Neuroanatomy

Question 1

Difference between ipsilateral and contralateral

Answer 1

Ipsilateral
- structures on the same side of the body
- e.g. olfactory bulbs send ipsilateral connections to the brain
Contralateral
- structure on opposite sides of the body
- e.g. left motor strip connects to the right side of the body

Question 2

Gross anatomy of the brain

Answer 2

Forebrain
- telencephalon (cerebral cortex, basal ganglia and limbic system)
- diencephalon (thalamus and hypothalamus)
Midbrain
- mesencephalon (tectum and tegmentum)
Hindbrain 
- metencephalon (cerebellum and pons)
- myencephalon (medulla oblongata)

Question 3

What is the anatomy and function of the brainstem

Answer 3

All structures from the thalamus to the spinal cord
Regulatory functions 
- eating, drinking
- body temperature
- sleep and waking 
- basic movement 
- learning
Generally, these structures rule functions that are hard-wired and autonomic

Question 4

Function of the thalamus

Answer 4

Relay centre for sensory information (touch, vision and hearing), located near the middle of the cerebral hemispheres

• fibres project to primary sensory areas in the neocortex
• vision, touch and hearing have separate nuclei
• most of connections arise from motor neurones from the neocortex

Question 5

Function of hypothalamus

Answer 5

Controls all aspects of motivated (pleasure and pain) and regulatory behaviour

• autonomic system
• superior to pituitary gland
• ‘master-gland’: closely involved in the regulation and secretion of hormones

Question 6

What is the reticular formation

Answer 6

Constellation of 90+ nuclei at the base of the brainstem

• bundle of fibres and projections that pass through to the forebrain from the spinal cord
• connections with the cerebral cortex and thalamus

Question 7

Function of cerebellum

Answer 7

Conspicuous bulbous structure, protruding from the posterior brain (‘little brain’)

• distinctive narrow folds, similar to sulci in the neocortex
• involved in aspects of learning and coordination of skilled or smooth movements
• posture, walking and equilibrium

Question 8

What is the limbic cortex

Answer 8

Three-layer cortical structure covering the periphery of the brainstem, on the ventral surface of the lateral ventricles
Known for its role in emotion, learning and memory
- also plays a small role in spatial learning and olfaction (memories of odour)

Question 9

What structures are found within the limbic cortex

Answer 9

Hippocampus - located next to lateral ventricles in the temporal lobe
Amygdala - located anterior to the hippocampus
Fornix - connects hypocampus with other regions of the brain

Question 10

What is the function of the hippocampus and the amygdala

Answer 10

Hippocampus
- along with fornix, mammillary bodies and cingulate gyrus is involved in learning and memory
Amygdala
- responsible for emotional respsonses
- sometimes involved with learning and memory of emotions

Question 11

Function of the fornix

Answer 11

A bundle of axons that connects hippocampus with other regions of the brain, including mammillary bodies (these contain some of the hypothalamic nuclei)

Question 12

Describe the cerebral cortex

Answer 12

Six-layered structure
Includes most of the two symmetrical cerebral hemispheres
- cerebral hemispheres contain the limbic cortex
- majority of surface of the cerebral hemispheres is called the neocortex
Part of the cerebral cortex is buried in the front lobes (i.e. taste, sensation and memory)

Question 13

What are sulci, fissures and gyri?

Answer 13

Sulci - small grooves on the surface of the cerebral cortex
Fissures - large grooves
Gyri - bulges between sulci or fissures

Question 14

Composition of the cerebral cortex

Answer 14

Mostly glia (support cells), and the cell bodies, dendrites and interconnecting axons of neurons
Neuron cell bodies are grayish matter (why the cortex is called gray matter)
Beneath cerebral cortex run millions of axons, ensheathed in myelin (white matter) - that connects the neurons of the cerebral cortex with those located elsewhere

Question 15

What are the major landmarks common to everyone’s cerebral cortex

Answer 15

Longitudinal fissure
- divides cortex into the right and left sides
Central suclus
- dividing line between the anterior and posterior regions of the cerebral cortex

Question 16

What is the corpus callosum

Answer 16

A band of axons that connects the left and right cerebral hemispheres
- connects topographically
- largest commissure of the brain (cross-hemispheric connection)
Allows the unification of out perceptions and memories

Question 17

Describe the basal ganglia

Answer 17

Collection of subcortical nuclei in the forebrain (lies beneath the anterior portion of the lateral ventricles)
Composed of
- candate nucleus
- putamen
- globus pallidus
Involved in the control of movement (frontal lobe)
Parkinson’s results in degeneration of connections between midbrain and caudate nucleus and putamen

Question 18

Four lobes of the brain

Answer 18

Frontal lobe - everything in front of the central sulcus
Parietal lobe - located behind the central suclus and caudal to the frontal lobe
Temporal lobe - lateral and ventral to the frontal and parietal lobe
Occipital lobe - back of the brain, caudal to the parietal lobe and temporal lobes

Question 19

Areas of the brain which receive contralateral information from the sensory organs

Answer 19

Primary visual cortex
- occipital lobe, upper and lower parts of calcarine fissure
Primary auditory cortex
- temporal lobe
Primary somatosensory cortex
- parietal lobe, vertical strip of cortex caudal to the central sulcus

Question 20

Describe the primary motor cortex

Answer 20

Just anterior to the central sulcus, and the primary somatosensory cortex
Directly involved in the control of movement
- neurons in different parts of the motor cortex are connected to different muscles in the body (homunculus)
Connections to muscles are contralateral