Sound and Vision Flashcards
Idealism
Assertion that reality is fundamentally mentally constructed and immaterial.
Realism
Advocated by empiricists. Reality does exist independently of observers.
Two main types of eye
Chambered (our eye) and compound (up to thousands of individual photoreceptor units, like dragonflies)
Physiology of the eye
Iris controls diameter/size of pupils and thus the light reaching the retina
Pupil - hole located in the center of iris allowing light to enter retina
Lens - optical device which transmits and refracts light, converging or diverging the beam
Cornea - transparent front part of eye that covers iris, pupil, and anterior chamber
Retina
Light-sensitive tissue lining the inner surface of the eye: optics of eye create an image of the visual world on the retina. Light that strikes retina initiates chemical and electrical events that trigger nerve impulses. These are sent to visual centers of brain through optic nerve.
Two kinds of photoreceptor cells
Rods: low levels of light, poor acuity
Cones: greater levels of light and color, good acuity
Optic chiasm
Crossing where the optic nerves from the left and right eyes partially cross
Optic Tract
Continuation of optic nerve - runs from optic chiasm to the lateral geniculate nucleus
Lateral Geniculate Nucleus
The primary relay center for information coming from the eyes. Located in the thalamus. 6 layers of cells: parvocellular layers (object processing) and magnocellular layers (motion)
Visual cortex
A number of regions in cortex. Multiple levels of complexity. V1-4: V1 is the primary/striate, it runs adjacent to the calcarine sulcus. V2-4 are extra striate.
Calcarine sulcus
where the primary visual cortex aka V1 is located
Retinotopic mapping
Center of the eye goes to V1, more and more peripheral go to v2, v3, and v4
Facial recognition
Fusiform face area plays crucial role in facial recognition/differentiating faces from object.
Superior temporal sulcus
Involved in changeable aspects of faces - expressions, direction of eye gaze, lip movement
Amygdala, insula, limbic system
Involved in emotion - receives information about expressions from superior temporal sulcus
Lateral fusiform gyrus
Perceiving invariant aspects of faces - perception of unique identity
Inferior occipital gyri
Early perception of facial features
Predictive vision
Faces are processed as a whole, not parts. Our brains are predictive and fill in gaps. That is why context matters with vision. Perceive emotions as different depending on the context.
Fovea
The central region of the eye - responsible for sharp central vision
Overview of vision pathway
Retina -> optic tract -> partial split at optic chiasm -> lateral geniculate cortex ->visual cortex ->dorsal/ventral pathway
Range of human hearing
20 Hz to 20 kHz
How hearing works
Sounds enter the canal, causing the tympanic membrane to vibrate. The membrane passes the oscillations to the malleus, incus, and stapes. These bones send the vibration to the cochlea, where there are tiny hairs in the ear connected to nerves that are moved as a result.
Belt and parabelt area in brain
Part of the auditory cortex. More responsive to complex stimuli = integrative and associated functions involved in pattern perception and object recognition
Tonotopic maps in auditory cortex
Different tones are mapped to different parts of the brain. Note that after a sound is initially processed it is passed on to brain areas involved in higher cognitive processing such as memory
Musical rewards
Endogenous dopamine release in striatum at peak emotional arousal while listening to music
Hearing speech sounds
Wernicke’s area and secondary auditory complex (belt areas)
Interaction of sound and vision
What we hear is influenced by what we see