Chapter 10 Flashcards
1
Q
hierarchical organization ex
A
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
2
Q
A
3
Q
spinal cord
A
- center for reflexes
- can mediate many reflexes, inlcuding limb approach to attack stimulus and limp withdrawl from noxious stimulation
- stepping responses and walking
4
Q
A
5
Q
hind brain
A
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
6
Q
low decerebrates
A
(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
7
Q
high decerebrates
A
(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
8
Q
midbrain
A
- 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
9
Q
mesencephalic child
A
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
10
Q
A
11
Q
diencephalon
A
- affect and motivation
- energizes and sustains behavior
12
Q
sham rage/quasi emotional phenomenon
A
(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
13
Q
A
14
Q
decorticated animals
A
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
15
Q
A
16
Q
modular organization Zeki 1993
A
- 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.
17
Q
modular organization Pauves et al 1992
A
- 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
18
Q
vertical modules
A
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
19
Q
spiny neurons
A
- excitatory
- 95% of excitatory synapses are found on the spines
- likely to have receptors for the excitatory transmitter glutamate or aspartate
- ex: pyramid cells
20
Q
pyramid cells
A
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
21
Q
A
22
Q
A
23
Q
spiny stellate cells
A
smaller stars shaped interneurons whose processes remain within the region of the brain, where the cell body is located
24
Q
aspiny neurons
A
- interneurons with short axons and non dendritic spines
- inhibitory
- likely use gamma aminobutyric acid GABA as neurotransmitter
25
Q
A
26
Q
neocortex layers
A
4-6 layers with different functions, different afferents, and different efferent axons
- thickness corresponds to function
- somatosensory cortex has a relatively large layer 4 and smaller 5
- motor cortex has relatively large layer 5 and smaller layer 4
- various cortical layers can be distinguished by the neuronal elements that each one contain
27
Q
neocortex layer 4
A
- input zone of sensory analysis
- receive projections from other cortical areas and other areas of the brain
28
Q
neocortex layer 5-6
A
- output zone
- send axons to other cortical areas or other brain areas
29
Q
mapping reality
A
Penfield 1950s
- stimulated their patient’s motor and somatosensory strips - identified two regions of parietal cortex that appeared to represent localized body parts (like leg and face)
- dozens of maps in each sensory modality
- multimodal cortex presumably function to combine characteristics of stimuli across different sensory modality
30
Q
multimodal cortex
A
Ghazanfar 2005
- the convergence of qualitatively different sensory info alters our perception of the world
- areas that have more than one sensory modality
- When monkeys listened to a recording of another monkey’s voice, the auditory neurons’ firing rate increased by about 25% if the voice was accompanied by a visual image of a monkey cooing, but only if the voice and facial movements were in synchrony
- shows that we have parallel cortical systems
- one system allows us to understand the world and the other to move us around and manipulate it
31
Q
Jerison 1991
A
our knowledge of reality is directly related to the structure and number of our cortical maps
32
Q
primary sensory cortex
cortical system
A
- primary sensory cortex - projects to interconnected sensory association regions
- these regions project to several cortical targets
- these targets can be the frontal lobe, the paralimbic cortex, the multimodal cortex, and the subcortical connections and loops
33
Q
A
frontal lobe
34
Q
primary motor cortex
A
- motor homunculous
- most sensory region fibers connect directly to primary motor cortex
- and may project either to the premotor or prefrontal cortices
35
Q
premotor cortex
A
(frontal lobe)
- ordering movements in time
- controlling hand, limb, or eye movements with respect to specific sensory stimuli
36
Q
prefrontal cortex
A
(frontal lobe)
- controlling movements in time
- forming short term memories of sensory info
37
Q
paralimbic cortex
A
- forming long term memories
- comprised of three layers adjacent and directly connected to the limbic structures of paralimbic cortex
- can be seen in two places:
- medial surface of temporal lobe
* perirhinal cortex, entorhinal cortex, and parahippocampal cortex
- medial surface of temporal lobe
- just above corpus callosum where it is referred to as the cingulate cortex
38
Q
neocortex
A
- recieves all sensory input through subcortical structures
- either directly from the thalamus
- or indirectly through midbrain structures such as the tectum
39
Q
subcortical loops
A
- each level interacts and is integrated with higher and lower levels by ascending and descending connections
- connect the cortex, thalamus, amygdala, and hippocampus
- indirect loop with the striatum connects with the thalamus
- plays some role in amplifying or modulating ongoing cortical activity
40
Q
binding problem
A
How does sensation in specific channels, whether touch, vision, hearing, smell, and taste combine into perceptions that translate as a unified experience that we call reality? → how the brain ties single and varied sensory and motor events together into a unified perception on behavior that will bring us to another point
41
Q
serial hierarchical model
A
Luria 1973
- anatomical criteria can help in delineating a hierarchical organization of cortical areas
- sensory unit: posterior cortex, parietal, occipital, temporal lobe
- motor unit: anterior cortex, frontal lobe
- zonal pathways
- sensory input enters primary sensory zone is elaborated in the secondary zone and is integrated in the tertiary zones of the posterior unit
- to execute an action, activation is sent from the posterior tertiary sensory zones to the tertiary frontal motor zone for formulation, to the secondary motor zone for elaboration and then to the primary frontal zone for execution
42
Q
zonal pathways
A
perceived that the cortical units worked in concert along zonal pathways
43
Q
serial hierarchical model assumptions
A
- the brain processes information serially
- serial processing is hierarchical
- our perception of the world is unified and coherent
44
Q
serial hierarchical model problems
A
- a strictly hierarchical processing model requires that all cortical areas be linked serially, but this serial linkage is not the case
- all cortical areas have reentrant reciprocal connections with the region to which they connect
- no simple feed forward system
- the fact that cortical operations are relayed directly to sub-cortical areas implies that cortical processing can bypass Luria’s model hierarchy and go directly to sub-cortical model structures
- we can experience a single precept despite the fact that no single terminal area is producing it
45
Q
distributed hierarchical system
A
Felleman & Essen 1991
- cortical areas are indeed hierarchically organized in some well-defined sense
- with each area occupying a specific position relative to others, but with more than one area occupying a given hierarchical level
- human connectome project: ambition venture aimed at shorting human brain connectivity using noninvasive mirror imaging in a population of 1200 healthy adults
- based on the observation that a living brain is always active by studying resting state fMRIs
62
Q
- 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
A
modular organization Pauves et al 1992
68
Q
4-6 layers with different functions, different afferents, and different efferent axons
- thickness corresponds to function
- somatosensory cortex has a relatively large layer 4 and smaller 5
- motor cortex has relatively large layer 5 and smaller layer 4
- various cortical layers can be distinguished by the neuronal elements that each one contain
A
neocortex layers
74
Q
- primary sensory cortex - projects to interconnected sensory association regions
- these regions project to several cortical targets
- these targets can be the frontal lobe, the paralimbic cortex, the multimodal cortex, and the subcortical connections and loops
A
primary sensory cortex
cortical system
79
Q
- recieves all sensory input through subcortical structures
- either directly from the thalamus
- or indirectly through midbrain structures such as the tectum
A
neocortex
82
Q
Luria 1973
- anatomical criteria can help in delineating a hierarchical organization of cortical areas
- sensory unit: posterior cortex, parietal, occipital, temporal lobe
- motor unit: anterior cortex, frontal lobe
- zonal pathways
- sensory input enters primary sensory zone is elaborated in the secondary zone and is integrated in the tertiary zones of the posterior unit
- to execute an action, activation is sent from the posterior tertiary sensory zones to the tertiary frontal motor zone for formulation, to the secondary motor zone for elaboration and then to the primary frontal zone for execution
A
serial hierarchical model
83
Q
perceived that the cortical units worked in concert along zonal pathways
A
zonal pathways
95
Q
cerebral cortex
A
special gray matter at the outer layer of the brain
105
Q
special gray matter at the outer layer of the brain
A
cerebral cortex
110
Q
A
paralimbic cortex
