Question | Answer |
What is the cerebral cortex? | very complex sheet of cells that surround the cerebral hemispheres |
How large is the cerebral cortex? | ~2.5 Ft2 area and ~4mm thick |
What is the two things the cerebral cortex is divided into? | neocortex, archicortex |
What does the neocortex make up? | the majority of cerebral cortex |
What does the arichortex make up? | hippocampus, ethorhinal cortex of cerebral cortex |
Where is the archicortex located? | inside the medial lobe |
Where does our site of conscious mental activities, cognitive capacities and other higher functions such as language reside? | neocortex |
What part of the brain makes us human? | neocortex |
How many neurons are in the neocortex? | ~30billion |
Which is more numerous and by how much neurons or glia? | glia, by ratio of 10:1 |
What are the columns of the neocortex? | basic modules which are highly preserved between orders |
Do humans or animals have more neocortex columns? | humans |
When talking about the neocortex what does tangential mean? | horizontal dimension parallel to the pial surface |
When talking about the neocortex what does radial mean? | vertical dimension at right angles to pial surface |
What is the cerebral cortex a part of: metencephalon, myencephalon, telencephalon, or diencephalon? | telencephalon |
What is the cerebral cortex derived from? | ectoderm |
How many layers are in the neocortex and how are they labeled? | 6; 1=most superficial and 6= most deep |
How many neocortical neurons use glutamate/ GABA? | 75% use glutamate, 25% use GABA |
What are the excitatory neurons of the neocortex? | pyramidal cells and spiny stellate cells |
What are spines? | small protrusions filled with actin on all dendrites of excitatory neurons |
What are spiny stellate neurons? | pyramidal cells which have lost their apical dendrite, the major component of layer 4, AKA excitatory interneuron local circuit neuron |
What do all pyramidal neurons have? | pyramidal shaped soma, single apical dendrite, several basal dendrites, an axon attached to deepest part of cell body |
Which neuronal circuits do pyramidal cells participate and why? | local and long range; because they have local synapses and project neurons out to have distal synapses |
What is the source of all corticofugal pathways? | pyramidal cells |
What do corticocortical associational pathways do? | connect cortical areas in the same hemisphere |
What do corticocortical commissural pathways do? | connect similar cortical areas in opposite hemispheres |
Which layers in the cortex does corpus collosum have axons? | 2 and 3 |
Neurons projecting out of the cortex are found in which layers? | 5 and 6 |
Callosal and ipsilateral corticocortical neurons are found in which layers? | 2 and 3 |
What does inhibitory neurons look like? | many varieties but always smooth and aspiny (no spines) |
How many columns do inhibitory neurons project? | locally tend to project in single columns |
Do inhibitory neuron ever exit the cortex? | no |
What are the three things to remember about inhibitory neocortical neurons? | release GABA can be one or more, smooth body, project locally |
Do glutamatergic neurons co-localize neuropeptides? | NO |
Do GABAtergic neurons co-localize neuropeptides? | yes |
What does layer 1 of neocortex contain? | inhibitory neurons no pyramidal cells |
What does layer 2 and 3 of neocortex contain? | excitatory neurons locally and intracortically projecting pyramidal neurons, small pyramidal neurons |
What does layer 4 of neocortex contain? | spiny stellate cells, major input layer of cortex, synaptic connections from thalamus |
What does layer 5 and 6 of neocortex contain? | locally and extracortically projecting pyramidal neurons, large pyramidal neurons |
What layers of the neocortex makes up the granular layer? | 1,2,3 |
What layers of neocortex makes up the supragranular layer? | 4 |
What layers of neocortex makes up the infragranular layer? | 5,6 |
True, False you are born with all the cortical neurons throughout adulthood? | false, cortical neurons are created even in adulthood |
What Brodman’s areas are associated with occipital lobe? | primary visual or striate = 17 associational visual or extrastriate =18,19 |
What Brodman’s areas are associated with parietal lobe? | primary somatosensory post central gyrus= 3,1,2 associational =5,7 gustatory – taste =43 |
What Brodman’s areas are associated with Temporal lobe? | primary auditory = 40,41,42 Wernike’s area =22 |
What Brodman’s areas are associated with Frontal lobe? | primary motor precentral gyrus= 4 frontal eyefield = 8 associational or pre-moter =6 Broca’s area speech= 44,45 |
What is a homunculus? | little man with exaggerated features to represent the amount of cortex dedicated to that area of the body |
What is plasticity? | ability of the brain to rewire itself |
What is the function of association fibers? | connects cortical sites within the same hemisphere |
What is the function of Commissural fibers? | connect hemispheres, most cross through the corpus callosum |
What do projection fibers do? | pass from cerebral cortex to structures such as thalamus, basal ganglia, brainstem, spinal cord etc. |
What does the superior longitudinal fasciculus do? | connects frontal and occipital lobes |
What does the arcuate fasciculus do? | connect frontal and temporal language areas |
What does the inferior longitudinal fasciculus do? | connects occipital lobe to temporal lobe |
What does the uncinate fasciculus do? | connects inferior frontal lobe with temporal lobe |
What does the cingulum do? | connects cingulated gyrus with archicortex |
What does the corpus callosum do? | connects corresponding regions of neocortex for all but temporal lobes |
What is the corpus callosum divided into? | rostrum, genu, body, splenium |
What kind of fibers do the splenium carry? | visual fibers |
What does the splenium connect? | occipital lobes |
What does the anterior commisure connect? | temporal lobes |
What do many of the fibers projecting away from the cortex travel through? | internal capsule |
State the information flow in the neocortex: | info>layer4 motor sensory>neocortex>spiny stellate neurons>supragranular layer>pyramidal neurons relay>primary neocortical area>secondary associated areas>higher order associated areas>connected with dorsal medial thalamic nuclei>opposite hemisphere |
Right handedness indicates: | left hemisphere dominance |
How prevalent is left hemisphere dominance? | 90% of population |
Where is language localized? | in left hemisphere of 90% of people |
Which hemisphere is primary controller of logic and analytic function? | left |
Which hemisphere is superior in musical skills, recognition of faces, emotions and spatial relationships? | right |
What is the grandmother cells function? | facial recognitions |
Where is grandmother cells found? | mostly in right hemisphere |
What two areas of the neocortex are predominately active for language function? | Broca’s area 44,45 and wernike’s area 22 in the temporal lobe |
Are the Broca’s and Wernike’s area connected if so by what? | yes, arcuate fasciculus |
State the language pathway: | auditory cortex>Wernicke’s area>Arcuate fasciculus>Broca’s area>Motor cortex> move mouth |
What is Wernicke’s area used for? | vocabulary, put words together |
What is Broca’s area used for? | info to move the mouth |
What is the motor speech area? | Broca’s area 44,45 |
What does lesions in Broca’s area cause? | expressive aphasia difficult labored talk, can still understand |
What is aphasia? | inability to speak |
What is expressive aphasia? | a motor aphasia , patient has trouble forming speech with mouth, language slow, labored, slurred, are able to understand language |
What does Wernicke’s area control? | vocabulary, phoneme, grammer bank and language comprehension |
What is Wernike’s aphasia? | sensory or receptive anaphasia where language comprehension is distorted and gibberish |
Can patients with Wernike’s aphasia able to understand language? | no |
Can patients with Wernike’s aphasia produce language? | not usually but occasionally create their own language |
What does transaction of the corpus callosum result in? | disconnects the two cerebral hemispheres =split brain syndrome |
What is split brain syndrome? | where information given selectively to one hemisphere is not available to the other hemisphere |
What causes unilateral neglect? | right parietal lesions |
What symptoms do patients with unilateral neglect present with? | they totally ignore the left part of their worlds = left visual fields and left side of their bodies |
Where in the cortex is propreceptive fibers in left foot? | medial portion of gyrus supplied by ACA |
What is the blood supply to lateral ventricle? | ACA, PCA, and MCA |
What is the blood supply to caudate? | MCA and ACA |
What is the blood supply to Thalamus? | PCA deep branches |
What is the blood supply to Internal capsule? | MCA deep branches, ACA |
What is the blood supply to Putamen? | MCA deep branches |
What is the blood supply to Globus Pallidus? | Anterior choroidal artery and MCA |
What is the blood supply to Hippocampal Formation? | Anterior choroidal artery |
What is the blood supply to Temporal lobe? | MCA and PCA |
What is the blood supply to caudate head? | ACA deep branches |
What is the blood supply to internal capsule anterior limb? | ACA and MCA |
What is the blood supply to internal capsule posterior limb? | Anterior choroidal artery |
What is the blood supply to Occipital lobe? | PCA and MCA |
Is the balance between excitation and inhibition maintained? | yes very carefully |
What happens if excitation is not kept under control? | brain gets over excited resulting in seizures |
What happens if you have to much inhibition to excitatory neurons? | coma |
Is GABA excitatory or inhibitory at early postnatal ages? | always inhibitory no matter what the age |