The Brain

Parts of the Brain

  • Divided into three sections

    • Hindbrain - oldest part of the brain

    • Midbrain - connects the sections

    • Forebrain - the rest, most in the section

Hindbrain

  • Medulla - vital part of the brain with many functions such as heart rate, blood pressure, and breathing

  • Pons - located in front of the medulla; involved in  regulating body movement, attention, sleep, and alertness

  • Cerebellum - Latin for “little brain”; balance and coordination functions

    • Neuroplasticity - the brain can reroute messages and change when there are parts of the brain missing to do many functions

Midbrain

  • Contains part of the Reticular Activating System (RAS)

    • Important for attention, sleep, and arousal

    • Drugs can affect the RAS - alertness and reaction time

  • Parts involved in vision and hearing

Forebrain

  • Made up of the Limbic System and Cerebrum

  • Four main areas

  • Thalamus - relay station for sensory stimulation

  • Hypothalamus - very tiny; includes functions like body temperature, storage of nutrients, motivation, emotion, hunger thirst, sexual behavior, caring for offspring, and aggression

    • Disruptions - unusual eating and drinking behaviors

  • Rest of the Limbic System - includes learning, memory, basic emotion, hunger, sex, and aggression

    • If damaged - people can recall new memories, not old ones and become more passive/aggressive

  • Cerebrum - Latin for “brain”; the cerebrum takes up a large part of human brains (70%)

  • Cerebral Cortex - outer layer of the brain; includes thinking, language, memory, emotions, complex motor functions, perceptions, etc.

    • 2 sides called hemispheres, divided into four parts (lobes). They have the same functions, just on opposite sides of the brain

    • Frontal Lobe - behind the forehead; motor cortex (motor functions)

      • Broca’s area - language area; nearly all right-handed people have language based in the left hemisphere

    • Parietal Lobe - lies to the top and rear of the head; skin senses

    • Temporal Lobe - lies to the side just below the ears; auditory

      • If damaged - may not be able to recognize common sounds

    • Occipital Lobe - at the back of the head; optic functions, primary visual area

  • Left vs Right Hemispheres: The hemispheres do not work independently of one another; one hemisphere plays a special role in language. Both are involved in logic, creativity, and intuition

  • Corpus Callosum: Aids in getting information from one side of the brain to the other

    • Split Brain Operations: corpus callosum is cut when a patient has a neurological disorder. Cutting the corpus callosum can reduce the severity and prevent the seizure from spreading

      • Effects: People will be able to describe verbally the objects they hold in their right hand, but not their left

How Do We Study the Brain?

  • Electrical Stimulation: Cut open the skull and touch the brain of a patient. Doctors are able to stimulate the brain and manipulate senses an movement of the body. Only done in neurological procedures. 

  • Electroencephalogram: used for studying dreams. Measures brain waves when a person is dreaming.

  • PET Scans: Used to see how the brain functions. Uses radioactive glucose in the brain to measure the bloodflow of the brain in a scan. Can show where a tumor is.

  • CAT Scan: Non-invasive scan that produces 3D images or internal organs, etc

  • MRI and fMRI: Magnetic Resonance Imaging/Functional Magnetic Resonance Imaging; used for minor problems and gives better resolution and scan of the brain, body part, etc.