Cortex Flashcards
Cerebral hemispheres =
a mantle of nervous tissue that overlies the brainstem and is divided at the midline into two mirrored halves.
The deep layers of the cortex contain _________________________________________ that interconnects the various areas of the overlying cortex.
white matter (axons)
The external surface of the cerebral hemispheres is composed of ____________________________________________________ which is convoluted.
gray matter (containing neuronal cell bodies)
On the external surface of the cerebral hemispheres, the crest of a given convolution is called a ______________________.
gyrus (gyri; pl.)
On the external surface of the cerebral hemispheres, a groove or depression in the surface of the cerebral hemispheres is called a ____________________________________.
sulcus (sulci; pl.) or fissure (deepest ones).
The cerebral cortex also has a functional organization which can be most easily demonstrated in the sensorimotor homunculi on either side of the ___________________________.
central sulcus.
Brodmann’s areas: In addition to subdividing the above lobes into gyri and sulci, they may also be subdivided according to the ___________________________ arrangement of the neurons as they are differentially arranged in the various regions of the cortex. Using this criterion, a variety of investigators have attempted to map the cerebral cortex, resulting in classification schemes ranging from 20 cortical areas to more than 200. The most widely referenced classification of cortical areas is that outlined by Brodmann, who identified more than 50 different cortical areas.
cytoarchitectural
Although Brodmann’s areas are primarily based on cytoarchitectural criteria, there is a strong association with discrete functions (taste, vision, primary motor, primary somatosensory, etc.). Although Brodmann’s areas generally follow discrete gyri they frequently overlap one or more gyri, or conversely, there may be ________________________ Brodmann’s area in one gyrus.
more than one
What are 3 functional categories of efferent neurons?
- projection
- association
- commissural
Define projection neurons (function category of efferent neuron):
to subcortical areas; basal ganglia, thalamus, brainstem, spinal cord
Define association neurons (function category of efferent neuron):
connections between areas of cortex in the same hemisphere
Define commissural neurons (function category of efferent neuron):
- connections between areas in different hemispheres (corpus callosum, anterior commissure)
Interhemispheric transfer of information - the two hemispheres are highly interconnected through the ______________________ and the ______________________. Each area of cortex on one side sends axons to the identical area on the other side.
corpus callosum
anterior commissure
What is the importance of hemispheric connectivity?
THIS CONNECTIVITY IS VERY IMPORTANT FOR STORING MEMORY ON BOTH SIDES OF THE BRAIN, FOR COMPARING THE LEFT AND RIGHT HALVES OF THE BODY AND EXTERNAL ENVIRONMENT.
Primary sensory cortices are the regions that first interpret the ___________________________________ information. It is very specific, just “pieces” of the actual perception of that sensation or thought.
Association areas are cortical areas that put the encoded sensation into _______________. Without association areas, the individual stimulus makes little sense.
encoding of sensory
context
Do association areas respond to multiple modalites or just a signle modality?
Association areas can be specific to a single modality or respond to multiple modalities.
Learning and memory - long term memory resides in the ________________but how and where is poorly understood. Latest idea is that memory is parceled out to anatomically separated areas that are close to the ________________ area. For example, the memory of a flower is stored as separate entities of smell, color, feel. There are cortical and _______________areas that are then connected to each of the modality specific association areas which seem to function in laying down the entire memory. These areas also seem to be critical in retrieval of memories, needing only a part of the entire memory to access the entire memory.
cortex
primary cortical
thalamic
Is the whole memory necessary for retrieval of the memory?
NO, retrieval of memories, needing only a part of the entire memory to access the entire memory.
Cerebral dominance and functional representation :
as we mature, one hemisphere or the other takes responsibility for language comprehension and speech.
Hand dominance is correlated with the ______________________.
dominant hemisphere
**but this is not how hemisphere dominance is determined
About 95% of all people are left hemisphere dominant and about 90% of people are right-handed; which is the dominant hemisphere of right handed people?
is controlled by the left hemisphere.
The non-dominant hemisphere appears to specialize in:
nonverbal, non-mathematical domains, functions such as music appreciation, artistic activity and appreciation for the significance of sensory stimuli (should we ignore or pay attention to the stimuli).
What is the dominant hemisphere is defined by?
the presence of language, both the speech component and the comprehensive component
Parts of the inferior frontal gyrus that lie anterior to the face region of precentral gyrus function in the motor part of speech production are known as:
(Broca’s area; Brodmann’s areas 44, 45).
Parts of the parietal lobe and superior temporal gyrus that are located at the caudal tip of the lateral fissure function in the comprehension of language =
(Wernicke’s area; Brodmann’s areas 22, 39)
In most individuals, whether right or left hand dominant, the dominant hemisphere is located in the _______ hemisphere as determined by the presence of language.
left
