Listen to the audio lecture while viewing these slides1Psychology 372Physiological PsychologySteven E. Meier, Ph.D.Sensation2Psyc 372 – Physiological PsychologySensation, Perception, and Cognition• All sensory systems operate the same, they only use different mechanisms.• Have a physical stimulus (e.g., weight, heat, cold, light)• The stimulus emits some sort of energy.• Energy activates some sort of receptor system.3Psyc 372 – Physiological PsychologySensation• The receptor system is designed to convert (transduce) the energy to action potentials.• You then organize the physical energy to neural energy by electrical/chemical reactions.4Psyc 372 – Physiological PsychologyPerception• You then organize and filter the energy as the information progresses through the different systems. • Ultimately, you develop patterns and process the material.5Psyc 372 – Physiological PsychologyCognition• Allows you to determine what the pattern means.• Uses different brain systems depending on the stimulus.6Psyc 372 – Physiological PsychologySummary• Sensation is involved with detecting the stimulus and converting the information to action potentials.• Perception is involved with organizing the action potentials.• Cognition is involved with giving the organization some meaning that we can understand.7Psyc 372 – Physiological PsychologySomatosenses• Provides information relating to events on the skin and to events occurring within the body.• Two groups• Cutaneous Senses•receive various signals from the skin that form the sense of touch•Pressure•Vibration•Heating/cooling•Stimuli that damage tissue (and produce pain)• Kinesthesia •Provides information about body position and move me n t•Are action potentials from receptors located within the joints, tendons, and muscles.8Psyc 372 – Physiological PsychologyTouch• Lots of Receptors• Three main Groups•Nociceptors• Cutaneous and Subcutaneous Mechanoreceptors• Muscle and Skeletal Mechanoreceptors9Psyc 372 – Physiological PsychologyThe SkinDermisEpidermisHair ReceptorMerkelsReceptorFree Nerve Ending10Psyc 372 – Physiological PsychologyNociceptors• Are receptors for detecting pa in.• Have free nerve endings within the skin that respond to stimuli• Also respond to heat, acids, and capsaicin•Four main types• MechanicalSharp, pricking pain• Thermal and Mechano-thermalSharp, prickling pain• Thermal and Mechano-thermalSlow, burning pain• PolymodalSlow, burning11Psyc 372 – Physiological PsychologyThe SkinDermisEpidermisHair ReceptorMerkelsReceptorFree Nerve Ending12Psyc 372 – Physiological PsychologyCutaneous and Subcutaneous Mechanoreceptors• Are responsible for Touch Sensations• Have several types of receptors.• Meissner’s Corpuscle Flutter• Pacinian Corpuscle Vibra tion• Ruffini Corpuscle Steady Skin Indentation• Merkel Receptor Steady Skin Indentation• Hair-guard Flutter•Others13Psyc 372 – Physiological PsychologyThe SkinDermisEpidermisHair ReceptorMerkelsReceptorFree Nerve Ending14Psyc 372 – Physiological PsychologyPain15Psyc 372 – Physiological PsychologyPain Receptors•Nociceptors• Are recept ors for pain• Have free nerve endings networks within the skin that respond to intense pressure• Also respond to heat, acids, and capsaicin • Receptors are activated by mechanical, chemical stimulation16Psyc 372 – Physiological PsychologyDifferent Systems for Touch and Pain• Dorsal-Column-Medial Lemniscal• Anterolateral17Psyc 372 – Physiological PsychologyDorsal-Column-Medial Lemniscal System•Involved with • Discriminative touch, •Vibration, • Perceiving and understanding the form and nature of objects (Stereognosis),• Receiving stimuli within the tissues of the arm (Propriception),• Weight discrimination.18Psyc 372 – Physiological PsychologyStructures Used• Uses the Fasciculus Gracilis and Fisciculus Cuneatus in the Do rsal Co lum n o f the Spina l Cord.• Sig nal C ro sses at the Medulla• Uses the Medial Lemniscus pathway from the Midbrain to the Thalamus.• Terminates in po sterio r latera l nucleus and posterior lateral group of the Thalamus.• Signal goes from Thalamus to primary and secondary somatic sensory cortices(Area 3 1 2) and posterior parietal cortex19Psyc 372 – Physiological PsychologyDorsal-Column-Medial Lemniscal System20Psyc 372 – Physiological PsychologyAnterolateral System• Responsible for •Pain•Cold•Warmth•Pressure•Tickle•Itch•Crude Touch21Psyc 372 – Physiological PsychologyStructures Used• Signal crosses at the spinal cord.• Uses the Lateral Sp ino thalamic Tract o f the • Spinal Cord to travel to the: •Reticular Formation•Tectum•Ventral Posterior Lateral Nucleus•Posterior nuclear group of the Thalamus•Intra liminar nuclei• Signal goes from Thalamus to primary and secondary somatic sensory cortices(Area 3 1 2) and posterior parietal cortex22Psyc 372 – Physiological PsychologyAnterolateral System23Psyc 372 – Physiological PsychologyMuscle and Skeletal Mechanoreceptors• Again, several different types• Muscle Spindle PrimaryLimb Proprioception• Muscl e Spindle SecondaryLimb Proprioception• Joint Capsule Mechanreceptors•Joint Capsule Pressure•Has a limited role in limb