BIOMED SCIE Lecture 18 neuroscience 3

• Cerebrum


  The largest division of the brain, essential for awareness, language, cognition, memory, and consciousness. Divided into two hemispheres, each divided into four lobes.
• Cerebral lobes


  • Frontal
  • Temporal
  • Occipital
  • Parietal
• Frontal lobe


  • Higher executive function, decision making, planning, memory aspects
• Temporal lobe


  • Auditory information, speech, memory processing, emotion
• Occipital lobe


  • Visual perception, colour, form
• Parietal lobe


  • Sensation, sensory perception and integration
• Cerebral cortex


  The outermost layer of gray matter making up the superficial aspect of the cerebrum
• Corpus callosum


  Links left and right hemispheres
• Studying the brain


  1. Electrical stimulation of different parts of the brain to see muscle response

  2. Stimulating different parts of the body to see brain electrical activity

  3. Using MRI to study small metabolic changes indicating brain activity
• Brain areas


  • Sensory areas
  • Association areas
  • Motor areas
• Sensory areas


  Receive impulses from sense organs and transmit them to the association areas
• Association areas


  Receive impulses, interpret them in the light of similar past experiences and transmit impulses to motor areas
• Motor areas


  Transmit impulses to the effectors, e.g. hands, feet
• The size of the sensory and motor areas is related to the number of receptors in that area, not the actual size of the organ
• The left and right cerebral hemispheres control the opposite sides of the body
• Cerebral cortex areas


  • Sensory area for impulses from eyes
  • Motor cortex (control of skeletal muscles)
  • Prefrontal cortex (decision making, planning)
  • Broca's area (forming speech)
  • Auditory cortex (hearing)
  • Wernicke's area (comprehending language)
  • Somatosensory cortex (sense of touch)
  • Sensory association cortex (integration of sensory information)
  • Visual association cortex (combining images and object recognition)
  • Visual cortex (processing visual stimuli and pattern recognition)
• Information processing in the cerebral cortex


  1. Sensory organs and somatosensory receptors provide input

  2. Thalamus directs different types of input to distinct cortical locations

  3. Adjacent areas process features of the sensory input and integrate information

  4. Integrated sensory information passes to the prefrontal cortex, which helps plan actions and movements
• Somatosensory and motor cortex organization

  • Genitalia
  • Toes
  • Abdominal organs
  • Tongue
  • Jaw
  • Lips
  • Face
  • Eye
  • Brow
  • Neck
  • Thumb
  • Fingers
  • Hand
  • Wrist
  • Forearm
  • Elbow
  • Shoulder
  • Trunk
  • Hip
  • Knee
• Broca's aphasia


  Brain lesions in a stroke patient who could understand language but could not speak, demonstrating the left frontal lobe was responsible for articulation of speech
• Wernicke's aphasia


  Stroke victim who could speak but made no sense, with the damaged area around where the temporal and parietal lobes meet in the posterior part of the left hemisphere. Deficits in language comprehension but intact articulation.
• Speech and language areas


  • Primary auditory cortex
  • Production of speech
  • Language comprehension
• Lateralization of cortical function


  The left hemisphere is more adept at language, math, logic, and processing of serial sequences. The right hemisphere is stronger at pattern recognition, nonverbal thinking, and emotional processing.
• Lateralization is partly linked to handedness. The differences in hemisphere function are called lateralization
• The two hemispheres work together by communicating through the fibers of the corpus callosum
• Split-brain language


  Approximately 200 million fibers relay information from one side of the brain to the other
• Left/right hemisphere specialization


  • Analytic thought/Holistic thought
  • Logic/Intuition
  • Language/Creativity
  • Math & Science/Art & Music
• Lateralization of speech and emotion

  • Left hemisphere: Language
  • Right hemisphere: Intonation and emotion in speech
• The ability to speak resides almost exclusively in the left hemisphere, while the ability to recognize faces resides almost exclusively in the right hemisphere
• Frontal lobe damage


  May impair decision making and emotional responses but leave intellect and memory intact
• Frontal lobes

  Have a substantial effect on "executive functions"
• Phineas Gage's personality, reasoning, and capacity to understand and follow social norms were diminished or destroyed after a detonation accident that damaged his frontal lobe
• Frontal lobe


  Plays an integral role in memory formation, emotions, decision making/reasoning, and personality
• Vision


  Right side of your brain controls your Left body functions• Left side of your brain controls your Right body functions
• Vision

  Each eyeball is divided into 2 parts– Right Visual Field– Left Visual Field
• vision


  Right Hemisphere receives visual info from LVF only• Left Hemisphere receives visual info from RVF only
• Sperry’s Split Brain


  a condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
• Phineas Gage


  Iillustrated little to no interest in hobbies or otherinvolvements that at one time he cared for greatly. ‘After theaccident, Gage became a nasty, vulgar, irresponsible vagrant.• His former employer, who regarded him as "the most efficientand capable foreman in their employ previous to his injury,"refused to rehire him because he was so different.’
• The Frontal Lobe of the brain is located deep to the

  Frontal Bone of the skull.
• • The Frontal Lobe plays an integral role in the following functions/actions:Memory FormationEmotionsDecision Making/ReasoningPersonality