Neuropsychology Midterm Flashcards
(208 cards)
1
Q
General Neuropsychology
A
the scientific study of the neural basis of human experience and behaviour
2
Q
Clinical Neuropsychology
A
evaluation and treatment of brain abnormalities affecting experience and behaviour
3
Q
Experience
A
end-product of perception, property of consiousness
4
Q
Behaviour
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the end-product of connotation, leads to purposive skeletal muscle activity
5
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Genetic information (nature)
A
information that is carried in an individuals DNA configuration, inherited from parents
6
Q
Memetic Information (nurture)
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information obtained from sensation/perception, stored in memory
7
Q
General Factors Affecting Brain Function
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Genetics, Nutrition, Experience, Vegetative Physiology, Tissue Ablation, Drugs, Electromagnetic energy
(Gorgeous Nannies Ejected Venom Towards Dopey Elvis)
8
Q
Evaluation of brain and behaviour through:
A
-behavioural assessment (of cognitive and psychomotor functions)
-monitoring local brain metabolism (fMRI, PET, etc.)
-monitoring local brain electrical activity (EEG and event-related potentials)
-temporarily altering local brain functions (using TMS)
9
Q
Central Nervous System
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brain and spinal cord
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Peripheral Nervous System
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-Somatic Nervous System (SNS): Sensorimotor connections
-Autonomic Nervous System (ANS): balances the internal organs through the parasympathetic and sympathetic nerves
11
Q
Rostral
A
towards the nose
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Caudal
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towards the tail
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Dorsal
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towards the back
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Ventral
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towards the belly
15
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Coronal
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(XY) vertical line down
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Saggital
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(YZ) horizontal line down
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Axial
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(XZ) cross section through the middle
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Nucleus
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cluster of cell bodies in the CNS
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Ganglion
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cluster of cell bodies in the PNS
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Anterior
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in front of
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Posterior
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behind
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Lateral
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side view
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Medial
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midline
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superior/inferior
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higher/lower
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ipsilateral
structures on the same side
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contralateral
structures on the opposite side
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bilateral
structures that lie in both hemispheres
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proximal
structures that are close to one another
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distal
structures that are far apart
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Nerve
collection of neuron axons in PNS
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Tract
collection of neuron axons in CNS
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Efferent
directed away from the brain
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Afferent
directed towards the brain
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Grey matter
nervous tissue that appears greyish due to the presence of unmyelinated neuronal cell bodies and axons (neocortex is predominantly grey matter)
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White matter
nervous tissue that appears light coloured due to the presence of myelinated axons (neuronal tracts are typically white matter)
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Layers or nuclei
a well-defined group of neuron cell bodies
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Parenchyma
tissues associated with function
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Neurons
the communicating and computing cells of the nervous system
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Glia
supporting cells (provide immunological and structural support, aid in transfer of glucose and oxygen from blood to neurons
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sensory neurons
carrying information from receptors to the brain
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motor neurons
carrying signals from the brain to muscles
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interneurons
which convey information between different types of neurons
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Astrocytes
star shaped glia: most abundant glial cells. regulate transmission of electrical impulses within the brain
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Microglia
account for 10-15% or all cells found within the brain, act as the first and main form of active immune defense in the CNS
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Ependymal cells
line the CSF-filled ventricles in the brain and the central canal of the spinal cord. nervous tissue cells with a ciliated simple columnar form
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Oligodendrocytes
provided support and insulation to axons in the central nervous system of some vertebrates
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Schwann Cells
provided support and insulation to axons in the peripheral nervous system of some vertebrates
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Important neuropsychologists
santiago ramon y cajal and camillo golgi
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Neuron Doctrine
-Neural units (brain is made up of individual specialized units
-Neurons are cells
-specialization (these units may differ in size,shape,structure, etc)
- nucleus is key (trophic center of the cell)
- nerve fibers are cell processes
- cell division
- contact (connected by sites of contact)
- law of dynamic polarization (there is a prederred direction for transmission from cell to cell)
-synapse (a barrier to transmission exits at the site of contact)
-unity of transmission (either excitatory or inhibitory contact not both)
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Dendrite
collects thousands of incoming signals
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soma
integrates signals from dendrites; generates signal that will travel down axon
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axon
conducts signals rapidly across long distances
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synapse
connect sensory organs, like those that detect pain or touch, in the PNS to the brain
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Parts of the neuron
Dendrite, hillock, soma, nucleus, axon, cytoplasm, terminal button, synapse, synaptic cleft, presynaptic membrane, postsynaptic membrane
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How neurons differ
dendritic tree complexity, types of synaptic receptors, types of activating neurotransmitters, axonal length, and cross-sectional area, arrangement of cell body axon (unipolar, bipolar, or multipolar), spatial and temporal integration, physical size, degree of axonal myelination
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Skull and vertebrae
the brain is enclosed in the neurocranium (posterior portion of the skull)
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Vertebral column
33 bones
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Meninges
3 membranes enclosing the CNS (dura mater, arachnoid mater, pia mater)
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Cerebrospinal fluid (CSF)
cushions the brain and spinal cord
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Pterion
one of the weakest parts of the skull, the junction of the parietal bone, temporal bone, sphenoid bone, and frontal bone.
- the anterior division of the middle meningeal artery runs under the pterion
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Meningeal arteries (mainly supply the dura region of the meninges)
- Anterior Meningeal artery - irrigates the meninges in the anterior cranial fossa
- Middle Meningeal Artery - irrigates the meninges in the middle cranial fossa
- Posterior Meningeal Artery - irrigates the meninges in the posterior cranial fossa
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Subdural hematoma
caused by bleeding of bridging veins across the subdural space
- Symptoms: Slurred speech, headache, inability to speak, loss of consciousness, numbness, seizures, visual problems, weakness
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Epidural hematoma
caused by bleeding of meningeal arteries resulting in blood pooling between the dura mater and the skull
- Symptoms: Confusion, dizziness, drowsiness or altered level of alertness, enlarged pupil in one eye, headache, loss of consciousness followed by alertness and then rapid deterioration, nausea
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Intracranial Blood Supply
- left and right internal carotid arteries ascend in the neck to enter the skull through the temporal bone
- left and right vertebral arteries ascend in the neck to enter the skull through the foramen magnum to supply blood to the brain parenchyma
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The circle of Willis
The joining area of several of arteries at the bottom (inferior) side of the brain
Acts as a pathway for blood trying to go through blocked arteries
“Plumber”
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The lumbar cistern
The CSF-filled area between the end of the spinal cord and the end of the vertebral column
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5 main parts of an adult brain
telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
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Telencephalon
comprised of the cerebral cortex, the hippocampus, amygdala, olfactory bulb, and basal ganglia
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diencephalon
containing the epithalamus, thalamus, hypothalamus, and third ventricle
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mesencephalon
composed of the tectum, and tegmentum
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metencephalon
differentiates into the pons and the cerebellum. contains a portion of the fourth ventricle and trigeminal nerve, abducens nerve, facial nerve, and a portion of the vestibulocochlear nerve
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Myelencephalon
the posterior region of the embryonic hindbrain from which the medulla oblongata develops
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cerebral cortex
- Associated with higher nerve functions (cognition, planning, skilled movement)
- Expanded through evolution
- 80% of the human brain
- Neocortex = 6 layers
- Allocortex = 3 layers
- Two cerebral hemispheres
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Primary areas of the cortex
receive/send information from/to the peripheral nervous system
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Secondary areas of the cortex
adjacent to primary areas, receive input from the primary areas, engaged in interpreting sensory input or organizing movements
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Tertiary areas (association cortex)
located between secondary areas, mediate complex activities
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Basal Ganglia (forebrain)
- collection of nuclei that includes the: putamen, globus pallidus, caudate nucleus, subthalamic nucleus, substantia nigra
- supports stimulus-response learning
- functions in sequencing movements
- modulates muscle force
- control and regulate activities of the motor and premotor cortical areas so that voluntary movements can be performed smoothly
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The Limbic System
a collection of functionally and anatomically interconnected structures ni the telencephalon and diencephalon
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Amygdala (limbic system)
emotion and species-typical behaviour
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hippocampus and fornix (limbic system)
memory and spatial navigation
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mammillary bodies (limbic system)
memory consolidation
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septum
emotion and species-typical behaviour
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cingulate cortex (cingulate gyrus)
integral part of the limbic system involved with emotion formation, learning and memory
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diencephalon
region between the telencephalon and brainstem consisting of the thalamus, hypothalamus, and epithalamus.
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Thalamus (diencephalon)
- relays all sensory information (except olfactory) to appropriate cortical targets
- relays information amongst cortical areas
- relays information between forebrain and brainstem
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Epithalamus
poorly understood, biorhythms, hunger, thirst
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mesencephalon (midbrain)
- uppermost portion of the brainstem
- cerebral peduncles fiber tracts containing the cortex, cerebellum, and spinal cord
- tectum inferior and superior colliculi
- tegmentum (covering or midbrain floor), and surrounds the cerebral aqueduct
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red nucleus (midbrain)
limb movements
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substania nigra
reward and initiation of movement
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peri-aqueductal gray matter
- species-typical behavior (ex. sexual behavior)
- modulating pain response
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Metencephalon
- pons (bridge) functionally connects cortex and cerebellum
- cerebellum- neuronal computer, involved in sensorimotor integration
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Myelencephalon
medulla oblongata: control of cardiac and respiratory functions; reflex centers for vomiting, coughing, sneezing, swallowing, etc. involving central pattern generators
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cranial nerves
12 pairs (24 nerves), descending from the olfactory nerve, sensory functions/motor functions
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cranial nerve names
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory, glossopharyngeal, vagus, spinal accessory, hypoglossal (old official owls tackled tasty amoebas frightfully and glorious vader snorted helpfully)
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Spinal cord
- courses through the vertebral canal, inside the vertebral column, from the foramen magnum to L1 and/or L2
- below L2 fibrous strands continue to the coccyx through the lumbar cistern
- each spinal segment has two pairs of somatic nerves associated with it (left and right SENSORY nerves entering the DORSAL HORNS of the spinal cord) (left and right MOTOR nerve exiting the VENTRAL HORNS of the spinal cord)
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Spinal nerves
31 mixed nerves that collectively transmit sensory, motor, and autonomic impulses between the spinal cord and the rest of the body (8 cervical pairs, 12 thoracic pairs, 5 lumbar pairs, 5 sacral pairs, 1 coccygeal pairs)
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The Bell-Magendie Law
the ventral spinal roots transmit motor impulses and the posterior roots sensory impulses
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myotomes
A group of muscles that are innervated by the motor fibers that stem from a specific nerve root - each muscle is innervated by the output of 1 or more spinal segments (cervical 3,4,5 = diaphragm muscles) (cervical 5 = shoulder movements and elbow flexion) (cervical 6 = wrist dorsiflexion) (cervical 7 = elbow extension) (cervical 8 = finger flexion)
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dermatome
An area of the skin that is innervated by the sensory fibers that stem from a specific nerve root
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cervical enlargement (somatic nervous system)
innervates the upper limbs via the Brachial Plexus
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lumbar enlargement (somatic nervous system)
innervate the legs via the lumbar plexus
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Cervical Plexus
complex neurologic structure located within the head and neck
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Brachial Plexus
a network of nerves located in the neck and axilla, composed of the anterior branches of the lower four cervical and first two thoracic spinal nerves (innervates the chest, shoulder, and arm)
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Lumbosacral Plexus
provides motor and sensory information to the lower abdominal, pelvic, and thigh regions
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Rhythmic and pattern-generators
automatic rhythmic movements that are driven by central pattern generators located in the brainstem (breathing, chewing, swallowing, sneezing, coughing) and the spinal cord (walking, running, swinging, swimming, scratching, ejaculation)
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sympathetic division (automatic nervous system)
arouses the body for action - "fight or flight", spinal nerves in the thoracic and lumbar regions are connected to the sympathetic ganglia, dilates pupil via pupillary dilator muscle
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Parasympathetic division (automatic nervous system)
calms the body down, rest and digest, connects with parasympathetic ganglia near target organs, constricts pupil via pupillary sphincter muscle
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Contralateral white matter projections
- CNS connects mainly with the contralateral body (each symmetrical half responds to sensory stimulation from the contralateral body or controls musculature on the contralateral body
- Decussations (sesnory and motor fibers cross the midline at the level of the spinal cord, corpus callosum, anterior and posterior commissures)
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Embryonic stage
the time of life from conception until the end of the 8th week
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Fetal stage
defined as the interval from the beginning of week 9 to week 38
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ectodermal germ layer
the outermost tissue layer of the embryo that differentiates to form the nervous system, tooth enamel, epidermis, the lining of mouth, anus, nostrils, sweat glands, hair and nails, etc
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milestones of neural system development
(1) closure of the neural tube (~ day 22)
(2) neurogenesis (~ 16 weeks)
(3) neuronal migration
(4) Cell differentiation glial cell proliferation
(5) Axonal and dendritic sprouting
(6) Synaptogenesis
(7) Neuronal cell death (apoptosis)
(8) Synaptic pruning
(9) Myelination (late adolescence/early adulthood)
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IQ tends to be higher when
- babies with higher birthweight
- children who grow taller in childhood and
adolescence
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Gale et al
found full-scale IQ at age 9 increased by ~2 points for each SD increase in head circumference at 9 months and by ~2.9
points for each SD increase in head circumference at 9 years of age...They concluded that “brain growth during infancy
and early childhood is more important than
growth during fetal life in determining cognitive function
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anterior cingulate coretex
rational cognitive functions - (error detection and conflict monitoring, reward anticipation, devision making, empathy, impulse control, emotion)
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inferior temporal cortex
where perception meets memory
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inferior temporal cortex
where perception meets memory (object identification)
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dorsolateral prefrontal cortex
executive functions (decision making, working memory, social cognition)
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neuroplasticity
the ability of nervous tissue to change the mapping of neural function to neural structure bc of changes in experience, behavior, anatomy, etc
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neuroplastic adaptivity
- makes it possible for the brain to create and maintain functional relationships
- CNS achieves adaptability by building, monitoring, and modifying
- it is necessary for the brain to calibrate its interaction with the body
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Principles of brain plasticity
- common to all nervous systems
- can be analyzed at many levels
- similar behavioral changes can correlate with different plastic changes
- experience-dependant changes interact
- neuroplasticity can be age/time dependant
- related to experience frequency
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Mendel's Second law
the law of independent assortment; the segregation of alleles is independent of each other.
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When neuroplasticity is demonstrated by behavioural change ...
- experience changes in neural structure/function
- altered experience
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When neuroplasticity is demonstrated by changes in cortical brain maps
- tonotopic areas in A1/A2 found to be increased in musicians compared to nonmusicians
- people did surgery to separate their webbed fingers, before surgery the unit had one cortical area, after surgery the cortical area was divided
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Focal hand dystonia
loss of independent control of one or more of the gingers on a hand (due to overlap of neurons controlling adjacent fingers)
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Jacobs and Scheibel
hypothesized that neuronal complexity is related to the computational demands placed on the cell
- took measurements of dendritic arborization from neurons in 2 regions of S1 (trunk and finger) and Wernicke’s area
- support for their hypothesis: trunk < finger < Wernicke’s area
- they also found a relationship between the complexity of dendritic arborization and the
the occupation of those whose brains were
studied
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Long-term potentiation (LTP)
Repetitive electrical pulses (potentiation) applied to brain tissues have been shown to alter the efficiency of synaptic transmission (neurons that fire together, wire together)
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Experimental kindling of seizures
Experimental procedure whereby the
repeated exposure to an electrical pulse is
sufficient to generate the seizure itself
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Neurogenesis
occurs in the hippocampus and olfactory bulb
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Kertesz two stages of brain injury recovery
- Stage 1: acute recovery: recovery from effects
of metabolic and membrane failure, neuro-
transmission deficits, hemorrhage and edema
some axonal regeneration occurs soon after injury with new synaptic connections
- Stage 2: longer-term brain reorganization;
axonal regeneration, collateral sprouting,
reprogramming (both cortical and subcortical
processes), etc.
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The Kennard Principle
the earlier in life the patient suffers brain damage the more functions are spared and the greater the chances of recovery of the lost ones
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The Neuron
the basic cellular unit of nervous tissue, they process information, communicate with other neurons, and control other tissues (ex. muscles/glands)
- they have the ability to generate and transmit signals
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Measuring a cell's electrical activity
- microelectrode (small enough to plan on or in an axon)
- oscilloscope (a device that measures electric potential as a function of time)
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Membrane potential
Unequal ion concentrations inside vs. outside the cell membrane produces result in a measurable voltage across the membrane
- Sodium chloride outside the cell
- potassium and large proteins inside the cell
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Maintaining the resting potential
1. negatively charged proteins stay inside cell bc the membrane is impermeable
2. potassium and chloride ions can pass through the membrane in either direction since there are no gated channels
3. sodium channels are gated (cannot always pass through membrane)
4. active ion pumps located in the membrane export 3 sodium ions from the cytoplasm to the interstitium and import 2 potassium from the interstitium to the cytoplasm with each pump cycle
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altering the neurons membrane potential
it is altered by changing the permeability
- adding positive ions will depolarize the membrane potential
- adding negative ions will hyperpolarize the membrane potential
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depolarization
when the change in the membrane potential goes from -70mV to values less negative (closer to 0)
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hyperpolarization
when the change in membrane potential from -70mV to values more negative (further away from 0)
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Graded potentials
found mainly in the dendrites (near the postsynaptic membranes)
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Action potentials
found mainly in the axon and terminal buttons
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Excitatory Post-Synaptic Potentials (EPSPs)
created by neurotransmitter chemicals binding to excitatory receptors embedded in the membrane of the neuron's dendrites, causing depolarization
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Inhibitory Post-Synaptic Potentials (IPSPs)
created by neurotransmitter chemicals binding to inhibitory receptors embedded in the membrane of the neuron's dendrites, causing hyperpolarization
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the action potential
- a change in the membrane potential generated in the neuron’s soma and propagated without decrement along the full length of a neuron’s axon to its terminal boutons.
- can carry information over great distances using changes in the production rate rather than changes in amplitude (as graded potentials do).
144
what causes an action potential
All of the EPSPs and IPSPs created within
the dendrites within a short time span are
ADDED TOGETHER (Integrated). The net
result affects whether or not an action
potential is created at the axon hillock.
145
Factors affecting the conduction velocity
of Action Potential along axons
- conduction speed varies inversely with the cytoplasm's electrical resistance
- an axon with a large cross-sectional area has lower cytoplasmic resistance (higher conduction velocity)
146
Factors affecting the speed of action potential propagation along axons
- varies inversely with the electrical capacitance of the axon membrane
- a myelinated axon with a large cross-sectional area has the highest conduction velocity
147
myelination
conduction of action potentials through myelinated axons is faster than unmyelinated axons
148
saltatory conduction
the action potential appears to jump from one node of Ranvier to the next
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neurotransmission
neurons communicate with one another through chemical signaling
150
effects of neurotransmitters
- bind to receptor sites on the post-synaptic membrane
- the binding process alters specific ionic permeability of the post-synaptic membrane at the local receptor site, resulting in a local graded potential
151
how does neurotransmission occur?
when there are EPSPs and IPSPs in the receiving neuron’s dendrites
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Ionotropic receptor
a receptor that contains a binding site for a neurotransmitter and an ion channel that opens when a molecule of the neurotransmitter attaches to the binding site
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metabotropic receptor
a receptor that contains a binding site for a neurotransmitter which activated an enzyme that begins a series of events, opening an ion channel elsewhere in the neuron's membrane when a molecule of the neurotransmitter attaches to the binding site
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G protein
a protein coupled to a metabotropic receptor; conveys messages to other molecules when a ligand binds with and activates the receptor
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Second messenger
a chemical produced when a G protein activates an enzyme; carries a signal that results in the opening of the ion channel or causes other events to occur in the cell
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reverberatory circuits
circuits that produce cyclical signaling activity
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neural coding
neurons code signals to create information
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neural integration
the process by which inhibitory postsynaptic potentials and excitatoty postsynaptic potentials summate and control the rate of firing a neuron
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nervous system agents
- Some NSAs can cause reversible changes, while others can cause permanent changes to neural function
- Some NSAs act as a neuroprotectant, resulting in the recovery or regeneration of affected neuron function
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psychopharmacology
a study that utilizes knowledge and skill from chemistry and neuroscience
161
neurotoxicity
most nervous system agents are neurotoxic at some dose level
- behavioral toxicology: subdiscipline of psychopharmacology that studies the effects of toxic levels of NS Agents on behavior, cognition, emotion, and consciousness
- MedWatch: USFDA medical product safety reporting program for health professionals, patients, and consumers
162
Pharmacodynamics
nervous system agents have different effects and mechanisms of action upon nervous tissue sites depending on the route of delivery, the amount taken
163
Pharmacokinetics
the time-course of NS agent action and movement throughout the body (affected by metabolism)
164
therapeutic effects
the intended consequences on the NS of a nervous system agent
165
side effects
effects that occur but are not related to the purpose of taking the drug (contraindications - negative side effects)
166
placebo effects
therapeutic effects not attributable to drug action (subjective symptoms)
167
the dose-response
the functional relationship between the
drug dose level & some dependent
measure of drug’s effect
168
dose-response descriptors
- Median Effective Dose (e.g., ED50) is the minimum dose level that produces a measurable therapeutic effect in 50% of the study sample
- Median Toxic dose (e.g., TD50) the minimum dose level that produces a measurable toxicity effect in 50% of the study sample
- Median Lethal dose (e.g., LD50), the minimum dose level that kills 50% of the study sample
169
operational definitions of dose response
- Subjective” Effects: experiential changes reported by the patient (e.g.,
changes in attention, mood, perception, etc.)
- Behavioral Effects: changes in patient’s behavior (indicating effects on memory, decision-making, communication, reaction time, fine motor coordination, speech, etc.)
- Physiological Effects: changes to vegetative physiologic functions such as breathing rate, heart rate, body temperature, appetite, tremors, sleep levels, etc.
170
prepulse inhibition deficit
a deficit of prepulse inhibition occurs when the presence of the prepulse fails to reduce the magnitude of the acoustic startle response to the subsequent loud noise burst
171
agonists
increase the efficiency of within or between neural signaling (two types: direct-acting agonists, and indirect-acting agonists)
172
antagonists
decrease the efficiency of within or between neural signaling (two types: direct-acting antagonists, and indirect-acting antagonists)
173
direct-acting agonists
NS Agents that directly bind to the membrane channels or postsynaptic receptors (ex. direct-binding agonist drugs include dopamine, nicotine, apomorphine)
174
indirect-acting agonists
agonists that enhance neurotransmitter actions by stimulating neurotransmitters' release (cocaine)
175
direct-acting antagonist
block cell membrane ion channels or block NT from binding to the postsynaptic receptors (atropine)
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indirect-acting antagonist
inhibit the release or production of NT (reserpine)
177
Channel openers
agonistic NS agents that facilitate the flow of ions across the cell membrane, affecting the dynamics of the membrane potential of cells,
including neurons
178
natural agents
a calcium channel agonist binds to the plasma membrane Ca++ pump and turns it into an ion channel
179
pharmaceutical channel openers
act by facilitating ion movement through neuron membranes (dependent on dose),
altering the rate of depolarization, increasing neuron ‘excitability’ and action potential conduction velocity.
180
11 ways that CNS agents affect synaptic neurotransmission
1. drug serves as a precursor - AGO
2. drug-inactivated synthetic enzyme; inhibits synthesis of NT - ANT
3. drug prevents the storage of NT in vesicles - ANT
4. drug stimulates the release of NT - AGO
5. drug inhibits the release of NT - ANT
6. drug stimulates postsynaptic receptors - AGO
7. drug blocks; postsynaptic receptors - ANT
8. Drug stimulates autoreceptors; inhibits synthesis/release of NT - ANT
9. drug blocks autoreceptors; increases synthesis/release of NT - AGO
10. drug blocks reuptake - AGO
11. drug inactivates acetylcholinesterase - AGO
181
Delivery of nervous system agents
orally, injection, inhalation, transdermal, anal suppositories
182
pituitary gland
of the hypothalamus receives blood-borne hormones, and itself, secretes hormones into the blood for circulation to target organs
183
area postrema
region that triggers vomiting response to blood-borne toxins
184
pineal gland
affected by cycling hormones (resulting in neural control over diurnal rhythms)
185
Cholinergic system
- acetylcholine generated in nuclei in the midbrain and basal forebrain
- participates in maintaining attention and waking EEG patterns
- involved in maintaining neuronal excitability - thought to be a key element in memory mechanisms
- loss of cholinergic neurons associated with alzheimer's disease
186
Dopaminergic system
- dopamine generated in nuclei in two distinct pathways
- nigrostriatal dopaminergic system: plays a role in coordinating movement
- mesolimbic dopaminergic system: plays a role in reinforcement and reward
- abnormal dopaminergic system function is associated with Parkinson's Disease and Schizophrenia, loss of impulse control, addictive behaviours
187
Noradrenergic system
Norepinephrine (noradrenalin) generated in
the locus coeruleus:
- Maintenance of emotional tone
- Decreased NE activity is thought to be
related to depression, hyperactivity and
ADHD
- Increased NE activity is thought to be
related to mania
188
Serotonergic system
- Produced in the Raphe nuceli in the
brainstem
- Loss of serotonin regulation associated with
OCD, tics and schizophrenia, sleep apnea,
etc.
- Decreased serotonin associated with
depression (possibly a different type from
that associated with Noradrenaline)
189
Analgesics (CNS Agent)
Nervous system agents that reduce pain at dose levels that don’t alter consciousness
Common classes of analgesics include:
. Salicylates e.g., aspirin, sodium salicylate
... Contraindications: gastric irritation, deafness
. Nonsalicylate, nonsteroidal anti-inflammatory
drugs (aka NSAIDS) -- e.g., ibuprofen
... Contraindications: nausea, vomiting, headache, blurred vision, dizziness, drowsiness
. Narcotic analgesics (aka opioids) –e.g., oxycodone, codeine, morphine
... Contraindications: addictive
190
Anorexiants (CNS Agent)
- Drugs used to treat obesity in patients who have not lost weight by dieting...
- Typically stimulate the satiety mechanisms of the hypothalamus and limbic system (e.g., phentermine – and other amphetamine derivatives)
191
Anticonvulsants (CNS Agent)
- Used to treat epileptic seizures by blocking sodium channels or enhancing the inhibitory action of gamma-aminobutyric acid (GABA)
- A wide variety of anticonvulsant drugs have
been developed to treat seizures. (e.g.,
Carbamazepine (trade name: Tegretol))
192
Antidepressants (CNS Agents)
- Used in the treatment of major depressive
disorder (MDD)
- Often used in combination with other drugs
directed at alleviation of symptoms
- Typically aimed at the potentiation of
serotonergic and/or adrenergic pathways
- e.g., selective serotonin reuptake inhibitors
(SSRIs) such as fluoxetine (trade name
Prozac)
193
Antiemetic/antivertigo agents (CNS Agents)
- Inhibit vomiting and nausea by blocking serotonin receptors in the CNS and GI tract
and dopamine and histamine receptors in the
brainstem
- Used to treat motion sickness, the side effects of opioids, and general anesthetics and chemotherapy
- Histamine receptor antagonists (aka antihistamines) e.g., dimenhydrinate (trade name Gravol)
194
antiparkinsonism agents (CNS Agent)
- Used to treat Parkinson’s disease, caused
by the loss of dopamine, an important
neurotransmitter associated with the basal ganglia.
- Antiparkinson agents replace dopamine or mimic dopamine’s effects on dopaminergic receptors in the postsynaptic membrane or prevent dopamine from being broken down chemically
- Examples of antiparkinsonism agents include
carbidopa / levodopa (trade name Sinemet)
195
antipsychotics (CNS Agents)
- Used to treat positive symptoms of schizophrenia (including hallucinations, delusions, paranoia, and disordered thought)
- First-generation (aka “typical” antipsychotics,
discovered in the 1940s) block D2(dopamine) receptors
- Second-generation (aka ”atypical” antipsychotics, discovered in the 1960s) block D2 receptors but for a shorter time period and ALSO block serotonin receptors.
- Examples: 1st gen: Chlorpromazine, 2nd gen: Risperidone
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Anxiolytics, sedatives, and hypnotics (CNS Agent)
- Used to treat chronic anxiety as well as panic
disorders by enhancing the action of GABA
(the most common inhibitory neurotransmitter
in the CNS)
- Examples of Benzodiazepines: diazepam
(trade name Valium) clonazepam (trade name
Klonopin) alprazolam (trade name Xanax)
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cholinergic (CNS Agent)
- Substances that modulate the effects of acetylcholine (aka Ach, a major neurotransmitter involved in learning and memory in the CNS and the main neurotransmitter of the parasympathetic division of the peripheral nervous system – and the first neurotransmitter to be discovered)
- Cholinesterase inhibitors (aka anti-cholinesterase) prevents acetylcholine breakdown by the enzyme cholinesterase in the synapse, leaving more Ach available for neurotransmission
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General anesthetics (CNS Agent)
- Compounds that produce reversible effects
including immobility, loss of consciousness,
amnesia, analgesia, and a reduction in autonomic activity, typically restricted to surgical procedures (intravenous injections typically initiate anesthesia and inhalants maintain it)
- The mechanism of action of general anesthetics is to inhibit CNS excitatory neurotransmission and/or activate inhibitory neural mechanisms.
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Muscle relaxants (CNS Agent)
- Chemicals that block the signaling action at
the neuromuscular junction (e.g. d-
tubocurarine chloride which acts as an
the antagonist for the nicotinic Ach receptor)
- Muscle relaxants are employed as part
of "balanced" general anesthesia: a triad of
barbiturate hypnosis, light inhalational
anesthesia and muscle relaxation drugs
200
Psychedelics (CNS Agents)
- A subclass of psychoactive drugs that cause
hallucinations and altered states of consciousness, changes in perception, cognition, and emotion
- Commonly used for religious rites, recreation, and, increasingly, psychotherapeutic treatment
- Hypothesized mechanism of action as a
“neuromodulator” – altering the effectiveness of various neurotransmitter systems
- Examples: mescaline, LSD, psilocybin
201
Psychostimulants (CNS Agents)
- substances that enhance neurotransmission by potentiating catecholaminergic and serotonergic pathways OR by inhibiting negative feedback through action on autoreceptors
- ex. amphetamines, cocaine, nicotine, caffeine, ephedrine
202
VMAT2 inhibitors (CNS Agents)
- a protein in the neuron membrane that transports monoamine neurotransmitters (e.g., dopamine, serotonin, histamine and norepinephrine) from the cytosol into synaptic vesicles
- VMAT2 function is also required for the vesicular release of GABA
- Patients with cocaine-induced mood disorders have lowered VMAT2 immunoreactivity (a measure of the amount of VMAT2 protein in neurons)
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Hormones
- Molecules produced by glands and“broadcast” (e.g., by the circulatory system)
- Hormones bind to receptors located in distant ‘target’ organs which regulate and control physiological and, through them, behavioral activities
- Water-soluble hormones are readily transported in the blood
- Lipid-soluble hormones must bond to carrier plasma glycoproteins
204
Endocrine hormone secretion
hormones secreted directly into the bloodstream via fenestrated capillaries, borne. to target tissues in blood
205
exocrine hormone secretion
hormones secreted via ducts
206
paracrine hormone secretion
hormones diffuse through the interstitial space to nearby target tissues
207
pheromone hormone secretion
hormones broadcast into the environment
208
neuroendocrine system
the CNS regulates body physiology through neuroendocrine integration, involving the hypothalamus that maintains homeostasis, and regulates metabolism, regulates reproduction, and energy utilization. This is achieved through the controlled secretion of hormones from the pituitary gland
