Lecture 6 Flashcards
What are association areas?
Area of higher cognitive function:
● They are not primary vision, motor or other basic sensory areas (around 80% of the cortex is association) -> combine all the information for the primary motor cortices and translates it into behaviour (also responsible for planning and storing of memories)
What does the parietal lobe specialize in?
Vision (part of the dorsal pathway), sensory perception integration (combining all sensory information), touch, movement, taste, spatial relations, reading, sensory aspects of episodic memory (thinking about events that happened in your life) and physical self
What are the main functions of the superior parietal lobe, inferior parietal lobe, somatosensory cortex, & precuneus?
-Superior Parietal Lobe: Spatial orientation
· Needed for visual perception
· Where something is
· Includes object manipulation
-Inferior Parietal Lobe: Spatial attention & multimodal sensory integration
· Needed for visual perception
· Paying attention to movement/location
· Produces complex sensory experiences
· Includes supramarginal gyrus: tactile perception and location of limbs (=ledematen)
-Somatosensory Cortex (postcentral lobe):
· The size of the area of each bodypart in the somatosensory cortex determines how sensitive and complex that part is
· Are also sectioned in corical columns
· Primary Motor Cortex is right next to the somatosensory cortex (motion vs feeling): very
similar, but not identical
-Precuneus: associative area
· Facilitate over 60 processes
· Visuo-spatial imagery (making mental images), first-person perspective, self-consciousness,
episodic memory retrieval
· Has a central role in the Default mode network (DMN): brain processes when brain is at
rest (not sleep) (mostly social activations)
What parts of the parietal lobe are in the dorsal stream?
Dorsal stream anatomy:
● “where/how” (path to parietal cortex, dorsal stream): specialised for spatial relations)
● Pathway from the V1 (in the occipital lobe) to the parietal lobe
● Dorsal stream is subdivided by the intraparietal sulcus (IPS) into the superior parietal lobe and
inferior parietal lobe -> which include the supramarginal gyrus
Describe basically (in broad terms) how the the somatosensory cortex is organized
Somatosensory cortex = parietal lobe
they are organized in cortical layers
What is the default mode network and how is the precuneus involved?
Has a central role in the Default mode network (DMN): brain processes when brain is at
rest (not sleep) (mostly social activations)
Precuneus is functionally central to to DMN
What is the temporal parietal junction and what are its main functions?
Where the two lobes meet
-Forms a bridge at the inferior parietal lobe & posterior superior temporal sulcus.
● Helps you re-orienting attention
● Theory of mind (thinking about what other people think)
● Empathy & self-awareness
● Connects environmental information to memories, emotions and existing knowledge
(also helps in translating it to language)
● Forms a bridge at the inferior parietal lobe & posterior superior temporal sulcus
What processes are lateralized for most people with parietal lesions?
Weigl’s sorting test: sorting the shapes and colours with each other -> mostly people with a lesion in the left parietal lobe experience trouble with this test (trouble in understanding the relation between the objects)
Common symptoms of parietal lesions:
● Defects in eye movement
● Misreaching
● Apraxia
● Impaired object recognition
● Right-left confusion
What were the 3 symptoms observed in Rezsö Bálint?
§ Could move his eyes but not fixate on visual stimuli
§ Displayed simultagnosia = could only attend to onestimuli at a time and would not notice other stimuli
§ Displayed optic ataxia = a difficulty in reaching for stimuli even when guided
What is astereognosis?
not being able to recognize an object by touch
What is stimulus extinction?
inability to detect a sensory event when it is paired with an identical
one on the opposite side of the body or visual field (e.g. cannot separate two touching’s at the
What is numb touch?
no more tactile perception, but are able to locate objects through touch
(feeling) -> Not aware of something touching you, but being able to point out where you were
touched.
What is asomatognosis and what are some of its varieties?
Asomatognosia: A loss of knowledge of one’s body, usually considered a type of agnosia caused by parietal lesion -> There are several types:
● Anosognosia: unawareness/denial of illness
● Anosodiaphoria: indifference to illness (you don’t care about your illness)
● Autopagnosia: inability to localise/name body parts
- Finger agnosia: the most common type of autopagnosia: unable to identify fingers
● Asymbolia for pain: absence of typical pain response
What is apraxia and what are a few types?
Apraxia: Loss of movement caused by a brain lesion and not by any damage related to the muscles or other body parts/processes
● Ideomotor apraxia: Disturbance to physical movements; unable to copy or make gestures (e.g., waving hello)
● Constructional apraxia: Disturbance to spatial processing; unable to build a puzzle or draw a picture.
● Speech apraxia: Disturbance to speech due to brain lesion and not caused by other types of language disorders
● Dressing apraxia: not being able to get dressed (because no more spatial relations)
What is contralateral neglect?
Sometimes called “Hemispatial Neglect”:
● When a parietal lobe lesion causes patient to ignore stimuli on contralateral (opposite) side of
body -> make senses due to crossing over (lesion is left HP, therefore ignore the right side of the body and visual field)
- “Contralateral side” is the side opposite the lesion
