Neuropsychology Flashcards
What are the functions of the occipital lobes?
Primarily vision, but functions extend beyond vision.
Separate anatomical regions within the occipital lobes take part in perception of what 3 things?
Form, movement, and colour.
What are the 3 major visual system routes in the occipital lobes?
- Ventral Stream (stimulus recognition), 2. Dorsal Stream (guidance of movement in space), and 3. Middle Stream (synthesis of the two)
What is an important aspect of the dorso-ventral stream in the occipital lobes?
In visual processing, neither route is a single unitary system. Clearly dissociable subsystems take part in various functions.
What 2 specialized functions appear to occur in the right occipital lobe?
Word recognition and mental rotation.
What are 6 major Occipital Lobe Landmarks? Hint: 4 sulci, 3 gyri
Parietal-occipital sulcus, Cuneate gyrus, Calcarine sulcus, Collateral sulcus, Lingual gyrus + sulcus, Fusiform gyrus
What is the occipital lobe sometimes referred to and why?
The “striate cortex” because it appears striped on stained cells.
What 3 functional zones can the parietal lobe be divided into?
- somatosensory processes 2. movement processes 3. spatial cognition
What zone of the parietal lobe takes place in somatosensory functions?
The most anterior zones
What zones of the parietal lobe controls visual guidance and movements of hands, fingers, limbs, head, and eyes?
The superior parietal region
What region of the parietal lobe has expanded in humans to control mental manipulation of objects?
The superior parietal region
What region of the parietal lobe can be thought of as having a “spatial” function?
The posterior parietal lobe
What region of the parietal lobe has a role in processes related to spatial cognition? What term is used to describe this?
The inferior parietal region; “quasi-spatial”
What symptoms are caused by damage to the somatosensory regions of the parietal lobe?
Deficits in tactile functions ranging from simple somatosensation to the recognition of objects by touch.
What symptoms are caused by damage to the posterior parietal lobe?
Deficits with visual guidance, hand and limb movements
What symptoms are caused by left parietal injury?
Limb apraxias, cognitive deficits in arithmetic and writing
What symptoms are caused by right parietal injury?
Constructional apraxias, contralateral neglect, deficits in spatial cognition
What neuropsychological tests are used to determine parietal lobe function?
Tactile tests, visual guidance of movement, spatial orientation, copying complex geometric figures, and mental rotation.
What areas does the Anterior Zone have in the parietal lobes?
Area S1, 1, 2, & 3
What areas does the Superior Parietal Zone have in the parietal lobes?
PE & PF
What areas does the Inferior Parietal Region have in the parietal lobes?
PG
What processes does the anterior zone of the parietal lobes take part in?
Somatic sensations or perceptions
What processes does the posterior zone of the parietal lobes take part in?
Integrating sensory input from somatic and visual regions, and from other sensory regions for the control of movements and spatial manipulations
What anatomical differences occur in the parietal lobes?
PG area is much larger on the left in humans (explaining language), PG (&STS) area is larger on the right side compared to the left.
What 4 functional zones can the temporal lobes be divided into?
- Auditory
- Visual
- Integration & Spatial Navigation
- Spatial & Object Memory
What anatomical areas are associated with the functional zones of the temporal lobes?
- Superior temporal gyrus (auditory)
- Inferior temporal cortex (visual)
- Amygdala (integration)
- Hippocampus & Associated Cortex (spatial + object memory)
What 2 characteristics are specialized in the processing of auditory info in the temporal lobes?
Speed and frequency
What sides of the temporal lobe are associated for what specialized characteristic of auditory processing? (Hint: it’s intuitive)
Left: speed, Right: complex frequency patterns
What deficits are produced as a result of damage to the auditory regions of the temporal lobes?
Recognition of language, music, and sound localization.
What 2 features does the temporal lobe add to auditory and visual info?
Tone (affect) and categorization (important in understanding and using sensory input).
What is the difference between how the parietal lobes process spatial info with respect to movement in the temporal lobes?
Whereas the parietal lobes process spatial location with respect to movement, the temporal lobes use spatial info as a feature of object recognition and in development of memories for object location.
What symptoms occur during damage to the visual systems in the temporal lobes?
Recognition of complex visual stimuli, faces
What symptoms occur as a result of damage to the medial temporal regions?
Deficits in affect, personality, spatial navigation, and object memory.
What neuropsychological tests are used to assess temporal lobe problems? Hint: 4
Auditory tests (dichotic listening), visual processing (object recognition), memory (verbal and non-verbal), and language.
What are the 5 major projection pathways of the temporal lobes?
- Hierarchical sensory pathway
- Dorsal Auditory pathway
- Polymodal pathway
- Medial Temporal projection
- Frontal lobe projection
With respect to the occipital lobes, what term can we use to describe the frontal lobes?
Can be conceived of as the “end point” for the visuomotor and object recognition functions that are initiated in the occipital lobes.
What is the frontal lobe’s main function?
To select behaviours with respect to context and internalized knowledge.
What 3 distinct functional zones can the frontal lobe be divided into?
- Motor Cortex
- Premotor Cortex
- Prefrontal Cortex
What is the motor cortex responsible for in the frontal lobe?
Movement
What is the premotor cortex responsible for in the frontal lobe?
Selecting movements
What is the prefrontal cortex responsible for in the frontal lobe?
Controlling cognitive processes so that appropriate movements are selected at the correct time and place.
What 2 regions can the premotor cortex be subdivided into and what are their functions?
- Lateral Area: responsible for selecting behaviours in response to environmental cues
- Supplementary Area: responsible for selecting behaviours with respect to internalized knowledge
What 3 categories are used to group the wide range of symptoms of frontal lobe damage?
- Disturbances in motor functions
- Loss of divergent thinking
- Impaired response inhibition and inflexible behaviour
- Poor temporal memory
- Impaired social and sexual behaviour
Describe the complementary effect of injury to the right and left frontal lobe.
Left: more likely to affect language or movement-related behaviours, Right: likely to alter non-language functions such as emotion
What 4 major tasks does the frontal lobe widely participate in?
- Attentional tasks
- Motor tasts
- Spatial problem-solving
- Semantic processing of words
What 3 disorders are implicated in frontal lobe dysfunction?
- Schizophrenia
- Parkinson’s
- Korsakoff’s Syndrome
What can we assume about the observed differences between the two brain hemispheres?
That the differences represent functional specializations of the hemispheres.
What confirmed evidence of lateral lesion (or split brain) patients explains the role of the two hemispheres?
The left hemisphere is implicated in language and motor functions and the right hemisphere has a complementary role in musical and spatial functions.
What 4 cautions must be underlined when considering the variations in cerebral asymmetry?
- Many functions of cerebral hemispheres are symmetrical rather than asymmetrical
- The functional differences between the two hemispheres are not absolute but relative
- Cerebral site is at least as important as cerebral side
- It’s a long inferential leap from the data to determine what those data mean.
What two demonstrations imply that asymmetrical variation is biologically based?
Sex and handedness.
Define “lateralization”
The idea that the two cerebral hemispheres have separate functions.
What are some characteristics of the right hemisphere of the brain?
Perceiving and synthesizing nonverbal info, music, facial expressions, movement on left side of body.
What are some characteristics of the left hemisphere of the brain?
Producing and understanding language, controlling movement of body on right side.
What are the first 4 (of 8) major anatomical differences between the two cerebral hemispheres?
- The right hemi is slightly larger and heavier than the left but the left hemi has more gray matter
- The temporal lobes display a marked structural asymmetry that may provide an anatomical basis for specialization of the L&R temporal lobes in language and music, respectively
- Asymmetry in the cortex of the temporal lobes is correlated with a midbrain asym in the thalamus. This asym compliments a functional asym in the thalamus, the left being dominant in language
- Slope of the lateral fissure is gentler on the left. The region of the temporoparietal cortex lying ventral to the lateral fissure therefore appears larger on the right.
What are the second 4 (of 8) major anatomical differences between the two cerebral hemispheres?
- Frontal operculum (Broca’s area) is organized differently on the left and right. L - production of grammar in language, R - tone of voice
- Distribution of various neurotransmitters is asym in cortical and subcortical regions.
- Right hemi extends anteriorly left extends farther posteriorly
- Anatomical asym is affected by sex and handedness
Define “double dissociation”
Two areas of the neocortex are functionally dissociated by two behavioural tests, each being affected by a lesion in one zone and not in the other.
Define “commisurotomy”
Procedure of cutting 200 million nerve fibres of the corpus callosum in severe seizure patients preventing the spread of electrical activity.
What is carotid sodium amobarbital injection?
Injecting into the carotid artery to produce a brief period of anaethesia in the ipsilateral hemisphere (to determine “handedness” of the brain).
What are the 4 General Effects of Conscious Brain Stimulation? Are the symptoms positive or negative?
- Can produce localized movements and dysthesias (+)
- Can produce “interpretive and experiential” responses (deja vu, dream states, etc) (+)
- Stimulation of left frontal or temporal regions may accelerate production of speech which may result from an “alert response” (+)
- Stimulation blocks function (-)
Describe asymmetry with respect to the visual system.
Stimuli in left visual field travel to right visual cortex. Info presented to only one visual field is processed most efficiently by the hemisphere that is specialized to receive it.
Describe asymmetry with respect to the auditory system.
When different stimuli are presented to each ear simultaneously, the path from the right ear to the speaking hemisphere has preferred access and the ipsilateral path from the left ear is suppressed because it takes a longer route to get there.
Describe asymmetry with respect to the somatosensory system.
Right advantage identifying letters and left hand for shapes. Left hand reads braille more efficiently.
Describe asymmetry with respect to the motor system.
Apraxia: copying sequences of movements. Two different types of experiments to assess motor asym: observation and interference.
What are the environmental theories in handedness?
- Behavioural Utility: sword and shield hypothesis, protecting heart, mother and baby
- Environmental Reinforcement: handedness is established by bias in environment
- Environmental Accident: genetically determined bias
What are the anatomical theories in handedness?
- Right-handedness results in enhanced maturation of left hemisphere
- Fundamental asymmetries in human body chemistry (heart, ovaries, etc)
What are the hormonal theories in handedness?
Brain plasticity can modify cerebral organization during early life leading to anatomical patterns of hemispheric organization, specifically, levels of testosterone.
What are the genetic theories in handedness?
Dominant genes exist for right or left-handedness.
What are the 5 functions of the visual areas of the brain in the occipital lobes? What happens when they are damaged?
V1: Line orientation (cortical blindness)
V2: Form
V3: Dynamic form (eliminate form perception)
V4: Colour (seeing in shades of grey)
V5: Motion (objects in motion vanish)
What are the 5 Major Functions beyond the Occipital Lobe?
- Vision for action: direct specific movement
- Action for vision: top-down, visual scanning
- Visual recognition: object and facial recognition/meaning
- Visual space: egocentric (self) and allocentric (objects relative to self)
- Visual attention: selective, divided, shifting
What are the 2 types of object agnosias and what do they do?
- Apperceptive agnosia: failure to recognize object but visual functions of acuity, colour, and motion are preserved. May also have simultagnosia: the inability to perceive more than one object at a time.
- Associative agnosia: failure to recognize objects despite apparent perception. Affects not only past knowledge but the acquisition of new knowledge.
What are 3 other visual agnosias?
- Prosopagnosia: “face blind” can’t recognize previousl known faces and/or facial expressions
- Alexia: inability to read
- Visuospatial agnosia: inability to find one’s way around familiar environments
What is considered a “hot area” of the parietal lobes?
TRJ: temporo-parietal junction
What are 2 basic uses of spatial information?
- Object-centered system (aka: allocentric spatial) info for object recognition to determine relations between objects (size, shape, colour, relative location)
- Viewer-centered system (aka: egocentric spatial) info for guidance of movement to objects
In regards to sensory info and the temporal lobes, what structure does this info pass through first?
The thalamus.
What lobe do ALL neural networks lead to?
The frontal lobes.
