CMN 548 Module 4 Study Guide
University of South Alabama
Primary Study Guide - Neurobiological Basis of Mental Illness
Sadock Comprehensive Text, Chapter 1
Section 1.2 – Functional Neuroanatomy Page 3
Classification of neurons: Projection or Local Circuit
1. Projection Neurons- have long axons and convey information:
a. from the periphery to the brain (sensory neurons)
b. from one brain region to another
c. from the brain to effector organs (motor neurons)
2. Local Circuit neurons or interneurons- have short axons and process information
within distinct regions of the brain.
Neurons can also be classified based on the neurotransmitters they contain (Substantia nigra =
dopamine), though some contain more than one. Must be viewed within the context of the neural
circuits they influence, as many psychiatric disorders result from complex coordinated activity
by ensembles of neurons.
Glial cells – Types:
1. Astrocytes – the most numerous glial cell type. Two kinds:
A. Protoplasmic Astrocytes – large, located exclusively in gray matter with many
fine and elaborate processes:
a. Participate in formation of the blood brain barrier
b. Remove glutamate and GABA from the synaptic cleft
c. Buffer the extracellular potassium concentration.
d. Regulate cerebral blood flow via the “Neurovascular bridge”
e. Help support the energy requirements of neurons - Endfeet astrocytes
extract glucose from the blood and convert it to lactate, which is then
released for neurons to use as an energy substrate
f. Involved in synaptic neurotransmission:
, i. Tripartite synapse – The peri-synaptic astrocyte is an active
partner in synaptic transmission. They express a variety of
receptors that are stimulated by pre-synaptic neurotransmitters.
Once activated, they release gliotransmitters that can stimulate the
post-synaptic neuron.
1. This allows for regulation of glutamatergic/excitatory and
GABAergic/inhibitory neurotransmitters
ii. Distinct astrocyte domains – Patterns of organization in which
individual astrocytes modulate the activity of neurons and
synapses.
B. Fibrous Astrocytes – small, less complex, reside exclusively in white matter.
Have overlapping processes:
a. Form endfeet that contact blood vessels, ependymal cells, axons, and
nodes of Ranvier.
b. Are the traditional, supportive neuroglia.
2. Oligodendrocytes and Schwann Cells- Small cells with a myelin sheath which
facilitates the conduction of action potentials.
• Oligodendrocytes – found in the CNS
• Schwann cells – found in the PNS
• Satellite oligodendrocytes- found in gray matter – may be involved in
regulating the environment around neurons
3. Microglia- Derived from macrophages
a. Act as scavengers that eliminate debris from neuronal death and injury.
b. Also regulate neurogenesis and synaptic function: are involved in synaptic
pruning of dendritic spines during postnatal development
c. Regulate the function of neuronal networks by monitoring the status of
synaptic connections and integrating new information when necessary.
Relationship between altered Glia cells and psychiatric disorders:
● Schizophrenia – Altered glial cell number in dorsal prefrontal cortex.
○ Disease process or a consequence of treating it?
● Depression- Altered glial cell number in the medial prefrontal cortex. Decrease in blood
flow in the prefrontal cortex may be linked to a reduction of blood vessel coverage by
astrocytic endfeet.
● Sleep disturbance- Clearance of neuronal and glial waste products through the
glymphatic system during normal sleep may be impaired.
Principles of Brain Organization: Connections – Page 6
Every function is a consequence of the activity of specific neural circuits. How circuits form:
• Each neuron extends an axon along distinct pathways guided by molecular cues in the
environment. Eventually leads to the formation of synapses with a specific target neuron.
, a. Collaterals – Some axons initially produce an excessive number of axon
branches and contact a broader set of targets than are present in the adult brain. During
adolescence, inappropriate connections are pruned.
Principles of neural circuit organization:
1. Connections are reciprocal- each region receives input from the regions to
which it sends axonal projections.
■ Direct – axons from one region directly innervate those in another or local
circuit interneurons are interposed between incoming axons and projection
neurons
■ Indirect – The reciprocating connection passes though one or more
additional brain regions/synapses before innervating the final brain region
2. Connections are divergent or convergent-
■ Divergent- conduction of information from a neuron/group of neurons to
a much larger number of neurons located in diverse portions of the brain.
● The Locus Coeruleus is a highly divergent system (a small group
of norepinephrine containing neurons in the brainstem that sends
axonal projections to the entire cerebral cortex).
■ Convergent- output of multiple brain regions is directed towards a single
area.
● Projection of association areas of the cerebral cortex to the
entorhinal region of the medial temporal lobe is a convergent
system.
■ Areas can display both convergence and divergence.
3. Connections among regions are organized in a hierarchical or parallel
fashion (or both):
■ Visual input is conveyed in a hierarchical fashion through several
populations of neurons in the retina to the lateral geniculate nucleus,
primary visual cortex, then progressively to the multiple visual associated
areas of the cerebral cortex.
● Within the hierarchical scheme, different types of visual
information may be processed in a parallel fashion through
different portions of the visual system.
4. Regions of the brain are specialized for different functions.
Structural Components: Major Brain Structures – Page 9
● The neural tube is composed of 3 primary vesicles:
1. Prosencephalon – Divides into two:
■ Telencephalon - cerebral cortex, the hippocampal formation, the
amygdala, and some components of the basal ganglia.
■ Diencephalon - thalamus, hypothalamus
2. Mesencephalon - Midbrain
3. Rhombencephalon - divides into two:
■ Metencephalon - pons and the cerebellum
, ■ Myelencephalon – medulla oblongata
● The Cerebral Cortex is divided into 4 regions:
1. Frontal lobe- anterior to the central sulcus.
■ Primary motor region - precentral gyrus
■ Premotor region
■ Prefrontal region - prefrontal cortex
● Dorsolateral region - manipulation of data during working memory
● Ventrolateral region - maintenance of information during working
memory
2. Parietal lobe
■ Primary somatosensory cortex - anterior parietal lobe
■ Visual and somatosensory regions - posterior parietal lobe.
3. Temporal lobe
■ Primary auditory cortex - superior temporal lobe.
■ Complex visual functions – inferior temporal lobe.
■ Superior temporal sulcus - receives a convergence of input from visual,
somatosensory and auditory sensory areas.
4. Occipital lobe
■ Primary visual cortex.
■ Insula- cortical region deep in the lateral sulcus, covered dorsally by the
frontal and parietal opercula and ventrally by the temporal operculum. Has
extensive connections with the amygdala and thalamus.
● Other brain structures:
○ Basal ganglia: made of the caudate nucleus, the putamen, and the globus pallidus.
Involved in the control of movement and certain cognitive processes.
○ The hippocampus and the amygdala - components of the limbic system, located
deep in the medial temporal lobe.
○ Thalamus - large structure composed of numerous nuclei that have distinct
patterns of connectivity with the cerebral cortex.
○ Hypothalamus - smaller structure involved in autonomic and endocrine
functions.
Ventricular System – Page 15
● The cavity of the neural tube becomes the ventricular system of the brain.
● Composed of two C- shaped lateral ventricles in the cerebral hemispheres that can be
divided into 5 parts:
1. The anterior horn - located in the frontal lobe
2. The body of the ventricle
3. The inferior or temporal horn – located in the temporal lobe
4. The posterior or occipital horn- in the occipital lobe
5. The atrium
• The foramina of Monro (interventricular foramina) - two apertures that connect lateral
ventricles with the third ventricle.
University of South Alabama
Primary Study Guide - Neurobiological Basis of Mental Illness
Sadock Comprehensive Text, Chapter 1
Section 1.2 – Functional Neuroanatomy Page 3
Classification of neurons: Projection or Local Circuit
1. Projection Neurons- have long axons and convey information:
a. from the periphery to the brain (sensory neurons)
b. from one brain region to another
c. from the brain to effector organs (motor neurons)
2. Local Circuit neurons or interneurons- have short axons and process information
within distinct regions of the brain.
Neurons can also be classified based on the neurotransmitters they contain (Substantia nigra =
dopamine), though some contain more than one. Must be viewed within the context of the neural
circuits they influence, as many psychiatric disorders result from complex coordinated activity
by ensembles of neurons.
Glial cells – Types:
1. Astrocytes – the most numerous glial cell type. Two kinds:
A. Protoplasmic Astrocytes – large, located exclusively in gray matter with many
fine and elaborate processes:
a. Participate in formation of the blood brain barrier
b. Remove glutamate and GABA from the synaptic cleft
c. Buffer the extracellular potassium concentration.
d. Regulate cerebral blood flow via the “Neurovascular bridge”
e. Help support the energy requirements of neurons - Endfeet astrocytes
extract glucose from the blood and convert it to lactate, which is then
released for neurons to use as an energy substrate
f. Involved in synaptic neurotransmission:
, i. Tripartite synapse – The peri-synaptic astrocyte is an active
partner in synaptic transmission. They express a variety of
receptors that are stimulated by pre-synaptic neurotransmitters.
Once activated, they release gliotransmitters that can stimulate the
post-synaptic neuron.
1. This allows for regulation of glutamatergic/excitatory and
GABAergic/inhibitory neurotransmitters
ii. Distinct astrocyte domains – Patterns of organization in which
individual astrocytes modulate the activity of neurons and
synapses.
B. Fibrous Astrocytes – small, less complex, reside exclusively in white matter.
Have overlapping processes:
a. Form endfeet that contact blood vessels, ependymal cells, axons, and
nodes of Ranvier.
b. Are the traditional, supportive neuroglia.
2. Oligodendrocytes and Schwann Cells- Small cells with a myelin sheath which
facilitates the conduction of action potentials.
• Oligodendrocytes – found in the CNS
• Schwann cells – found in the PNS
• Satellite oligodendrocytes- found in gray matter – may be involved in
regulating the environment around neurons
3. Microglia- Derived from macrophages
a. Act as scavengers that eliminate debris from neuronal death and injury.
b. Also regulate neurogenesis and synaptic function: are involved in synaptic
pruning of dendritic spines during postnatal development
c. Regulate the function of neuronal networks by monitoring the status of
synaptic connections and integrating new information when necessary.
Relationship between altered Glia cells and psychiatric disorders:
● Schizophrenia – Altered glial cell number in dorsal prefrontal cortex.
○ Disease process or a consequence of treating it?
● Depression- Altered glial cell number in the medial prefrontal cortex. Decrease in blood
flow in the prefrontal cortex may be linked to a reduction of blood vessel coverage by
astrocytic endfeet.
● Sleep disturbance- Clearance of neuronal and glial waste products through the
glymphatic system during normal sleep may be impaired.
Principles of Brain Organization: Connections – Page 6
Every function is a consequence of the activity of specific neural circuits. How circuits form:
• Each neuron extends an axon along distinct pathways guided by molecular cues in the
environment. Eventually leads to the formation of synapses with a specific target neuron.
, a. Collaterals – Some axons initially produce an excessive number of axon
branches and contact a broader set of targets than are present in the adult brain. During
adolescence, inappropriate connections are pruned.
Principles of neural circuit organization:
1. Connections are reciprocal- each region receives input from the regions to
which it sends axonal projections.
■ Direct – axons from one region directly innervate those in another or local
circuit interneurons are interposed between incoming axons and projection
neurons
■ Indirect – The reciprocating connection passes though one or more
additional brain regions/synapses before innervating the final brain region
2. Connections are divergent or convergent-
■ Divergent- conduction of information from a neuron/group of neurons to
a much larger number of neurons located in diverse portions of the brain.
● The Locus Coeruleus is a highly divergent system (a small group
of norepinephrine containing neurons in the brainstem that sends
axonal projections to the entire cerebral cortex).
■ Convergent- output of multiple brain regions is directed towards a single
area.
● Projection of association areas of the cerebral cortex to the
entorhinal region of the medial temporal lobe is a convergent
system.
■ Areas can display both convergence and divergence.
3. Connections among regions are organized in a hierarchical or parallel
fashion (or both):
■ Visual input is conveyed in a hierarchical fashion through several
populations of neurons in the retina to the lateral geniculate nucleus,
primary visual cortex, then progressively to the multiple visual associated
areas of the cerebral cortex.
● Within the hierarchical scheme, different types of visual
information may be processed in a parallel fashion through
different portions of the visual system.
4. Regions of the brain are specialized for different functions.
Structural Components: Major Brain Structures – Page 9
● The neural tube is composed of 3 primary vesicles:
1. Prosencephalon – Divides into two:
■ Telencephalon - cerebral cortex, the hippocampal formation, the
amygdala, and some components of the basal ganglia.
■ Diencephalon - thalamus, hypothalamus
2. Mesencephalon - Midbrain
3. Rhombencephalon - divides into two:
■ Metencephalon - pons and the cerebellum
, ■ Myelencephalon – medulla oblongata
● The Cerebral Cortex is divided into 4 regions:
1. Frontal lobe- anterior to the central sulcus.
■ Primary motor region - precentral gyrus
■ Premotor region
■ Prefrontal region - prefrontal cortex
● Dorsolateral region - manipulation of data during working memory
● Ventrolateral region - maintenance of information during working
memory
2. Parietal lobe
■ Primary somatosensory cortex - anterior parietal lobe
■ Visual and somatosensory regions - posterior parietal lobe.
3. Temporal lobe
■ Primary auditory cortex - superior temporal lobe.
■ Complex visual functions – inferior temporal lobe.
■ Superior temporal sulcus - receives a convergence of input from visual,
somatosensory and auditory sensory areas.
4. Occipital lobe
■ Primary visual cortex.
■ Insula- cortical region deep in the lateral sulcus, covered dorsally by the
frontal and parietal opercula and ventrally by the temporal operculum. Has
extensive connections with the amygdala and thalamus.
● Other brain structures:
○ Basal ganglia: made of the caudate nucleus, the putamen, and the globus pallidus.
Involved in the control of movement and certain cognitive processes.
○ The hippocampus and the amygdala - components of the limbic system, located
deep in the medial temporal lobe.
○ Thalamus - large structure composed of numerous nuclei that have distinct
patterns of connectivity with the cerebral cortex.
○ Hypothalamus - smaller structure involved in autonomic and endocrine
functions.
Ventricular System – Page 15
● The cavity of the neural tube becomes the ventricular system of the brain.
● Composed of two C- shaped lateral ventricles in the cerebral hemispheres that can be
divided into 5 parts:
1. The anterior horn - located in the frontal lobe
2. The body of the ventricle
3. The inferior or temporal horn – located in the temporal lobe
4. The posterior or occipital horn- in the occipital lobe
5. The atrium
• The foramina of Monro (interventricular foramina) - two apertures that connect lateral
ventricles with the third ventricle.
