Psych - 1101 - Brain

The Split-Brain Experiment

Definition: Research on patients whose corpus callosum (connection between the two hemispheres) was surgically cut to treat severe epilepsy

• Left hemisphere: language, speech, logical thinking

• Right hemisphere: visual-spatial skills, emotions, facial recognition

Example:

• Object shown to right visual field → person can name it

• Object shown to left visual field → person cannot name it but can draw or point to it

Key Point: The experiment showed that the two brain hemispheres have specialized functions and normally work together through the corpus callosum.

Corpus Callosum

Definition: A thick band of nerve fibers connecting the left and right cerebral hemispheres

• Function:

  • Allows communication and coordination between the two hemispheres

  • Helps integrate sensory, motor, and cognitive information

• Importance:

  • Essential for normal brain functioning

  • Damage or cutting (split-brain) leads to hemisphere separation effects

Key Point: acts as a bridge between the two sides of the brain

Brain Plasticity

• Definition: The brain’s ability to change, adapt, and reorganize itself

  • Occurs through forming new neural connections

  • Strongest during childhood, but continues throughout life

Examples:

• Learning new skills

• Recovery after brain injury

• Brain areas taking over functions of damaged areas

Key Point: shows that the brain is flexible, not fixed, and shaped by experience and environment.

The Hindbrain

• lower part of the brain

• Controls basic life functions and movement coordination

Main Parts

• Medulla: Breathing, heart rate

• Pons: Sleep, arousal, balance

• Cerebellum: Coordination, posture, motor learning

The Midbrain

• Located between the hindbrain and forebrain

• Involved in vision and hearing reflexes

• Helps control movement and alertness

• Acts as a relay station for sensory information

Key Point: supports sensory processing and motor control

The Forebrain

• Largest and most developed part of the brain

• Responsible for higher mental functions

Includes:

• Cerebrum: Thinking, memory, hormones

• Thalamus: Sensory relay station

• Hypothalamus: Homeostasis, hormones

• Limbic system: Emotions and memory

Key Point: controls thinking, emotion, and complex behaviour

Medulla

• Located at the base of the brainstem, just above the spinal cord

• Regulates vital autonomic functions such as breathing, heart rate, and blood pressure

• Control important reflexes like swallowing, coughing, sneezing, and vomitting

• Acts as a pathway for nerve signals between the brain and spinal cord

Key Point: essential for basic survival functions

The Reticular formation (RAS)

• Network of neurons running through the brainstem

• Controls arousal, alertness,and consciouness

• Helps regulate the sleep-wake cycle

• Filters incoming sensory information to determine what deserves attention

Key Point: keeps the brain awake, alert, and attentive

Pons

• Part of the hindbrain and brainstem

• Helps regulate sleep and dreaming

• Assists in breathing and facial movements

• Acts as a bridge connecting different parts of the brain

Key Point: supports sleep, breathing, and communication between brain regions.

Cerebellum

• located at the back of the hindbrain

• Coordinates voluntary movements

• Maintains balance and posture

• Involved in motor learning and timing

Key Point: ensures smooth and precise movement.

Thalamus

• Acts as the sensory relay station of the brain

• Directs sensory information (except smell) to the cerbral cortex

• Helps regulate alertness, consciousness, and sleep

Hypothalamus

• Involved in emotions and drives vital to survival (fear, hunger, thrust, and reproduction)

  • Maintains Homeostasis

• Controls the endocrine system througt the pituitary gland

• Regulates emotions, stress, and sexual behaviour

Pituitary gland

• Small endocrine gland connected to the hypothalamus that releases many hormones and regulates other endocrine glands

• Known as the master gland of the endocrine system

• Releases hormones that control other endocrine glands

• Regulates growth, reproduction, and stress

Limbic System

• Interconnected group of structures that influences emotions and memory

• Group of brain structures involved in emotions, motivation, and memory

• Includes the amygdala, hippocampus,and hypothalamus

• Plays a key role in emotional behaviour and learning

Hippocampus

• Involved in the storage of new infromation in memory (learning)

• Locatied in the limbic system

• Essential for forming new memories

• Helps with learning and spatial navigation

Amygdala

• Involved in the arousal and regulation of emotions and the initial emotional response to sensory information

• Part of the limbic system

• Process emotions, especially fear and aggression

• Plays a role in emotional learning and memory

Cerebral Hemisphere

• The two halves of the cerebum: left and right

• Each hemisphere controls opposide side of the body and has specialized functions

• Left = language and logic, Right = creativity and spatial skills

Lateralization

• The specialiation of functions in the left and right cerebral hemisphere

• Left Hemisphere: Language, logic, analytical thinking

• Right Hemisphere: creativity, spatial ability, facial recognition

Cerebral Cortex

• Several thin layers of densely packed cells covering the cerebrum

• Responsible for higher mental functions

• The outer layer of the cerebrum responsible for higher brain functions

• Controls thinking, perception, memory, language, and voluntary movements

• Divided intro frontal, parietal, temporal, and occipital lobes

Occipital Lobes

• Located at the back of the cerabral corte

• Responsible for processing visual information

• Helps in recognizing shapes, colours, and motion

Parietal lobes

• Receive signals from bodily sensations such as touch pain and temperature

• The somatosensory cortex registers information from the skin sense

• Aphasia or agnosias: Damage to the left parietal lobe

Temporal lobes

• Located on the sides of the cerebral cortex near the ears

• Responsible for hearing, language comprehensions, and memory

• Plays a role in emotional processing and facial recogniztion

Frontal Lobes

• Directing thought processes

• Prefrontal lobe is the seat of executive functions

• Working memory, flexible thinking, and self-control

• The primary motor cortex within the frontal lobe is responsible for the control of body movements

• Responsible for decision-making, problem-solving, planning, and voluntary movement

• Controls personality, emotions, and speech production (Broca’s area)