Mock 3

Explanation:

The outcome of meiosis is four (genetically unique) haploid cells, compared with the two (genetically identical) diploid cells produced from mitosis. Meiosis is thus a reduction division where one diploid cell with two copies of each chromosome yields four haploid cells containing a single copy of each chromosome.

Explanation:

Clonidine is a sympatholytic medication, which is classified as a centrally acting a2 adrenergic agonist. It has specificity towards the presynaptic a2 receptors in the vasomotor center in the brainstem.

Explanation:

The involvement of insula in disgust recognition has been reported in behavioural and functional imaging studies. Both strong and mild expressions of disgust activated the same sites in the anterior insula.

Explanation:

Hemi-neglect is not a part of the tetrad described in Gerstmann syndrome.

Explanation:

The Wisconsin Card Sorting Test (WCST) is a neuropsychological test of ‘set-shifting’, i.e., the ability to display flexibility in the face of changing schedules of reinforcement.

Explanation:

The risk of inducing a switch to mania is less with SSRIs and more with other classes of antidepressants such as TCAs, MAOIs and SNRIs.

Explanation:

Drugs with significant anticholinergic properties such as amitriptyline are notorious to cause signs of prostatism in elderly males. They may produce urinary retention and sometimes bladder distension.

Explanation:

Hemiballismus is usually a unilateral, non-rhythmic, rapid, non-suppressible, violent, flinging movement of the proximal arm. Hemiballismus is caused by a lesion, usually an infarct, around the contralateral subthalamic nucleus. Although disabling, hemiballismus is usually self-limited, lasting 6 to 8 weeks. Treatment with antipsychotics is often effective.

Explanation:

Fragile-X, tuberous sclerosis, neurofibromatosis, hypomelanosis of Ito, Moebius syndrome, Rett syndrome, and Down syndrome are some of the medical conditions associated with autism.

Explanation:

Eye-gaze avoidance is a striking phenotypic feature in fragile X syndrome.

Explanation:

D-serine is an endogenous ligand for the glycine site of the N-methyl-D-aspartate receptor. Some recent studies suggest that there is a low affinity and stereo-selective site at the agonist-binding pocket of AMPA receptors as well for D-amino acids such as d-serine.

Explanation:

Raven’s Progressive Matrices (often referred to simply as Raven’s Matrices) are multiple-choice intelligence tests of abstract reasoning that provide culturally unbiased IQ estimates. Rey Osterrieth test comprises of copying a complex figure initially and then reproducing it from immediate and delayed recall that tests both visual memory and constructional ability.

Explanation:

Fluoxetine has the longest half-life of all the SSRIs, one to three days, because of a metabolite. Paroxetine, the SSRI with a long t1/2 compared to the others, has a half-life of only 21 hours.

Explanation:

Due to its longer half-life, missing fluoxetine for a day or two will not usually cause acute withdrawal symptoms. This is a safe bet for the patient described in this question.

Explanation:

Anticholinergic syndrome results from the inhibition of cholinergic neurotransmission at muscarinic receptor sites. Psychotropics such as phenothiazines, tricyclic antidepressants and antiparkinsonian agents have anticholinergic properties. When they are administered in combination, the action of these drugs becomes additive resulting in anticholinergic syndrome. Features of a mild organic brain syndrome, which includes disorientation, difficulty in concentrating and impaired short­term memory are seen, especially noticeable at nighttime. Other physical symptoms include flushing, dry skin and mucosa, mydriasis with loss of accommodation and fever.

Explanation:

Anterograde amnesia is seen most frequently in patients who have sustained injuries to the medial temporal lobes or the diencephalon (Graff-Radford, Tranel, Von Hoesen, and Brandt, 1990). The medial temporal lobe contains the amygdala and the hippocampal formation, and animal experiments in primates have shown that damage to these two areas causes more severe anterograde amnesia. These two areas also send fibers to the diencephalon, and it is unclear if damage to the diencephalon affects the hippocampus and amygdala also.

Explanation:

Interphase is the ‘holding’ stage.

Explanation:

Face perception is an ability that involves many areas of the brain. Brain imaging studies have typically shown a great deal of activity in the area of the temporal lobe known as fusiform gyrus, an area also known to cause prosopagnosia when damaged bilaterally.

Explanation:

Anticipation refers to an inheritance pattern in which individuals in the most recent generations of a pedigree develop a disease at an earlier age or with greater severity than does those in previous generations. This is mostly due to the gradual expansion of trinucleotide repeat polymorphisms (this instability is called dynamic mutation). The phenomenon of anticipation is seen in Huntington’s disease. The inheritance of HD from the father is associated with a greater expansion of the repeats and an earlier age of onset. In approximately one-third of cases in which the father passes on the gene to his offspring, there is an expansion resulting in juvenile-onset HD. Characteristic protein deposits form nuclear inclusions in neurons of HD patients.

Explanation:

The fresh leaves of Catha edulis from East Africa were used as a stimulant for amphetamine-like effects from the main ingredient cathinone. Cathinone has most of the CNS and peripheral actions of amphetamine. It is typically absorbed buccally after chewing the leaf and being an alkaloid, gets metabolized rapidly with low chances of toxicity.

Explanation:

Occlusion of the anterior cerebral artery may result in weakness and sensory loss of the contralateral foot and leg; gait apraxia and urinary incontinence (with bilateral damage in the acute phase). This sometimes resembles the triad of Normal Pressure Hydrocephalus where identical anatomical structures are implicated albeit presenting with an insidious or subacute onset. In left-sided lesions, some cases present with transcortical motor aphasia.

Explanation:

Clonidine is an Alpha-2 adrenergic receptor agonist. Agonist effects at these receptors, which are located presynaptically in adrenergic neurons, reduce the release of epinephrine from these neurons.

Explanation:

Lithium chloride causes a concentration dependent block of the peak sodium current in cardiac pacemakers, but even at therapeutic doses, abnormal ECG can be documented, often with no clinical implications. Fine hand tremor is a common side effect often seen at lower doses; coarse tremor indicates toxicity.

Explanation:

Involvement of more family members and higher severity of expression of a multifactorial trait may mean higher polygenic contribution to the inheritance. Ethnic and gender differences are well noted in multifactorial inheritances.

Explanation:

Cough and cold medications bought over the counter often contain alcohol and can precipitate such Disulfiram reaction. Severe Antabuse reaction (also known as disulfiram reaction) is characterized by respiratory depression, seizures, cardiovascular collapse, and even death.

Explanation:

The Hayling Sentence Completion Test takes about five minutes to administer and yields three different measures of executive functioning. It consists of two sets of 15 sentences each having the last word missing. In the first section, the examiner reads each sentence aloud, and the participant has to simply complete the sentences (response initiation speed). The Brixton Spatial Anticipation Test measures the ability to detect rules in sequences of stimuli. It is perceptually simple and does not require a verbal response. It is thus appropriate for people who are suffering from a wide range of associated deficits such as those involving speech production or reading.

Explanation:

Carbamazepine has a tendency to induce its own metabolism leading to reduced plasma steady state levels.

Explanation:

In 1993, a polymorphism in the apolipoprotein E4 allele (apoE4) was discovered to be a major risk factor for late-onset Alzheimer disease. This gene promotes the deposition of beta-amyloid protein in the brain, contributing to the formation of senile plaques. People who have inherited a single E4 allele of apolipoprotein (APOE) experience up to a three to fivefold increase in risk of developing Alzheimer disease.

Explanation:

Diazepam is a benzodiazepine which has a very long elimination half-life (20 – 100 hours with an active metabolite 36 – 200 hours); as a result withdrawal symptoms are not very common with diazepam.

Explanation:

D2­like receptors (D­2, D­3 and D­4) have both pre­synaptic and post­synaptic inhibitory effect. D1 like receptors (D1 and D5) have only postsynaptic inhibition effect.

Explanation:

In terms of histological changes, no evidence for astrogliosis in schizophrenia has been reported. Reduced cell numbers or cell size has been described especially affecting neurons in the hippocampus and dorsolateral prefrontal cortex. The Increase in neuronal density, which may relate to the observed decrease in neurone size has been reported. Subtle cytoarchitectural anomalies were described in the hippocampal formation and frontal cortex. Synaptic studies in the hippocampus and DLPFC in schizophrenia show decrements in presynaptic markers.

Explanation:

Weight gain may be more pronounced in children than adults with antipsychotics, and this may limit their use. Clonidine has been shown in open studies to reduce the severity and frequency of tics and could bring a substantial reduction in tics.

Explanation:

CGG repeats at q27 of X chromosome is associated with macrocephaly and mental retardation during childhood.

Explanation:

The combination of carbamazepine and clozapine is generally contraindicated. First, carbamazepine and clozapine each produce hematologic side effects at higher frequencies than do most other available drugs. Another consideration is that carbamazepine lowers the level of clozapine, possibly more than it lowers levels of traditional neuroleptics.

Explanation:

Dynorphin, a natural brain endorphin, is far more potent than morphine or any other known endorphin. With such high potency, dynorphin can bind with great specificity to pain receptors. Dynorphins, endorphins, and enkephalins arise from different biosynthetic pathways.

Explanation:

Addison’s syndrome may result from adrenal destruction by autoimmune disease, metastatic cancer, tuberculosis, or human immunodeficiency virus infection or secondary to suppression of ACTH secretion by chronic corticosteroid therapy. Symptoms include postural hypotension, anorexia, nausea and vomiting, and weakness. Psychiatric symptoms include apathy, anhedonia, fatigue, and depressed mood. Adrenal insufficiency can be mistaken for depressive disorder. Though a loss of appetite is seen in both, vomiting is almost never due to isolated depression.

Explanation:

As carriers are possible in AR transmission, ‘hidden relatives’ may give birth to unwell children.

Explanation:

Allergic dermatitis and photosensitivity can occur with low­potency agents. Long­term chlorpromazine use can cause blue­gray discoloration of skin areas exposed to sunlight. This is reversible. Irreversible retinal pigmentation is associated with the use of high dose thioridazine (above 1000 mg a day).

Explanation:

Damage to the flocculonodular lobe (the vestibular part) may show up as a loss of equilibrium and, in particular, an altered walking gait, with a wide stance that indicates difficulty in balancing. Damage to the lateral zone, or the cerebrocerebellum, results in problems with skilled voluntary and planned movements. This can cause manifestations like hypotonia, dysarthria and dysdiadochokinesia and tremors.

Explanation:

Treatments for akathisia include reducing the antipsychotic drug or change to an atypical drug. A reduction in symptoms of akathisia may be seen with propranolol, clonazepam, mirtazapine, trazodone, mianserin and cyproheptadine.

Explanation:

EBV (Infectious Mononucleosis) has not been implicated in learning disability syndromes. In pregnant women, measles (rubeola) unlike German measles (rubella) does not cause any congenital anomalies / learning disabilities.

Explanation:

Cheese can induce tyramine related reaction in those on MAOIs.

Explanation:

The corpus callosum forms the major connection by which the hemispheres communicate with one another. The genu of the corpus callosum contains fibers that pass from the frontal lobe of one side to that of the other.

Explanation:

The mechanism of action of Cyproterone acetate is to block testosterone receptors. The direct antiandrogenic effect of Cyproterone is to block the binding of dihydrotestosterone to the specific receptors in the prostatic carcinoma cell. In addition, cyproterone exerts a negative feed-back on the hypothalamo-pituitary axis, by inhibiting the secretion of LH resulting in diminished production of testicular testosterone.

Explanation:

Thymidine deprivation can make the fragile sites of the chromosome obvious for detection.

Explanation:

There is a 77% increase in risk for Afro-Caribbean people to develop clozapine-induced neutropenia. Other risk factors include young age and having a low baseline white cell count.

Explanation:

Tay-Sachs disease is caused by a deficiency of the enzyme Hexosaminidase. It is inherited as an autosomal recessive disorder. Clinical features are apparent by around six months of age and usually results in death by the age of four.

Explanation:

Gottesman and Shields re-introduced the endophenotypes concept.

Explanation:

In CNS neurons, inhibitory transmitters open chloride channels. In addition, second messengers that mediate inhibition work by operating on potassium channels.

Explanation:

Treatment with clonazepam has shown to be effective in REM sleep behavioural disorders.

Explanation:

Bupropion is an atypical antidepressants have dopaminergic and noradrenergic actions, and it has been advocated by NICE for smoking cessation.

Explanation:

Dual role transvestism is a milder form of gender dysphoria. The individual wears clothes of the opposite sex in order to experience temporary membership in the opposite sex. The individual experiences a sense of appropriateness by wearing clothes of the other gender. There is no sexual motivation for the cross-dressing. The individual has no desire for a permanent change to the opposite sex.

Explanation:

The stimulant effect of the Khat plant was originally attributed to cathine, but this was disputed by reports showing the plant extracts from fresh leaves contained another substance more active than cathine ­ called cathinone. Cathinone is not very stable and breaks down to produce cathine and norephedrine. This explains why fresh leaves are more stimulating, and the habit of chewing Khat is more or less confined to the regions where it is cultivated.

Explanation:

Diazepam has the most rapid onset of action among orally administered benzodiazepines.

Explanation:

Friedreich’s ataxia is caused by a defect in a gene called Frataxin (FXN), which is located on chromosome 9. Changes in this gene cause the body to produce too much of a part of DNA called trinucleotide repeat (GAA). Normally, the body contains about 8 to 30 copies of GAA. Those with Individuals with Friedreich’s ataxia have as many as 1,000 copies. The more copies of GAA a patient has, the earlier in life the disease starts and the faster it gets worse. Friedreich’s ataxia is an autosomal recessive genetic disorder.

Explanation:

HIV dementia can present with the above features. See Neuroscience section on HIV

Explanation:

Buprenorphine is a partial agonist at the mu-opioid receptor and has a reduced risk of fatal respiratory depression.

Explanation:

Catechol­O­methyltransferase and monoamine oxidase are critical for the metabolic degradation of catecholamines

Explanation:

Therefore, female pseudohermaphroditism is a condition in which the gonadal sex is female, but the external genitalia are masculinized, caused by high androgen levels. This is most commonly caused by hyperplasia of the adrenal gland as a result of the genetic defects of steroidogenesis, called the virilizing congenital adrenal hyperplasias (CAHs)

Explanation:

Gait disturbance is more likely to improve following ventriculo-peritoneal shunting in NPH.

Explanation:

more than 13 = beta; 8 ­ 13 = alpha; 4­8 = theta; less than 4 = delta

Explanation:

The addition of Aripiprazole to Clozapine may be particularly effective in reversing metabolic effects (such as weight gain) and could be used as an augmenting agent to Clozapine.

Explanation:

Inferior Olivary Nucleus has a role in motor coordination by providing CLIMBING FIBERS to the cerebellum. Lesion results in motor incoordination of the contralateral arm and leg (unlike other cerebellar lesions which cause ipsilateral dysfunction)

Explanation:

It has been suggested that positive symptoms could be associated with excessive DA transmission in subcortical regions, whereas negative symptoms could be related to a concomitant deficit in cortical DA transmission. Earlier fMRI investigations, without pharmacologic challenge, have found some evidence for the concept of frontal hypoactivity, by showing reduced activation during prefrontal cognitive tasks (working memory, attention, and executive functions) in the ventrolateral prefrontal cortex (VLPFC), dorsolateral prefrontal cortex (DLPFC), and anterior cingulate in nonmedicated or medication-naive patients, relative to healthy controls.

Explanation:

‘Category fluency test’ is a frontal lobe function test for lexical fluency. The task involves listing names of animals or listing the items to buy in a supermarket. It tests not only the speed and accuracy but also the ability to shift from a narrow set to the next.

Explanation:

In those taking valproate alone, 1 in 100,000 patients. Risk factors for hepatotoxicity include young age (less than ten years old), sensitivity during the first few months of treatment, severe epilepsy, and use of multiple drugs.

Explanation:

Cross tolerance refers to decreased response to one medication due to exposure to a different medication. Here exposure to barbiturates has produced cross-tolerance to benzodiazepines.

Explanation:

Antipsychotics, methylphenidate, acetazolamide, aspirin, cimetidine, thiazides, fluoxetine and sodium bicarbonate increase tricyclic antidepressant (TCA) concentrations. Cigarette smoking decreases their concentration through its action on the 1A2 enzyme.