week 4 Anatomy of the Nervous System

Question 1

After studying the material below, you should be able to indicate on an appropriate diagram the position of the following neuroanatomical spatial and directional terms:

dorsal versus ventral
medial versus lateral
anterior versus posterior
sagittal plane
coronal plane
horizontal plane
ipsilateral versus contralateral
proximal versus distal

Answer 1

Sagittal plane= dissects b/n left and right left and right .
Coronal plane dissects b/n rostral and caudal
Ipsilateral =same side

Question 2

Outline the major divisions of the peripheral nervous system, including the autonomic nervous system.

Answer 2

Peripheral nervous system includes Somatic Nervous System (sense organs and muscles) and Autonomic Nervous System (organs). Even though classed as peripheral, there are cns connections (it is just not entirely in cns).

Question 3

Label on a diagram the major components of the spinal cord, including the dorsal and ventral roots, dorsal root ganglion, and also identify the ventral and dorsal sides of the spinal cord.

Answer 3

3

Question 4

Compare and contrast the functions of the sympathetic and parasympathetic nervous system

Answer 4

Autonomic NS consists of
SYMPATHETIC NS;flight/flight response.Thoracolumbar ganglia which are usually close to spinal cord. Many organs influenced.Sweat glands, adrenal glands and piloerector muscles have only sympathetic input. Increases hr. AND
PARASYMPATHETIC NS; “rest and digest”, decreases hr, increased digestive acyivity, libido, includes the cranial nerves and the sacral nerves. Ganglia are near organs.

Question 5

Identify the structures that form part of the Hindbrain.

Answer 5

Medulla, Pons and Cerebellum.
Note that the Brainstem is a combination of hindbrain, midbrain and forebrain structures.

Question 6

Identify the structures that form part of the Midbrain.

Answer 6

Tectum, Tegmentum, Superior Colliculus, Inferior Colliculus, Substantia Nigra.

Question 7

Identify the structures that form part of the Forebrain.

Answer 7

cerebral cortex,
Hippocampi, Basal Ganglia, Thalamus, Hypothalamus, Pituitary gland.

Question 8

Where possible, suggest some basic functions of the above structures. Base this on evidence arising from the behavioural deficits associated with neural damage to these structures (Note, you do NOT need to know the cranial nerves).

Answer 8

Medulla;input/output for cranial nerves. Control of v+, heartrate, breathing, cough,sneeze.
Pons;where the cranial nerves cross, such that left side controls right side body etc. Some problem with cells in pons can cause narcolepsy (genetic)
cerebellum;gross motor control and coordination. Deficits result in problems with shifting attention from one stimulus type to another, jerky movements and difficulty assessing rhythyms. Integrates what are doing and what want to do.
Tectum;
Tegmentum;
Superior Colliculus;processing of vision. Damage to means very difficult to be able to detect a scene change.
Inferior Colliculus;processing of hearing
Substantia nigra;leads to dopamine-containing pathway, facilitates readiness for movement
Cerebral cortex;includes movement, planning, language, motivation
Hippocampi;critical for memory
Basal Ganglia;damage to results in impaired movement eg Parkinsons, eg Huntington’s.Integrates motivation and emotion. Critical for learning and experience.
Thalamus;processes most sensory information (excluding olfactory)
Hypothalamus;control of eating and drinking, temperature control, regulation of pituitary gland,sexual behaviour
Pituitary gland;

Question 9

Identify the ventricles of the brain.

Answer 9

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Question 10

Identify (on a diagram) the Basal Ganglia (substantia nigra, globus pallidus, thalamus, caudate nucleus, Putamen). These are covered in the week 6 seminar and the lecture on Movement.

Answer 10

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Question 11

Identify (on a diagram) the amygdala and fornix covered in the week 6 seminar and the lecture on emotion.

Answer 11

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Question 12

Identify (on a diagram) and Understand the main functions of the Parietal Lobe.

Answer 12

Knowing where one is in space. Monitors eye, head and body position. Also required for numerical information/understanding.

Question 13

Identify (on a diagram) and Understand the main functions of the Temporal Lobe.

Answer 13

Functions of the Temporal lobe; hearing, advanced visual processing, understanding language (usually left ), facial recognition,
A tumour here may cause elaborate auditory or visual hallucinations.
Damage here (and in amygdala and hippocampus)can cause Kluver-Bucy Syndrome-previously wild/aggressive monkeys once damaged here fail to show normal fear and put virtually anything in their mouth.

Question 14

Identify (on a diagram) and Understand the main functions of the Occipital Lobe

Answer 14

Visual info. Includes Primary visual Cortex and damage here results in cortical blindness (normal plr but no conscious visual perception, not even in dreams).

Question 15

Identify (on a diagram) and Understand the main functions of the Frontal Lobe.

Answer 15

Frontal lobe includes Primary Motor Cortex and the Prefrontal Cortex. Planning, Initiative, Memory, attention, social inhibitions.Movement, working memory.Emotion.

Question 16

Understand what is meant by the binding problem. What are the implications of the functional modularization of the brain that we witnessed in the above sections to the binding problem?

Answer 16

“The Binding Problem” asks how all the many functions of the brain are coordinated?More specifically how different brain areas cohese to create a single integrated experience of an object.
Whilst having a modular understanding of the brain, is valid and useful and doesn’t explain integration and how that is achieved. In addition it makes it difficult to bear in mind that neurons and their roles can actually be far more fluid, and firing under different circumstances.

Question 17

Identify (on a diagram) the corpus callosum.

Answer 17

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Question 18

Explain how the left and right halves of one’s visual field are ‘mapped’ onto one’s retina then one’s brain hemispheres by way of the optic chiasm and explain how this differs fundamentally from what occurs in auditory pathways.

Answer 18

In animals with lateral eyes, arrangement is a bit different, but in humans;both eyes see both halves of the world with each cerebral hemisphere connecting to the ipsilateral half of each retina. ie left cerebral hemisphere connects with left part of BOTH retinas. The left parts of both retinas observe the RIGHT visual field. The optic chiasm is where the nerve tracts fromthe retinas cross in passage to hemispheres. There is a small region in the middle of both retinas, which connects to both hemispheres.
Sensory inputs from ears, go to both sides of the brain, but there is an increased “focus” in the hemisphere for the contralateral ear.

Question 19

Explain what split brain surgery entails.

Answer 19

separation of the Corpus Callosum. This impedes information exchange between the two hemispheres. Has successfully reduced frequency and severity of intractable epilepsy but has also lead to;
difficulty using hands together in unfamiliar tasks (can manage with familiar tasks), ability to use hands far more independently,inability to perceive the right brain’s vision. Extremely rare for this surgery to now being considered a viable option.

Question 20

Explain what the behaviour of split-brain patients (give an example) demonstrates about the independence of functioning of the brain hemispheres and the role of the corpus callosum in integrating these functions.

Answer 20

Person with split brain might eg be shown word “hatband” in middle of visual field.Reports seeing “band” as was seen by left hemisphere. Unable to say what right hemisphere saw (in left visual field) but left hand is able to point to a “hat”.
The opposing “wills “ of split brain are marked in first few weeks after surgery but do lessen in time. Other strategies develop. eg show right hemisphere something, left hemisphere doesn’t know what but asked a yes/no question pertaining to it, will guess. If wrong, right hemisphere might cause face to frown and left hemisphere can interpret this and change answer…

Question 21

Understand the dominant role of the left hemisphere (for most people) in language.

Answer 21

Left hemisphere is dominant for speech production in 95% of right handers and also 80% of left handers. Right hemisphere can understand speech but not produce it(usually).
Lateralization= division of labour between the 2 hemispheres.
Planum Temporale larger on left for most people.

Question 22

Be able to list some functions that appear to be right hemisphere dominant (for most people).

Answer 22

Right hemisphere for most people seems better at spatial comprehension. If are the rare one who is right hemisphere dominant for speech, are also left dominant for spatial comprehension. When right hemisphere inactivated by anaesthetic, could describe scenes but without emotion. So right brain seems more involved in emotion experiencing.

Question 23

sulci

Answer 23

grooves

Question 24

gyri

Answer 24

bumps. Cingulate gyrus very important in OCD.

Question 25

simultagnosia

Answer 25

problems with being aware of things simultaneously