Chapter 3: Anatomy & Research Methods Flashcards
neuroanatomy
anatomy of the nervous system
central nervous system (CNS)
brain and spinal cord
peripheral nervous system (PNS)
connects the brain and spinal cord to the rest of the nervous system (it is the nerves outside of the brain/spine)
somatic and autonomic nervous system are part of the PNS
somatic nervous system
consists of the axons conveying messages from the sense organs to the CNS and from the CNS to the muscles
autonomic nervous system
controls the heart, intestines, and other organs. it has some of its cell bodies within the brain or spinal cord and some in clusters along the sides of the spinal cord
made up of the sympathetic and parasympathetic nervous system
sympathetic nervous systems
network of nerves that prepare the organs for a burst of vigorous activity, consists of chains of ganglia just to the left and right of the spinal cord’s central regions (the thoracic and lumbar areas); Sympathetic axons prepare the organs for “fight or flight,” such as by increasing breathing and heart rate and decreasing digestive activity. Because the sympathetic ganglia are closely linked, they often act as a single system “in sympathy” with one another
sweat glands, the adrenal glands, the muscles that constrict blood vessels, and the muscles that erect the hairs of the skin
parasympathetic nervous system
called the “rest and digest” system, facilitates vegetative, nonemergency responses; related to, and generally the opposite of, sympathetic activities
parasympathetic ganglia are not linked to one another, they act more independently than the sympathetic ganglia do
also known as the craniosacral system because it consists of the cranial nerves and nerves from the sacral spinal cord
axons release the neurotransmitter acetylcholine onto the organs. Most sympa- thetic nervous system axons release norepinephrine, although a few, such as those onto the sweat glands, use acetylcholine.
decreases heart rate, increases digestive rate, and in general, conserves energy
dorsal
toward the back
ventral
toward the stomach
anterior
toward the front end
posterior
toward the rear end
superior
above another part
inferior
below another part
lateral
toward the side, away from the midline
medial
toward the midline, away from the side
proximal
located close (approximate) to the point of origin or attachment
distal
Located more distant from the point of origin or attachment
ipsilateral
On the same side of the body (e.g., two parts on the left or two on the right)
contralateral
On the opposite side of the body (one on the left and one on the right)
coronal/frontal plane
A plane that shows brain structures as seen from the front
sagittal plane
A plane that shows brain structures as seen from the side
horizontal/transverse plane
A plane that shows brain structures as seen from above
spinal cord
part of the CNS within the spinal column; communicates with all the sense organs and muscles except those of the head. It is a segmented structure, and each segment has on both the left and right sides a sen- sory nerve and a motor nerve
contains cell bodies of the motor neurons
sends sensory informa- tion to the brain and receives motor commands from the brain. All that information passes through tracts of axons in the spinal cord.
dorsal root ganglia
cell bodies of the sensory neurons are in clusters of neurons outside the spinal cord
ganglia = cluster of neurons outside the CNS
nucleus = cluster of neurons inside the CNS
gray matter
the centerof the cord is densely packed with cell bodies and dendrites. Many neurons from the gray matter of the spinal cord send axons to the brain or to other parts of the spinal cord through the white matter
white matter
contains myelinated axons
hindbrain
posterior part of the brain, consists of medulla, the pons, and the cerebellum.
brainstem
medulla and pons, the midbrain, and certain central structures of the forebrain constitute the brainstem
medulla
an enlarged extension of the spinal cord
the head and the organs connect to the medulla and adjacent areas by 12 pairs of cranial nerves
cranial nerves originating in the medulla control vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing
pons
lies anterior and ventral to the medulla; axons from each half of the brain cross to the opposite side of the spinal cord so that the left hemisphere controls the muscles of the right side of the body and the right hemisphere controls the left side
cerebellum
large hindbrain structure with many deep folds; contributions to the control of movement, balance, coordination, shifting attention between auditory and visual stimuli, timing, learning, conditioning
midbrain
early in development the midbrain is in the middle of the brain, although in adult mammals it is dwarfed and surrounded by the forebrain. Consists of the tectum, tegmentum, superior and inferior colliculus, and substantia nigra
tectum
roof of the midbrain
superior & inferior colliculus
swellings on each side of the tectum
Both are important for sensory processing—the inferior colliculus for hearing and the su- perior colliculus for vision
tegmentum
intermediate level of the midbrain
tectum covers the tegmentum, but the tegmentum covers several other midbrain structures.
substantia nigra
gives rise to a dopamine-containing pathway that facilitates readiness for movement
forebrain
most prominent part of the mammalian brain, consists of two cerebral hemispheres, one on the left and one on the right
each hemisphere is organized to receive sensory information, mostly from the contralateral (opposite) side of the body; controls muscles, mostly on the contralateral side, by way of axons to the spinal cord and the cranial nerve nuclei
consists of thalamus, hypothalamus, cerebral cortex, hippocampus, and basal ganglia
limbic system
several interlinked structures that form a border around the brainstem
includes the olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus of the cerebral cortex
hypothalamus
essential for control of eating, drinking, temperature control, and reproductive behaviors.
Partly through nerves and partly by releasing hormones, the hypothalamus conveys messages to the pituitary gland, altering its release of hormones.
amygdala
most central for evaluating emotional information, specially with regard to fear
thalamus
pair of structures (left and right) in the center of the forebrain
Most sensory information from a sensory system goes first to the thalamus, which processes it and sends output to the cerebral cortex
cerebral cortex sends information back to the thalamus, prolonging and magnifying certain kinds of input and focusing attention on particular stimuli
pituitary gland
endocrine (hormone-producing) gland attached to the base of the hypothalamus
synthesizes hormones that the blood carries to organs through- out the body
basal ganglia
group of subcortical structures lateral to the thalamus, include three major structures: the caudate nucleus, the putamen, and the globus pallidus
damage to the basal ganglia impairs movement, as in conditions such as Parkinson’s disease and Huntington’s disease
integrate motivational and emotional behavior to increase the vigor of selected actions
nucleus basalis
receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex
key part of the brain’s system for arousal, wakefulness, and attention
hippocampus
large structure between the thalamus and the cerebral cortex, mostly toward the posterior of the forebrain
critical for certain types of memories, especially memories for individual events. It is also essential for monitoring where you are and where you are going.
ventricles
four fluid-filled cavities within the brain
Each hemisphere contains one of the two large lateral ventricles
cerebrospinal fluid (CSF)
clear fluid similar to blood plasma produced by the ventricles; provides buoyancy to help support the weight of the brain
cushions the brain against mechanical shock when the head moves; provides hormones and nutrition for the brain and spinal cord
meninges
membranes that surround the brain and spinal cord.
Although the brain has no pain receptors, the meninges do
cerebral cortex
composed of four lobes: frontal lobe, parietal lobe, temporal lobe, and occipital lobe
responsible for the higher-level processes of the human brain, including language, memory, reasoning, thought, learning, decision-making, emotion, intelligence and personality
The cells on the outer surface are gray matter, and their axons extending inward are white matter
corpus callosum
the primary commissural region of the brain consisting of white matter tracts that connect the left and right cerebral hemispheres
anterior commissure
white matter tract (a bundle of axons) connecting the two temporal lobes of the cerebral hemispheres across the midline
laminae
layers of cell bodies that are parallel to the surface of the cortex and separated from each other by layers of fibers
six of them are contained in the cerebral cortex; vary in thickness and prominence
columns
organized cortex cells
cells within a given column have similar prop- erties to one another
occipital lobe
posterior end of the cortex; main target for visual information
eyes provide the stimulus, and the visual cortex provides the experience
parietal lobe
vital for sensory perception and integration; monitors all the information about eye, head, and body positions and passes it on to brain areas that control movement
essential not only for spatial information but also numerical information
central sulcus
deep groove in the surface of the cortex
postcentral gyrus
receives sensations from touch receptors, muscle-stretch receptors, and joint receptors
temporal lobe
lateral portion of each hemisphere, near the temples
primary cortical target for auditory information; left temporal lobe—is essential for understanding spoken language
also contributes to complex aspects of vision, including perception of movement and recognition of faces; emotional and motivational behaviors
frontal lobe
containing the primary motor cortex (precentral gyrus) and the prefrontal cortex
Separate areas are responsible for different parts of the body, mostly on the contralateral (opposite) side but also with slight control of the ipsilateral (same) side
precentral gyrus (primary motor cortex)
specialized for the control of fine movements; No area in the motor cortex controls just a single muscle
prefrontal cortex
Neurons in the prefrontal cortex have huge numbers of synapses and integrate an enormous amount of information
regulates our thoughts, actions and emotions through extensive connections with other brain regions
functions of the prefrontal cortex
posterior portion is associated mostly with movement. The middle zone pertains to working memory, cognitive control, and emotional reactions. anterior zone of the prefrontal cortex is important for making decisions, evaluating which of several courses of action is likely to achieve the best outcome
people with damage to the pre- frontal cortex have trouble on the delayed-response task, in which they see or hear something, and then have to respond to it after a delay.
binding problem
question of how various brain areas produce a perception of a single object
binding occurs if you perceive two sensations as happening at the same time and in approximately the same place
ablation
removal of a brain area, generally with a surgical knife
lesion
made when surgical removal is difficult, usually for tiny structures below the surface of the brain
stereotaxic instrument
device for the precise placement of electrodes in the brain
By consulting a stereotaxic atlas (map) of a species’ brain, a researcher aims an electrode at the desired position relative to landmarks on the skull. ; drills a small hole in the skull, inserts the electrode (insulated except at the tip), lowers it to the target, and passes an electrical current just sufficient to damage that area.
transcranial magnetic stimulation (TMS)
application of magnetic stimulation to a portion of the scalp, can stimulate neurons in the area be- low the magnet, if the stimulation is sufficiently brief and mild. With stronger stimulation it inactivates the neurons, producing a “virtual lesion” that out- lasts the magnetic stimulation itself
procedure enables researchers to study behavior with some brain area active, then inactive, and then active again
optogenetics
using light to control a limited population of neurons
nvestigator can control the ex- citation or inhibition of one type of neuron in a small brain area with millisecond accuracy.
electroencephalograph (EEG)
records electrical activity of the brain through electrodes— ranging from just a few to more than a hundred—attached to the scalp ; Electrodes glued to the scalp measure the average activity at any moment for the population of cells under the electrode. The output is then amplified and recorded.
evoked potentials/responses
same device used for an EEG can also record brain activity in response to a stimulus
magnetoencephalograph (MEG)
measures the faint magnetic fields generated by brain activity
recording identifies the approximate location of activity to within about a centimeter; has excellent temporal resolution, showing changes from one millisecond to the next
can identify the times at which various brain areas respond and thereby trace a wave of brain activity from its point of origin to the other areas that process it
positron-emission tomography (PET)
provides a high- resolution image of activity in a living brain by recording the emission of radioactivity from injected chemicals
first, the person receives an injection of glucose or some other chemical containing radioactive atoms. Because the most active brain areas increase their use of glucose, tracking the levels of glucose tells us something about brain activity. When two detec- tors record gamma rays at the same time, they identify a spot halfway between those detectors as the point of origin of the gamma rays. A computer uses this information to determine how many gamma rays came from each spot in the brain and therefore how much of the radioactive chemical is located in each area
most radioactivity are presumably the ones with the most active neurons.
requires exposing the brain to radioactivity, a poten- tial hazard
functional magnetic resonance imagine (fMRI)
modified version of MRI based on hemoglobin (the blood protein that binds oxygen) instead of water
Researchers set the fMRI scanner to detect the amount of hemoglobin with oxygen. When a brain area becomes more active, two relevant changes occur: First, blood vessels dilate to allow more blood flow to the area. Second, as the brain area uses oxygen, the percentage of hemoglobin with oxygen decreases. An fMRI scan responds to both of these processes; requires a comparison task
Researchers often examine the mean results for a group of participants, ignoring important differences among individuals
phrenology
relating skull anatomy to behavior
issues: skull shape does not match brain anatomy, based many conclusions on small numbers of people who apparently shared some personality aspect and a similar bump on the skull.
computerized axial tomography (CT/CAT scan)
physician injects a dye into the blood to increase contrast in the image, and then places the person’s head into a CT scanner. X-rays are passed through the head and recorded by detectors on the opposite side. The CT scanner is rotated slowly until a measurement has been taken at each angle over 180 degrees. From the measurements, a computer constructs images of the brain.
magnetic resonance imaging (MRI)
applies a powerful magnetic field to align all the axes of rotation, and then tilts them with a brief radio frequency field.
When the radio frequency field is turned off, the atomic nuclei release electromagnetic energy as they relax and return to their original axis. By measuring that energy, MRI devices form an image of the brain
