Flashcards in Cerebral Cortex Deck (69):
What is the Brodmann area for the motor cortex?
What is the Brodmann area for the sensory cortex?
What is the Brodmann area for the visual cortex?
What is the function of the cerebral cortex?
It analyzes, plans, initiates response using the sensory pathways in order to gather information.
What is the function of the reticular system?
The reticular system adjusts the level of responsiveness of the brain and cerebral cortex in particular
What are the types of cortex?
What makes up most of the cortex?
Neocortex - it has 6 layers in the cortex
What does the archicortex make up?
Hippocampus - 3 layers
What does the paleocortex make up?
Telencephalon and Olfactory - 3-5 layers
Are most of the brain cells pyramidal or non-pyramidal?
Pyramidal. 80% of the brain cells are pyramidal
How many nerve cells are in the brain and how many of them are from the cerebral cortex?
86 billion with 19% of them being from the cerebral cortex.
Describe the features of pyramidal cells.
They have a long apical dendrite and a basal dendrite. The axons leave the cortex and are excitatory, using glutamate as a NT.
Describe the features of the non-pyramidal cells.
They are of many various shapes. The axons do not leave the cortex and are inhibitory, using GABA as a NT.
They are the interneurons of the cerebral cortex.
What cells are in the agranular layers of the neocortex?
Large Pyramidal Cells
What cells are in the granular layers of the neocortex?
How is the neocortex organized?
Where is the genu of the corpus callosum located?
Where is the anterior body of the corpus callosum located?
Frontal Lobes posterior to the Genu
Where is the posterior body of the corpus callosum located?
Where is the splenium of the corpus callosum located?
Occipital and Temporal Lobe
What does the anterior commissure connect?
It interconnects the temporal lobe and component's of olfactory system
Do the left and right pre central gyri have symmetrical connections?
Describe the association bundles of the cortex.
They are corticocortical connections in the same hemisphere and none are discrete point-to-point. Fibers travel in both directions, leaving and entering.
What is the Brodmann area for the auditory cortex?
Where is the visual cortex?
Where is the somatosensory cortex?
Where is the auditory cortex?
Transverse Temporal Gyrus
Where is the motor cortex?
What are unimodal association areas?
They are more complex response functions that analyze information and extract additional information from it
What are multimodal association areas?
They are “high level intellectual functions”: Association areas send converging inputs; may respond to multiple stimuli or under particular circumstances. They do not have homoncular distributions.
What can injury to the unimodal association areas cause?
What can injury to the right inferior parietal lobule (multimodal association) cause?
What can injury to the left parietal area cause?
What is the function of the prefrontal area?
It is involved in working memory and decision making and executive functions of the brain, like planning, insight, foresight and basic aspects of personality.
What is the function of the dorsolateral aspect of the prefrontal area?
It is more important for working memory, attention, and logical aspects of problem solving
What is the function of the ventromedial aspect of the prefrontal area?
It has extensive limbic connections and are more important for emotional aspects of planning and decisions
What is the function of the limbic area?
It is involved in emotion and drive related behavior.
All cortical areas receive corpus callosum commissural fibers except for which areas?
– Exception – Hand area of somatosensory and motor cortex
– Exception – Area 17, not representing those areas adjacent
to the vertical midline
– Exception – Temporal lobe connections which travel
through the anterior commissure
What are disconnection syndromes and what are they caused by?
They often result from white matter damage that interferes with connections of the cortical areas.
Ex: Alexia without Agraphia
Describe the findings in Alexia without Agraphia.
Often caused from a stroke of the left posterior cerebral artery, which affects vision. Vision is cut from the right of both eyes and the left field of vision can be seen but when it is sent to the left part of the occipital, the interpretation does not work so they cannot understand when they read.
Where is Wernicke's Area located and what is its function?
Superior Temporal Gyrus and it is where language comprehension is housed.
Where is Broca's Area located and what is its function?
Inferior Frontal Gyrus and it is where the motor component of speech is housed.
What is the arcuate fasciculus?
It is what connects Wernicke's and Broca's Area.
What results due to a lesion of Broca's Area?
Poor verbal fluency, naming and repetition but unhindered comprehension.
What occurs due to a lesion of Wernicke's Area?
Normal verbal fluency but poor verbal repetition, naming and comprehension.
What occurs due to a lesion of the arcuate fasciculus?
Good verbal fluency and comprehension but poor verbal naming and repetition.
Describe reticular neurons.
They are very long neurons that give off a lot of dendrites at right angle to their axons.
What are the coordinating functions of the reticular formation in the brainstem?
Unique cytoarchitecture (allows convergence of somatosensory information and divergence of efferent outputs).
– Sleeping and Wakefulness
– Pattern generator (eye, chewing, swallowing, coughing,
– Centers for respiratory/cardiovascular/micturition control
Where do the nuclei of the reticular formation extend?
They extend almost up to the thalamus down to the medulla and are arranged in 3 columns.
What are the 3 columns of the reticular formation and their functions?
Midline Zone - aminergic neurons
Paramedial Zone - effector
Lateral Zone - sensory
Where do the afferents of the reticular formation primarily project to?
Primarily project to the gigantocellularis, caudal and oral pontine nuclei – the medial or paramedian group
What are the afferent projections of the reticular formation?
– Corticoreticular – Motor and premotor cortex onto neurons of origin of the reticulospinal tract (medial group).
– Tectoreticular – superior colliculi origin
– Cranial nerves (trigeminal, vestibular, auditory and CN IX & X)
– project to the lateral parvocellular area
– Cerebelloreticular – primarily from the fastigial nucleus
– Spinoreticular – receives collaterals from spinothalamic tract, widespread bilateral distribution, no somatotopy
Where do the efferents of the reticular formation primarily project to?
Arise from the gigantocellularis, caudal and oral pontine nuclei – the medial group
What are the efferent projections of the reticular formation?
Spinal cord termination – Pontine and Medullary reticulospinal tracts
Brain stem termination – Reticulobulbar tract and Central tegmental tract
What do the midline neurons of the reticular formation use as a neurotransmitter?
What is the cerulean nucleus involved in?
What does the ventral tegmentum nucleus use as a neurotransmitter?
What is the magnus raphe nucleus involved in?
What NT does the cerulean nucleus use?
What NT does the raphe nuclei use?
What are the largest territorial distribution of any CNS neurons?
Serotonergic Projections (such as raphe nuclei)
What is the function of the Ascending Reticular Activating System (ARAS)?
It plays a role in your level of alertness, sleep-wake rhythms and alerting retactions.
Describe the various parts of the subcortical modulating system that is involved in maintaining consciousness.
– Raphe nuclei (serotonin)
What are some of the main roles of sleep for humans?
Brain shrinks and organizes information
Describe the transition from wake to sleep and vice versa.
Both occur very abruptly.
Describe the amount of REM sleep you undergo as the night goes on.
It increases through the night
What are some of the differences between REM and non-REM sleep?
REM sleep has much more detailed dreams with irregular pulse and respiration.
Non-REM has less detailed dreams and more regular pulse and respiration.
What is the primary chemical responsible for maintaining wake states and what is it secreted by?
Lateral Hypothalamus - secretes orexin which
is one of the primary NT that stabilizes wake states and makes sure REM/non-REM is turned off