4.5: Neural explanations

Question 1

Neural explanation

Answer 1

The neural explanation is the perception of OCD as resulting from abnormally functioning brain mechanisms

Question 2

What have some forms of OCD been linked to?

Answer 2

Some forms of OCD have been linked to breakdowns in immune system functioning

Question 3

Some forms of OCD have been linked to breakdowns in immune system functioning, such as what?

Answer 3

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting:

1. Streptococcal (throat) infections
2. Lyme’s disease
3. Influenza

Question 4

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
What would this indicate?

Answer 4

This would indicate a biological explanation through damage to neural mechanisms

Question 5

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Who is such onset of the disorder more often seen in?

Answer 5

Such onset of the disorder is more often seen in children than adults

Question 6

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
What do PET (positron emission tomography) scans also show?

Answer 6

PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients

Question 7

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
What have drugs that increase serotonin activity been found to do?

Answer 7

Drugs that increase serotonin activity have been found to reduce the symptoms of OCD

Question 8

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, what does it suggest?

Answer 8

Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder

Question 9

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder.
What do PET scans also show?

Answer 9

PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex

Question 10

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder.
PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex, a brain area associated with what?

Answer 10

PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex, a brain area associated with:

1. Higher level thought processes
2. The conversion of sensory information into thoughts

Question 11

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder.
PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex, a brain area associated with higher level thought processes and the conversion of sensory information into thoughts.
The brain area is thought to help initiate activity upon receiving impulses to act and then to stop the activity when the impulse lessens.
A non-sufferer may have an impulse to wash dirt from their hands, but once this is done, the impulse to perform the activity stops and therefore so does the behaviour.
It may be that those with OCD have difficulty in doing what?

Answer 11

It may be that those with OCD have difficulty in:
1. Switching off
Or,
2. Ignoring
impulses

Question 12

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder.
PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex, a brain area associated with higher level thought processes and the conversion of sensory information into thoughts.
The brain area is thought to help initiate activity upon receiving impulses to act and then to stop the activity when the impulse lessens.
A non-sufferer may have an impulse to wash dirt from their hands, but once this is done, the impulse to perform the activity stops and therefore so does the behaviour.
It may be that those with OCD have difficulty in switching off or ignoring impulses, so that they turn into what?

Answer 12

It may be that those with OCD have difficulty in:
1. Switching off
Or,
2. Ignoring
impulses, so that they turn into obsessions

Question 13

Some forms of OCD have been linked to breakdowns in immune system functioning, such as through contracting streptococcal (throat) infections, Lyme’s disease and influenza.
This would indicate a biological explanation through damage to neural mechanisms.
Such onset of the disorder is more often seen in children than adults.
PET (positron emission tomography) scans also show relatively low levels of serotonin activity in the brains of OCD patients.
Because drugs that increase serotonin activity have been found to reduce the symptoms of OCD, it suggests that the neurotransmitter may be involved with the disorder.
PET scans also show that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex, a brain area associated with higher level thought processes and the conversion of sensory information into thoughts.
The brain area is thought to help initiate activity upon receiving impulses to act and then to stop the activity when the impulse lessens.
A non-sufferer may have an impulse to wash dirt from their hands, but once this is done, the impulse to perform the activity stops and therefore so does the behaviour.
It may be that those with OCD have difficulty in switching off or ignoring impulses, so that they turn into obsessions, resulting in what?

Answer 13

It may be that those with OCD have difficulty in:
1. Switching off
Or,
2. Ignoring
impulses, so that they turn into obsessions, resulting in compulsive behaviour

Question 14

What are the genes associated with OCD likely to affect?

Answer 14

The genes associated with OCD are likely to affect:
1. The levels of key neurotransmitters
,as well as
2. Structures of the brain

Question 15

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
What are these?

Answer 15

These are neural explanations

Question 16

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help do what?

Answer 16

One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood

Question 17

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
What are neurotransmitters responsible for doing?

Answer 17

Neurotransmitters are responsible for relaying information from:
1. One neuron
to
2. Another

Question 18

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then what?

Answer 18

If a person has low levels of serotonin, then:

1. Normal transmission of mood-relevant information does not take place
2. Mood, and sometimes other mental processes, are affected

Question 19

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
What may at least some cases of OCD be explained by?

Answer 19

At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain

Question 20

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.
Some cases of OCD, and in particular hoarding disorder, seem to be associated with what?

Answer 20

Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision making

Question 21

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.
Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision making.
What may this in turn be associated with?

Answer 21

This may in turn be associated with abnormal functioning of the lateral (side bits) of the frontal lobes of the brain

Question 22

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.
Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision making.
This may in turn be associated with abnormal functioning of the lateral (side bits) of the frontal lobes of the brain.
What are the frontal lobes?

Answer 22

The frontal lobes are the front part of the brain (behind your forehead)

Question 23

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.
Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision making.
This may in turn be associated with abnormal functioning of the lateral (side bits) of the frontal lobes of the brain.
The frontal lobes are the front part of the brain (behind your forehead) that are responsible for what?

Answer 23

The frontal lobes are the front part of the brain (behind your forehead) that are responsible for:

1. Logical thinking
2. Making decisions

Question 24

The genes associated with OCD are likely to affect the levels of key neurotransmitters, as well as structures of the brain.
These are neural explanations.
One explanation for OCD concerns the role of the neurotransmitter serotonin, which is believed to help regulate mood.
Neurotransmitters are responsible for relaying information from one neuron to another.
If a person has low levels of serotonin, then normal transmission of mood-relevant information does not take place and mood, and sometimes other mental processes, are affected.
At least some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.
Some cases of OCD, and in particular hoarding disorder, seem to be associated with impaired decision making.
This may in turn be associated with abnormal functioning of the lateral (side bits) of the frontal lobes of the brain.
The frontal lobes are the front part of the brain (behind your forehead) that are responsible for logical thinking and making decisions.
What is there also evidence to suggest?

Answer 24

There is also evidence to suggest that an area called the left parahippocampal gyrus, associated with processing unpleasant emotions, functions abnormally in OCD

Question 25

Neural explanations are that changes in genes could impact what?

Answer 25

Neural explanations are that changes in genes could impact the functioning of neural systems

Question 26

Neural explanations are that changes in genes could impact the functioning of neural systems.
What are the 3 neural explanations?

Answer 26

The 3 neural explanations are:

1. Low levels of serotonin
2. Basal ganglia
3. Observed in OCD patients

Question 27

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
1. Low levels of serotonin:
It may be that serotonin prevents what?

Answer 27

It may be that serotonin prevents the repetition of tasks

Question 28

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
1. Low levels of serotonin:
It may be that serotonin prevents the repetition of tasks and is what, before it is able to inhibit the repetition of an action that may result in obsessive thoughts?

Answer 28

It may be that serotonin prevents the repetition of tasks and:
1. Is in too low a level
Or,
2. Is removed too quickly from synaptic systems
,before it is able to inhibit the repetition of an action that may result in obsessive thoughts

Question 29

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
2. Basal ganglia:
Communication between the basal ganglia and others may be disrupted in OCD patients, why?

Answer 29

Communication between:
1. The basal ganglia
2. Others
may be disrupted in OCD patients, because it is observed that OCD often occurs in people with Parkinson’s disease

Question 30

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
2. Basal ganglia:
Communication between the basal ganglia and others may be disrupted in OCD patients, because it is observed that OCD often occurs in people with Parkinson’s disease, a disorder of what?

Answer 30

Communication between:
1. The basal ganglia
2. Others
may be disrupted in OCD patients, because it is observed that OCD often occurs in people with Parkinson’s disease, a disorder of the basal ganglia

Question 31

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
2. Basal ganglia:
Communication between the basal ganglia and others may be disrupted in OCD patients, because it is observed that OCD often occurs in people with Parkinson’s disease, a disorder of the basal ganglia.
What is Parkinson’s disease linked to?

Answer 31

Parkinson’s disease is linked to repetitive motor functions

Question 32

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
2. Basal ganglia:
Communication between the basal ganglia and others may be disrupted in OCD patients, because it is observed that OCD often occurs in people with Parkinson’s disease, a disorder of the basal ganglia.
Parkinson’s disease is linked to repetitive motor functions.
What can reduce symptoms in severe cases?

Answer 32

Cutting the connection to the frontal cortex can reduce symptoms in severe cases

Question 33

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
3. Observed in OCD patients:
What does the orbitofrontal cortex do?

Answer 33

The orbitofrontal cortex:

1. Predicts future events
2. Controls impulses from the limbic system

Question 34

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
3. Observed in OCD patients:
What does the parahippocampal gyrus do?

Answer 34

The parahippocampal gyrus regulates unpleasant emotions

Question 35

Neural explanations are that changes in genes could impact the functioning of neural systems.
The 3 neural explanations are low levels of serotonin, basal ganglia and observed in OCD patients.
3. Observed in OCD patients:
In OCD patients, what has been observed?

Answer 35

In OCD patients:
1. Excess activity in the orbitofrontal cortex
2. Abnormal activity in the parahippocampal gyrus
has been observed

Question 36

Neural explanations research:
Pichichero (2009) reported that case studies from the US National Institute of Health showed that children with streptococcal (throat) infections often displayed sudden indications of OCD symptoms shortly after becoming infected.
Such children also often exhibited symptoms of Tourette’s syndrome.
This supports the idea that such infections may be having an effect on neural mechanisms underpinning OCD.

Fallon and Nields (1994) reported that 40% of people contracting Lyme’s disease (a bacterial infection spread by ticks) incurred neural damage, resulting in psychiatric conditions, including OCD.
This suggests that the neural explanation can account for the onset of some cases of OCD.

Zohar et al. (1987) gave mCPP, a drug that reduces serotonin levels, to 12 OCD patients and 20 non-OCD control participants, finding that the symptoms of OCD were significantly enhanced in the OCD patients.
This suggests that the sufferers’ condition was related to abnormal levels of serotonin.

Hu (2006) compared serotonin activity in 170 OCD sufferers and 250 non-sufferers, finding serotonin levels to be lower in the OCD patients.
This supports the idea of low levels of serotonin being associated with the onset of the disorder.

Answer 36

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Question 37

Evaluation:
For:
1. There may well be a genetic connection to neural mechanisms, through such mechanisms (for example, levels of serotonin activity) being regulated by genetic factors.
A NIMH (National Institute for Mental Health) study examined DNA samples from sufferers and found OCD to be associated with 2 mutations of the human serotonin transporter gene (hSERT), which led to diminished levels of serotonin.

2. There is some supporting evidence.
   There is evidence to support the role of some neural mechanisms in OCD.
   For example, some antidepressants work purely on the serotonin system, increasing levels of this neurotransmitter.
   Such drugs are effective in reducing OCD symptoms and this suggests that the serotonin system is involved in OCD.
   As well as this, OCD symptoms form part of a number of other conditions that are biological in origin, like Parkinson’s disease (Nestasdt et al, 2010).
   This suggests that the biological processes that cause the symptoms in those conditions may also be responsible for OCD.
3. Research by Hu (2006) found genetic differences between 170 OCD sufferers and 250 controls that impacted the function of serotonin transporters in the brain, supporting genetic and neural explanations.

Against:
1. It is thought that infections that reduce immune system functioning don’t actually cause OCD, but may instead trigger symptoms in those more genetically vulnerable to the disorder.
The onset of the disorder generally occurs very quickly after infection, usually within one to 2 weeks.

2. To what extent abnormal levels of serotonin and activity within the frontal orbital cortex are actual causes of OCD or merely effects of the disorder has not been established.
3. Despite the fact that research indicates there are neural differences between OCD sufferers and non-sufferers, it is still not known how these differences relate to the precise mechanisms of OCD.
4. Not all sufferers of OCD respond positively to serotonin-enhancing drugs.
   This lessens support for abnormal levels of the neurotransmitter being the sole cause of the disorder.
5. It is not clear exactly what neural mechanisms are involved.
   Studies of decision making have shown that these neural systems are the same systems that function abnormally in OCD (Cavedini et al, 2002).
   However, research has also identified other brain systems that may be involved sometimes, but no system has been found that always plays a role in OCD.
   We cannot therefore really claim to understand the neural mechanisms involved in OCD.
6. We should not assume that the neural mechanisms cause OCD.
   There is evidence to suggest that various neurotransmitters and structures of the brain do not function normally in patients with OCD.
   However, this is not the same as saying that this abnormal functioning causes the OCD.
   These biological abnormalities could be a result of OCD, rather than its cause.
7. The serotonin-OCD link may be simply co-morbidity with depression.
   Many people who suffer OCD become depressed.
   Having 2 disorders together is called co-morbidity.
   This depression probably involves (though is not necessarily caused by) disruption to the serotonin system.
   This leaves us with a logical problem when it comes to the serotonin system as a possible basis for OCD.
   It could simply be that the serotonin system is disrupted in many patients with OCD, because they are depressed, as well.
8. While the effectiveness of drug treatments (SRRIs) indicate the validity of neural explanations, drugs that work on the serotonin system could simply cover up symptoms, not treat the root cause.
9. This biological explanation could be criticised as biologically determinist, as it suggests that OCD is due to uncontrollable gene and neuronal factors.
   However, cognitive explanations say that OCD is due to faulty information processing and by the use of conscious thought in challenging irrational beliefs, OCD symptoms can be reduced.
   This is a soft determinist view.
10. This biological explanation could also be criticised as biologically reductionist.
    OCD is a complex emotional experience.
    Biological explanations ignore the role of family members or cognitive explanations that also provide effective treatments and are based on a more complex system of irrational thought processing.

Answer 37

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