15 Intro to the Cerebral Cortex Flashcards
What is the importance of the central sulcus in relation to the topography of the brain?
central suclus devices the frontal and parietal lobe
What do the longitudinal, transverse and sylvan/lateral fissure separate respectively?
longitudinal (two cerebral hemispheres) transfers (cerebrum and the cerebellum) and sylvan (divides temporal lobe and frontal/parietal lobes)
What structure lies behind the transverse fissure?
insula
Describe the variety of paths that are contained in the cortical white matter.
white matter is deep and axons can go locally or to other cortical/non cortical areas (corticortical, through commissure, cortico-spinal, cortico-bulbar, short association fibers, superior longitudinal fasciculus)
What types of cells would you expect to see in the layers of the cortex?
pyramidal and stellate cells (excitatory- glutamate) and interneurons (inhibitory- GABA)
Name two areas, that unlike the neocortex, do not have 6-layers
paleocortex (ie. pyriform cortex) and archicortex (hippocampus)
Which Brodman’s areas represent areas that are now know as the optical and auditory cortex?
optical (17) auditory (41-42)
What is important to remember about functional mapping of the cortex?
some functions are distributed between multiple areas and connections between areas play an important role in function
Describe 4 different methods for determining cortical function experimentally.
- create a lesion and observe the deficit 2. stimulate an area and observe the resulting action 3. record the amount of electrical activity based on given stimuli 4. watch for increased blood flow with given stimuli (fMRI)
What are the four main types of functional regions?
primary sensory area, primary motor area, association area, and limbic area (** remember that many higher order processes are not confined to a single cortical area but instead distributed in a network)
Name the 6 distinct areas of primary sensory cortex.
visual (occipital midline), auditory (lower lip of sylvan fissure), vestibular (insular and upper lip of sylvan fissure), somatosensory (posterior to central sulcus), gustatory (anterior to vetibular) and olfaction (base of brain)
All input to the primary sensory cortex from the receptors is processed through the ________ before it reaches the primary sensory cortices (except for olfaction, which erectly goes to the olfaction cortex)
thalamus
Where are the motor cortices located?
anterior to the central sulcus
What is the function of association cortex?
process raw sensory signals into complex concepts that can be remembered and used to create new ideas that can be formulated into action (notice, assign significance and make meaningful response)
Name the three major subdivisions of the association cortex.
unimodal motor, unimodal sensory and multimodal
What is unimodal motor?
divided into supplementary motor cortex (SMA) and lateral premotor cortex (PMC) which both deal with more complex motor patterns generally internally generated selected movement – receives mostly input from the primary motor cortex and sends output to LMN
What is unimodal sensory?
areas near primary sensory cortices that respond to more complex stimuli via communication within and to primary sensory cortices
What does multimodal association cortex?
areas of higher cortical function that are distributed through networks that are still being figured out including preprocessed inputs from thalamus (not from sensory or motor thalamus), cortical areas or subcortical inputs
How does spatial neglect demonstrate the function of the association cortex?
damage to the TPO junction causes the patient to ignore things in contralateral space: neglect may be due to disruption of the connection between the visual cortex dorsal (where) and ventral (what) areas (BONUS: TPO lesions are most prominent on the right side because its perception is bilateral and when interrupted, the left side provides only unilateral perception)
What function does the frontal association cortex linked with?
two sections: dorsalateral prefrontal cortex (cognitive, executive functions and working memory) and ventromedial prefrontal cortex (emotional, affective functioning, planning and social restraint)
Name the limbic areas (part of the limbic system)
parahippocampal gyrus, cingulate gyrus, septal area connected by the fiber pathway- cingulum
What is the proposed function of the limbic system?
a conduit from the “thinking brain” to the “emotional” brain (described in the papez circuit)
What is apraxia?
loss of the ability to perform complex motor tasks in the absence of paralysis
What features would you find in the frontal lobe?
primary motor cortex, premotor cortex and supplementary motor areas, Broca’s (speech), working memory, personality, insight, foresight and reward
What features would you find in the parietal lobe?
rostrally: primary and secondary somatosensory cortex; caudally: association areas, body image and spatial orientations and Wernicke’s area (language and reading skills)
What features would you find in the occipital lobe?
primary visual on the medial surface, secondary and higher order visual association areas
What features would you find in the insular lobe?
anterior and posterior: taste/flavor centers, body state awareness, regulation of autonomic function, time perception and more
