Biopsychology part 4 exam 1

• In general the various areas of secondary motor cortex are thought to
program specific motor sequences
• Neurons that fire in response to making a particular response, observing somebody else making the response, or just thinking about the response are called
mirror neurons
• The somatotopic map of the primary motor cortex is called the
motor homunculus
• In 1937, the primary motor cortex was mapped by electrically stimulating the cortex of conscious human subjects who were undergoing neurosurgery. This was accomplished by
Penfield and Boldrey
• The _______has been found to be doubly represented in each primary motor area of monkeys?
contralateral hand
• The only parts of each motor homunculus to receive somatosensory feedback directly from skin are the
hand areas
• The primary motor cortex receives cutaneous feedback from only one part of the body: the hands. This feedback likely plays an important role in
• Long bursts of stimulation applied to the primary motor cortex elicit
complex natural-looking response sequences
• In the primary motor cortex, the neurons that participate in the movement of a particular finger are
widely distributed over the somatotopic hand area
• A study of the firing of primary motor cortex neurons while monkeys moved freely about indicated that their firing was often related to the
end point (i.e., target) of the movement
• In a remarkable demonstration, Belle, the owl monkey, controlled the movements of a robotic arm
with the activity of neurons in her primary motor cortex
• A deficit in the ability to recognize objects by touch is called
• It has been estimated that over half the neurons of the brain are in a structure that constitutes only 10% of the brain's total mass. This structure is the
• Recent fMRI studies have changed the traditional view of the cerebellum by suggesting that in addition to its sensorimotor functions it is involved in
control and learning of cognitive responses
• The _________receives information from various parts of the cortex and feeds it back to motor cortex
basal ganglia
• The _____is part of a loop including the cortex and the basal ganglia
• Signals from the left primary motor cortex descend through the spinal cord white matter in one of
four major tracts
• The decussation in the medullary pyramids is part of the
dorsolateral corticospinal tract
• The cell bodies of Betz cells are found in the
primary motor cortex
• The axons of Betz cells are part of the
dorsolateral corticospinal tract
• In general, the dorsolateral corticospinal tract controls the muscles of the
hands and feet
• Only primates and a few other species, such as hamsters and raccoons, have cortical neurons that synapse directly on
motor neurons that project to the muscles of the fingers and thumb
• In neuroanatomy, "rubro" refers to the
red nucleus
• Most axons of the dorsolateral corticorubrospinal tract synapse on
interneurons of the spinal gray matter that in turn synapse on motor neurons that project to the distal muscles of the arms and legs
• The brain stem structure, the_______, receives direct sensory information about balance
vestibular nucleus
• The midbrain structure, the______, receives visual and auditory information about spatial location
• In general, the ventromedial descending motor tracts control the muscles of the
• Monkeys had difficulty letting go of food after their
dorsolateral corticospinal tracts were transected
• Monkeys could not move their fingers independently after transections of the
dorsolateral corticospinal tracts
• In the transection experiments of Lawrence and Kuypers, monkeys with all their dorsolateral motor pathways transected sat with their arms hanging limply by their sides. However, these same monkeys had no difficulty
using their arms for standing, walking, and climbing
• When a motor neuron fires, all of the muscle fibers of its motor
unit contract together
• The motor units in the ________are most likely to be the smallest?
• The motor units of the thumb, fingers, and face contain the
fewest muscle fibers
• There is _____motor neuron in the typical motor unit
1 (one)
• All of the motor neurons that innervate the fibers of a single muscle are called its
motor pool
• So-called fast muscle fibers
are pale
• The biceps and triceps are
• Bob tried to open a jar of pickles, but the lid did not budge. The muscles of his hands and arms were
in isometric contraction
• Increases in muscle tension in the absence of any shortening of the muscle are said to be
• Muscles are protected from damage caused by excessive contraction by
Golgi tendon organs
• Intrafusal is to extrafusal as
muscle spindle is to skeletal muscle
• Muscle spindles provide the CNS with information about muscle
• The patellar tendon reflex is a
stretch reflex
• During a stretch reflex, the extrafusal motor neuron is excited directly by the
spindle afferent neuron
• The latency of withdrawal reflexes indicates that the fastest withdrawal reflex neural circuit involves
2 synapses
• ____________helps distribute the work between different motor neurons of a muscle's motor pool
Recurrent collateral inhibition
• Recurrent collateral inhibition is mediated by
Renshaw cells
• If given the correct sensory feedback, the cat spinal cord is capable of controlling
walking movements
• The results of the treadmill experiment by Grillner (1985) suggest that part of the central sensorimotor program for walking is in the
spinal cord
• According to current theory, the sensorimotor system
comprises a hierarchy of central sensorimotor programs
• The fact that the same basic movement can be carried out in different ways involving different muscles is called
motor equivalence
• One fMRI study indicated that the central sensorimotor programs for signing one's name are stored in
secondary motor cortex
• Response chunking and changing the level of control are thought to be important processes in
sensorimotor learning
• Theories of sensorimotor learning emphasize two kinds of learning-related changes in sensorimotor programs:
chunking and transferring much of the control of the response to lower levels of the nervous system
• A major finding of the Jenkins and colleagues PET study of motor learning was that the
contralateral primary motor and somatosensory cortexes were equally activated during well-spiced and newly learned sequences
• The process of the growth of a fertilized egg into a mature nervous system is called
• The case of Genie emphasizes the role of
experience in human neural and psychological development
• A zygote divides to form
two daughter cells
• The first major phase of neurodevelopment is induction of the
neural plate
• The neural plate is a patch of
• Totipotential means that a developing cell
is capable of developing into any type of cell in the organism
• The very first cells to develop in the embryo are
• Embryonic cells that have the potential for unlimited renewal and have the ability to develop into different kinds of mature cells if they are transplanted to different sites are often called
embryonic stem cells
• Immature cells that have the potential to develop into various kinds of mature cells are called
multipotent cells
• The neural plate develops directly into the
neural groove
• The neural groove develops into the neural
• By 40 days after conception, three swellings become visible at the anterior end of the human neural tube. The most anterior of these swellings eventually develops into the
• By 40 days after conception, swellings are clearly visible at the anterior end of the neural tube. There are
• After the formation of the neural tube, the number of cells destined to become part of the adult nervous system
increases rapidly
• Most cell division in the developing neural tube occurs in the
ventricular zone
• Most neural proliferation occurs in the layer of the neural tube that is adjacent to
the fluid-filled central canal
• Neural tube cells migrate radially
along special glial cells
• In addition to the radial migration of developing neurons, there is considerable ______migration.
• There seem to be two different mechanisms of neural migration: glial-mediated migration and
somal translocation
• Research on the migration of future neocortical neurons has made one important point: ______is everything.
• The pattern of migration of future neocortical neurons is referred to as
inside out
• During the formation of the neural tube, a few cells break off from the neural plate and form a structure that lies dorsal to the tube. This structure is the neural
• The neural crest develops into the
peripheral nervous system
• Cell adhesion molecules are thought to mediate
• ____________are amoeba-like in their appearance and movements
Growth cones
• At the tip of each growing axon or dendrite is an amoeba-like process called
a growth cone
• Growth cones extend and retract finger-like cytoplasmic extensions as if they were feeling their way. These extensions are called
• Sperry's experiments on eye-rotation in frogs led to an influential hypothesis that explains how growth cones find their way to their targets: the
chemoaffinity hypothesis
• Frogs, unlike mammals, have retinal ganglion cells that are capable of
• In frogs, salamanders, and other simple vertebrates, retinal ganglion cells project primarily to the
• In Sperry's classic studies of eye rotation and regeneration of the optic nerves, he assessed the visual capacities of his subjects by assessing their ability to
strike accurately at fly-like stimuli
• Sperry's initial version of the chemoaffinity hypothesis of axon growth has difficulty accounting for
the ability of axons to follow exactly the same circuitous route to their target in every member of a species
• The first growth cone of a developing tract to reach the target is called a
pioneer growth cone.
• Only those growth cones that are not pioneer growth cones can normally find their way to their targets by
• If an optic nerve of a mature frog is transected and half of the associated retina is destroyed,
the axons grow out from the remaining retinal ganglion cells to targets systematically distributed over the entire optic tectum
• In support of the topographic-gradient hypothesis, it has been shown that
the synaptic connections originally formed by retinal ganglion cells on the optic tectums gradually shift as both the eyes and optic tectums grow at different rates during development
• Eyes and optic tectums grow at different rates. As they grow, the synaptic connections that were originally formed on the tectum by axons of retinal ganglion cells shift so that the retina is always fully and faithfully mapped on the tectum. This finding supports the
topographic-gradient hypothesis
• Less is known about synapse formation than axon growth because synapse formation requires
coordinated activity in at least two cells
• A recent finding is that synaptogenesis depends on the presence of
• When it comes to synaptogenesis, neurons display a substantial degree of
• In vitro, neurons will form synapses
with almost any neuron
• Neuron death
is a stage of normal early neural development
• Evidence suggests that many neurons die during development because of
their inability to compete successfully for their target's neurotrophins
• Most of the cell death associated with early development of the brain is
• Apoptosis is safer than necrosis because apoptosis does not involve
• The general effect of synapse rearrangement is to
focus the output of each neuron on fewer postsynaptic cells
• The development of the human brain is unique in that
it develops so slowly
• Between birth and adulthood, the size of the human brain
• With a few exceptions, all of the neurons that will compose the adult human brain have developed and are in their appropriate location by the
seventh month of prenatal development
• Synaptic density in the primary visual cortex of infants
is maximal by the seventh or eighth postnatal month, and then it declines
• The course of human cognitive development is thought to reflect development in the
prefrontal cortex
• Perseveration is the tendency to
continue making formerly correct responses that are currently incorrect
• Perseverative errors are often made by children between the ages of
7 to 12 months
• Neurons and synapses that are not activated by experience usually
do not survive
• The disruptive effects of total visual deprivation of the left eye on subsequent vision through the left eye are greater when the
deprivation occurs early in life and right eye is not deprived at the same time
• One eye only has to be totally deprived of stimulation for _____early in life in order to produce significant reductions in the proportion of visual cortex neurons that can be activated by stimulation of the deprived eye
a few days
• A few days of early monocular deprivation produces a massive decrease in the axonal _______of lateral geniculate nucleus neurons that normally conduct signals from the deprived eye.
• Knudsen and Brainard (1991) raised barn owls with vision-displacing prisms over their eyes. This led to the ontogenetic development of
a corresponding shift in the auditory topographic map in the tectum
• Several studies have shown that early music training increases the size of the
auditory cortex that responds to complex musical tones.
• It is now generally acknowledged that adult brains are
auditory cortex that responds to complex musical tones
• The first evidence that new neurons can be created in the brains of adult animals came in the early 1980s from the study of
• Studies have shown that about ______new neurons are created each hour in the hippocampus of adults
• Adult stem cells that migrate to the olfactory bulbs are created at certain sites in the
ependymal layer
• Adult stem cells that become hippocampal neurons are created near the
• The function of the neurons created in the adult hippocampus by neurogenesis is
currently unknown
• The area of somatosensory cortex receiving input from the left hand was found to be bigger in
musicians who finger stringed instruments with the left hand
• Autism usually becomes apparent
before the age of 3 years
• A major feature of the symptoms of autism is their
• ______of individuals with autism are savants
• Evidence suggests that autism
is caused by several genes and interactions with the environment
• Both autism and Williams syndrome are associated with
mental retardation
• Considering their mental retardation, people with Williams syndrome tend to have remarkably good
language ability
• Although they have many cognitive problems, Williams people have good
musical abilities and language abilities
• Most cases of Williams syndrome are associated with
a missing section on chromosome 7
• Despite general cortical thinning in cases of Williams syndrome, the thickness of the _______cortex is often normal, or even greater than normal.
superior temporal
• People with Williams syndrome tend to look like