L5-L6 Flashcards
Anatomy of the Visual System:
Through which structure do photons/lightwaves enter?
the Cornea (outermost layer)
Anatomy of the Visual System: Which structure controls how much light is let in?
the Iris
Anatomy of the Visual System: Which structure does the light go through after the iris?
the Pupil
Anatomy of the VS: Which structure contains layers of (photoreceptors and glial) cells?
the Retina
Anatomy of the VS: Which structure is known as the point of CENTRAL vision?
the Fovea
Anatomy of the VS: Which structure is an extension of the central nervous system where signals converge?
the Optic Nerve
What is the definition of perception?
Our experience of the sensory world
What does the existence of illusion tell us?
That our VS does not work like a camera
Does our VS have direct access to physical properties of the world?
No. Our brain is constantly making predictions of what we visually perceive
Visual information from LEFT and RIGHT sides of the visual field enter BOTH sides of our eyes. Is this true?
Yes
The visual pathway: Which structure does the photons cross before reaching the Primary Visual Cortex (V1)?
the Optic Chiasm
What is the structure made up of bundle of nerve fibers that extends from the optic chiasm?
the Optic tract
Where is the Occipital lobe?
on the most POSTERIOR part of the cortex
What are the 2 key functions of the Occipital lobe?
- Processing integration
- Interpretation
of the visual stimuli
Region (A) is the most posterior part of the Occipital lobe and region (B) is anterior of (A)
A: V1
B: Visual Association Area
The CENTRAL part of the visual field is at the (A) of the brain, the (B) areas of the VF are located more anteriorly, the TOP part of the VF is in the (C) part of the occipital lobe
A: back
B: peripheral
C: lower
V1 feeds information to …
V2: Secondary visual cortex
What are the examples of extrastriate cortex?
V2, V3, V4, V5
Which condition is usually caused by a stroke and results is loss of sight of HALF of the visual field? Where are its lesions?
HEMIanopia
- lesions are from the optic tract to the occipital cortex
What is color ANOMIA?
inability to NAME colors
What is color AGNOSIA?
inability to RECOGNIZE colors
What is ACRHOMATOPSIA called in simple terms?
inability to perceive colors = COLOR BLINDNESS
A patient has difficulties locating objects in space despite being able to see them. Which part of their brain has been damaged?
the occipital cortex
A patient has difficulties in recognizing or reading written words. Which part of their brain has been damaged?
the occipital cortex
Patient LM is a 43 year old female who has an irreversible damage to V5 after thrombosis bilateral damage (blood clotting problem). What is the V5 responsible for and what is her condition called?
V5 is responsible for detecting visual MOTION
- it is the Visual Motion area (MT)
Her condition is called AKINEtopsia, or in simple terms, ‘world in snapshots’
Two parallel visual streams: (A) stream projects from Occipital to Temporal cortex. What is this stream?
Ventral stream
(vent=going under; since occipital to temporal is lower than occipital to parietal, it is like taking a vent)
Two parallel visual streams: (B) stream projects from Occipital to Parietal cortex. What is this stream?
Dorsal Stream
Name the WHAT visual stream and its key function.
Ventral stream: for recognizing objects
Name the WHERE and HOW stream and its key function
Dorsal stream: for guiding actions
What is the difference between COLOR agnosia and VISUAL-FORM agnosia?
color: inability to recognize colors
visual form: inability to recognize OBJECTS
What is face blindness called in other terms? Which stream must be damaged for this condition?
PROSOPagnosia.
The ventral stream
Which condition has PRESERVED object recognition but DEFICIT in visually-guided movements? Which stream must be damaged for this condition?
Optic Ataxia
- the posterior parietal cortex or the Dorsal stream
What are the 3 key functions of the Temporal lobe?
- Auditory processing
- Language processing
- Memory formation and storage
Which lobe is involved in olfaction, emotional processing, visuospatial processing and music?
the Temporal lobe
Which lobe is the Wernicke’s area in? What is this area responsible for?
the LEFT Temporal lobe. It is responsible for language comprehension (thus called fluent APHASIA)
Wernicke’s area is located in between Primary (A) cortex and Primary (B) cortex. (B) is more anterior than (A)
A: Auditory
B: Olfactory
The Temporal lobe is … hence the LEFT and RIGHT lobes have different functions.
ASYMMETRICAL
What is the Left Temporal lobe responsible for? (2)
- Verbal Memory
- Speech processing
(since Wernicke’s area is located on the left side)
What is the Right Temporal lobe responsible for? (3)
- Non-verbal memory
- Musical processing
- Facial processing (Fusiform face area)
Which structure in the Parietal lobe transforms VISUAL representations into an AUDITORY code?
the Angular gyrus
Aphasia is a common effect of stroke that about 1/3 of patients are affected. What are its 2 main classifications?
- Broca’s aphasia; non-fluent
- expression is affected - Wernicke’s aphasia; fluent
- comprehension is affected
Damage to this cortex could result in auditory disturbance, disorders of music perception, long-term memory problems, altered personality and affective behaviour. Which cortex lesion is this?
Temporal cortex region
What is Amusia?
music perception disorder
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
Sensation
The process of organizing and interpreting sensory information
Perception
Study of the relation between physical stimulation and psychological experience
Psychophysics
What are the 8 main stimuli?
- Olfaction and gustation
- Tactile
- Audition
- Vision
- Vestibular system - Balance
- Proprioception - Position
- Interoception - internal state
- Thermosensation - Temperature
- Nociception - Pain
Perception is fundamentally a … phenomenon
Multisensory
Synesthesia is …
merging of the senses
Synesthesia has 5 main characteristics
- Involuntary
- Consistent
- Memorable
- Heritable
- Prevalent
What is Grapheme-Color synaesthesia?
Letter, numerals with colors
What is Music-Color synaesthesia?
seeing colors when they hear sounds
What is Lexical-Gustatory synaesthesia?
experiencing tastes in mouth when reading or speaking
What is Number-Form (= Sequence-Space) synaesthesia?
involuntary mental maps of any group of numbers
What is Mirror-Touch synaesthesia?
observing someone receiving touch invoking physical sensation on corresponding body part
When activity in one area kindles activity in another area it is … which is probably due to DEFECTIVE NEURAL PRUNING from prenatal period
Hyperconnectivity
Triggering stimulus is (A) and the resultant synaesthetic experience is (B)
A: Inducer
B: Concurrent
What are the 2 major theories of synaesthesia?
- Individual differences
- Mysterious: subjective altered reality
What is a possible cause of synaesthesia?
Genetic disposition
- probabilistic but not inevitable
- might have different neurocognitive architecture
Near-universally experienced associations between seemingly unrelated sensory features is called
Cross-Modal correspondences
Cross-Modal Transfer
Who questioned: “the blind man be made to see: query, whether by his sight, before he touched them he could now distinguish and tell which is the globe, which the cube?”
W. Molyneux
Who answered to Molyneux by saying that the formerly blind man would have to LEARN through EXPERIENCE of simultaneous touch and sight to distinguish between the objects by sight alone?
B. Berkeley
As a response to Molyneux’s question and Berkeley’s hypothesis, Held et al concluded what about the Haptic (touch)-Visual Transfer?
- Able to match touch-touch and sight-sight
- But not touch-vision
- After a short period of experience, they can match touch-vision
Held et al suggested that the rapid acquisition of haptic-visual ability could be due to … interaction already being in place before they were behaviourally manifested
Cross-Modal
Multisensory illusion of Audiovisual integration is also called…
McGurk effect
McGurk effect states that auditory and visual signals are forced to come together in a … percept even though the senses could be independently recognized and interpreted
Single
What is a multisensory illusion of feeling of owning an artificial body which substitutes the real body as the origin of perceptual sensations?
Body-Ownership illusion
Damage to Lower parts of the visual system leads to lack of (A) or blindness
Damage to Higher areas leads to specific deficits in (B) which is ability to see but inability to recognize
A: sensation
B: perception
… transforms visual representations into AUDITORY code
Angular Gyrus
