Physio Psych

2/12/25 

-structure of vertebrate nervous system 

• Central nervous system (CNS) 

• Brain and spinal cord 

• Peripheral nervous system  

• Connects brain and spinal cord to rest of body 

-anatomical terms referring to directions  

• Dorsal 

• Ventral 

• Anterior 

• Posterior 

• Superior 

• Inferior  

-The Spinal Cord 

• Part of the CNS found within spinal column 

• Communicates with sense organs and muscles 

• Except those of head 

• Entering dorsal roots 

• Carry sensory information 

• Exiting ventral roots 

• Carry motor information 

• Consists of two types of matter 

• Grey matter  

• Center of spinal cord 

• Densley packed with cell bodies and dendrites 

• White matter 

• Myelinated axons 

• Carry information from gray matter to brain or other areas of spinal cord 

• Each segment sends sensory information to brain and receives motor commands 

-the autonomic nervous system 

• Sends and receives messages to regulate automatic behaviors  

• Heart rate 

• Blood pressure 

• Respiration 

• Digestion 

• Divided into two subsystems 

• Sympathetic nervous system 

• Parasympathetic nervous system 

-the sympathetic nervous system 

• Prepares organs for rigorous activity 

• Increases heart rate, blood pressure, respiration, etc. 

• “Fight or flight response” 

• Primary neurotransmitter 

• Norepinephrine 

-the parasympathetic nervous system 

• Facilitates vegetative and nonemergency responses  

• Decreases functions increased by sympathetic nervous system 

• Dominant during relaxed states 

• “Rest and digest” 

• Primary neurotransmitter 

• Acetylcholine 

-major divisions of the vertebrate brain 

• Forebrain 

• Midbrain 

• Hindbrain 

-the hindbrain 

• Consists of the  

• Pons- Latin for bridge 

• Cerebellum: largest region of the hindbrain 

• Movements and balance 

• Spatial reasoning 

• Sound discrimination 

• Sensory integration 

• Medulla: located just above spinal cord 

• Vital reflexes  

• Breathing, heart rate, vomiting, salivation, coughing, sneezing 

• Cranial nerves 

• Allow the medulla to control sensations from head, muscle movements in head, and many parasympathetic outputs 

-the midbrain 

• Contains the following structures  

• Tectum: roof of the midbrain 

• Superior colliculus and inferior colliculus: processes sensory information 

• Substantia nigra: gives rise to the dopamine-containing pathway facilitating readiness for movement 

-the forebrain 

• Most prominent part of mammalian brain 

• Two cerebral hemispheres 

• Consists of outer cortex and subcortical regions 

• Outer portion = “cerebral cortex” 

• Each side receives sensory information and controls motor movement from contralateral side of body 

• Basal ganglia: compromises the caudate nucleus, the putamen, and the globus pallidus 

• Associated with planning of motor movement, and with aspects of memory and emotional expression 

• Also important for attention, language planning, and other cognitive function 

2/17/25 

-the ventricles 

• Four fluid-filled cavities within brain’s central canal containing cerebrospinal fluid 

• CSF: clear fluid found in brain and spinal cord  

• Provides “cushioning” for brain 

• Reservoir of hormones and nutrition for brain and spinal cord 

-the meninges 

• Membranes that surround brain and spinal cord 

• Dura matter 

• Archanoid layer  

• Subarachnoid space 

• Pia mater 

• Contain pain receptors 

• Meningitis: inflammation of meninges (is painful) 

• Swollen blood vessels in meninges are responsible for  

• Migraines 

-the cerebral cortex 

• Most prominent part of mammalian brain 

• Consists of cellular layers on outer surface of cerebral hemispheres 

• Divided into two halves 

• Joined by two bundle of axons 

• Corpus callosum 

• Anterior commissure 

• More highlight developed in humans than other species 

-the four lobes of the cerebral cortex 

• Occipital lobe 

• Located at posterior end of cortex 

• Contains primary visual cortex 

• First area of cortex to process visual information 

• Highly responsible for visual input 

• Damage can result in cortical blindness 

• Parietal lobe 

• Contains primary somatosensory cortex 

• Primary target for 

• Touch sensations 

• Information from muscle-stretch receptors and join receptors 

• Processes and integrates information about eye, head, and body positions from information sent from muscles and joints 

• Temporal lobe 

• Located on lateral portion of each hemisphere near temples 

• Primary auditory cortex 

• Essential for processing spoken language 

• Responsible for complex aspects of vision, including movement and some emotional and motivational behaviors 

• Klüver-Bucy syndrome: associated with temporal lobe damage 

• Frontal lobe 

• Contains prefrontal cortex and precentral gyrus 

• Precentral gyrus 

• Primary motor cortex 

• Responsible for control of fine motor movement 

• Prefrontal cortex 

• Most anterior portion of frontal lobe 

• Integration center for all sensory information and other areas of cortex 

-prefrontal cortex 

• Posterior area 

• Movement 

• Middle area 

• Cognitive control 

• Emotional reactions 

• Working memory 

• Holding info in mind and manipulating it 

• Anterior area 

• Decision making 

• Reward value 

-prefrontal lobotomy 

• Surgical damage to prefrontal cortex 

• In 1940s and 50s, about 40,000 performed 

• Mostly schizophrenics 

• Later depression, anxiety 

• Side effects 

• Apathy 

• Lack of ability to plan 

• Memory disorders 

• Lack of emotional expression 

• Impulsivity 

• Incontinence 

-research methods 

• Main categories of research methods to study brain 

• Examining effects of brain damage 

• Examining effects of stimulating a brain area 

• Record brain activity during behavior 

• Correlate brain anatomy with behavior 

-effects of brain damage 

• Experimental brain damage 

• Damage to brain created through 

• Removal of brain tissue 

• Electrical current 

• Neurotoxic chemicals 

• Measure behavioral effects of damage 

• Transgenic animals 

• Affects cell, transmitter or receptor 

2/19/24 

-transcranial magnetic stimulation 

• Uses intense magnetic field on portion of scalp to temporarily deactivate neurons 

• Creates reversible lesion 

• Allows researchers to study behavior with a brain area active, them inactive, then active again 

• Advantages 

• We can do this in people 

-recording brain activity 

• EEG: electroencephalograph 

• Records electrical activity produced by various brain regions 

• Event-related potentials: change in electrical potential because of sort of event 

• Poor spatial resolution: image isn’t particularly exact 

• Good temporal resolution: can pick up changes in brain activity that happen in milliseconds after the event occurs 

• Can only measure activity on outer cortical layer 

• PET: positron-emission tomography 

• Positron-emitting isotopes attached to reagents (oxygen or glucose) 

• Labeled regents injected into blood stream 

• More active areas of brain require more oxygen and glucose 

• Radio-reagents build in more active areas 

• Good spatial resolution: good at showing which spaces are and aren’t active 

• Poor temporal resolution: slightly slower at catching reactions 

• FMRI: functional magnetic resonance imaging 

• More active areas in brain 

• Use more oxygen 

• BOLD signal 

• Blood oxygen level dependent signal 

• Oxygen consumption in brain provides picture of activation 

• Safer and less expensive than PET 

• Good spatial resolution 

• Poor temporal resolution 

Chapter 5 

-general principles of perception 

• Specialized receptors for each sensory system 

• Sensitive to particular type of energy 

• Law of specific nerve energies 

• Activity by particular nerve conveys particular type of information to the brain 

-the eye 

• Light enters through pupil 

• Focused by lens and cornea onto rear surface of eye 

• Retina 

• Lined with visual receptors 

• Importantly: 

• Image reverted and flipped on retina 

• Left to right and top to bottom 

-route within the retina: bipolar cells 

• Rods and cones 

• Primary visual receptors 

• Bipolar cells 

• Ganglion cells 

• Axons of ganglion cells come together to form optic nerve 

• Horizontal and amacrine cells 

• Alter signaling between cell levels 

-the optic nerve 

• Axons of ganglion cells 

• Exit through back of eye and travel to brain 

• First stop: LGN of thalamus 

• What do we refer to the area of exit as? 

• Blind spot 

-the fovea 

• Central portion of retina 

• Allow for acute and detailed vision 

• Packed tight with receptors 

• Cones 

• Each cone in fovea 

• Attaches to single bipolar cell and single ganglion cell 

• Provides direct line to brain 

• Allows for precise visual acuity 

-the periphery of the retina 

• Periphery to retina 

• Greater number of receptors converge into ganglion and bipolar cells 

• Peripheral vision 

• Lower acuity 

• Greater light sensitivity 

-visual receptors: rods and cones 

• Rods 

• Most abundant in periphery 

• Respond to faint light  

• Cones 

• Most abundant in and around fovea  

• Essential for color vision 

• More useful in bright light 

• Provide about 90% of visual input       

• Ratio of rods to cones higher in nocturnal species 

2/24/25 

-color vison 

• Visible light portion of electromagnetic spectrum 

• Color perception dependent upon wavelength of light 

• Light itself DOES NOT have color 

• “visible” wavelengths dependent upon species’ receptors 

-specificity of color vision 

• Depends on specific receptors within eye 

• Two major interpretations of color vision 

• Trichromatic theory 

• Opponent process theory 

-trichromatic theory 

• Color perception occurs through the relative rates of response by three kinds of cones  

• Short wavelength 

• Medium wavelength 

• Long wavelength  

• Each cone responds to a specific range of wavelengths 

• Ratio of activity across three cones determines color 

• More intense light? 

• Increases brightness but does not change ratio 

-color vision deficiency 

• Impairment in perceiving color differences 

• Gene responsible contained on X chromosome 

• Caused by either lack of a type of cone or a cone with abnormal properties 

• Most common form 

• Red and green deficiency 

• Long and medium wavelength cones have some photopigment 

-the opponent-process theory 

• Color perception in paired opposites 

• Brain mechanisms that perceive color on a continuum 

• Red to green  

• Yellow to blue 

• Possible mechanism for theory 

• Bipolar cells are excited by one set of wavelengths and inhibited by another 

-an overview of the mammalian visual system 

• Rids and cones make synaptic contact with horizontal cells and bipolar cells 

• Horizontal cells 

• Cella that make inhibitory contact with bipolar cells 

• Bipolar cells synapse onto amacrine cells and ganglion cells 

• Amacrine cells 

• Make inhibitory contact with ganglion cells 

• Ganglion cell axons form optic nerve 

-lateral inhibition in the retina 

• Reduction of activity in one neuron by activity in neighboring neurons 

• Emphasizes borders of objects 

• Response of visual receptor cells 

• Net result of excitatory and inhibitory messages received 

-processing in the retina 

• Part of thalamus 

• Specialized for visual perception 

• Destination for most ganglion cell axons 

• Sends axons to: 

• Occipital cortex 

-further processing 

• Receptive field 

• Part of visual field that either excites or inhibits a cell 

• For a visual receptor (rod or cone) 

• Point in space from which light strikes it 

• For other visual cells 

• Derived from visual fields of cells that feed it information 

-the primary visual cortex 

• Aka Area V1 

• Receives information from lateral geniculate nucleus (LGN) 

• Responsible for first stages of visual processing 

• Activity corresponds to conscious visual experience 

• Activity increases in V1 when creating mental image 

• Aphantasia 

• Lack of visual imagery 

-parallel processing in the visual cortex 

• 80 brain areas that contribute to vision in different ways 

• Different areas for 

• Shape 

• Color 

• Location detection 

• Movement detection 

-the ventral and dorsal streams 

• The ventral stream 

• Visual path through temporal cortex 

• The “what” path 

• Specialized for identifying and recognizing objects 

• The dorsal stream 

• Visual path through parietal cortex 

• The “how” path (previously referred to as “where” pathway 

• Important for visually guided movements 

2/26/25 

-recognizing faces 

• Face recognition occurs relatively soon after birth 

• People with cataracts removed at 2-6 months develop nearly normal vision 

• Slight difficulties in distinguishing faces 

• Newborns show strong preference for right-side-up face 

• Supoorts idea of built-in face recognition system 

• Facial recognition continues to develop gradually into adolescence 

-prosopagnosia 

• The impaired ability to recognize faces 

• Occurs after damage to fusiform gyrus (FFA) of inferior temporal cortex 

• The FFA responds strongly to faces 

Chapter 6 

-sound and the ear 

• How do we experience sounds 

• Sound wave detection 

• What are sound waves 

• Period compression of air, water, or other media 

• Vary in amplitude and frequency 

-properties of sound 

• Amplitude 

• Intensity of sound wave 

• Larger waves= louder sounds 

• Frequency 

• Number of compressions per second 

• Measured in hertz (Hz) 

• Related to pitch  

• Children hear higher frequency than adults 

• Ability to recognize high frequencies diminishes with 

• Age 

• Exposure to loud noises 

-structures of the ear 

• Outer ear 

• Pinna 

• Responsible for 

• Altering reflection of sound waves into middle ear 

• Localizing sources of sound 

• Middle ear 

• Tympanic membrane 

• Vibrates when struck by sound waves 

• Also known as ear drums 

• Connects to three tiny bones (ossicles) 

• Hammer, anvil, stirrup 

• Transform waves into stronger waves to oval window 

• Inner ear 

• Oval window 

• Transmits waves through viscous fluid of inner ear 

• Cochlea 

• Snail-shapes structure 

• Contains three fluid-filled tunnels 

• Scala vestibuli, scala media, and the scala tympani 

• Hair cells 

• Auditory receptors 

• Lie between basilar membrane and tectorial membrane 

• Excite cells of auditory nerve when displaced by vibrations in fluid of cochlea 

-variations in sensitivity to pitch 

• Absolute pitch (“pitch perfect”) 

• Ability to hear a note and identify it  

• Genetic predisposition may contribute to it 

• Main determinant 

• Early and extensive musical training 

-the auditory cortex 

• Primary auditory cortex (area A1) 

• Destination for most auditory info 

• Located in superior temporal cortex 

• Contralateral organization 

• Each hemisphere receives most information from opposite ear 

-organization of the auditory cortex 

• Parallels visual cortex 

• Anterior temporal cortex 

• What pathway for sound 

• Sensitive to sound patterns 

• Posterior temporal cortex 

• Where pathway 

• Important for sound localization 

• Damage to superior temporal cortex 

• Motion deadness 

• Requires experience to develop properly 

-hearing loss 

• Two categories of hearing impairment 

• Conductive or middle ear deafness 

• Nerve deafness or inner ear deafness 

-conductive/middle ear deafness 

• Bones of middle ear fail to traansmit sound waves properly to the cochlea 

• Causes 

• Disease 

• Infections 

• Tumorous bone growth 

• Normal cochlea and auditory nerve 

• Allow people to hear own voice clearly 

• Can be corrected by surgery or hearing aids that amplify stimulus 

-nerve or inner-ear deafness 

• Results from damage to cochlea, hair cells, or auditory nerve 

• Can be confined to one part of cochlea 

• People can hear only certain frequencies 

• Can be inherited or cause by prenatal problems or early childhood disorders 

-hearing, attention, and old age 

• Brain areas responsible for language comprehension become less active 

• Decrease in inhibitory neurotransmitters in auditory areas 

• Trouble suppressing irrelevant sounds and attending to important ones 

• Hearing improves if listener watches speaker’s face 

-sound localization 

• How do we localize sounds? What are the three cues we use to accomplish sound localization 

• Depends upon comparing the responses of the two ears 

• Three cues 

• Sound shadow 

• Volume related 

• Time of arrival 

• Phase difference

3/3/25 

-the mechanical senses 

• Respond to pressure, bending, or other distortions of receptor 

• Touch 

• Pain 

• Vestibular sensation 

-somatosensory receptors 

• Touch receptors come in many forms 

• Stimulation opens sodium channels 

• Trigger action potential 

• Two types located close to surface of skin 

• Merkel Disks (receptors) 

• Fire continuously while stimulus is present 

• Sensing fine details 

• Meissner corpuscle 

• Fire only when a stimulus is first applied and when it is removed 

• Controlling-handgrip 

-Merkel Disks 

• Receptors respond to light touch 

• Important for sensing fine detail and shape 

• Sex difference in touch sensitivity? 

• Men and women have same number of Merkel disks 

• Women tend to have smaller fingers 

• Results in Merkel disks compacted into a smaller area 

• Two types located deeper in the skin 

• Ruffini cylinder 

• Fire continuously to stimulation 

• Perceive stretching of skin 

• Pacinian corpuscle 

• Fire only when stimulus is first applied and when it is removed 

• Associated with sensing rapid vibrations and fine texture 

-pain 

• Experience evoked by harmful stimulus 

• Purpose? 

• Directs one’s attention toward a danger 

• Pain sensation begins with least specialized of all receptors  

• Bare nerve endings 

• unmyelinated 

• Nociceptors 

• Axons carrying pain info have little or no myelin 

• Speed of transmission determined by? 

• Thickness of axons 

• Sharp pain transmitted via thicker axons 

• Dull pain transmitter via thinner axons 

• Mild pain 

• Triggers release of glutamate in spinal cord 

• Stronger pain  

• Triggers release of glutamate 

• Releases several neuropeptides 

• Substance P 

• CGRP (calcitonin gene-related peptide) 

-spinal pathways for touch and pain 

• Pain information 

• Crosses to contralateral side at once 

• Toch information 

• Does not cross until medulla 

-emotional pain  

• Emotional associations of pain 

• Painful stimuli 

• Activate a path through reticular formation of medulla 

• Other areas involved 

• Several central nuclei of thalamus  

• Amygdala  

• Hippocampus  

• Prefrontal cortex 

• Cingulate cortex 

• Areas impacted during hypnotic suggestions against pain 

• Hurt feelings activate same pathway 

• Having a broken heart is painful 

-relieving pain 

• Opioid mechanisms 

• Systems sensitive to opioid drugs and similar chemicals 

• Opiates bind to receptors in spinal cord and periaqueductal gray area of midbrain 

• Endorphins 

• Endogenous morphine 

• Group of chemicals that bind to same receptors as morphine 

 3/3/25

-more ways of relieving pain  

• Placebo 

• Cannabinoids  

• Chemicals found in marijuana 

• Act mainly in periphery of body 

• Intoxication not necessary for pain relief