Cerebral Cortex Flashcards
nucleus definition
collection of neuron cell bodies in CNS
tract definition
collection of axons in CNS
ganglia definition
collection of neuron cell bodies in PNS
what percentage of the brain is made up by the cerebrum
83%
what does the cerebrum control
- higher mental functions including all conscious thoughts and intellectual functions
- Processes somatic sensory and motor information
how is cerebrum divided
into left and right cerebral hemispheres
what is grey matter made of
cell bodies
where is grey matter found
cerebral cortex
how much of cerebral cortex is its surface area
1/3
how much of cerebral cortex is in sulci
about 2/3
where is cerebral cortex thickest
over crest of convolution
where is cerebral cortex thinnest
in depth of sulci
why does the cerebral cortex have a folded surface area
increases surface area
gyrus definition
elevated ridge
sulcus definition
shallow depression
fissure definition
deep groove
how many neurons in cerebral cortex
1 trillion
how many glial cells in cerebral cortex
1 billion
what is white matter
myelinated axons which connect cerebral cortex with other brain regions
three types of white matter fibres
- commissural fibres
- association fibres
- projection fibres
commissural fibres function
- connect cortices of right and left cerebral hemispheres
- largest bundle forms corpus callosum
association fibres function
connect regions of the cerebral cortex within one hemisphere
two types of association fibres
- short (arcuate)
- long (longitudinal)
short association fibres function
connect adjacent gyri
long association fibres function
connect distant gyri (different lobes)
projection fibres function
- leave white matter
- form internal capsule
two categories of projection fibres
corticofugal and corticopedal
corticofugal fibres
terminate in basal nuclei, brainstem or spinal cord
corticopedal fibres
typically originate in the thalamus and terminate in the cerebral cortex
what is layer I also called
molecule layer
what is molecule layer made of
sparse, nonspecific afferents
what is layer II aslo known as
outer granule cell layer
what is layer II made of
interneurons for non-specific afferent input
what is layer III also known as
Outer pyramidal cell layer
what is layer III made up of
small and medium pyramidal cells, short association output
what is layer IV also known as
inner granule layer
what is layer IV made up of
mainly interneurons for specific afferent input
what is layer V also known as
inner pyramidal cell layer
what is layer V made of
largest pyramidal cells, long projection neurons and long association output
what is layer VI also known as
multi-form layer
what is layer VI made up of
variably shaped cells, projection and long association output
pyramidal neurons
- Long elongated
- Their axons project from white matter, so the vast majority are projection neurons
- Exitatory (glutamate or aspartate neurotransmitters)
are pyramidal cells homogenous or heterogenous
homogenous
what percentage of all cells in cortex are pyramidal
60-70%
non-pyramidal neurons
- Stellate and basket cells mainly
- Small and multipolar
- Mainly found in Layer IV
- Axons stay in grey matter
- Interneurons
- Inhibitory (GABA)
are non-pyramidal neurons homogenous or heterogenous
heterogenous
what percentage of all cells in cortex are non-pyramidal
30-40%
what does the frontal lobe control
- initiation and control of voluntary movement
- expressive langauge function
- higher function of mood, personality, judgement, motivation and executive functions
parietal lobe fuction
- perception and discrimination of somatic sensory stimuli
- involved in integrating visual and somatic sensory information
temporal lobe function
- auditory perception and discrimination
- receptive language function
- olfaction
- learning and memory function
occipital lobe function
- visual perception and recognition
- insular - buried in lateral sulcus
- receives taste afferent information
- associated with somatic sensory and limbic function
- influences autonomic functions
where is brocca’s area
left side of fronal lobe
where is Wernicke’s area
left side of temporal lobe
where are the motor areas
precentral gyrus of frontal lobe and primary motor cortex
motor areas function
directs voluntary movement
where are the sensory areas
- post central gyrus of parietal lobe
- primary sensory cortex
sensory areas function
receives somatic sensory information
examples of sensory somatic information
- touch
- pressure
- pain
- vibration
- taste
- temperature
what are association areas
any brain region that recieves input from more than one sensory modality
three examples of association areas
- parietal cortex
- temporal cortex
- frontal cortex
parietal cortex function
attends to stimulu in external and internal environments
temporal cortex function
identifies nature of stimuli
frontal cortex function
plans an appropriate response to stimuli
where is prefrontal cortex
anterior part of frontal lobes, lies in front of the motor and premotor areas
prefontal cortex function
- coordinates information from all other association areas
- important in intellect, planning, reasoning, mood, abstract ideas, judgement, conscience and accurately predicting consequences
what is hemispheric lateralization
functional differences between left and right hemispheres
what does lef hemisphere control (in most people)
reading, writing, maths, decision-making, logic, speech and language
what does the right hemisphere control (in most people)
recognition, affect, visual/spatial reasoning, emotion and artistic skills
