Test Questions

Question 1

Which region of the brain serves as the “setpoint detector” for detecting changes in our homeostatic state? For example, this brain region allows us to detect when our body is too cold and coordinates neuronal responses to re-establish our normal body temperature. (1 mark)

Answer 1

The hypothalamus serves as the setpoint detector and regulates homeostasis by detecting changes in body temperature and activating responses to restore balance.

Question 2

What is the difference between “grey” and “white” matter in the brain? (1 mark)

Answer 2

Grey matter contains neuron cell bodies, dendrites, and synapses for short-term processing, while white matter has myelinated axons for long-term signal transmission between brain regions.

Question 3

What is the difference between dorsal and ventral roots in the spinal cord (i.e. what type of information does each root carry?) (1 mark)

Answer 3

Dorsal roots carry sensory (afferent) information from the body the brain, while ventral roots carry motor (efferent) information from the brain to muscles.

Question 4

What part of the hippocampal circuit allows us to complete a pattern from partial cues, such as identifying an elephant from just a few body parts? (1 mark)

Answer 4

The CA3 region of the hippocampus allows pattern completion by using partial cues to retrieve the full memory.

Question 5

How was the existence of “chemical transmission” demonstrated experimentally? (2 marks)

Answer 5

Demonstrated experimentally by Otto Loewi when he showed that stimulating the vagus nerve of a frog’s heart released a chemical (later identified as acetylcholine) that could slow down the heartbeat of another heart when transferred, proving nerve impulses are transmitted chemically, not just electrically.

Question 6

If you wanted to test working memory in primates, what task would you use, and which brain region would be activated while performing this task? (2 marks)

Answer 6

The delayed response task, where a primate remembers an object’s location after a delay, would be used. The dorsolateral prefrontal cortex is activated, which is involved in maintaining and manipulating working memory.

Question 7

Why do people with Korsakoff’s syndrome display both retrograde and anterograde memory deficits? (2 marks)

Answer 7

Korsakoff’s syndrome involves damage to the mammillary bodies and thalamus, which impairs both the ability to form new memories (anterograde) and retrieve old ones (retrograde) due to disrupted memory consolidation.

Question 8

Can we effectively model human brain disease using animal models? Provide 2 points supporting your claim. (2marks)

Answer 8

Animals can serve as models for human brain function and disease because:
1. Their brain anatomy is similar to ours
2. They respond similarly to external agents like drugs or toxins.

Question 9

Select 2 of these structures involved in “prospection” or imagining the future and describe what they contribute to the process of imagining future events. (2 marks)

Answer 9

1. The medial prefrontal cortex is involved in planning and decision-making, helping us imagine future scenarios
2. The precuneus contributes by facilitating self-reflection and mental imagery, allowing us to envision future events.

Question 10

A pharmaceutical company wants you to design drugs to selectively target the cognitive components of post-traumatic stress disorder (PTSD). What brain structures would you target? Generally, what aspects of cognition are these regions involved in? (2 marks)

Answer 10

1. Target the amygdala, involved in fear and emotional responses
2. The prefrontal cortex, responsible for regulating emotions and decision making

• Targeting these regions could help manage PTSD’s cognitive symptoms, like intrusive memories and fear responses.

Question 11

You are trying to understand how the brain processes different types of information by presenting various images to monkeys while recording their global brain activity. You notice a large increase in the activity of neurons in the pulvinar nucleus of the thalamus. What does activity of these neurons signify? Give an example of an image that would elicit this response. (2 marks)

Answer 11

• The pulvinar nucleus is involved in attention and sensory processing.
• Activity in this area signifies a prioritization of visual stimuli, such as an image of a predator like a snake, which demands attention.

Question 12

Is dopamine a reward signal? Why or why not? (use an experimental example to support your claim) (2 marks)

Answer 12

Dopamine signals reward anticipation rather than the reward itself. Schultz’s experiment found that dopamine neurons fired when monkeys expected a reward based on a cue, not when the reward was received. This shows dopamine’s role in anticipating and motivating toward rewards, not just experiencing them.

Question 13

The human working memory system is composed of prefrontal cortex, anterior cingulate cortex, parietal lobe, Broca’s areas, and the occipital lobe. Pick 2 of these structures and outline their roles in working memory processes. (2 marks)

Answer 13

The prefrontal cortex is crucial for maintaining and manipulating information in working memory. The parietal lobe integrates spatial and sensory information to help maintain focus and processing in working memory tasks.

Question 14

What is one of the first examples of brain surgery? How do we know these individuals survived? (2 marks)

Answer 14

One of the earliest examples of brain surgery is trepanation, performed in ancient times. Evidence of bone regrowth around the edges of the skull holes shows that many individuals survived.

Question 15

Is the cortex required for generating behaviors consistent with a “rage” response in cats? Describe why or why not. (1 mark)

Answer 15

No, the cortex is not required for generating a rage response in cats. Subcortical structures like the hypothalamus and brainstem control these behaviors, while the cortex mainly modulates and regulates them.

Question 16

You work as a zoo veterinarian and notice that the monkeys are exhibiting excessive hyperactivity and overt sexuality. Moreover, when you approach them, they do not show the same degree of defensive caution they normally would. You discover the troop has a virus that affects brain function. What do you believe is causing this behavior (which brain structure is affected and what human condition does this mimic?) (2 marks)

Answer 16

The virus is affecting the temporal lobes, particularly the amygdala, leading to behavior that mimics Kluver-Bucy Syndrome. Damage to this area causes symptoms like reduced fear, hyperactivity, and inappropriate sexual behavior.

Question 17

Long-term depression (LTD) is a cellular model for forgetting. At the synaptic level, how does LTD promote the loss of memories? (2 marks)

Answer 17

Long-term depression (LTD) weakens synaptic connections by reducing the numebr of receptors (like AMPA receptors) on the postsynaptic neuron. This makes neuron communication less effective, leading to memory loss.

Question 18

Parkinson’s disease is a neurodegenerative disorder characterized by impaired movement control. Which brain structure is implicated in PD and how is this neurodegenerative disorder treated? (2 marks)

Answer 18

• Parkinson’s disease involves degeneration of the substantia nigra, leading to reduced dopamine levels.
• Treatment often includes dopamine replacement therapy, such as L-DOPA supplementation, deep brain stimulation, gene therapy or neural grafts with stem cells to improve motor control.

Question 19

In depression, we observed Increased patterns of blood flow in the amygdala and medial prefrontal cortex. What cognitive aspects of depression do these brain regions mediate? (2 marks)

Answer 19

The amygdala mediates emotional reactivity and negative emotions in depression, while the medial prefrontal cortex mediates rumination and difficulties in emotion regulation.

Question 20

After imaging a patient’s brain, you notice that the amygdala in each hemisphere shows reduced activity, due to what appears to be advanced calcification. What emotion would you predict they would be the least able to detect when viewing pictures of people’s faces? What strategy would you offer to overcome this deficit? (2 marks)

Answer 20

• The patient would have trouble detecting fear
• To help, instruct the patientto focus on the eyes of people’s faces which has been shown to improve fear recognition.

Question 21

Following a stroke, a patient has difficulty generating speech, repeating the same nonsense syllables. Despite this speech deficit, they fully understand what others are saying to them. What deficit would you predict they will have, and which brain region is damaged? (2 marks)

Answer 21

The patient likely has Broca’s aphasia, characterized by difficulty in speech production but intact comprehension.
- The damaged region is the Broca’s area in the left frontal lobe, specifically in the posterior part of the frontal gyrus.

Question 22

Selective serotonin re-uptake inhibitors (SSRIs) are used to treat depression and anxiety. Describe their mechanisms of action, focusing on changes in the hippocampus. (2 marks)

Answer 22

Selective serotonin reuptake inhibitors (SSRIs) prevent the reuptake of serotonin, increasing serotonin levels and prolonging its effect at synapses. This boosts neurogenesis and glucocorticoid receptor expression in the hippocampus, restoring its ability to inhibit the HPA axis and reduce chronic stress, thereby improving mood and anxiety symptoms.

Question 23

Aplysia (sea slugs) can modify the withdrawal of their gills following stimulation, which requires changes at synaptic contacts within their neural circuits. With short-term sensitization, when tail shock is paired with siphon stimulation, we see a PKA-dependent increase in glutamate release. What additional mechanisms support long-term sensitization of the gill withdrawal reflex? (2 marks)

Answer 23

For long-term sensitization, sustained PKA signaling activates transcription factors like CREB, causing gene expression changes and new protein synthesis that strengthen and grow synaptic connections.

Question 24

We discussed the negative impacts of chronic stress on neurons within the hippocampus. Describe 1 negative effect of chronic stress within the hippocampus and propose a strategy for reversing this effect.

Answer 24

Chronic stress can reduce neurogenesis in the hippocampus, but regular exercise can help restore it by increasing BDNF levels​

Question 25

After a motorcycle accident, a patient shows damage to their ventromedial hypothalamus. What is the function of this area and what changes in behaviour would you predict based on this lesion? (2 mark)

Answer 25

The ventromedial hypothalamus regulates satiety and aggression. Damage to this area could result in hyperphagia (overeating) and increased aggression.

Question 26

You are running an experiment to determine if a mouse has been chronically stressed by looking at the characteristics of neurons (synapses, spine density, dendritic morphology) in the amygdala. What would you predict would be the changes that you would see in these neurons in the stressed mouse? What does this tell you about the effects of stress on emotion? (2 marks)

Answer 26

In a chronically stressed mouse, there is expansion of dendritic arbors, increased spine density, and increase functional synapses in the amygdala. These changes enhance emotional memory processing and threat detection, intensifying emotional responses like fear and anxiety.

Question 27

Age-related memory loss continues to be a major medical issue. Based on your knowledge of memory structures and glutamatergic receptors, design an experiment that would allow you to restore memory function. You can use any approach you like and be sure to mention the brain region you would target and the receptors that you would manipulate (3 marks)

Answer 27

- I would target the hippocampus, a key region involved in memory consolidation. The experiment would involve administering a selective NMDA receptor agonist, such as D-cycloserine (DCS), which enhances NMDA receptor activity, promoting synaptic plasticity and long-term potentiation. - In rodents (aged 18-24 months), I would assess spatial memory improvements using the Morris water maze, with control groups receiving a placebo to ensure reliability of results. In humans (aged 60-80 years), memory function would be evaluated through a virtual navigation task before and after DCS administration. - Memory improvements would be measured by comparing pre- and post-treatment performance. This approach would test the treatment's effectiveness in both species and show its potential for human use.

Question 28

A war veteran complains of recurrent, involuntary recall of combat experiences. What brain disorder are the likely presenting with? If you wanted to treat this by reducing activity of a nuclei group in the brainstem, which one would you target and why? (3 marks)

Answer 28

The veteran is likely experiencing PTSD, which causes involuntary recall of traumatic memories. To treat this, you would target the locus coeruleus in the brainstem, as it is involved in the regulation of norepinephrine and plays a key role in the stress response and hyperarousal symptoms in PTSD. Reducing its activity may help lessen PTSD symptoms.

Question 29

After the surgery which removed his hippocampi, was “H.M.” able to form any types of memory? Make the case for why or why not. (3 marks)

Answer 29

H.M. was unable to form new declarative memories (facts and events), as the hippocampus is crucial for the formation of these types of memory. However, he could still form procedural memories (skills and habits), as the brain structures involved in procedural memory, such as the basal ganglia, were unaffected. This demonstrates that some memory functions, like procedural memory, are independent of the hippocampus.

Question 30

An army veteran returning from service has perseverative (repeated), involuntary recall of traumatic events, along with diminished activity in their medial prefrontal cortex and increased activity in their insula. Which brain disorder do they likely have? What do these brain regions contribute to this disorder (what are the functions of these brain areas)? (3 marks)

Answer 30

The veteran likely has PTSD, which causes involuntary recall of trauma. The medial prefrontal cortex, which regulates emotions and fear responses, shows reduced activity, leading to poor emotional control. The insula, involved in processing emotions and bodily sensations, has increased activity, causing heightened emotional and physical distress.

Question 31

We know that exposure to stress in utero (while pups are in their mom's womb) can impacts stress resilience of the pups as they develop. If the dame (rat mom) tonically stressed, describe what the effects would be on the following brain regions (amygdala, hippocampus) and why this would make the pups less stress resistant ( 3 marks)

Answer 31

Prenatal stress increases amygdala activity, making the pups more anxious and emotionally reactive. It also weakens the hippocampus’s ability to control cortisol, leading to poor stress regulation. Together, this causes a heightened and prolonged stress response, making the pups less resilient to stress.

Question 32

During a traumatic stress response, noradrenaline (norepinephrine) projections from the locus coeruleus (LC) reduce executive function and increase emotion salience. Describe the structures and receptors that mediate this effect. (3 marks)

Answer 32

-During a traumatic stress response, high levels of noradrenaline weaken dorsolateral prefrontal cortex inputs, which reduces executive function. - Dopamine and noradrenaline strengthen the output of the amygdala through D1, alpha 1 and beta 1 adrenergic receptors, increasing the emotional salience of memories. - This is further enhanced by the amygdala increasing locus coeruleus firing, creating a positive feedback loop

Question 33

What is the difference between the reticular (“net”) theory and the “neuron doctrine”? Which theory ultimately proved correct and what evidence solidified this claim? (3 marks)

Answer 33

- The reticular ("net") theory proposed that the nervous system was a continuous, interconnected network, while the neuron doctrine stated that the nervous system was made up of distinct, individual cells called neurons. -The neuron doctrine ultimately proved correct, and this was solidified by the use of electron microscopy, which revealed the existence of synaptic gaps between neurons.

Question 34

Implanting an electrode in this subcortical brain structure will result in rats pressing a bar to activate the electrode to the point of exhaustion, even foregoing tasty food or sex. Which brain area is the electrode implanted into? What neurochemical does this structure respond to? Where does it project to control executive function? (3 marks)

Answer 34

The electrode is implanted into the nucleus accumbens, a key reward center. This structure responds primarily to dopamine, associated with pleasure and reward. It projects to the prefrontal cortex, which controls executive functions like decision-making.

Question 35

The brain is divided into 4 lobes. Name the lobes and an associated function for each lobe (4 marks)

Answer 35

1. Frontal Lobe: Higher order processes (decision-making, problem-solving, and executive functions) 2. Parietal Lobe: Processes sensory information, such as touch and spatial awareness. 3. Temporal Lobe: Involved in hearing, language comprehension, memory formation 4. Occipital Lobe: Primarily responsible for visual processing

Question 36

Conditioned fear memories in rodents require association of a conditioned stimulus (a tone) with an unconditioned stimulus (a shock). Starting with the auditory cortex and somatosensory cortex, outline the pathway through which these associations are formed, including where the memories are generated and the downstream structures that mediate the physiological and behavioral responses (4 marks)

Answer 36

Conditioned fear memories in rodents involve associating a conditioned stimulus (tone) with an unconditioned stimulus (shock). Auditory information from the tone is processed in the auditory cortex and relayed via the medial geniculate nucleus (MGN) to the amygdala. Simultaneously, pain signals from the shock are conveyed from the somatosensory cortex and somatosensory thalamus to the amygdala. These sensory signals converge in the lateral amygdala (LA), forming the memory of the association between the tone and shock. The central amygdala (CE) then projects to downstream structures: the central gray (CG) for freezing behavior, the lateral hypothalamus (LH) for blood pressure control, and the paraventricular nucleus (PVN) for hormone release, driving the physiological and behavioral fear responses.

Question 37

Which of the following neuromodulators serves as a "motivation" signal in the brain? Choose 1. A) noradrenaline B) acetylcholine C) serotonin D) dopamine E) glutamate

Answer 37

Dopamine is known as the "motivation" signal in the brain because it is involved in the reward system, driving behaviors by providing a sense of pleasure or anticipation of a reward