Review 1
Chapter 14
1. What brain structures belong to the basal ganglia? How would you characterize the function of the basal ganglia? What do the symptoms of Huntington's and Parkinson's Disease suggest about basal ganglia functions?
Structures of BG . Caudate nucleus . Putamen Globulus pallidus Substantia nigra Subthalamic nucleus
BG function Selection and initiation of willed movement Receive info from all cortical area Output- thalamus-> frontal cortex Choose and initiate action BG> VLo (thalamic nuc)-> area 6
Parkinson's disease slow movement, rigidity, tremors when at rest loss dopamenergic input from substantia nigra to striatum (nigrostriatal pathway) treatment: L dopa-> inc dopamine in SMA activity
Huntington's disease dysknesia, jerky, flinging movement, dementia loss inhibition via loss of neurons in caudate putman & globus pallidus o loss of neurons in striatum= reduce inhibitory movement age= 30-45 single dominant gene treatment= not very effective
2. The primary motor cortex "controls movements, not individual muscles." What does this mean, and what evidence supports it? Pathway from motor cortex-> motor neurons in spine essential for fine, individual movement of extremities especially fingers Electrical stimulation of M1 Contraction of small group of muscles= M1 control movement not individual m
3. How is it that the motor cortex can direct precise movements even though single neurons are "broadly tuned"? What does broadly tuned mean? What is a population vector (direction vector)?
Population vector Neurons in arm region of M1 is activated by arm movement in its preferred direction, & fires less to movement in other direction. When arm moves in a certain direction, a population of neurons in M1 fires More neurons fire= more forceful movement . A population vector predicts the direction of movement The vectors for each cell plotted together for each direction of movement, then averaged to yield a population vector. Recording from a single neurons in M1 are used to construct the vector Many neurons are activated with each movement Activity level of each neuron represents a "vote" Direction of movement is determined by a tally of votes
Recording from single neurons in M1 Neurons in M1 control movements, not single muscles. (divergence) Neurons in M1 encode the amount of force that is necessary to make the particular movement. Neurons in M1 have a preferred direction for movement but are broadly tuned. A consensus--the population vector--predicts the direction of movement.
Broad tuning neurons still fire less in opposite direction
Chapter 15
1. Describe the differences in how the hypothalamus communicates with the anterior vs. posterior pituitary.
Anterior pituitary the body's "master gland." under the control of neurons in the periventricular area called parvocellular cells. Parvocellular neurosecretory neurons (hypothal) Release RFs into capillary of pituitary stalk RF travel to anterior pi Pi cells release hormones Hormones reach target cells in body and brain
Posterior pituitary Magnocellular Release oxytosin/ vasopressin into capillary of post pit
Hormones reach target cells in body and brain
2. Describe how the hypothalamus, pituitary, and adrenal gland are involved in stress. Stress response periventricular hypohal secrete->