Psych 3

• Neurons


  Cells that convey sensory information into the brain, carry out operations, and transmit commands to the body
• Neuron structure


  • Cell body
  • Nucleus
  • Dendrites
  • Axon
  • Axon terminals

  
• Nomenclature for brain structures is inconsistent

  
• Frame of reference for brain discussion

  • Brain–body orientation: human face
  • Spatial orientation: other body parts and body orientation
  • Anatomical orientation: direction of section through the brain from perspective of the viewer

  
• Directional terms


  • Dorsal: toward the back
  • Ventral: toward the stomach
  • Anterior: toward the front
  • Posterior: toward the rear
  • Superior: above another structure
  • Inferior: below another structure
  • Lateral: toward the side
  • Medial: toward the middle
• Nerve


  A bundle of axons running together (in the peripheral nervous system)

  
• Neuron


  A single neural cell
• Tract


  A bundle of axons running together in the central nervous system

  
• Nucleus


  Group of cell bodies in the central nervous system
• Ganglion


  Group of cell bodies in the peripheral nervous system
• Types of neurons


  • Motor neuron: carries commands to the muscles and organs
  • Sensory neurons: Carry information from the body and outside world into brain and spinal cord
  • Interneurons: neurons which connect one neuron to another in the same part of brain or spinal cord

  
• Afferent


  Into the central nervous system (incoming information)

  
• Efferent


  Out of the central nervous system (outgoing information)

  
• Large-scale divisions of the nervous system

  • Forebrain: highly developed, numerous functions
  • Midbrain: reflex actions and voluntary movements
  • Hindbrain: vital functions and coordinating movements

  
• Cerebral Cortex


  • Outer layer of frontal lobe
  • Cerebral hemispheres: large, wrinkled structures dominating brain's appearance
  • Dorsal or superior part of the brain and that are covered by the cortex

  
• Cortex


  Outer surface of brain; mostly made up of the cell bodies of neurons
• Gyrus


  Each ridge in surface of the brain

  
• Sulcus


  Groove or space between two gyri
• Fissure


  Large groove or space between two gyri
• Lateral ventricles


  • Winged-shaped cavities filled with cerebrospinal fluid (CSF) made by a network of interconnected blood vessels
  • CSF suspends the brain, acts as shock absorber, provides stable environment for optimal function
• Hemispheric divisions


  • Frontal lobe (executive function)
  • Parietal lobe (sensory integration)
  • Temporal lobe (auditory, taste, smell, memory)
  • Occipital lobe (visual)

  
• Allocortex


  Three-layered and four-layered cortex, composed of a number of below-surface structures (e.g. Limbic system, components of olfactory system), evolved earlier than the neocortex
• Neocortex


  Six-layered cortex, outer layer that is visible when we look at the surface of the brain

  
• Principal structures of the Limbic System

  • Amygdala
  • Hippocampus
  • Cingulate cortex
• Functions of the Limbic System


  • Regulates emotional and sexual behaviors
  • Regulates memory
  • Regulates spatial navigation
• Amygdala


  • Increases electrical activity in its neurons when we are under threat
  • Involved in fight or flight response
  • Remembers events tied to strong emotions
  • Receives sensory input to determine emotional value/intensity of a stimulus

  
• Hippocampus


  • Assists the process of declarative memory formation
• Cingulate cortex


  • Helps focus attention and thoughts, especially on things that are unpleasant to us (e.g. physical and emotional pain)
• Principal structures of the Olfactory System


  • Pyriform cortex
  • Amygdala
  • Dorsomedial thalamus
  • Vomeronasal organ (VNO): sensory neurons that detect pheromones
• Principal structures of the Basal Ganglia

  • Caudate nucleus
  • Putamen
  • Globus pallidus
• Functions of the Basal Ganglia


  • Controls voluntary and involuntary movement
• Thalamus


  • Relays incoming sensory information through groups of neurons that project to the appropriate region in the cortex
  • Actively filters incoming sensory information
• Hypothalamus


  • Regulates the autonomic and endocrine systems
  • Involved in hunger responses, sexual behavior, temperature control, and aggression
  • Involved in homeostasis
• Structures of the Midbrain

  • Reticular formation
  • Superior and inferior colliculi
  • Red nucleus
  • Substantia nigra
  • Tectum vs tegmentum
• Reticular Formation


  • Helps to regulate awareness and attention
  • Filters out irrelevant stimuli
  • Regulates sleep and wakefulness (arousal)
  • Coordinates several brain areas
• Structures of the Hindbrain


  • Medulla
  • Pons
  • Cerebellum
• Medulla


  • Controls heart activity and circulation
  • Regulates breathing
  • Involved in coordinating swallowing and digestion
  • All sensory and motor nerve tracts ascend from the spinal cord and descend from the brain
• Pons


  • Relay station for signals between higher levels of the nervous system and lower levels
  • Coordinates with the cerebellum and rest of the brain
  • Connects to muscles and glands in face and neck
• Cerebellum


  • Controls bodily coordination, balance, and muscle tone
  • Active in fine motor control and smoothing out movements
  • Helps with sequences of actions
  • Involved in procedural memory (memory of motor skills)
• Nerves


  • Twelve pairs of cranial nerves
  • Thirty pairs of spinal nerves divided into five anatomical regions: cervical, thoracic, lumbar, sacral, and coccygeal
  • Dermatomes: body segments associated with nerve