| Qualia | Private conscious experiences of sensation or perception |
| Psychophysics | Defining quantitative relationships between physical and psychological (subjective) events |
| Method of Constant Stimuli | A Psychophysical method in which many stimuli, ranging from rarely to almost always perceivable are presented one at a time. Participants respond to each presention: Yes/No, Same/Different and so on |
| Method of Limits | A psychophysical method in which the particular dimension of the stimulus, or the difference between two stimuli, is varied incrementally until the participant responds differently |
| Method of Adjustment | A method of limits in which the participant controls the change in the stimulus |
| Magnitude Estimation | A psychophysical method in which the participant assigns values according to perceived magnitudes of the stimuli |
| Stevens's Power Law | A principle describing the relationship between stimulus and resulting sensation that says the magnitude of subhective sensation is porportional to the stimulus magnitude raised to an exponent |
| Supertaster | An individual who experiences the most intense taste sensations |
| Sensitivity | In reference to signal detection theory, a value that defines the ease with which an observer can tell the difference between the presence and absence of a stimulus or the difference between stimulus 1 and 2 |
| Criterion | In reference to signal detection theory, an internal threshold that is set by an observer. If the internal response is above criterion, the observer gives one response (i.e, 'yes I hear that'). Below criterion, the observer gives another response (No, I hear nothing) |
| Wavelength | The distance required for one full cycle of oscillation for a sine wave |
| Positron Emission Tomography (PET) | An imaging technology that enables us to define locations in the brain where neurons are especially active by measuring the metabolism of brain cells using safe radioactive isotopes |
| Functional Magnetic Resonance Imaging (fMRI) | A variant of MRI that makes it possible to measure localised patterns of activity in the brain. Activated neurons provoke increased blood flow, which can be quantified by measuring changes in the response of oxygenated and deoxygenated blood to strong magnetic fields |
| Sensation | The ability to detect a stimulus and, perhaps, to turn that detection into a private experience |
| Perception | The act of giving meaning to a detected sensation |
| Dualism | The idea that the mind has existence separate from the material world of the body |
| Materialism | The idea that only matter exists and that all things - including the mind and consciousness - are the results of interactions between said bits of matter |
| Psychophysics | Defining quantitative relationships between physical and psychological (subjective) events |
| Panpsychism | All matter has consciousness |
| Just Noticeable Difference (JND) | Smallest detectable difference beween two stimulie, or the minimum change in a stimulus that enables it to be correctly judged as different from a reference stimulus |
| 2-point touch threshold | The minimum distance at which 2 stimuli are just perceptible as separate |
| Weber Fraction | The constant of proportionality as defined by Webers Law |
| Weber's Law | The principle describing the relationship between stimulus and resulting sensation that says the JND is a constant faction of the comparison stimulus |
| Absolute Threshold | The minimum amount of stimulation necessary for a person to detect a stimulus of 50% all of the time |
| Fechner's Law | A principle describing the relationship between stimulus and resulting sensation that says the magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity |
| Cross-modality matching | The ability to match the intensities of sensations that come from different sensory modalities. This ability allows insight into sensory differences. E.g., a listener might adjust the brightness of a light until it matches the loudness of a tone |
| Signal Detection Theory | A Psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise. Measures obtained from a series of presentations are sensitivity (d' ) and criterion of the observer |
| Sine Wave | A simple, smootly changing oscillation that repeats across space |
| Receiver Operating Characteristic (ROC) Curve | In reference to studoes of signal detection, the graphical plot of the hit rate as a function of the false-alarm rate. If these are the same, points fall on the diagonal, indiciating that the observer cannot tell the difference between the presence and absence of the signal. As the observer's sensitivity increases, the curve bows upward toward the upper left corner. That point represents a perfect ability to distinguish signal from noise |
| Blood oxygen level-dependent (BOLD) signal | The ration of oxygenated to deoxygenated hemoglobin that permits the localisation of brain neurons that are most involved in a task |
| Computed Tomography (CT) | an imaging technology that uses X-ray to create images of slices through volumes of material (i.e, the human body) |
| Magnetic Resonance Imaging (MRI) | In imaging technology that uses the responses of atoms to strong magnetic fields to form images of structures like the brain. The method can be adapted to measure activity in the brain as well. |
| Even-related Potential (ERP) | A measure of electrical activity from subpopulation of neurons in response to particular stimuli that requires averaging many EEG recordings |
| Magnetoencephalography (MEG) | A technique that measures changes in magnetic activity across populations of many neruons in the brain |
| Electroencephalography (EEG) | A technique that, using many electrodes on the scalp, measure electrical activity from populations of many neurons in the brain |
| Neuroimaging | A set of methods that generate images of the structure and/or function of the brain. In many cases, these methods allow us to examine the brain in living, behaving humans. |
| Vitalism | The idea that there is a force in life that is distince from physical entities |
| Abducens (VI) Nerves | The 6th pair of cranial nerves, which innervate the lateral rectus muscle of the eyeballs |
| Trochlear (IV) Nerves | The 4th pair of cranial nerves which innervate the superior oblique muscles of the eyeballs |
| Polysensory | Referring to blending multiple sensory systems |
| Oculomotor (III) Nerves | The 3rd pair of cranial nerves, which innervate all the extrinsic muscles of the eye except the lateral rectus and the superior oblique muscles, and which innervate the elevator muscles of the upper eyelid, the ciliary muscle, and the sphincter muscle of the pupil |
| Optic (II) Nerves | The 2nd pair of cranial nerves which arise from the retina and carry visual information to the thalamus and other parts of the brain |
| Vestibulocochlear (VIII) Nerves | The 8th pair of cranial nerves, which connect the inner ear with the brain, transmitting impulses concerned with hearing and spatial orentation. The vestibulocochlear nerve is composed of the cochlear nerve branch and the vestibular nerve branch |
| Olfactory (I) Nerves | The 1st pair of cranial nerves. The axons of the olfactory sensory neurons bundle together after passing through the cribriform plate to form the olfactory nerve, which conducts impulses from the olfactory epithelia in the nose to the olfactory bulb. |
| Optic (II) Nerves | The 2nd pair of cranial nerves which arise from the retina and carry visual information to the thalamus and other parts of the brain |
| Doctine of Specific Nerve Energies | A doctrine, formulated by Johannes Müller, stating that the nature of a sensation depends on which sensory fibers are stimulated, rather than how they are stimulated |
| Cycles per degree | The number of pairs of light and dark bars per degree of visual angle |
| Cranial Nerves | Twelve pairs of nerves that originate in the brain stem and reach sense organs and muscles through openings in the skull |
| Spatial frequency | The number of cycles of a grating per unit of visual angle |
| Phase | A fraction of the cycle of the sine wave described in degrees or radians. In reference to hearing, phase can be used to describe fractions of a period that relate to time. |
| Period | In reference to hearing, the time required for a full wavelength of an acoustic sine wave to pass by a point in space |
| Accessory Olfactory Bulb (AOB) | A nerual structure found in nonhuman animals that is smaller than the main olfactory bulb and located behind it and that receives input from the vomeronasal organ |
| Fourier Analysis | A mathematical procedure by which any signal can be separated into component sine waves at different frequences. Combining these sine waves will reproduce the priginal signal |
| Anosmia | The total inability to smell, most often resulting from sinus illness or head trauma |
| Amygdala-Hippocampal Complex | The conjoined regions of the amygdala and hippocampus, which are key structures in the limbic system. This complex is critically involved in the unique emotional and associative properties of olfactory cognition |
| Basal Cell | One of the three types of cells in the olfactory epithelium. Basal cells are the precursor cells to olfactory sensory neurons |
| Aromatherapy | The manipulation of odors to influence mood, performance and well-being as well as the physiological correlates of emotion such as heart rate, blood pressure and sleep |
| Binaral Rivalry | Competition between the two nostrils for odor perception. When a difference scent is presented to each nostril simultaneously, we perceive each scent to be alternating back and forth with the other, and not as a blen of the two scents |
| Chemosignal | Any of various chemicals emitted by humans that are deteced by the olfactory system and that may have some effect on the mood, behaviour, hormonal status and or sexual arousal of other humans |
| Binaral Rivalry | Competition between the two nostrils for odor perception. When a difference scent is presented to each nostril simultaneously, we perceive each scent to be alternating back and forth with the other, and not as a blen of the two scents |
| Cognitive Habituation | The psychological process by which after long-term exposure to an odor, one no longer has the ability to detect that odor or has very diminished detection ability |
| Cilium (pl. Cilia) | any of the hairlike protrustions on the dendrites of olfactory sensory neurons. The receptor sites for odorant molecules are on the cilia, which are the first structres involved in olfactory signal transduction |
| Cross-adaptation | The reduction in detection of one odorant following exposure to a prior odorant. Cross-adaptation is presume to occur because the components of the odors in question share on or more olfactory receptors for their transduction, but the order in which odorants are presented also plays a role |
| G Protein-coupled Receptor (GPCR) | Any of the class of receptors that are present on the surface of olfactory sensory neurons. All GPCRs are characterised by a common structural feature of seven membrane-spanning helices |
| Cribriform Plate | A bony structure riddled with tiny holes that separates the nose from the brain at the level of the eyebrows. The axons from the olfactory sensory neurons pass through the tiny holes of the cribriform plate to enter the brain. |
| Glomerulus (sing. Glomeruli) | Any of the spherical conglomerates containing the incoming axons of the olfactory sensory neurons. Each OSN converges onto two glomeruli (one medial, one lateral) |
| Entorhinal Cortex | A phylogenetically old cortical region that provides the major sensory association input into the hippocampus. The entorhinal cortex also receives direct projections from olfactory regions. |
| Gustation | Sense of taste |
| Granular Cells | Like mitral cells, granular cells are at the deepest level of the olfactory bulb. They comprise an extensive network of inhibitory neurons, integrate input from all the earlier projections, and are thought to be the basis of specific orderant identification |
| Juxtaglomerular Neurons | The first layer of cells srrounding the glomeruli. They are a mixture of excitatory and inhibitory cells and respond to a wide range of odorants. The selectivity of neurons to specific odorants increases in a gradient from the surface of the olfactory bulb to the deeper layers |
| Ipsilateral | Referring to the same side of the body (or brain) |
| Limbic System | The group of neural structures that includes the olfactory cortex, the amygdala, the hippocampus, the piriform cortex and the entorhinal cortex. The limbic system is involved in many aspects of emotion and memory, Olfaction is unique among the senses for its direct connection to the limbic system |
| Learned Taste Aversion | The avoidance of a novel flavour after it has been paired with gastric illness. The smell, not the taste, of the substance is key for the learned aversion response in humans |
| Main Olfactory Bulb (MOB) | The rounded extension of the brain just above the nose that is the first region of the brain where smells are processed. In huymans, we refer simply to olfactory bulbs |
| Mitral Cell | The depest layer of neurons in the olfactory bulb. Each mitral cell responds to only a few specific odorants |
| Lordosis | The position that females of some species need to assum in order to be impregnated. It involves the downward curving of the spinal column and exposure of the gentials |
| Nasal Dominance | The asymmetry characterising the intake of air by the two nostrils, which leads to differing sensitivity to odorants between the two nostrils. Nasal dominance alternates nostrils through the day, but there is no predictability about when the nostrils alternate |
| Odorant Receptor (OR) | the region on the cilia of olfactory sensory neurons where odorant molecules bind |
| Odorant | A molecule that is defined by its physicochemical characteristics, and that can be translated by the nervous system into the perception of a smell |
| Odor Hedonics | The liming dimension of odor perception, typically measured by ratings of an odors perceived pleasantness, familiarity and intensity |
| Odor | The translation of a chemical stimulus into the sensation of an odor percept. i.e, the cake has a chocolate odor |
| Olfatory Bulb | A blueberry-sized extensions of the brain just above the nose, where olfactory information is first processed. There are 2 olfactory bulbs, one in each brain hemisphere, corresponding to the right and left nostrils |
| Olfactory Cleft | A narrow space at the back of the nose into which air flows and where the olfactory epithelium is located |
| Olfaction | Sense of smell |
| Olfactory Epithelium | A secretory mucous membrane in the human nose whose primary function is to detect odorants in inhaled air. Located on both sides of the upper protion of the nasal cavity and the olfactory clefts, the olfactory epithelum containts three types of celles: olfactory sensory neurons, basal cells and supporting cells |
| Olfactory Sensory Neuron (OSN) | One of three cell types - the main one - in the olfactory epithelium. OSNs are small neurons located beneath a mucous layer in the epithelium. The cilian on the OSN dendrites contain the receptor sites for odorant molecules |
| Olfactory Tract | The bundle of acons of the mitral and tufted cells within the olfactory bulb that sends odor information to the primary olfactory cortex |
| Olfactory Nerves (I) | The first pair of cranial nerves. The axons of the olfactory sensory neurons bundle together after passing through the cribriform plate to form the olfactory nerve, which conducts impulses from the olfactory epithelia in the nose to the olfactory bulb |
| Orbitofrontal Cortex (OFC) | The part of the frontal lovbe of the cortex that lies behind the bone (orbit) containing the eyes. The OFC is responsible for the conscious experience of olfaction, as well as the integration of pleasure and displeasure from food |
| Orthonasal Olfaction | Sniffing in and perceiving odors through our nostrils, which occurs when we are smelling something that is in the air |
| Olfactory White | The olfactory equivalent of white noise or the colour white. When at least 30 odorants of equal intensity that span the olfactory physiochemical and psychological space are mixed, they produce a resultant odor perception that is the same as that of every other mixture of 30 odorants meeting the same span and equivalent intensity criteria, even though the various mixtures do not share any common odorants |
| Primary Olfactory Cortex or Piriform Cortex | The neural area where olfactory information is first processed. It comprises the amygdala, parahippocampal gyrus and interconnected areas and it interacts closely with the entorhinal cortex |
| Receptor Adaptation | The biochemical phenomenon that occurs after continual exposure to an odorant, whereby receptors are no longer available to respond to the odorant and detection ceases |
| Primer Pheremone | A pheremone that triggers a physiological change among conspecifics. This effect usually involves prolonged pheremone exposure |
| Retronasal Olfaction | Perceiving odors through the mouth while breathing and chewing. This is what gives us the experience of flavour |
| Releaser Pheremone | A pheremone that triggers an immediate behavioural response among conspecifics |
| Specific Anosmia | The inability to smell on specific compound amid otherwise normal smell perception |
| Shape-Pattern Theory | The current dominant biochemical theory for how chemicals come to be perceived as specific odors. |
| Stereoisomers | Isomers in which the spatial arrangements of the atoms are mirror-image rotations of one another, like a right and left hand |
| Staircase Method | An example of the Method of Limits: A stimulus is presented in an ascending concentration sequence until detection is indicated and then the concentration is shifted to a descending sequence until the response changes to 'no detection' |
| Tip-Of-The-Nose Phenomenon | The inability to name an odor, even though it is very similar |
| Supporting Cell | One of the three types of cells in the olfactory epithelium. Supporting cells provide metabolic and physical support for the olfactory sensory neurons |
| Trigeminal (V) Nerve | The Fifth cranial nerve, which transmits information about the 'feel' of an odorant as well as pain and irritation sensations |
| Triangle Test | A test in which a participant is given three odorants to smell, of which two are the same and one is different |
| Tufted Cells | The next layer of cells after the juxtaglomerular neurons. They respond to fewer odorants than the juxtaglomerular cells, but more than neuronas at the deepest layer of cells |
| Vibration Theory | Proposes that every odorant has a different vibrational frequency and that molecules that produce the same vibrational frequencies will smell the same |
| Tufted Cells | The next layer of cells after the juxtaglomerular neurons. They respond to fewer odorants than the juxtaglomerular cells, but more than neuronas at the deepest layer of cells |
| Chorda Tympani | The branch of cranial nerve VII that carries taste information from the anterior mobile tongue. The chorda tympani exits the tongue with the lingual branch of the trigeminal nerve and then passes through the middle ear on its way to the brain |
| Vomeronasal Organ (VNO) | Found in nonhuman animals, it is a chemical sensing organ at the base of the nasal cavity with a curved tubular shape. The VNO evolved to detect chemicals that cannot be processed by Ors, such as large and or aqueous molecules. Also called Jacobson's organ |
| Filiform Papillae | Small structures on the tongue that provide most of the bumpy appearance. Filiform papillae have no taste function |
| Circumvallate Papillae | Circular structures that form an inverted V on the rear of the tongue. Moundlike structures, each surrounded by a trench. These papillae are much larger than fungiform papillae |
| Fungiform Papillae | Mushroom-shaped structures that are distributed most densely on the edges of the tongue, especially on the tip. Taste buds are buried in the surface |
| Foliate Papillae | Folds of tissue containing taste buds. Foliate papillae are located on the rear of the tongue lateral to the circumvallate papillae, where the tongue attaches to the mouth |
| Insular Cortex | The primary cortical processing area for taste- the part of the cortex that first receives taste information. |
| Heterodimer | A chain of two molecules that are different from each other |
| Specific Hungers Theory | The idea that deficiency of a given nutrient produces craving for that nutrient |
| Labelled Lines | A theory of sensory coding in which each nerve fiber carries a particular stimulus quality |
| Microvilli | Slender projections of the cell membrane on the tips of some taste bud cells that extent into the taste pore |
| Nontaster (of PTC/PROP) | An individual born with two recessive alleles for the TAS2R38 gene and unable to taste the compounds PTC and PROP |
| Monosodium Glutamate (MSG) | The sodium salt of glutamic acid (an amino acid) |
| Retronasal Olfactory Sensation | Sensation of an odor that is perceived when chewing and swallowing force an odorant in the mouth up behind the palate into the nose |
| Taste Receptor Cell | A cell within the taste bud that contains sites on its apical projection that can interact with taste stimuli |
