1. The cerebral cortex has four lobes, each is specialized for different activities. The lobes and some of their functions: –Occipital lobe- initial processing of visual input –Temporal lobe - primary auditory cortex, integration of multiple sensory inputs, Wernicke’s area –Parietal lobe - somatosensory processing. Each region of parietal cortex receives somesthetic and proprioceptive input from a specific body area, mostly from the opposite side of the body. –Frontal lobe - voluntary motor activity, speaking ability (Broca’s area), and elaboration of thought. Stimulation of different areas of its primary motor cortex moves different body regions.

2. Frontal lobe Central sulcus Parietal lobe Parietooccipital notch Occipital lobe Cerebellum Brain stem Temporal lobe Lateral fissure

3. Occipital lobe Primary visual cortex

4. Wernicke’s area Temporal lobe Primary auditory cortex

5. Central sulcus Somatosensory cortex Posterior parietal cortex Wernicke’s area Parietal lobe

6. Left hemisphere Cross-sectional view Temporal lobe Sensory homunculus

7. Primary motor cortex Central sulcus Broca’s area Frontal lobe Premotor cortex

8. Left hemisphere Cross-sectional view Temporal lobe Motor homunculus

9. Central sulcus Parietal-temporal-occipital association cortex Limbic association cortex Prefrontal association cortex Association areas of the cortex carry out many higher functions: Association Areas of the Cerebral Cortex planning for voluntary activity, decision-making, creativity, and developing personality traits integrates somatic, auditory, and visual sensations from these three lobes involved with motivation, emotion, and memory

10. Sensory input Primary sensory areas (somatosensory, 1 o visual, 1 o auditory cortices) Higher sensory areas Association areas Higher motor areas Primary motor areas Motor output

11. Fundamentals of Sensory Systems A. General Concepts in Sensation and Perception Function of sensory systems Visceral versus sensory afferents Sensation versus perception Psychophysics B Receptor Structure and Function Specific for particular forms of energy Vary across sensory systems Perform common function (transduction) in unique ways Sites of convergence and divergence C. Peripheral Organization Labeled Line Principle Topographic projections Mechanisms to enhance contrast sensitivity D.Central Processing Includes sensory cortex and association areas Response Maps and Plasticity

12. Variable perceptions from the same visual input Do you see two faces in profile, or a wine glass?

13. Do you “see” a white square that is not really there?

14. Receptor Morphologies Reflect Specialized Functions Photoreceptors Mechanoreceptors Thermoreceptors Osmoreceptors Chemoreceptors Nociceptors CATEGORIES OF RECEPTORS

15. Receptor Potentials are GRADED Generator potential: Somatosensory Receptor potential: Auditory/Visual

16. Stimulus off Slowly adapting Stimulus on Time Receptor potential (mV) Stimulus strength Tonic Receptors Muscle Stretch, Proprioception

17. Stimulus off Rapidly adapting Stimulus on Time Receptor potential (mV) Stimulus strength Off response Phasic Receptors skin touch

18. Doctrine of Specific Energy or Labeled Line Principle “Phantom” Pain

19. Coding of Sensory Information Stimulus PropertyCoding Mechanism Stimulus ModalityDistinguished by the type of receptor activated (what)and the specific pathway that transmits this information to a particular area of (sensory) cerebral cortex Stimulus LocationDistinguished by location of activated receptive (where)field, and the pathway that is activated to transmit this information to the area of cerebral cortex representing that location. Stimulus IntensityDistinguished by the frequency of action (how much?)potentials and the number of receptors activated.

20. Receptor endings of afferent neurons Receptive fields on skin surface Receptive Field Size Determines Acuity Sensory homunculus

21. Stimulated less Stimulated most Receptor pathways Skin surface Frequency of action potentials Baseline level of activity Location on skin Mechanisms To Enhance Acuity

22. Transmission stopped Lateral inhibition Frequency of action potentials Baseline level of activity Area of sensation on skin Transmission stopped Transmission continues

23. Center/Surround Organization of Receptive Fields

24. Sensory Pathways: CNS

25. Primary Sensory and Association Areas of Cerebral Cortex

26. Practical Applications