Chapter 10 Flashcards
(114 cards)
hierarchical organization ex
grooming in the rat (Kent Berridge & Ian Whishaw 1992)
- many levels of the nervous system participate in producing the elements and the organization of grooming behavior
- grooming behavior is produced from many levels - spinal cord to cortex
- each region adds difference to behavior


spinal cord
- center for reflexes
- can mediate many reflexes, inlcuding limb approach to attack stimulus and limp withdrawl from noxious stimulation
- stepping responses and walking


hind brain
postural support
- cranial nerves have motor nuclei in hindbrain - host efferent outgoing fibers that controlled muscles in head and neck
- sensory input also includes spinal motor system
low decerebrates
(Bazett & Penfield 1922)
- if hindbrain and spinal cord remain connected from injury, but disconnected from the rest of the brain
- difficulty maintaining consciousness
- inactive when undisturbed
- no effective ability to thermoregulate
- ability to swallow food
- affective behaviors when stimulated
- effective emotional behaviors shown
- slow-wave sleep and active sleep
- sudden collapse accompanied by loss of all body tone that lasts from 15 sec - 12 min → active REM sleep
high decerebrates
(Bard & Macht 1958, Bignall & Schramm 1974)
disconnected diencephalon from the midbrain regions
intact olfactory, hypothalamus, pituitary
- respond to simple visual and auditory stimulation
- automatic behaviors
- voluntary movements
- hormonal system and homeostasis
midbrain
- all of the subsets of voluntary movements
- bc they are executed through lower level postural support and reflex systems, voluntary movement can also be elicited by lower level sensory input bc they are executed through lower level postural support and reflex systems
- integrated with lower-level sensory inputs by both ascending and descending connections
- effective automatic movements
- ascending and descending connections
mesencephalic child
Brachville 1971
- had no brain above the diencephalon
- response did not change in magnitude and did not habituated, gradually decrease in intensity, to repeated presentations
- so they concluded that the forebrain is not important in producing movements but is important in not generating and inhibiting them


diencephalon
- affect and motivation
- energizes and sustains behavior
sham rage/quasi emotional phenomenon
(Canon & Britain, 1924)
- displays sympathetic nervous system signs of rage
- to occur, the posterior part of the hypothalamus must be intact
- suggest that the diencephalon energizes an animal’s behavior


decorticated animals
removal of neocortex
- typical sleeping-waking cycles
- ability to sequence series of movements
- ability to generate biologically adaptive behaviors by inhibiting
- ex: decorticated animal walks until it finds food or water, and then inhibits walking to consume the food or water -> the basal ganglia probably provides the circuitry required for the stimulus to inhibit movement so that ingestion can occur
- do not build nests, some nest building behaviors
- do not hoard food, but might carry food around
- difficulty making skilled movements w tongue and limbs because cannot protrude the tongue or extend one limb
- Oakley 1979: decorticated animals perform well in tests of classical conditioning, operant conditioning, approached learning, cue learning, pattern discrimination
- cortex is not essential for learning itself
- fail at learning complex pattern discernations and how to find their way around a space


modular organization Zeki 1993
- cortical module might be performing same basic function throughout cortex
- most interaction between the cortical layers take place vertically within the neurons, directly above or below adjacent layers
- vertical bias —> basis for 2nd type of neocortical organizations —> columns or modules
- evidence comes from standing and probing methodologies
- physiological way evidence
- If microelectrode is placed in the somatosensory cortex and lowered vertically from layer one to layer five for ex, all the neurons encountered appear functionally similar, the functional similarity of cells across all six layers at any point in the cortex.
modular organization Pauves et al 1992
- some modular patterns in the cortex may correspond to secondary functions of cortical organization
- one possibility is that cortical modules may be an incidental consequence of synoptic processing in the cortex

vertical modules
efficient pattern of connectivity
- nerve cells easily distinguished in the cortex has spiny neurons or aspiny neurons by the presence or absence respectively of dendritic spines
spiny neurons
- excitatory
- 95% of excitatory synapses are found on the spines
- likely to have receptors for the excitatory transmitter glutamate or aspartate
- ex: pyramid cells
pyramid cells
spiny neurons
- send info from a cortical region to another cortical region of the central nervous system
- efferent projection neurons of the cortex
- largest population of cortical neurons
- found in layer 2,3,5,6





spiny stellate cells
smaller stars shaped interneurons whose processes remain within the region of the brain, where the cell body is located
aspiny neurons
- interneurons with short axons and non dendritic spines
- inhibitory
- likely use gamma aminobutyric acid GABA as neurotransmitter






















