Chapter 10

Question 1

Highest Remaining Functional Area = Spinal

Answer 1

Structure involved - spinal cord
Behaviours - reflexes
No voluntary movements: reflexes are possible
Responds to appropriate sensory stimulation by stretching, withdrawal, etc

Question 2

Highest Remaining Functional Area = Hindbrain

Answer 2

Called - Low decerebate
Structure involved - medulla, pons, cerebellum
Hindbrain and spinal cord connected, but not to rest of body
Behaviours - Postural support
Units of movement when stimulated (hissing, biting, chewing) - exaggerated standing, postural reflexes, elements of sleepwalking behaviour

Question 3

Highest Remaining Functional Area = Midbrain

Answer 3

Called - High decerebate
Structure involved - tectum, tegmentum
Diencephalon separate from midbrain
Behaviours - spontaneous movement
Voluntary and automatic movements are intact
Simple visual and auditory stimulation, automatic hens (grooming), when stimulated subsets voluntary movement (standing, walking, jumping, climbing)

Question 4

Highest Remaining Functional Area = Diencephalic

Answer 4

Structure involved - hypothalamus, thalamus
Intact olfactory system, hypothalamus, pituitary
Damage separates diencephalon from cerebral hemispheres and basal ganglia
Behaviours - affect and motivation
Sham-rage; sham-motivation
Spontaneous voluntary movement - excessive and aimless
Well integrated but poorly directed affective behavour, effective thermoregulation

Question 5

Highest Remaining Functional Area = Decorticate

Answer 5

Structure involved - basal ganglia
Decortication - removal of neocortex; basal ganglia and brainstem = intact
Behaviours - self-maintenance
Rats eat, drink, sleep, navigate, copulate, and groom normally
Links voluntary movements and automatic movements sufficiently well for self-maintenance in a simple environment

Question 6

Highest Remaining Functional Area = Typical

Answer 6

Structure involved - cortex
Behaviours - control and intention
Adapts behaviours to new situations
Provides the planning requiredfor complex behaviours
Sequences of voluntary movement in organized patterns, responds to patterns of sensory stimulation
Circuits for forming cognitive maps and for responding to the relationships between objects, events, and things
Adds emotional value

Question 7

Early myelination

Answer 7

Primary sensory and motor areas

Simple functions

Question 8

Middle and late myelination

Answer 8

Secondary sensory and motor areas

Increasingly complex

Question 9

Spiny Neurons

How many types of cells?

Answer 9

Dendritic spines that extend the dendritic surface area
Excitatory - glutamate

2 types of cells
Pyramidal - long axons, largest population of cortical neurons, efferent projections - transmit info over long distances
Found in layers 2,3,5,6 - in 5 are the largest and project from the cortex to the brainstem and spinal cord
2,3 are smaller and project to other cortical regions

Spiny stellate - star-shaped interneurons that transmit information within the vicinity of their cell body

Question 10

Aspiny Neurons

Answer 10

No dendritic spines
Inhibitory - GABA but remarkably chemically diverse
Appearance largely based on configurations of axons and dendrites
E.g. basket - axon projects horizontally, forming synapses that envelop the postsynaptic cell like a basket
Double-bouquet - proliferation of dendrites on either side of the cell body - like 2 flower bouquets aligned stem to stem

Question 11

Cortical layers

Answer 11

1-3 Integrative functions
4 Input zone
5-6 Output zone - mostly motor

Question 12

Motor cortex layers

Answer 12

Into the thamalus from the subcortical structures, reorganizing then sending to the cortical layers
1-3 reciprocal connections
4 - thalamus - main input

Motor - large 3- cortical to cortical connections
4 - mostly sensory - really small
5/6 - 1/2 the size of 3 - still large - to be able to send further
5 - cortical - subcortical / cortical - spinal
6 - cortical - thalamic

Question 13

Somatosensory cortex layers

Answer 13

Thinner in general
Large 4 
Small 1,2,3,5   - thick for incoming and thalamus
2 - cortical-cortical
3 - cortical-cortical
5 - cortical - subcortical - cells are large -> cell body in a cortex (ex. motor) than axon in spinal cord
6 - cortical - thalamic
No cortical spinal

Question 14

Specific afferents

Answer 14

Bring info to a specific area (and layer) of the cortex
Terminate in discrete areas -> usually only 1/2 layers
E.g. Thalamic inputs to the primary visual cortex
E.g. from thalamus and amygdala - most end in 4 (may me more superficial)

Question 15

Non specific afferents

Answer 15

Terminate over large regions
Sometimes release into extracellular space
Serve general functions, such as maintaining a level of activity or arousal so that the cortex can process information
E.g. Noradrenergic projections from the brainstem

Question 16

Where do most cortical interactions occur?f

What do they create

Answer 16

Vertically within neurons directly above or below adjacent layers

Columns, spots, stripes
- Groups of 150-300 neurons = minicircuits
Cells horizontal of each other react similarly

Question 17

Homunculi

Answer 17

Cortical areas responsible for basic tactile sensations

Question 18

Sensory maps

Answer 18

Organize the processing of information in a modality specific manner (visual, tactile, auditory, etc)

Question 19

Multimodal cortex

Answer 19

Areas that function in more than one sensory modality

Combine characteristics of stimuli across different sensory modalities - e.g. visualize something we’ve only touched

2 types - one recognizes and processes info while the other controls movement related to information in some way

Question 20

Parallel cortical systems

Answer 20

One to understand the world and the other to move us around and manipulate our world

Question 21

Structure of the Cortex

4 systems

Answer 21

1. Frontal lobe - motor cortex
   Motor homunculus
   Premotor cortex (just in front) - ordering movements in controlling hand, limb, eye movements with respect to sensory stimuli
   Prefrontal - remainder of frontal lobe - controls movements in time/forming short term memories of sensory information
2. Paralimbic cortex - long-term memories
3. Multimodal cortex - integration of information from multiple modalities
4. Subcortical connections and loops

Sensory regions proprioceptive fibers - direct to primary motor cortex, may go to premotor/frontal

Question 22

What is the binding problem

Answer 22

How does the brain rapidly integrate information from different cortical areas to allow our environment to be perceived coherently?
Synchronization of the activity of reciprocally connected brain areas binds information

Question 23

3 Solutions to the binding problem

Answer 23

1. Higher order cortical center - receives input and integrates info into a single perception -> no area exists
2. Interconnect all different cortical areas -> but not all connect with one another
3. Intracortical networks of connections among subsets of cortical regions

Question 24

Anterior cortex

Answer 24

Motor unit

Frontal lobe - formulates intentions, organizes and executes actions

Question 25

Posterior cortex

Answer 25

Parietal, occipital, and temporal lobes

Receives sensations, processes them, and stores them as information

Question 26

Does the human brain possess unique characteristics?

Answer 26

4 allegedly unique mental abilities
1. grammatical language
2. Phonological imagery - ability to use language to make mental images
Higher density of cortical neurons - higher processing capacity
Expanded frontal, temporal, and parietal association cortices - more complex processing of information
3. Von Economo neurons - theory of mind - capacity to understand another’s mental state and to take it into account
4. Certain forms of intuition