Sensation and Perception

    Cards (49)

    • What are the main topics covered in the lecture plan on Sensation & Perception?
      General principles of sensory coding, colours from sensation to perception, and parallel processing in the visual cortex.
    • What is the role of sensory systems in relation to physical events in the world?
      Sensory systems detect physical events, process the information, and convey it to the brain.
    • How does sensory processing occur in relation to conscious awareness?
      Much sensory processing occurs below the level of conscious awareness.
    • What factors influence sensory processes?
      Sensory processes depend on the magnitude of stimulus, the adaptation state of the system, and internal noise.
    • What is perception in the context of sensory information?
      Perception is the organization, identification, and interpretation of sensory information to understand the environment.
    • Why have sensory systems evolved in species?
      Sensory systems have evolved to provide information relevant to survival within an ecological niche of a species.
    • What is the limitation of sensory systems in terms of stimulus response?
      Sensory systems respond to only a fraction of the full physical range of any stimulus category.
    • Who proposed the Law of Specific Nerve Energies and what does it state?
      Johannes Müller proposed it, stating that each nerve fiber is activated primarily by a certain type of stimulus.
    • What is the process of transduction in sensory receptors?
      Transduction is the conversion of specific types of energy into electrical signals by sensory receptors.
    • What are the five major sensory systems defined by Aristotle?
      Vision, Hearing, Smell, Taste, and Touch.
    • What is proprioception and its role in the body?
      Proprioception enables conscious awareness of the posture and movements of the body, particularly the limbs and head.
    • What does exteroception involve?
      Exteroception involves touch, contact, pressure, stroking, and vibration, along with active motor components.
    • What is interoception and its significance?
      Interoception is the sense of the internal state of major organ systems, crucial for regulating autonomic functions.
    • What is the function of association cortices in the brain?
      Association cortices integrate sensory information from multiple modalities with information from other brain regions.
    • What are the four attributes mediated by sensory systems?
      Modality, Location, Intensity, and Duration of a stimulus.
    • What type of sensation do Merkel cells and Ruffini endings respond to?
      They respond to steady pressure.
    • What sensation does Meissner's corpuscle detect?
      Meissner's corpuscle detects tingling sensations.
    • What sensation does Pacinian corpuscle detect?
      Pacinian corpuscle detects vibration sensations.
    • How do olfactory receptors function in sensory transduction?
      Olfactory receptors bind specific odorant molecules and depolarize the sensory nerve via a second messenger system.
    • What happens to photoreceptors when they absorb light?
      Photoreceptors hyperpolarize when absorbing light, closing their channels.
    • What do tuning curves of sensory receptors measure?
      Tuning curves measure the minimum amplitude of stimulation needed to activate a sensory receptor over a range of stimulus energies.
    • How does the human ear's sensitivity vary across frequencies?
      The human ear is sensitive to a range of frequencies from 20 Hz to 20 KHz, with hair cells having differential sensitivity.
    • How do the sensitivities of rods and cones differ under varying light conditions?
      Cones are more sensitive in light, while rods are more sensitive in the dark.
    • What does spatial awareness involve in sensory perception?
      Spatial awareness involves locating the site of stimulation, discriminating size and shape, and resolving fine detail of the stimulus.
    • How does the density of sensory receptors affect visual resolution?
      The density of sensory receptors and the size of the receptive field determine the resolution of the visual image.
    • What is lateral inhibition and how does it affect perception?
      Lateral inhibition enhances contrast in perception by inhibiting neighboring cells, creating perceptual illusions like the staircase illusion.
    • How is the intensity of sensation determined?
      The intensity of sensation is determined by the stimulus amplitude.
    • How is stimulus intensity encoded in sensory nerves?
      Stimulus intensity is encoded by the frequency of action potentials in sensory nerves.
    • How do slowly and rapidly adapting mechanoreceptors respond to stimuli?
      Slowly adapting mechanoreceptors respond throughout a continuous stimulus, while rapidly adapting mechanoreceptors respond only at the beginning and end of the stimulus.
    • How many rods and cones are there in the retina?
      There are about 20 million rods and 6 million cones in the retina.
    • Why are the proximal neurons shifted to the side in the fovea?
      To allow light a direct pathway to the photoreceptors, minimizing distortion.
    • What is the significance of the visual image received at the foveola?
      It is the least distorted visual image due to the direct pathway to photoreceptors.
    • Who proposed the trichromatic theory of color vision?
      Thomas Young and Hermann von Helmholtz proposed the trichromatic theory.
    • What does the trichromatic theory state about color vision?
      Color vision is based on three principal colors and the relative activity in a three-receptor system.
    • What visual phenomena does the trichromatic theory not explain?
      • After-images
      • Simultaneous color contrast
    • What is simultaneous color contrast?
      It is the condition where two surfaces with the same spectral composition appear to have different colors against different backgrounds.
    • What are the colors that produce other colors when additively mixed together called?
      These are called primary colors.
    • Who proposed the opponent color theory?
      Ewald Hering proposed the opponent color theory.
    • What are the seven steps of the principle of visual perception?
      1. Light enters the eye
      2. Projects onto the retina
      3. Photoreceptors convert light to signals
      4. Signals travel through optic nerves
      5. Partial crossing at the optic chiasm
      6. Information processed in the thalamus
      7. Sent to visual cortices in the occipital lobes
    • What are the two pathways in parallel processing of visual information?
      The 'Where or How' pathway and the 'What' pathway.
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