23A Cerebral Cortex Flashcards Preview

Clinical Neuroscience weeks 1-3 > 23A Cerebral Cortex > Flashcards

Flashcards in 23A Cerebral Cortex Deck (54):
1

Cerebral cortex develops as outpocketings of

Prosencephalon

2

Up until 6 mos, the cerebral cortex is smooth or...

Lissencephalic

3

By birth at nine months, the cerebral cortex is said to be Gyrencephalic or...

coverd with gyri and sulci

4

Three types of cortex have been defined based on histology

1) Allocortex- 3 layers
2) Isocortex- 6 layered
3) Mesocortex- 3-5 layers

5

Archicortex formed from which pallium

medial

6

Paleocortex formed from which pallium

lateral

7

Neocortex formed from which pallium?

Dorsal {Pallium

8

How many cortical layers are there?

6

9

Layer 1 is called

molecular layer

10

Layers 2,3 called

superficual pyramidal layer

11

Layer 4 called?

Granular layer

12

Layer 5 called?

Deep pyramidal cell layer

13

Layer 6 called

polymorphic layer

14

Supragranular layer

layers 1-3, because 4 = granular,
This makes 5-6 subgranular

15

Pyramidal vs non-pyramidal

pyramidal- pear shaped soma and a single dominant apical dendrite. Send axons deep to the white matter and are projection neurons. Project locally and to other areas. Excitatory. Glutamate as transmitter

non-pyramidal- mostly GABAergic neurone which are local only,,,only project into a local area of cortex. Typically multipolar or bipolar

16

Spiny vs Aspiny

pyramidal = spiny
non-pyramidal- sparsely spiny

17

What is a spiny stellate cell

found in layer 4 of primary sensory cortex. Mostly subtypes of pyramidal cells but only project locally. Called non-yramidal

18

Main input to most cortical neurons is from

other cortical neurons

19

What is the main extrinsic input to cortex?

Thalamus

20

What are the two types of Thalamic input?

Specific- from thalamic nuclei that project into a single cortical area and concerns a single modality such as VL (motor cortex neuron), VPL (somatosensory cortex neuron)

Non-specific- comes from thalamic nuclei that integrate information from many sources. This input is important for general brain states and arousal.

21

Specific thalamic nuclei generally project to what layer of the cortex?

Layer 4

22

Non-specific thalamic afferents generally project to what cortical layer

Layer 1

23

Pyramidal cells in what layers are the main source or cortico-cortical connections>

II and III... Association fibers and callosal projections....some also project to the striatum which surprisingly is still a part of the telencephalon

24

Association Fibers?

Pyramidal cells which project ipsilaterally (local and long distance)

25

Callosal projections

pyramidal cells which project contralaterally, via the corpus callosum

26

Layer V pyramidal neurons are what

The main output neurons of the cortex

27

Layer VI pyramidal neurons are what

They project primarily to the Thalamus

28

The Thalamocortical feedback loop is the basis for several thalamocortical thythms observed in EEG....important in regulation of sleep-wake cycle, consciousness, and several pathologic conditions

ok

29

Since most inputs to pyramidal cells come from other pyramidal cells, this system of mutual excitation wold lead to an unstable network if not for less numerous non-pyramidal inhibitory neurons. (80% pyramidal and excitatory, 20% non pyramidal)

ok

30

A central belief regarding cortical function is that the cortex is composed of repeated modules called cortical columns.

ok

31

Macrocolumn=

all of the cells allied together for a particular function. The idea is that a macrocolumn is the basic functional unit.

32

The basic idea is that all of the pyramidal cell members of a developmental mini-column are ancestors of a single precursor cell in the ventricular zone of the embryonic cerebral vesicles

ok

33

What is association cortex

Cortex that is not primary motor or sensory...all 6 layers very obvious...called homotypic

34

Non-asssocaition areas where cortex layers are less obvious are called

heterotypic

35

Which layer of cortex is virtually absent from Primary Motor cortex?

Granular layer...thus motor cortex is referred to as agranular

36

Which layer is very large?

Layer V is very large in motor cortex because it has large pyramidal cells to project to spinal cord and subcortical motor centers

37

Primary Sensory cortex

Large granular layer

38

Primary Motor Cortex = what Brodmans areas

4

39

Primary somatosensory cortex is brodmann's area number what?

3, 1, 2

40

Primary visual cortex is brodman number

17

41

Primary auditory complex brodmann area

41,42

42

Brodmans area 6?

Premotor cortex- unimodal association area

43

Brodman area 5,7

unimodal association areas for somatesthesias

44

General layout of a somatosensory and motor homunculus?

Medial --> Lateral

Lower limb, trunk, shoulder, arm, hand, neck, head, mouth, throat

Basically, lower limb in the mid-sagital area and upper limb on the lateral surface of the pre- or post-central gyri. Can be used to localize strokes since the middle cerebral artery supplies the putside of the cortex while the anterior cerebral artery supplies the mid-sagital area

45

Parietal association cortex is important for

attention to the physical world

46

Temporal association complex is important for

naming things

47

Prefrontal cortex acts as the overall executive for behavior

ok

48

Occipital association cortex is concerned with?

Visual system

49

If the parietal cortex is damaged in the dominant hemisphere (left side for right handers and usually left handers as well) what occurs?

Patients suffer from language disorders (aphasias)

50

What occurs with non-dominant parietal damage?

sensory neglect...pts ignore sensory experiences on the half of the body contralateral to the injury. this the non-dominant parietal association cortex is necessary for attention to the internal and external environment

51

Temporal association cortex important for

recognizing and naming objects

52

Pre-frontal association cortex

Largest component of the cortex. Important for determining personality and our sense of self

53

What are teh two components of the Pre-frontal cortex?

Dorsolateral- working memory and planning behaviors
orbitofrontal- aggression and emotions

54

PFC allows us to choose between actions. Mnemonic RIO stands for what

Restraint
Initiative
Order