Neurophysiology (PNS)

Question 1

Oblation of the amygdala results in?

Answer 1

Kluver bucy syndrome
with symptoms such as; visual agnosia, inability to show fear and anxiety as well as loss of aggressiveness.

Question 2

What are association areas in the cortex?

Answer 2

Association areas in the cortex are regions responsible for integrating information from different sensory & motor areas.
They simultaneously recieve and analyse signals from multiple regions of both the motor and sensory cortices as well as subcortical structures.

Question 3

What are the 3 most important association areas?

Answer 3

1. Parieto-Occipito-Temporal association areas
2. Prefrontal association areas
3. Limbic association areas

Question 4

Talk about the Parieto-Occipito-Temporal area (P-O-T area)

Answer 4

The Parieto-Occipito-Temporal association area lies in the large parietal and occipital cortical space bounded by
1. Somatosensory cortex- anteriorly
2. Visual cortex - posteriorly
3. The auditory cortex laterally.
P-O-T area provides a high level of interpretative meaning for signals from all surrounding sensory areas.
Other association areas include; Wernicke’s area, Broca’s area, Angular gyrus.

Question 5

What are the functions of Parieto-Occipito-Temporal (P-O-T) association area

Answer 5

1. Analysis of all spatial coordinates of the body. It receives visual sensory information from the posterior occipital cortex and simultaneous somatosensory information from the anterior parietal cortex.
2. From all information, it computes the coordinates of all visual, auditory and body surroundings.

Question 6

The area for language comprehension is also called?

Answer 6

Wernicke’s area.
It lies behind the primary auditory cortex. It is the most important region of the entire brain for higher intellectual functions because almost all such intellectual functions are language based.

Question 7

The Angular gyrus area has what function?

Answer 7

The angular gyrus also known as the area for initial processing of visual language.
It is needed to make meaning out of the visually perceived words.
Without it, one can have an excellent language through hearing but not through reading.

Question 8

Talk about the Broca’s area?

Answer 8

The Broca’s area is responsible for naming objects. Here the names are learned mainly through auditory input, whereas the physical natures of the objects are learned mainly through visual input.

Question 9

Talk about the Prefrontal association area

Answer 9

This area has the ability of calling forth information from widespread areas of the brain and using this information to acheive deeper thought patterns for attaining goals.
It also functions in the elaboration of thoughts.
The prefrontal association area works with the motor cortex to plan complex patterns and sequence of motor movement.
The prefrontal association area also plays a role essential to carrying out thought processes in the mind.

Question 10

What is working memory?

Answer 10

Working memory refers to the ability of the prefrontal association areas to keep track of many bits of information simultaneously and to cause recall of this information instantaneously as it is needed for subsequent thoughts

Question 11

Briefly talk about the limbic association area?

Answer 11

This area is found in the anterior pole of the temporal lobe. This area is concerned primarily with behavior, emotion and motivation

Question 12

Explain the limbic system as the neural basis of motivated or instinctual behavior & emotion.

Answer 12

The word limbic means border. The limbic system refers to brain structure that lie in the border region between the hypothalamus & it’s related structure on one hand and the cerebral cortex.

The Limbic system is a complex network of brain structure involved in various functions, including emotion, memory, motivation, and behavior. It is often referred to as the emotional brain due to it’s central role in regulating emotional responses and behaviors e.g Fear, Rage, Pleasure, Sexual behavior, Appetite, etc

Question 13

Explain the components of the limbic system

Answer 13

1. Limbic cortex
2. Subcortical structures ( Amygdala and hippocampus)
3. Diencephalon (Hypothalamus & Thalamus)

Question 14

Mention the characteristics of the limbic system?

Answer 14

1. Connection with the neo-cortex
2. There’s a prolonged after discharge of the limbic circuit following stimulation.

Question 15

What is the papez circuit?

Answer 15

The Papez circuit is a closed circuit of information flow between the limbic system, hypothalamus, and thalamus.

Question 16

What is the fornix?

Answer 16

Fornix refers to bundles of nerve fibres that connect the hippocampus to other limbic system structures, the hypothalamus and mammilary bodies.

Question 17

What are the functions of the limbic cortex and consequence of ablation to those structures?

Answer 17

The limbic cortex

Question 18

What are the dysfunctions of the limbic system?

Answer 18

1. Abnormalities in the function of anterior Cingulate manifest in; PTSD(Post Traumatic Stress Disorder), depression, schizophrenia, OCD(obsessive-compulsive disorder)

Question 19

Explain basal ganglia

Answer 19

Basal ganglia are group of nerve cells deeply situated in the cerebral hemisphere. They are sub cortical nuclear masses (grey matter islet) located at the base of the forebrain playing many roles.

Question 20

Talk briefly about the thalamus

Answer 20

The thalamus is like a hub, it receives alot of impulses and relays sensory (visual, auditory, & tactile) and motor information to the cerebral cortex.

Question 20

What parts of the basal ganglia are strongly associated with emotion & motivation?

Answer 20

1. Ventral pallidum
2. Ventral tergmental area

Question 21

What is the Cingulate gyrus

Answer 21

Cingulate gyrus is a belt of grey matter which surrounds the corpus callosum(the fibre tract that connects the 2 hemispheres

Question 22

What is the hippocampus

Answer 22

Hippocampus is vital in consolidation of short to long term memories.

Question 23

Talk about the hypothalamus

Answer 23

The hypothalamus located in the Diencephalon just like the thalamus, controls & regulates many basic functions for supporting life.
The hypothalamus maintains the body in homeostasis, regulating temperature, sex drive, appetite & satiety. It also controls the autonomic nervous system and is responsible for increase in heart rate & blood pressure.

Question 24

What are the components of the basal ganglia

Answer 24

1. Caudate nucleus
2. Putamen
3. Substantia nigra
4. Subthalamic nuclei
5. Globus pallidus

Here is a mnemonic to remember: Chioma Plays Soccer, Scores Goals.

Question 25

The caudate nucleus & putamen together is called?

Answer 25

Corpus striatus

Question 26

The putamen & Globus pallidum are together called?

Answer 26

Lenticuar nucleus

Question 27

Define locomotion

Answer 27

Locomotion is the ability to move from place to place. Locomotion involves repetitive coordinated contraction and relaxation of several muscle groups in the limbs occurring sequentially.

Question 28

What happens when you walk?

Answer 28

When you walk, the motor neurons & locomotor centres in the CNS are responsible for initiating waking, determining it’s speed, distance or direction. But the repetitive walking pattern of putting one leg in front of another is controlled by pattern generators located in the spinal cord.

Question 29

Explain spectrum of movements

Answer 29

the spectrum of movement refers to a wide range of motor behaviors, from conscious and intentional actions to automatic and reflexive responses.

Question 30

What are reflex actions?

Answer 30

Reflex actions are involuntary, automatic responses to certain stimuli, example is withdrawal from hot object. They follow a separate pathway and have a high speed transmission rate.

Question 31

What are voluntary actions?

Answer 31

Voluntary actions are program dependent, consciously initiated movements. They take time to develop e.g throwing a ball, drawing, etc

Question 32

What are semi automatic Actions?

Answer 32

Semi automatic Actions refer to spectrum of movements that are neither purely voluntary or purely reflex. They require both and are interchangeably controlled consciously and unconsciously.
E.g; walking, chewing, swimming, breathing.
These rhythmic movements are controlled by pattern generators in the spinal cord.

Question 33

Mention the hierarchy in motor system, beginning from the lowest to the highest

Answer 33

1. Spinal cord(lowest)
2. Brainstem
3. Primary motor cortex
4. Premotor cortex

Question 34

Talk about the spinal cord as the lowest level in motor system hierarchy?

Answer 34

The spinal cord contains the circuitry for simplest reflex movements, e.g maintenance of muscle tone in response to gravity, withdrawal reflex, bladder emptying

Question 35

Talk about the Brainstem in motor system hierarchy?

Answer 35

The brain stem contains neural systems that are necessary for integrating motor commands descending from the cortex & processing information from the spinal cord & special senses.
The Brainstem participates in control of postural reflex which aids balance.

Question 36

Talk about the motor cortex in motor system hierarchy?

Answer 36

The primary motor cortex is in the premotor gyrus (Brodmann area 4). It is the 3rd level in motor system hierarchy.
It controls muscle contraction and it gets it’s instructions from the premotor areas