Neurosurgical Aspects

Clinical implications in neurosurgery (Pain)

Layers Isocortex

I) Lamina molecularis

II) Lamina granularis externa

III) Lamina pyramidalis externa

IV) Lamina granularis interna

V) Lamina pyramidalis interna

VI) Lamina multiformis

What were Brodmann areas identified by/through?

Structure of Isocortex in the areas according to staining

Cranial Nerves locations

Cranial nerves functions

Pain medication

• Peripheral

• Non-Steroidal anti-inflammatory drugs (Ibuprofen, Aspirin,

Diclofenac): inhibition of the biosynthesis of

prostaglandins

• Also antifebrile and anti-inflammatory

• Central

• Opioids: binding to endogenous opioid-receptors in the

central and peripheral nervous system

• Also constipating, against dry cough, anaesthetic

Name the two fibre types involved with nociception!

Adelta - initial, sharp

C - slower, dull

Where are the cell bodies of the primary afferent pain fibres?

The cell bodies of primary afferent pain fibers are located in the dorsal root ganglia.

Where are the cell bodies of the secondary afferent pain fibres?

Secondary afferent pain fibers have cell bodies in the dorsal horn of the spinal cord.

Where do the neurons processing pain project from the lateral

thalamic nuclei?

Neurons processing pain project from the lateral thalamic nuclei to various cortical areas. Including primarily the somatosensory cortex

What is the cause of neuropathic pain?

Neuropathic pain often results from nerve damage o

What is allodynia?

Allodynia is a condition where normally non-painful stimuli cause pain due to altered processing in the nervous system.

Amygdala

What does the Motor Cortex M1 Hormuculus look like?

Differences between precentral () and postcentral (_) Homunculus?

primary motor cortex (M1)

• arbitray movement (pyramidal) BA 4

Non-dominant parietal lobe (posterior parietal cortex)

-> loss of spatial orientation

Non-dominant parietal lobe (inferior parietal lobe)

-> Hemineglect: contralateral (visual) stimuli or even half of the body are „neglected"

Dominant parietal lobe (posterior parietal cortex)

-> Apraxia: loss of ability to perform learned movement-patterns

Premotor cortex (PMA)

• movement control (extra-pyramidal) BA 6 & 8

Supplementary motor area (SMA)

• initiation of movement BA 6 & 8

Frontal eye field

• horizontal (saccadic) eye movement BA 8

Broca

• speech production/ writing (unilateral !!!) BA 44 & 45

protopathic sensibility

• unconscious proprioception

• rough touch

• rough vibration-pressure

• pain

• temperature

1: primary somatosensory cortex

proprioception/exteroception BA 1,2 (indirect) ,3 a / b (direct)

2: secondary somatosensory cortex

interpretation of somatosensory input BA 5,7

3. posterior parietal cortex

spatial orientation / movement patterns BA 5,7

Gyrus angularis

connection auditory and visual input and speech

BA 39

transverse temporal gyri (Heschl's gyri)

• (directional) hearing

BA 41, 42

Superior temporal gyrus (Wernicke's area)

Interpretation of the „heard" BA 42,43

Papez circuit (limbic system)

Hippocampal formation (subiculum)

Fornix

Mammillary bodies

Mammillothalamic tract

Anterior thalamic nucleus

Cingulum

Entorhinal cortex

Hippocampal formation

temporal lobe (Hippocampus & limbic)

Hippocampus- memory, behaviour, emotions, vegetative function

Cingulate gyrus - drive, vegative function

Parahippocampal gyrus & Area entorhinalis- memory, sensory information

to hipoocampus

Amygdala- affective behaviour, emotional learning, vegetative function

Mammillary body- memory, affective behaviour, vegetative function

Surgeon's no-touch area

Insula!

"multisensory cortex"

nasal: special visceroaffernt

occipital: special somatosensory

taste -> primary gustatory cortex

position and movement

pain

1: primary visual cortex

• vision

cortical blindness: Anton's syndrom BA 17

2: secondary visual cortex

BA 18

3: tertiary visal cortex

BA 19

4: additional visual areas

BA 20

Visual pathway lesions

Main Fibre tracks

epicritic sensibility

• fine touch

• fine vibration pressure

• two-point discrimination

• conscious proprioception

prefrontal cortex (PFC)

• memory, drive, morals & ethics,

bladder control etc.

Somatosensory system - pathways

Ascending tracts of the spinal cord

fine touch

highly localized touch produced by

application of an object to the skin

• receptors

Meissner's corpuscles

Merkels discs

• types

tactile localization: the ability to localize point of touch without visual control

tactile discrimination: the ability to perceive two points of touch without visual control as two points

stereognosis: the ability to recognize a similiar object without visual control