prosencephalon (forebrain)- telencephalon Flashcards
what are the 3 parts of the telencephalon?
- outer gray cerebral cortex- pallium
- mass of white fibers- centrum semiovale
- deep in white matter- neuron cell bodies called basal ganglia
telencephalon has 4 lobes on each side
frontal, temporal, parietal, occipital
the insula (isle of reil) and limbic region are sometimes called?
lobes and pseudolobes
general functions of the telencephalon?
- final integration of neural mechanisms
- initiation center for voluntary actions
- memory and associative memory
- abstract thinking- prefrontal- broadmann 9 through 12
what is the surface area of the cerebral cortex/pallium?
2.5 square feet- 2/3 of area is down in the sulci
in most areas the gyrus sulcus is ____ than the sulcus cortex?
thicker
what are the 2 subdivisions of the cerebral cortex/pallium?
neocortex- 90% of total cortex- cells and cell layers homogenous
allocortex- 2 parts (olfactory and hippocampal) heterogenous
what are the 6 common laminae of the neocortex? arranged external to internal
molecular lamina I- lots of synapses external granular lamina II external pyramidal lamina III internal granular lamina IV internal pyramidal lamina V multiform lamina VI
the molecular layer is which layer?
outermost and nearest to pia mater; filled with synaptic activity
describe external granular layer- II
small, closely packed granular neurons
axons extend into deeper lamina of same cortex area
intracortical association layer
describe the external pyramidal layer- lamina III
small pyramidal shaped neuron cell bodies
axons extend out of cortex to white matter and then return to gray matter
-projection, association and commissural fibers
intercortical association layer
lamina II and III are also called?
associative lamina- best developed in human brain
describe internal granular layer- IV
small closely packed cell bodies
specific thalamic inputs arrive here
well developed sensory areas (touch, pain, sight etc)
describe internal pyramidal layer- V
large pyramidal- shaped neuron cell bodies
giant pyramidal Betz cells here as well
axons project to other brain and cord centers from here
describe multiform layer- VI
mix of incoming and outgoing fibers
large number of projection neurons- especially to thalamus
laminae V and VI are sometimes called?
projection laminae
what are the parts of the basal ganglia? all bilateral
caudate nucleus
putamen nucleus
globus pallidus or paleostriatum
amygdaloid complex or archistriatum
putamen and globus pallidus together are called?
lenticular nucleus
striatal lesions normally lead to?
dyskinesia (muscle tone disturbances)
dyskinesia examples?
tremor
chorea
ballism or hemiballism
tremors usually come from a lesion where?
in the cerebellum
example of chorea?
huntingtons chorea- graceful involuntary movements of extremities, facial muscles, tongue etc- corpus striatum begins to deteriorate- deficiency of GABA
ballism or hemiballism is a more violent movement and can occur from lesions where?
globus pallid us which communicates with subthalamic nucleus
describe the caudate nucleus
has a head, body and tail
head region is continuous with the putamen nucleus by gray matter bridges
afferent fibers of caudate nucleus synapse in the caudate from?
all lobes of the cortex, the thalamus, substantia nigra and putamen
efferent fibers of caudate extend to?
putamen, globus pallidus, substantia nigra and thalamus
what is the most lateral of the corpus striatal nuclei?
putamen nucleus
afferent and efferent fibers of putamen are ______ as caudate?
the same
the _____ is part of the lenticular nucleus along with the putamen
globus pallidus
afferents of globus pallidus include axons from
caudate
putamen
subthalamic
describe the efferent fibers of globus pallidus
primary efferent outflow from corpus striatum- anterior aspect of thalamus
what is the ancient part of the basal ganglia located in the temporal lobe ?
amgydala
inputs for the amygdala from?
olfactory tract, hypothalamus and neocortex
amygdaloid activity is associated with?
increased inhibition- fear and anger
what is the name for the collective white matter of telencephalon?
centrum semiovale
what are the fiber types in the white matter of telencephalon?
projection- afferent and efferent
commissural- corpus callosum (300 million neurons)
projection axons in the white matter utilize what?
corona radiata and internal capsule
what are the different parts of the corpus callosum?
splenium, body, genu, rostrum, forceps anticus, forceps posticus and tapetum
what is the most abundant part of the white matter?
association axon bundles (fasciculi)
the corpus callosum is only found in?
placental mammals
