Higher brain functions

Question 1

Describe the structural organisation (neuroanatomy) of the sympathetic division of the autonomic nervous system.

Answer 1

1. The cell bodies of the preganglionic neurons are located in the lateral horn of the spinal cord at the thoracolumbar level (T1-L3)
2. They project through the ventral roots to either a paravertebral ganglion or a prevertebral ganglion before synapsing onto postganglionic neurons that project to the target organ/tissue.

Question 2

What is true about circadian rhythms (several answers can be correct).

A. Circadian rhythms are about 25 hours (rather than 24 hours)

B. SCN is most sensitive to light in the evening and morning (dusk and dawn)

C. Light on the skin can set the circadian rhythm

D. More daylight helps us keep a stable rhythm

E. Some retinal ganglion cells are sensitive to light and project directly to SCN

Answer 2

B. SCN is most sensitive to light in the evening and morning (dusk and dawn)

D. More daylight helps us keep a stable rhythm

E. Some retinal ganglion cells are sensitive to light and project directly to SCN

Question 3

Define the concept of allostasis.

Answer 3

Allostasis: Process to maintain homeostasis (e.g. changes in blood pressure, stress hormones, inflammatory cytokines etc). OR: stability to change

Question 4

Define the concept of allostatic load.

Answer 4

Allostatic load: Cumulative changes as a result of allostasis (e.g. neural remodelling or atherosclerosis, increased hip:waist ratio, insulin resistance, increased blood pressure, changes in high/low density lipoprotein)

Question 5

Explain how working memory can be retained after the stimuli have stopped?

Answer 5

Neurons in the dorsolateral prefrontal cortex (DLPC) are activated by the stimuli and remain active during the period that the memory is retained.

Question 6

The prefrontal cortex ‘control system’ is seen to support flexible behaviors like planning and decision making. The dorsolateral prefrontal cortex (DLPFC) is associated with one particular element of control. Describe this element and two of its important functions.

Answer 6

1. Working memory.

Two major functions are:

(a) maintaining rules that govern behaviour
(b) regulating other circuits to make them more or less responsive.

Question 7

Describe the anatomical pathway for autonomic control of blood pressure. Which sensory receptors are involved?

Answer 7

Feedback loop/Receptors: Baroreceptors (primary) and chemoreceptors (secondary)

1. Parasympathetic pathway (Blood pressure↑)

Sensory pathway: Baroreceptors -> vagal nerve -> brainstem -> nucleus of the solitary tract

Motor pathway: Nucleus of the solitary tract -> preganglionic parasympathetic neurons in brainstem -> nucleus ambiguous -> vagal nerve -> cardiac plexus -> postganglionic neurons projecting to the heart and decrease heart frequency.

2. Sympathetic pathway (Blood pressure↑)

Motor pathway: NTS -> sympathetic preganglionic neurons in the spinal cord (intermediolateral column) -> paravertebral ganglion -> postganglionic neurons -> heart.

+ sympathetic preganglionic neurons projecting to blood vessel are inhibited. This results in decreased heart frequency and contractility and vasodilatation -> a decrease in blood pressure.

A fall in blood pressure will result in the opposite effects, i.e. inhibition of parasympathetic outflow to the heart, and stimulation of sympathetic outflow to the heart and blood vessels.

Question 8

Briefly, describe the process and brain structures that are most central for the acquisition of declarative new (explicit/episodic) and old (explicit/semantic) memories.

Answer 8

Acquisition and consolidation occur primarily in the hippocampus whilst storage over time occur in specialized areas of the association cortex.

Amygdala is relevant for emotional content/value.

The frontal cortex is relevant for strategies/planning

Question 9

Describe with a few words the difference or similarity between low and high levels of glucocorticoids (i.e. cortisol) in terms of their general effects on inflammation.

Answer 9

Lower levels stimulate inflammatory processes

Higher levels suppress inflammation.

Question 10

The reward system is important for guiding us in what we want and to reward us when we carry out different behaviours. Which brain regions are part of the mesolimbic dopamine system?

Answer 10

Mesolimbic pathway—transports dopamine from the VTA to the nucleus accumbens and amygdala.

Question 11

What part(s) of the prefrontal cortex and cingulum is/are involved in emotion regulation?

A) Dorsolateral prefrontal cortex

B) Medial prefrontal cortex

C) Posterior cingulum

D) Anterior Cingulum

Answer 11

B) Medial prefrontal cortex

D) Anterior Cingulum

Question 12

Injuries to what area(s) can give rise to hemispatial neglect syndrome (spatial neglect)?

A) Dorsolateral prefrontal cortex

B) Medial prefrontal cortex

C) lesions in the left parietal lobe

D) lesions in the right parietal lobe

Answer 12

D) lesions in the right parietal lobe

Question 13

Which of these areas are central for forming procedural memories?

A) hippocampus

B) prefrontal cortex

C) basal gangliga

D) cerebellum

Answer 13

B) prefrontal cortex

C) basal ganglia

D) cerebellum

Question 14

What primary input(s) set(s) the phase of the suprachiasmatic nucleus?

A) Light via intrinsically photosensitive retinal ganglion cells (ipRGCs)

B) Darkness

C) Physical activity

D) Melatonin

Answer 14

A) Light via intrinsically photosensitive retinal ganglion cells (ipRGCs)

D) Melatonin

Question 15

What neurotransmitter(s) promote(s) REM-sleep?

A) Dopamine

B) Histamine

C) Noradrenaline/Norepinephrine

D) Acetylcholine

Answer 15

D) Acetylcholine in the pontine reticular formation

Bonus: Serotonin and noradrenalin inhibits rem

Question 16

What brain region(s) are central for reactive (fast) fear reactions (so called “fear circuits”)?

A) Periaqueductal gray (PAG)

B) Amygdala

C) Cerebellum

D) Hypothalamus

Answer 16

A) Periaqueductal gray (PAG)

B) Amygdala

D) Hypothalamus

Question 17

What brain region(s) are central for stress responses?

A) Hypothalamus

B) Pituitary gland

C) Pineal gland

D) The Striatum

Answer 17

A) Hypothalamus

B) Pituitary gland

Question 18

Which of the following brain region(s) are central for working memory?

A) Prefrontal cortex

B) Parietal cortex

C) Thalamus

D) insula

Answer 18

A) Prefrontal cortex (planning, regulating behaviour)

B) Parietal cortex (visual/motorspatial)

Question 19

What parts of the prefrontal cortex and cingulum are involved in emotion regulation?

Answer 19

Orbitofrontal and medial PFC

Anterior/rostral Cingulum

Question 20

What parts of the prefrontal cortex and cingulum are involved in non-emotional regulation?

Answer 20

Dorsolateral PFC and caudal Cingulum

Question 21

What kind of attentional problems can arise from cortical leasons in the right parietal lobe?

Answer 21

can lead to left hemispatial neglect syndrome (spatial neglect is also correct)

Question 22

Describe at least two characteristics of the differences between top-down (endogenous) v.s. stimulus-driven (exogenous) driven attention.

Answer 22

Top-down regulated attention is controlled, slower, has limited capacity, and needs effort. Top-down related attention is also part of working memory.

Stimuls-driven attention is fast, has near to unlimited capacity, needs little effort and hard to change.

Question 23

Some brain functions are lateralized. Name two functions that are lateralized and the central brain areas for these functions.

Answer 23

Speech production = Broca’s area

Speech processing = Wernicke’s area is lateralized so that

Somatosensory and motor processing is lateralized

Frontal eye field (FEF) is the area in the dorsolateral prefrontal cortex

Question 24

The Mesolimbic dopamine system is believed to play an important part in the reward system. Which brain regions are part of the mesolimbic dopamine system? Give evidence for this hypothesis.

Answer 24

Response: Ventral Tegmental Area (VTA) and nucleus accumbens/ventrala striatum. Evidence: “In principle, all addictive agents increase dopamine levels in this system. - Also natural rewards (like sex) activate this system. - Dopamine neurons that originate from these areas and that project to nucleus accumbens regulate “salience” (motivation and desire), which is important input for choosing between different behaviors. - Rats learning self-administration of drugs stop taking them if you block dopamine receptors at the nucleus accumbens with a D2-receptor antagonist.

Question 25

Which role does the mesolimbic dopamine system play in addiction?

Answer 25

1. learning which stimuli gives reward
2. Mediates “wanting”
3. addiction (and abuse) leads to downregulation of the dopaminergic system, which results in the need to increase the dose to get the same effect.

Question 26

Many organisms on the planet have mechanisms assuring a stable diurnal rhythm. What are the main functions of the circadian system in humans?

Answer 26

Synchronization of biological processes in the body so that they are aligned with each other and the environment.

Adaptation to changes of light/darkness in the environment.

Anticipate and prepare the body for the changes in light/darkness.

There are clear patterns of brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle.

Question 27

Explain how light at different times of the day affects (= “entrain”) the circadian system. The answer should include a description of how light can be used to make a person more of a morning type (rather than an evening type). Also, describe other factors that should be considered for effectively entraining (setting) the phase of a person’s circadian rhythm.

Answer 27

Light in the morning shortens the circadian rhythm making a person more of a morning type.

Light in the evening/night will delay the rhythm so that a person becomes more of an evening type.

Light resets the oscillations in the SCN through a mechanism involving melanopsin-containing retinal ganglion cells that project directly to the SCN via the retinohypothalamic tract.

The rhythmic release of melatonin is regulated by the central circadian rhythm generator-the suprachiasmatic nucleus (SCN) of the anterior hypothalamus.

Question 28

Describe Seyle’s “General Adaptation Syndrome”, and how it relates to health.

Answer 28

1) alarm reaction and mobilization phase
2) resistance phase where a person cope with the stressor(s)
3) exhaustion phase where resistance is no longer possible

Question 29

Describe the major neural and neuroendocrinological pathways involved in the stress response. This explanation should include how they work in the time domain. Also, give an example of a situation and explain how the different stress pathways respond to this.

Answer 29

The ANS reacts to acute stress and the changes occur in seconds, the first response being an inhibition of the parasympathetic nervous system, directly followed by an activation of the sympathetic nervous system. This has large effects on our physiology, cognitive functioning and beahviour. For example, the fast ANS affects pupil size, heart rate, blood pressure, hand sweating and sharpens focus.

The HPA-axis takes longer time to react, normally 20-30 minutes, and regulates many body processes including metabolic, digestion, immune functioning, For example, cortisol assures availability of glucose so that the person has energy to deal with a stressful situation.

Question 30

Our understanding of the prefrontal cortex (PFC) has increased substantially the last 20 years with brain imaging techniques such as fMRI. Pair the brain areas in the PFC to the following functions: 1) Emotion regulation, 2) Regulation of non-emotional content, 3) Speech production.

Answer 30

1) Orbifrontal cortex 2) Dorsolateral prefrontal cortex 3)Broca’s area

Question 31

Evolutionary pressures that have formed our brains include a need for fast information flow, damage resistance and manageable energy consumption. With respect to the connectivity structure of the cortex, specify how it supports ”functional specialization” and ”functional integration”.

Answer 31

Cells that fire together, wire together

1. energy-efficient and plastic

Functional integration relies on “hub regions” mainly found along a central-axis, and hub regions tend to be characterized by their involvement in many different cortical functions.

Question 32

The Mesolimbic dopamine system is believed to play an important part in the reward system. Which brain regions are part of the mesolimbic dopamine system? Give evidence for this hypothesis.

Answer 32

Ventral Tegmental Area (VTA) and nucleus accumbens/ventrala striatum. Evidence: “In principle, all addictive agents increase dopamine levels in this system. - Also natural rewards (like sex) activate this system. - Dopamine neuron that originates from these areas and that projectes to nucleus accumbens is regulating “salience” (motivation and desire), which is important input for choosing between different behaviors. - Rats learning self-administering drugs stop taking them if you block dopamine receptors at the nucleus accumbens with a D2-receptor antagonist.

Question 33

What evidence goes against that the mesolimbic system mediates reward?

Answer 33

1. pleasure effects cannot be blocked with dopamine receptor antagonists
2. some addictive drugs, e.g. benzodiazepines do not stimulate this system
3. dopamine seems to be more involved in the “wanting”, while opioids are released when the goal is achieved.

Question 34

Which role does the mesolimbic dopamine system play in addiction?

Answer 34

1. learning what gives reward
2. active in response to cueing stimuli
3. Prolonged addiction leads to downregulation of the dopamine system (i.e. higher dose for same effect).

Question 35

What central function does the anterior cingulum has for when we decide between different behaviours?

Answer 35

It keeps track of how much you value different things, i.e. reward anticipation.

Question 36

What parts of the prefrontal cortex and cingulum are involved in emotion regulation?

Answer 36

Orbifrontal PFC/mPFC and anterior/rostral Cingulum

Question 37

What parts of the prefrontal cortex and cingulum are involved in the regulation of nonemotional regulation?

Answer 37

Dorsolateral PFC and caudal Cingulum

Question 38

Describe the structural organisation (neuroanatomy) of the parasympathetic division of the autonomic nervous system.

Answer 38

The cell bodies of the preganglionic neurons originate from either the cranial nerves 3, 7, 9 or 10 or the lateral horn of the spinal cord at the sacral level ( S1-5) and project through the ventral roots to synapse onto postganglionic neurons that project to the target organ/tissue.