Neuropsychology 2307 Midterm #2 Flashcards
neurolinguistics
the neural mechanisms in the brain that control the comprehension, production, and acquisition of language
Segmented Bilateral Organism
- Local, centralized networks within each segment
- Longitudinal transmission of information up and down the body axis between segments
Decussation of vertebrate brains
All vertebrate brains are crossed over: left connects with the right side of the body and vice versa
Broca’s area
region in left frontal lobe for speech production
Golgi’s stain
sliced brain then stained it to see nerve cell bodies / tissue / individual neurons under light microscopy
Fritsch & Hitzig
electrical stimulation of dog’s brain to identify motor cortex
Neuron
cell in nervous system specialized to transmit electrical signals to other neurons via synapses
Glia
provide immunological and structural support; aid in transport of material from blood to neuron; largest number of cells in CNS
Nerve
when neuron axon is in the PNS
Tract
when neuron axon is in the CNS
Afferent
towards the brain (sensory)
Efferent
away from the brain (motor)
Grey matter
unmyelinated cells and dendrites of neuron - cognition
white matter
bundles of myelinated axons that connect grey matter to each other & carry nerve impulses - acting / sensing
Parenchyma
functional tissue of an organ (neurons and glia)
Ipsilateral
on the same side
Contralateral
on opposite side
bilateral
on both sides / in both hemispheres
proximal
near to the structure
distal
far from the structure
ganglion
cluster of cells in the PNS; can form swelling on nerve fibre
sagittal
YZ plane; divides structure into left/right; parallel to sagittal suture
coronal
XY plane; divides it into front and back
Dorsal
towards the top (or back); posterior (behind)
ventral
towards the belly or bottom (inferior)
caudal
tail
rostral
nose or anterior or frontal
medial
midline
superior
above
inferior
below
Graded potential
changes in membrane potential that vary in size, as opposed to being all-or-none; amplitude is proportional to the strength of the stimulus (NOT all or none)
Neurons
Electrically irritable communicating and computing cells of the nervous system
Glia
supporting cells: provide immunological and structural support, aid in transfer of materals from blood to neurons, etc.
Action potential
movement of sodium and potassium across the cell membrane; electrical signal that allows neurons to communicate quickly over long distances (frequency proportional to stimulus intensity)
Intra / extra neuronal signals
signals within neuron is electrical; between neuron it’s chemical
Types of Neurons
- sensory neurons (carrying information from receptors to the brain),
- motor neurons (carrying signals from the brain to muscles) and
- interneurons (which convey information between different types of neurons
neurotransmitter
chemical messenger; transmit signals from one neuron across a synapse to another neuron or muscle cell or gland cell
Synaptic Transmission
- changes in the electrical properties of the receiving neuron.
- these changes are called “postsynaptic potentials”
- Post-synaptic potentials are within the receiving neuron’s dendritic tree
Post Synaptic Potentials PSP’s
- Excitatory Post Synaptic Potentials (EPSPs) created in the receiving neuron’s dendrites increase the likelihood of the production of an AP on its axon
- Inhibitory Post Synaptic Potentials (IPSPs) created in the receiving neuron’s dendrites decrease the likelihood of the
- EPSPs and IPSPs are integrated in the soma over both space and time
- Whether an AP is created in the axon hillock depends upon the nature of this sum.
synaptic cleft
space between the pre and post synaptic neurons; interstitium
Astrocyte
glia that regulates transmission of electrical signals within the brain; feeds, supports and holds neurons in place
Microglia
“pac-men”, main immune defense in CNS; eats anything foreign that could damage CNS
Ependymal glia
pump CSF into ventricles; produce CSF; keep producing
Oligodendrocytes
Glia that make myelin; insulate axons in CNS; don’t regenerate; can myelinate many neurons
Schwann cells
Glia that myelinate axons in PNS (one Schwann cell will myelinate one segment of an axon); can self-repair
Neuron doctrine
(Cajal) nerous system is made up of discrete and individual cells
Law of Dynamic Polarization
Flow is L to R from dendrite to axon terminals
Dale’s Law
each nerve terminal releases a single type of neurotransmiter
Parts of a Neuron
Dendrite, Soma and Axon
- Dendrite: collects the incoming signals
- Soma: integrates signals generates the ones to travel down axon
- Axon: Conducts the signals across distances
All parts: Dendrite, Axon, Soma, Hillock, Terminal Boutons, Cytoplasm, Membranes (pre synapt and post synapt), Nucleus, Organelles
Integrated
added together, summed up
Cytoplasm
Jelly like substance in the cell body (proteins, ions)
Axon Hillock
part of the soma that connects to the axon
Organelle
tiny cellular structure that performs specific functions within a cell. Organelles are embedded within the cytoplasm of cells
Terminal Button
structure at end of axon that could have synapse on it
Post-synaptic membrane
on dendritic tree of the receiving neuron
Neural stem cell
Can self-renew (mitosis), lead to progenitor cells
Progenitor cells
develop from stem cells - lead to Blasts
Blasts
primitive nervous system cells, develop into neurons and glia
Differences between neurons
- dendritic tree complexity
- types of receptors
- types of NT’s
- axonal length
- arrangement of cell body to axon
- spatial and temporal integration
- physical size
- degree of axonal myelination
Divisions of Nervous System
- CNS - brain and spinal cord
- PNS - Somatic and Autonomic nervous system
Somatic - sensorimotor connections via spinal cord and cranial nerves
Autonomic -sympathetic and parasympathetic nerves
Somatic nervous system
in PNS; detects info about external world; sensorimotor connections from spinal cord and cranial nerves
Support and Protection of CNS
- Skull (brain pan) and vertebrae (33)
- Meninges
- Cerebrospinal Fluid
Meninges
3 membranes that enclose the CNS: Dura mater, Arachnoid mater, Pia mater (closest to cortex)
Cerebrospinal fluid
cushions the brain and spinal cord; produced in the ventricles (ependymal glia) recycled through the ventricle system; complete cycle every 24 hours
Brain Blood Supply
L&R Carotid Arteries and L&R Vertebral Arteries ascend in the neck to enter the skull through the foramen magnum to supply blood to the brain. Connect at base of brain for form:
–Anterior Cerebral Artery
–Middle Cerebral Artery
–Posterior Cerebral Artery
Meningeal Blood Supply
- Anterior Meningeal Artery – irrigates the anterior cranial fossa
- Middle Meningeal Artery – irrigates the middle cranial fossa
- Posterior Meningeal Artery –irrigates the posterior cranial fossa
Fossa
3 large depressions in the floor of the cranial activity (posterior fossa lodges cerebellum, medulla & pons)
Foramen magnum
hole at base of the skull (floor of fossa) through which spinal cord and vertebral arteries
Cranial arteries
4 of them: L&R Carotid, L&R Vertebral; supply blood to the brain; branch into anterior, middle and posterior arteries; each irrigates its own fossa
Basilar artery
irrigates the brain stem; at front of brain stem. forms from joining of two vertebral arteries
Circle of Willis
brain’s arteries; blood flows to the brain from vertebral and internal carotid arteries
Hematoma
bleed from artery or vein within brain; the wall of a blood vessel, artery, vein has been damaged and blood has leaked into tissues where it does not belong.
Subdural hematoma
blood below the skull and Dura mater; bleeding of bridging veins
Symptoms:
slurred speech / headache / inability to speak /
loss of consciousness or coma / numbness (may be in several areas of the body) / seizures / visual problems
weakness
Epidural hematoma
bleeding of meningeal arteries (between Dura and skull); medical emergency; can produce shift midline
Cribreform plate
between anterior cranial fossa and nasal cavity; olifactory afferents pass through here
Ventricular system
4 ventricles in brain plus the cerebral aqueduct; filled with CSF; connects 3rd and 4th ventricles for CSF flow
hydrocephalus
if CSF can’t get out through aqueduct so need stent to let the fluid out
Telencephalon
cerebrum; cerebral cortices; lobes: frontal, parietal, occiptal, temporal, insular
Basal ganglia
Basal forebrain nuclei
Subcortical white matter
Diencephalon
forebrain; neocortex, basal ganglia, limbic system, thalamus, hypothalamus
Mesencephalon
Mid-brain; part of brain stem
Metencephalon
embryonic part of hind brain that becomes pons and cerebellum
Myelencephalon
After brain; embryonic part of hind brain that develops into medulla oblongata
Cerebral cortex
80% human brain; 6 layers (older cortex - allocortex has 3 layers and thinner); 2 hemispheres; bilaterally symmetrical but not mirror images functionally
Neocortex
- 80% human brain
- expanded most during evolution
- 6 layers - no myelin (layer IV important as it receives info from outside the cortex and V &VII go outside cortex)
- Allocortex 3 layers which are thinner (hippocampus and olifactory bulb)
- two cerebral hemispheres
- frontal lobes larger than primates
- right under the Pia mater
Fissures, Sulci and Gyri
- Fissure - cleft in the cortex that is deep enough to indent the ventricles
- Sulcus (pl. sulci) - shallow cleft in the cortex
- Gyrus (pl. gyri) - ridge in the cortex
Organization of the Cortex
- Primary - receive and send info to and from PNS
- Secondary - receive input from Primary; interpret sensory input or organize movement
- Tertiary - (Association Cortex) - mediate complex activities
Cytoarchitectonic maps of Cerebral Cortex
map of the brain based on organization, structure and distribution of the cells
Broadman’s atlas (44 areas)
Forebrain
- Neocortex
- Basal Ganglia
- Limbic System
2 and 3 are subcortical
Limbic System
- In telencephalon and diencephalon
- functionally and anatomically connected
- Amygdala - Emotion and species-typical behaviors
- Hippocampus - Memory and spatial navigation
- Septum - Emotion and species-typical behavior
- Cingulate Cortex (cingulate gyrus)- - emotion formation, learning and memory
- limbic cortex is immediately superior to the corpus collosum (dammage pathinomic)
Basal Ganglian
- Putamen, Globus Pallidus, Caudate Nucleus (stimulus response learning / sequencing)
- Sub-thalamic
- supports complex movements and computations (disorders of this area will be movement-oriented)
Diencephalon
- Hypothalamus - interacts with pituitary gland, movatied behavior, affects metabolism
- Thalamus
- Pineal gland
- Posterior Pituitary
Thalamus
Thalamus relays info to targets (it bridges the cortex and spinal cord) and projects it back
**can modify info on way to the cortex
controls sleep and awake state
Thalamus is in 2 halves
Receives auditory, somatosensory and visual signals
Hypothalamus
Hypothalamus regulates temperature, when should eat and when stop eating, hormones, circadian rhythm and more
Midbrain / Mesencephalon
- top of the brain stem
- Cerebral peduncles: connec the cortex, cerebellum and spinal cord
- Tectum (ceiling) inf.(ears) and sup. colliculi (eyes)
- Tegmentum (midbrain floor) surrounds cerebral aqueduct - eye movements and tracking
- cortical blindness: get input from retina so avoid objects but not sure why (act like you can see)
- Red nucleus - limb movements
- Periaqueductal grey matter: species-typical behavirs (sexual behavior and pain response)
- Substantia Nigra - reward / initiation (dopamine)
Metencephalon
Pons and Cerebellum (litle brain)
- Pons connects cortex and cerebellum
- Cerebellum - sensorimotor integration
- If damage cerebellum lose equilibrium (wide stance like a toddler), impairment to skilled motor activity
Myelencephalon
Medulla Oblongata
- cardiac and respiratory functions; reflex centers for vomiting, coughing, sneezing, swallowing, etc.
- reflexive processes
- reticular formation: arousal level (like 2 hot dogs)
- vision, hearing, somatosensory signals thru here
- Pyramids: in medulla
Cranial Nerves
- 12 pairs (24 nerves)
- in PNS called nerves / in CNS called tracts
- cranial nerves pass through the meninges (which determines what is CNS/PNS) so technially CNS too
- descend from brain stem (anterior)
- superior to inferior
- sensory and motor functions (some just one)
- On Old Olympus’ Towering Top A Finn and German Vend Some Hops…Some say marry money but my brother says big boobs matter more
List Cranial Nerves
- Olfactory
- Occiptal
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Auditory (vestibulocochlear)
- Glossopharygeal
- Vagus
- Spinal Accessory
- Hypoglossal
Spinal Cord
- 31 segments - each one 2 pairs somatic nerves
- L Sensory - enter L Dorsal
- R Sensory - enter R Dorsal
- L Motor - exit L Ventral
- R Motor - exit R Ventral
Bell Magendie Law
SAME DAVE
S - Sensory A - Afferent M - Motor E - Efferent
D - Dorsal A - Afferent V - Ventral E - Efferent
Myotome
- Muscle and nerve collectively
Examples:
- Cervical 3, 4, 5 Diaphram
- Cervical 5 Shoulder movements / elbow flexion
- Cervical 6 - wrist dorsiflex
- Cervical 7 - elbow extension
- Cervical 8 finger flexion
Dermatome
an area of the skin supplied by nerves from a single spinal root.
Thickenings in Spinal Cord
- Cervical Enlargement - innervates upper limbs through brachial Plexus
- Lumbar Enlargement - innervates lower limbs
Central Pattern Generators
- provide rhythmic patterned outputs without sensory feedback
- neuronal circuits
- in all evolved animals with locomotion (relieves us from having to calculate how to do something like walk or breathe)
Autonomic Nervous System
- Sympathetic (Fight or Flight) - arouses body for action - Stimulatory
- Parasympathetic - (Rest and Digest) - Inhibitory
Tractography
Traces axon bundles through the brain in 3D
Mapping connection amongst brain areas
- Long connections - one lobe to another
- Relatively short connections - one part of lobe to another part same lobe
- Interhemisphereic connections: homotopic points (in “typcial” brain) and heterotopic points (in patients with Agenisis of Corpus Collosum AgCC) - missing part of CC
- The connection is through Thalamus
Commissures
- Contralateral white matter projections
- CNS connects mainly with contralateral body
- Decussations: sensory and motor fibres cross the midline at the spinal cord, corpus collosum and anterior and posterior commissures
Corpus Collosum
9 components
- Rostrum
- Inferior Genu
- Superior Genu
- Posterior Genu
- Anterior midbody
- Middle midbody
- Posterior midbody
- Isthmus
- Splenium
Brain Commissures
- Corpus Collosum
- Anterior Commissure
- Hippocampal Commissure
- Habenular Commissure
- Posterior Commissure
- Supraoptic Commissures
Diffusion Tensor Imaging
- Tracks flow of water
- Measures direction and get picture of region of brain where water flow signal is large
- travels on large tracs, axonal fibres
Arcuate Fasciculus
- curved bundle
- grey matter tract that connects Broca’s Area (production of speech) with Wernicke’s area (comprehension of speech)
- Wernicke’s Aphasia: can produce speech but it is garble and
- Broca patients can understand but not really speak
Development of Myelination
- central to peripheral
- caudal to rostral - frontal lobes last to myelinate and can take into 20’s
- dorsal to ventral
- sensory then motor
- Last areas to myelinate:
- anterior cingulate cortex
- inferior temporal cortex
- dorsolateral prefrontal cortex
