Chapter 3 - Anatomy & Research Methods & Module 4.3 - Plasticity after Brain Damage Flashcards
What is the central nervous system? (CNS)
The brain and spinal cord
What is the peripheral nervous system (PNS)?
Connects the brain and spinal cord to the rest of the body.
What is the somatic nervous system?
Part of the PNS, consists of the axons conveying messages from the sense organs to the CNS and from the CNS to the muscles.
What is the autonomic nervous system?
Part of the PNS - controls the heart, intestines and other organs.
Define dorsal
Toward the back and away from the stomach side. The top of the brain is dorsal.
Define ventral
Toward the stomach
Define anterior
Toward the front end
Define posterior
Toward the rear end
Define superior
Above another part
Define inferior
Below another part
Define lateral
Toward the side - away from the midline
Define medial
Toward the midline
Define proximal
Located close (approximate) to the point of origin or attachment
Define distal
Located more distant from the point of origin
Define ipsilateral
On the same side of the body
Define contralateral
On opposite sides of the body
Define coronal plane
Frontal place - brain structure as seen from the front
Define sagittal plane
As seen from the side
Define horizontal plane
As seen from above
What is the spinal cord
The spinal cord is part of the CNS and is located in the spinal column. It communicates with all the sense organs and muscles except of the head. Entering dorsal roots carry sensory information and exiting ventral roots carry motor information.
Cell bodies of sensory neurons are in clusters of neurons outside the spinal cord, called the dorsal root ganglia. Cell bodies of motor neurons are inside the spinal cord.
What does gray matter contain?
Cell bodies and dendrites. Many neurons from the gray matter send axons to the brain or other parts of the spinal cord through the white matter, containing myelinated axons.
What does the autonomic nervous system consist of?
Neurons that receive information from and send information to the heart, intestines and other organs. It consists of the parasympathetic and sympathetic nervous system.
What is the sympathetic nervous system?
A network of nerves that prepare the organs for vigorous activity, consists of chains of ganglia just to the left and right of the spinal cords central regions (thoracic and lumbar areas).
What does the sympathetic nervous system do?
It prepares organs for flight or fight responses. It increases breathing, increases heart rate, and decreases digestive activity. The sweat glands, adrenal glands, muscles that constrict blood vessels and erect hairs on the skin all have sympathetic inputs.
What does the parasympathetic nervous system do?
Facilitates vegetative non-emergency responses. It decreases heart rate, increases digestive activity and sexual arousal. It consists of the cranial nerves and nerves from the sacral spinal cord. Long preganglionic axons extend from the spinal cord to parasympathetic ganglia close to each internal organ. Shorter postganglionic fibres extend from the ganglia into the organs.
How do parasympathetic and sympathetic axons work?
Parasympathetic axons release acetylcholine onto the organs. The sympathetic axons release norepinephrine.
What is the hindbrain?
It consists of the medulla, pons, midbrain and certain central structures of the forebrain.
What is the medulla?
The medulla oblongata is just above the spinal cord and is an extension of the spinal cord into the skull. It controls vital reflexes, such as breathing, heart rate, vomiting, salivation, coughing and sneezing - through the cranial nerves, which control sensations from the head, muscle movements in the head and parasympathetic output to the organs. Damage to the medulla is often fatal and large doses of opiates suppress activity in the medulla often causing death. Nuclei for cranial nerves V to XII are in the medulla.
What is the pons?
The pons is anterior and ventral to the medulla. In the pons, axons from each half of the brain cross to the opposite side.
What is the cerebellum?
The cerebellum has many deep folds. It controls movement and is important for balance and coordination. It impacts on attention, auditory and visual systems and timing.
What is the midbrain?
The tectum is the roof of the midbrain. The swellings on each side of tectum are superior colliculus (important for vision) and inferior colliculus (important for hearing) and are important for sensory processing.
The tegmentum is under the tectum.
The substantial nigra - gives rise to a dopamine containing pathway that facilitates readiness for movement.
What is the limbic system?
It forms a border around the brainstem. Structures are important for motivation and emotions, such as eating, drinking, sexual activity, anxiety and aggression. The limbic system contains the olfactory bulb, hypothalamus, hippocampus, amygdala and cingulate gyrus of the cerebral cortex.
What is the diencephalon?
The thalamus and hypothalamus. It is a section distinct from the telencephalon (rest of the forebrain).
What is the thalamus?
The thalamus is a pair of structures (left and right) in the centre of the forebrain. Most sensory information goes to the thalamus which processes it and sends output to the cerebral cortex. The cerebral cortex sends information back to the thalamus, focusing its attention on particular stimuli.
What is the hypothalamus?
Ventral to the thalamus. The hypothalamus conveys messages to the pituitary gland, altering its release of hormones.
What is the pituitary gland?
An endocrine (hormone-producing) gland attached to the base of the hypothalamus by a stalk that contains neurons, blood vessels and connective tissue. It synthesises hormones that the blood carries to organs throughout the body.
What is the basal ganglia?
A group of subcortical structures lateral to the thalamus. Includes the caudate nucleus, putamen and the globes pallidus. It integrates motivational and emotional behaviour to increase visor of selected actions. It is important for movement, learning and remembering skills and habits as well as other types of learning that grows gradually.
What is the basal forebrain?
The nucleus basalis - on the ventral surface of the forebrain and receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine in the cerebral cortex. Key part of the brains system for arousal, wakefulness, attention and sleep.
What is the hippocampus?
Located between the thalamus and cerebral cortex, towards the posterior of the forebrain. Involved in memory.
What is the central canal?
The nervous system begins development as a tube surrounding a fluid canal. It is called the central canal in adulthood. The central canal is a fluid-filled channel in the centre of the spinal cord.
What are the ventricles?
Four fluid-filled cavities within the brain. Each hemisphere contains a large lateral ventricle. Toward their posterior they connect to the third ventricle at the midline, separating the left thalamus from the right thalamus. The their ventricle connects to the fourth ventricle in the centre of the medulla.
What is cerebrospinal fluid (CSF)?
CSF is produced by cells called choroid plexus. CSF fills the ventricles, flowing from the lateral ventricles to the third to the fourth. Some then flows into the central canal of the spinal cord. In the subarachnoid space, the blood reabsorbs the CSF. CSF cushions the brain against mechanical shock and provides buoyancy. CSF provides a reservoir of hormones and nutrition for the brain and spinal cord. If flow of the CSF is obstructed, it accumulates within the ventricles or subarachnoid space, increasing pressure on the brain. When in infants, the skull bones spread, causing an overgrown head. Called hydrocephalus and can lead to mental retardation.
What is gray and white matter?
Cells on the outer part of the cerebral cortex are gray matter. Axons extending inwards are white matter. Neurons in each hemisphere communicate with neurons in the corresponding part of the other hemisphere through the corpus callous and the anterior commissure.
What are laminae?
Laminae are layers of cell bodies that are parallel to the surface of the cortex and separated from each other by layers of fibres. The cerebral cortex contains up to 6 distinct laminae.
What are columns?
Cells are organised into columns of cells perpendicular to the laminae. Cells within a given column have similar properties to each other.
What is the occipital lobe?
Posterior end of the cortex - visual cortex or striate cortex. Damage to the occipital lobe results in normal eye and pupillary reflexes but no conscious visual perception or imagery.
What is the parietal lobe?
Located between the occipital lobe and the central sulcus (deep grove in the surface of the cortex). Area just posterior to the central sulcus is the post central gyrus (primary somatosensory cortex) - receives sensation from touch receptors, muscle-stretch receptors and joint receptors. Parietal lobe monitors body position and spatial and numerical information.
What is the temporal lobe?
The lateral portion of each hemisphere. Auditory information - left temporal lobe helps us to understand spoken language. Contributes to complex aspects of vision, including perception of movement and recognising faces. Important for emotional and motivational behaviours.
What is the frontal lobe?
Contains the primary motor cortex and prefrontal cortex. Percentile gyrus - posterior portion of the frontal lobe just anterior to the central sulcus - responsible for control of fine motor movements.
What are prefrontal labotomies?
Removal of the prefrontal cortex. Resulted in apathy, loss of ability to plan and take initiative, memory disorders, distractibility, loss of emotional expressions.
What does the prefrontal cortex do?
The prefrontal cortex contributes to attention, working memory, decision-making and planning movements.
What is a stroke? What types of strokes are there?
A cerebrovascular accident. Ischemia - blood clot or obstruction in artery.
Haemorrhage - ruptured artery.
What is ischemia?
A type of stroke - neurons deprived of blood lose oxygen and glucose supplies.
What is haemorrhage?
The brain is flooded with blood, oxygen and calcium.
How do strokes impact on the brain?
Both types lead to deem - accumulation of fluid and increased pressure on the brain. It impairs the sodium-potassium pump, leading to accumulation of sodium inside neurons. Provokes release of glutamate which overstimulates neurons, damaging neurons and synapses.
What can help with a stroke?
Ischemia patients can be given tPA (tissue plasminogen activator) to break up blood clots. Needs to be within 4 1/2 hours of stroke. Generally given to all stroke patients as haemorrhage is rare. tPA can cause death in haemorrhage patients but they have increased risk of death anyway.
Cooling protects the brain after schema by reducing overstimulation, apoptosis and inflammation.
What role does pleasure play?
It helps to nourish and sustain an animals interest in the things they need to survive (i.e. food, sex, social community).
What is the pleasure and reward centre of the brain?
The nucleus accumbens and cingulate cortex - they are activated by dopamine, which is released by neurons that originate near the brainstem.
What does dopamine do?
Dopamine plays a greater role in motivation than pleasure (i.e. a rat with low dopamine levels will starve to death unless actively nursed).
Are wanting and liking the same thing?
No, they are controlled by different mechanisms in the brain.
What happens to a virus that manages to cross the blood-brain barrier and enter the brain?
It stays in the nervous system throughout the person’s life.
Which part of the nervous system prepares the body for “fight or flight” activities?
Sympathetic
Membranes that surround the brain and spinal cord are called:
Meninges
Seeing a snake come out of the drain in the bathtub might increase your heart rate, dilate your pupils, cause you to sweat, and raise the hair on your neck. These responses are due to the activity of the _____ nervous system.
Sympathetic
Damage to the basal ganglia would most likely cause problems with:
Movement
What type of glial cells myelinate axons in the brain and spinal cord?
Oligodendrocytes
The ____ constitutes a higher percentage of the brain in primates than in other species of comparable size.
Cerebral cortex
People with damage of the parietal cortex tend to have trouble _____.
Locating objects in space
Together, the somatic nervous system and the autonomic nervous system make up the _____ nervous system.
Peripheral
The surface of a dendrite is lined with specialized junctions through which the dendrite receives information from other neurons. What are these junctions called?
Synaptic receptors
Gray matter in the brain and spinal cord is mainly composed of what structures?
Cell bodies and dendrites
Which part of the cerebral cortex is most important for the sense of touch?
Parietal lobe
The thalamus can be thought of as a:
Relay centre
Which of the following is an important function of the blood-brain barrier?
It protects the brain from most viruses
The limbic system is important for:
Emotional behaviours
Which lobe seems to be especially involved in the comprehension of spoken language in humans?
Temporal
Which lobe contributes to perception of movement and recognition of faces?
Temporal
Secretions from which gland will also affect the secretion of hormones from the thyroid gland, adrenal gland, and ovaries or testes?
Pituitary gland
What is contained in the ventricles of the brain?
Cerebrospinal fluid
The prefrontal cortex is important for:
Working memory
Which lobe contains the primary motor cortex and the prefrontal cortex?
Frontal
Which of the following means “toward the back”?
a. Ventral
b. Proximal
c. Medial
d. Dorsal
Dorsal
The study of relating skull anatomy (bumps and depressions) to behavior is known as:
Phrenology
Electroencephalography records neural signals generated by the activity of populations of neurons. T or F
True
Bumps and depressions in the skull are closely related to how well-developed the underlying brain areas are. T or F
False
A stereotaxic instrument would most likely be used for:
Placing an electrode in the brain
One major problem with studies that use PET or rCBF is:
choosing an appropriate comparison condition.
Computerized axial tomography creates an image from:
X-rays
How does the method of transcranial magnetic stimulation of brain areas differ from magnetic inactivation?
Brain activation results from mild, brief magnetic stimulation.
Which of the following techniques is dependent upon the release of oxygen from hemoglobin molecules? Select one: a. MRI b. PET c. rCBF d. fMRI
d. fMRI
Which method is dependent upon injecting a radioactive chemical into the blood to measure blood flow?
a. magnetic stimulation
b. PET
c. CAT
d. fMRI
b. PET
Evoked potentials in the brain are most likely to be detected by a(n): Select one: a. CAT scan. b. MRI. c. EEG. d. PET scan.
c. EEG.
What does dorsal mean and what is it’s opposite?
Towards the back, away from the stomach side. Opposite is ventral.
What term means toward the side, away from the midline and what is its opposite?
Lateral; medial
If two structures are both on the left side of the body, they are ______ to each other. If one is on the left and the other is on the right, they are _____ to each other.
ipsilateral, contralateral.
The bulges in the cerebral cortex are called _____. The grooves between them are called ______.
Gyri; sulci
Sensory nerves enter which side of the spinal cord, dorsal or ventral?
Dorsal.
Which functions are controlled by the sympathetic nervous system? Which are controlled by the parasympathetic nervous system?
The sympathetic nervous system prepares the organs for vigorous flight or fight activity. The parasympathetic system increases vegetative responses such as digestion.
Of the following, which are in the hindbrain, which in the midbrain, and which in the forebrain: basal ganglia, cerebellum, hippocampus, hypothalamus, medulla, pituitary gland, pons, substantia nigra, superior and inferior colliculi, tectum, tegmentum, thalamus.
Hindbrain: cerebellum, pons, medulla
Midbrain: substantia nigra, superior and inferior colliculi, tectum and tegmentum.
Forebrain: basal ganglia, hippocampus, hypothalamus, pituitary gland, thalamus.
If several neurons of the visual cortex all respond best when the retina is exposed to horizontal lines of light, then those neurons are probably in the same ______.
Column
Which lobe of the cerebral cortex includes the primary auditory cortex?
Temporal lobe.
Which lobe of the cerebral cortex includes the primary somatosensory cortex?
Parietal lobe.
Which lobe of the cerebral cortex includes the primary visual cortex?
Occipital lobe.
Which lobe of the cerebral cortex includes the primary motor cortex?
Frontal lobe.
What are the functions of the prefrontal cortex?
The PFC is essential for important attention, working memory and weighing the pros and cons of a possible action.
What is meant by the binding problem, and what is necessary for binding to occur?
The binding problem is the question of how the brain combines activity in different brain areas to produce unified perception and coordinated behaviour. Binding requires identifying the location of an object and perking sight, sound and other aspects of a stimulus as being simultaneous. When the sight and sound appear to come from the same location at the same time, we bind them as a single experience.
What is the difference between a lesion and an ablation?
A lesion is damage to a structure. An ablation is removal of the structure.
What determines whether ontogenetic stimulation excites a neuron or inhibits it?
Optogenetic stimulation activates a light-sensitive protein. If that protein opens a sodium channel in the membrane, the result is excitation of the neuron. If it opens a chloride channel, the result is inhibition.
What does fMRI measure?
It detects an increase in blood flow to a brain area immediately after an increase in brain activity and it also detects a slightly slower increase in the percentage of haemoglobin lacking oxygen.
Suppose someone demonstrates that a particular brain area becomes active when people are listening to music. When that area becomes active later, what if anything can we conclude?
Without further evidence, we should not draw any conclusion. Perhaps the person is listening to music again, but this area may perform functions other than listening to music. A good test of how well we understand the area would be to find out whether we can use fMRI recordings to guess which type of music someone is hearing (or if they are listening at all).
What are the similarities and differences between MRI and fMRI?
Both methods measure the responses of brain chemicals to a magnetic field. MRI shows the anatomy of the brain. fMRI shows which brain areas are most active at the moment.
What are the two kinds of strokes and what causes each kind?
Ischemia (more common) - result of an occlusion of an artery.
Hemorrhage is the result of a ruptured artery.
Why is tPA not helpful in cases of hemorrhage?
The drug tPA breaks up blood clots, and hemorrhage results from a ruptured blood vessel, not a blood clot.
If one of your relatives has a stroke and a well-meaning person offers a blanket, what should you do?
Refuse the blanket. Recovery will be best if the stroke victim remains cold.
After someone has a stroke, would it be best (if possible) to direct stimulant drugs to the cells that were damaged or somewhere else?
It is best to direct the amphetamine to the cells that thad been receiving input from the damaged cells. Presumably, the loss of input has produced diaschisis.
Is collateral sprouting a change in axons or dendritic receptors?
Axons
Is denervation supersensitivity a change in axons or dendritic receptors?
Dendritic receptors.
What is responsible for phantom limb experience?
Synapses that used to receive input from the now amputated part become vacant. Axons representing another part of the body take over those synapses. Now stimulation of this other part activates the synapses associated with the amputated area, but that stimulation feels like the amputated area.
