for seeing, hearing, tasting, touching.

• Also routes info from higher brain to medulla and cerebellum.

Reticular Formation - older

• Network of neurons extending from spinal cord through brainstem and thalamus.

• Filters incoming stimuli and relays important info to other brain regions.

• Enables arousal.

• Info traveling from spine to thalamus sometimes passes through here.

Cerebellum (“Little Brain”) - older

• Rear of brainstem; baseball-sized with two wrinkled halves.

• Functions:

  • Nonverbal learning and memory.

  • Judging time, emotion, sounds, textures.

  • Coordinates voluntary movement and balance (with pons).

• Alcohol impairs cerebellar function

The Limbic System

• Includes amygdala, hypothalamus, and hippocampus (conscious memories).

• Border Between Oldest and Newest Parts

Amygdala - limbic

• Two lima bean-sized neural clusters.

• Electrical stimuli cause aggression and fear.

• Processes emotional memories, fear responses, and perception of emotion.

• Not the sole location for anger or emotion—other areas also participate.

Hypothalamus - limbic

• Regulates hunger, thirst, body temperature, sexual behavior, circadian rhythm, ANS → maintains steady internal state.

• Monitors body’s condition via blood chemistry and input from other brain regions.

• Interaction example:

  • Cerebral cortex thinks about sex → hypothalamus secretes hormones → pituitary gland activates sex glands → intensifies sexual thoughts in cortex.

• Demonstrates feedback between nervous system and endocrine system.

• Contains pleasure/reward centers:

  • Rats self-stimulate this area.

  • Reward system promotes survival behaviors (eating, drinking, sex via dopamine).

• Malfunction in this system → reward deficiency syndrome → craving to relieve negative feelings or seek pleasure.

• Research:

  • Limbic stimulation explored for search and rescue motivation enhancement.

Hippocampus - limbic

Responsible for the transfer of short-term memory to long-term memory

Basal Ganglia - limbic

Plays a role in habit-forming and procedural memory (habits). Seen in Eugene Pauly who had lost his amygdala and hippocampus but not his basal ganglia.

Nucleus accumbens - limbic

Plays a role in addiction and motivations

Brain Plasticity and Repair

• The brain's ability to change, reorganize after damage, or form new pathways based on experience.

• Greatest in children but remains somewhat in adults.

Reorganization

• Slow-growing tumor disrupts language on left → right takes over.

• Amputated finger’s sensory area taken over by adjacent fingers → increased sensitivity.

• Blindness/deafness: unused sensory areas repurposed.

  • Blind read Braille → visual cortex used.

  • Deaf use ASL → auditory cortex processes visual input.

• Phantom limb sensations → reorganized cortex interprets signals as real.

• Similar reassignment occurs when damage frees up brain areas.

Neurogenesis (Creation of New Neurons)

• New neurons form from the deep brain and migrate to new connections when reorganization is insufficient.

• Master stem cells (from embryos) can become any brain cell → may replace lost neurons.

• Promoters of neurogenesis: Exercise, sleep, low stress, stimulating

Constraint-Induced Therapy

• Rewires brain and improves dexterity in stroke victims or brain-damaged patients.

• Retrains functioning limb and forces use of damaged limb → recovers skill by migrating functions to new regions

Older brain networks

basic life functions, memory, emotion, drives

New neural networks (in cerebrum)

specialized thinking, perceiving, speaking

distributive processing

several parts of the brain have to work together in order to
help us create and retrieve memories, results in cognitive processes in memory research

name and label the parts of a brain