Exam 1 Sensation vs Perception Methods Neurophysiology Neuroanatomy What are the 5 main methods we discussed for studying sensation and perception 1 Thresholds 2 Scaling a Absolute threshold minimum intensity that can be detected 50 of the time a Magnitude estimation estimate magnitude of a stimulus Ex Pain b Cross modality matching subject asked to match intensities of sensations that come from different sensory modalities i Ex Adjust brightness of light to match loudness of tone 3 Signal Detection Theory a measuring difficult decisions b The ability to detect the signal in noise 4 Sensory Neuroscience 5 Neuroimaging a How our perception of the world depends on the activity of our sensory nerves at least as much as it depends on the world itself b Rate law The strength of a stimulus is represented by the rate of firing of an axon The size of each action potential is always constant a Associating activity in various brain regions with perceptions or experiences b fMRI i Functional magnetic resonance imaging ii Activated neurons induce increased blood flow we can measure changes in blood flow c PET scan i Positron emission tomography ii Identify active areas of brain by measuring decay of safe radioactive isotopes What is psychophysics What are some examples of psychophysical methods a The science of defining quantitative relationships between physical and psychological events b Why i Because there is a difference between changes in physical stimuli and our perception of them ii Because there is a difference between sensation and perception c Examples Hearing Audition What is the just noticeable difference The minimum intensity needed to perceive a difference between 2 stimuli What is the 2 point threshold The closest distance 2 points of stimulation touch can be and still be perceived as What are 3 methods of measuring the absolute threshold 2 distinct points 1 Method of constant stimuli 2 Method of limits 3 Method of adjustment What is cross modality matching What is magnitude estimation Subject asked to match intensities of sensations that come from different sensory modalities Ex Adjust brightness of light to match loudness of tone Subject assigns values according to perceived magnitudes of the stimulus Kind of like Rate your pain on a scale from 1 10 but the subject can assign numbers as the magnitude of the stimulus changes What does Steven s Power Law tell us about our perception of changes in stimulus intensity Even though our response with regard to stimulus intensity changes for each sense the same law applies for each sense What is signal detection theory and why is it more relevant to the real world than absolute thresholds The body of research that studies the detection of signal in noise More relevant to the real world because Because we don t live in a lab Noise in the environment Because variability in threshold has a lot to do with the subject Noise in the nervous system Subject s expectations biases Understand the web activity on psychophysics 3 slanted lines and you determine if they are all slanted at the same angle or different angles and it takes you through a signal detection theory activity What is sensory neuroscience What does evolution have to do with this o How our perception of the world depends on the activity of our sensory nerves at least as What are 2 neuroimaging techniques o fMRI Functional magnetic resonance imaging Activated neurons induce increased blood flow we can measure changes in blood flow o PET scan Positron emission tomography Identify active areas of brain by measuring decay of safe radioactive isotopes What are the parts of a neuron Could you label those parts of a neuron Could you draw label a neuron There are two kinds of brain cells neurons and glia Neurons are different from other cells in some very important ways They DIFFER from other cells in their morphology shape and in that they are They also DIFFER sort of from other cells in that they communicate over long generally postmitotic distances with each other Be able to draw What is a synapse Terms presynaptic postsynaptic synaptic gap ie synaptic cleft Neurons form synapses with each other where a neurotransmitter is relayed from one neuron to another The postsynaptic region is the side containing the soma and the dendrites The presynaptic cell is at the end of the axon Where the postsynaptic and presynaptic parts of the neuron meet they form a synaptic gap What are the 3 main types of neurons Most neurons are multipolar many dendrites and almost always an axon Bipolar 2 processes off of soma soma just keeps neuron alive Bipolar neurons are typically found in the sensory system Unipolar 1 process off of soma Are mainly in the skin to detect stimulus like touch pain and temperature What are the different types of glia What are their specific functions Oligodendrocytes Schwann cells CNS In brain and spinal cord Specialized types of glia that build the myelin sheaths that surround and insulate certain vertebrate actions PNS In periphery Specialized types of glia that build the myelin sheaths that surround and insulate certain vertebrate actions In general what is different between glia and neurons Four main functions of glial cells To surround neurons and hold them in place To supply nutrients and oxygen to neurons To insulate one neuron from another To destroy pathogens and remove dead neurons Neurons An electrical charge called an action potential travels down the neuron causing the release of the neurotransmitter The action potential is simply the movement of ions into and out of the axon Neurons do the actual communicating by sending messages Glia helps the neurons There are more glia than neurons How can you connect neurons What would be the functional significance of such connections You can have a 1 1 ratio relay Many 1 ratio gain complexity 1 many ratio arousal What is the difference between an inhibitory neuron and an excitatory neuron Excitatory Inhibitory When the neurotransmitter like glutamate excites the postsynaptic region side with soma and dendrites When a neurotransmitter like GABA inhibits the postsynaptic region What is a neurotransmitter Chemicals released from one neuron that affect a second neuron They are contained at the terminal end of the axon and are for chemical transmission between neurons Can either excite or inhibit the receiving neuron What are the parts of a synapse What is the presynaptic cell and what is the postsynaptic cell Integration of
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