Quiz 2 Flashcards
Visual Perception
Visuoperception is an active, creative, constructive process that transforms transient light patterns on retina into stable, coherent percepts that are affected by prior experience and other brain modules
(Hardwired by genes, but individual experience can modulate those systems and also modified by other systems)
Binding Mechanism
Perception of location, motion, depth, form, color are processed all along and between the two pathways–> involve different types of neurons and different brain structures (modules)
Selective attention affects what we perceive as most important
This attentional aspect of consciousness and the “binding problem” are considered to be among the most complex problems facing neuroscience
Ventral Stream
From occipital to inferior/ventral temporal lobe: processes object recognition (the “what” of vision, what it looks like)
Where is movement processed?
Medial temporal (MT/V5) and Medial Superior Temporal (MST)
Dorsal Stream
From occipital to parietal lobe to guide movements (the “how” of vision-where it is and if it’s moving)
Integrates visuospatial with data about movement from medial temporal, medial superior temporal
Parietal lobe is critical for…
SELECTIVE/FOCUSED ATTENTION
- Selection of restricted sample of sensory data
- Focusing on “target” stimulus & avoiding distractors
- Bottom-up processes may bias attention by salient features of stimuli (limbic system could also active here and may affect ability to perceive accurately)
- Top-down processes from cortex helps to avoid distractions.
Selective Attention
Separates signal from noise by quieting sensory system and amplifying signal
Like a “spotlight”
Posterior spotlights
- posterior parietal, especially right
- Selects location
- Critical for ability of neurons (especially visual) to highlight one sensory input while keeping others in background - Right posterior parietal lobe (PPL) is critical for switching attention.
- Posner’s “disengage, move, engage” model
Hemispatial (contralateral) neglect (“inattention”)
Neglect of contralateral side…people neglect information in one hemisphere.
- Usually vision (but may include other sensory modalities)
- Left side is much more commonly neglected because right PPL is involved in selective attention for both sides
Anosagnosia
Loss of awareness of deficits (physical & cognitive)
- Left side of body is usually more “neglected.”
- More common w/ right parietal lesions
- May occur w/ right prefrontal lesions
Binding and consciousness
A unified, conscious experience is achieved through
- Connectivity
- Synchrony/timing
Agnosia
“Lack of knowledge” due to perceptual deficit w/ intact sensation
Visual Agnosia
Inability to recognize/perceive visual objects (or drawings) and to draw or copy them
Prosopagnosia
Inability to recognize familiar faces due to inability to disambiguate individual stimuli.
- Memory and visual-perceptual issue
- Usually due to bilateral lesions in occipito-temporal cortex & white matter
Aphasia
Acquired difficulty in comprehending or formulating verbal content of language.
-Thought-language disconnect
-May disrupt:
Syntax – Grammatical structure
Lexicon – “Dictionary” of word meanings
Word morphology – Combination of
phonemes to make words
Wernicke’s (receptive, sensory, fluent) aphasia
Difficulty comprehending verbal content of language
Three Impairments:
- Impaired phonemic recognition
- Impaired speech
- Impaired writing– also frequently experience apraxia (difficulty making movements), which extend beyond mere writing.
Anomia
Loss of naming ability, usually w/ left-hemisphere lesions
Receptive dysprosody
Difficulty comprehending emotion, intonation, inflection in language
Pt often experiences social, interpersonal difficulties due to failure to pick up subtle inflections and cues from others.
Usually from lesions in area homologous (same area in opposite hemisphere) to Wernicke’s area in right hemisphere.
Where is music primarily processed?
Right hemisphere, where prosody (loudness, pitch, timbre, & rhythm) is processed
Sensory Integration
integration of somatosensory, auditory, visual information
- Generates knowledge - Understanding of meaning & relationships among recognized sensory inputs
- Sends to frontal lobes for “final” integration with limbic input
Reading and math performed here
Acalculia
Loss of math ability
Alexia
Loss of reading ability. at one point had normal reading ability but loses it