Cognition Flashcards
Cognition
Involves integration of information. Produces a perceptual “whole” Guides choice of appropriate behaviors.
Default network
Involved in: autobiographical memories, planning future, making moral decisions, daydreaming or mind-wandering
Task positive network
Active when performing some tasks
When can the default network be disturbed?
Depression
OCD
Schizophrenia
Autism
Primary areas of cortical organization
Primary Motor Cortex
Primary somatosensory cortex
Primary auditory cortex
Primary visual cortex
Association cortex
Unimodal (one sensory modality) and multimodal (across modalities)
Unimodal areas
Premotor cortex
Visual association cortex
Auditory association cortex
Somatosensory association cortex
Primary sensory cortex gets input from where?
Sense-specific thalami nucleus and other cortical areas
Association cortex getting information from where?
Multimodal thalamic nuclei
Sensory cortex and association cortex output?
Other cortical areas. Can be cortical-cortical connections or callosal connections. Thalamus and other subcortial structures
Where does output from layer 5 go?
To thalamus and other subcorticla structures (basal ganglia, midbrain, brainstem, spinal cord)
Where does output from layer 6 go?
Thalamus
Association cortex function
Integrate input from different modalities, mediate “internal” cognition”, mediate between sensory inputs and appropriate behavioral output
Main inputs to the cortex
Thalamus, other cortical regions, brainstem nuclei (modulatory)
Main outputs
Cortical regions and to subcortical structures (including feedback to thalamus)
Modulatory inputs come from where?
Thalamus and brainstem
Which has a higher density of corticocortical connections (primary cortex and association cortex)
Association cortex
Parietal cortex
Visual attention, localization, spatial relationships, motor programs
Limbic cortex
Emotion and memory
Temporal cortex
Recognition and object identification, language
Prefrontal cortex
Planning and decision making, working memory
Parietal association cortex (nondominant hemisphere)
Attention, visuospatial localization, spatial relationships
Parietal association cortex (dominant hemisphere)
Skilled movements, right-left orientation
Posterior parietal cortex damage symptoms?
Spatial neglect (nondominant hemisphere) Motor apraxias (dominant hemisphere)
Spatial neglect
Failure to acknowledge half of the world, sensory systems are intact. Occurs in about 1/2 of right hemisphere strokes.
How can you test for spatial neglect?
Ask to copy pictures
Motor apraxia
Loss of ability to perform skilled motions.
Sensory and motor systems intact
Ideomotor apraxia
Involves gestures or the use of tools.
How can you test for ideomotor apraxia?
-have patients pantomime use of imaginary tools, imitate the action, use actual tool.
What indicates ideomotor apraxia damage?
Use of hand in place of imaginary tool
Orofacial apraxia
Inability to make specific facial movements
Ideational apraxia
Inability to sequence actions
Face neurons
Each neuron responds to particular features. Together they build a unified image
Agnosias
Deficits in recognition. Inability to recognize or identify objects even when sensory systems working normally. Damage to several cortical areas can produce agnosia of different types
Prosopagnosia
Inability to recognize faces.
Visual agnosia
Inability to recognize an object by sight (Recognition by other senses still intact)
Astereognosia
Inability to recognize an object by touch alone
Cause of prosopagnosia
Bilateral lesion in the inferior temporal cortex
Cause of visual agnosia
Damage to unimodal visual cortex
Cause of astereognosia
Damage to unimodal somatosensory cortex
Associative visual agnosia
Can identify, but not by name
Cause of associative visual agnosia
Damage to posterior parietal cortex
Finger agnosia
Inability to identify fingers individually.
Cause of finger agnosia
Damage to angular gyrus of dominant parietal cortex
Gerstmann syndrome
Finger agnosia, acalculia, agraphia, right-left confusion
Prefrontal cortex
Planning, making decisions, purposeful action, sequencing behaviors over time, selection and exclusion of appropriate behavior, working memory
Damage to prefrontal cortex leads to?
-Loss of impulse control
-Socially inappropriate behavior
-Disordered thought
-Inability to plan
-Repetition of a behavior
Inability to use information to guide behavior
Wisconsin card sorting test
Tests ability to be flexible with changing schedules of reinforcement
Maturation of cortex
Develops rapidly in the first year of life. Particularly sensitive to damage from stressors in infancy and early childhood
What happens to the cortex when it matures?q
Changes in synaptic density, myelination, and gray matter thickness
Do changes in the cortex occur uniformly?
No. Roughly a posterior-to-anterior gradient.
- Sensorimotor
- Less connected association areas
- Highly connected prefrontal, posterior parietal last.
Which cortex connections mature first?
Local connections
Which cortex areas are the first to degenerate?
Last areas to mature
