Pretest Q's Flashcards
An MRI administered to a patient revealed the presence of a tumor situated in the region of the cerebellopontine angle. The patient noted considerable weakness when attempting to bite. Which CN is affected?
The tumor affected the motor component of the trigeminal nerve (H). The motor root lies medial to the sensory root and innervates the muscles of mastication.
A 43-year-old female experienced dizziness, loss of balance, some nystagmus, and ringing in the ear. A neurological exam suggested damage to a cranial nerve, perhaps associated with a small peripheral tumor. On the illustration in Question 25, which is the affected cranial nerve?
First-order neurons from the labryinth organs (semicircular canals, saccule, utricle) convey info. concerning position of the head in space along with the vestibular component of CN VIII (D). This nerve enters the brain laterally at the level of the upper medulla.
A 28-year-old man was exposed to very cold temperatures for several days and noted sometime afterward that he was unable to smile and display other aspects of facial expression on one side of his face.
The facial nerve (C) exits the brain at the level of the ventrolateral aspect of the caudal pons, and its special visceral efferent component innervates the muscles of facial expression. Damage to this nerve causes loss of facial expression on the side of the face ipsilateral to the affected nerve.
An elderly man complained of having some difficulty seeing. An ophthalmological examination revealed that he had an upper quadrantanopia. Which location on the illustration is the most likely locus of the lesion?
The neurons on the lower bank of the calcarine fissure are part of the primary visual cortex (C) receive inputs that reulate to the upper visual fields since it is part of the
A 69-year-old woman was admitted to the hospital after being diagnosed with a stroke. After a few days, she presented with difficulty in performing voluntary movements, she lacked coordination, and her movements were clearly jerky in appearance. Which location on the illustration is the most likely locus of the lesion?
The basilar portion of the pons (D) lies in the ventral half of this region of the brainstem. It receives inputs from each of the lobes of the cerebral cortex, which it then relays to the cerebellum. Disruption of any part of this circuit would affect inputs from the cerebral cortex to the hemispheres of the cerebellar cortex, which eliminates key inputs necessary for smooth, coordinated movements.
A 78-year-old woman was admitted to a local hospital after finding that she was unable to move her right arm and leg. In addition, she displayed diminution in strength of chewing, facial expression, and speech. An MRI revealed the presence of a tumor situated in the brainstem. Which structures shown on the illustration in Question 25, would most likely be affected by the tumor?
The cerebral peduncle (G) is situated in the ventrolateral aspect of the midbrain and contains fibers of cortical origin that project to all levels of the neuraxis of the brainstem and spinal cord. A lesion in this region would affect UMNs that control motor fxns associated with both the body and the head region, producing weakness in strength of the muscles of the ipsilateral head and paralysis of the contralateral leg and arm.
A 48-year-old man had been suffering from epilepsy for a number of years. Drug treatment for this disorder had not been successful and, moreover, in recent months, seizure activity had begun to spread to other regions of the brain, including the opposite side of the brain. For this condition, surgery was indicated in order to reduce the spread of the seizures. Which of the structures on the illustration would most likely be targeted by the neurosurgeon?
The corpus callosum (F) constitutes the major channel by which the cerebral cortex on one side can communicate with the cortex of the opposite side (commissure). In order to stop the spread of seizures from one hemisphere to the other, cutting of the corpus callosum is carried out.
An elderly patient who had been diagnosed with a brain tumor found that he was unable to verbally express his thoughts in a meaningful way. Which place on the illustration is the most likely location of such a lesion?
The motor speech area, or Broca’s area (F) is situated in the inferior aspect of the frontal lobe immediately rostral and slightly ventral to the precentral gyrus. Lesions of this region produce impairment of the ability to express words in a meaningful way or to use words correctly.
A patient brought into surgery for localization of a brain tumor was given an MRI and asked to move the fingers of his right hand. Which is the most likely site on the illustration where the MRI would display a population response of neuronal activation?
Cells in the “arm” area of the primary motor cortex (H) project their axons to the cervical level of the spinal cord and are activated at the time when a response of this limb occurs.
Following her admission to the emergency room of a local hospital, a 71-year-old female received a diagnosis of having had a small brainstem stroke. After two weeks, the patient appeared normal, with the exception that her tongue deviated to the left side when she was asked to protrude it. Which structure shown on the illustration was most clearly affected by the stroke?
The hypoglossal nerve (L) exits the brain at the level of the middle of the medulla between the pyramid and the olive. These fibers innervate muscles that move the tongue toward the opposite side.
A lesion of the hypoglossal nucleus or its nerve will result in a deviation of the tongue to the side of the lesion because of the unopposed action of the contralateral hypoglossal nerve, which reamins intact.
An investigator wishes to determine the effects of stimulation of the output neurons of the hippocampal formation upon excitability levels of the target neurons in the diencephalon. In which of the structures shown in the illustration should he place the stimulating electrode?
The major output pathway of the hippocampal formation is the fornix (A). The msot effective way of activating the output pathways of the hippocampal formation would be to stimulate the fibers in the fornix.
. A neurological examination was given to a 60-year-old female because she was experiencing double vision and was unable to abduct the left eye. The examination revealed the likely presence of a small lesion of the brainstem. Which of the cranial nerves shown on the illustration was affected by this lesion?
The abducens nerve (J) exits the brain at a ventromedial position at the level of the medulla-pontine border and its fibers innervate the lateral rectus muscles.
First-order somatosensory fibers from the region of the faceenter the brain laterally at the level of the pons as the sensory root of the trigeminal nerve (I).
A 48-year-old woman complained of stomach pains. The diagnosis revealed an ulceration of the stomach wall due to overactivity of the parasympathetic input to the stomach. It was recommended that the patient have the cranial nerve which innervates the stomach wall, partially severed. On the illustration, which is the affected cranial nerve on the figure in Question 25?
Fibers that arise from the dorsal motor nucleus and nucleus ambiguus exit the brain on the lateral side of the medulla as part of the vagus nerve (K) and innervate the myenteric plexus and smooth muscles of the stomach which function to produce gastric secretions.
A 30-year-old man complained that he was having difficulty seeing properly and, in particular, was experiencing double vision. The ophthalmologist noted that the patient’s right eye was normally abducted downward and the pupil was dilated. A subsequent MRI indicated the presence of a tumor impinging upon a cranial nerve. On the illustration in Question 25, which is the affected cranial nerve?
The oculomotor nerve (B) exits the brain at the level of the ventromedial aspect of the midbrain. Damage results in a loss of ability for medial gaze and the eye would be down and out.
. Damage to which region(s) shown in the illustration will likely cause disruption of memory and emotional processes?
The mammillary bodies (A), which lie on the ventral surface of the brain at the caudal aspect of the hypothalamus, receive many of their inputs from the hippocampal formation and is involved in memory function and regulation of emotional behavior.
A patient experienced great difficulty in appreciating the meaning of spoken or written words. Which place on the illustration is the most likely locus of a lesion that would cause such a deficit?
Damage to the cells situated in the region of the dorsal border of the superior temporal gyrus and the adjoining area of the inferior parietal lobule (Wernicke’s area, C) causes impairment in the appreciation of the meanings of written or spoken word.
A 67-year-old female was admitted to a hospital after she reported to her primary care physician that she had been having very painful headaches. Further examination revealed the presence of significant increases in intracranial pressure. After viewing an magnetic resonance imaging (MRI), the neurologist concluded that the woman’s condition was due to the presence of a developing tumor along the rostral aspect of the medial wall of the lateral ventricle. Which of the structures in the illustration would be most likely to contain this tumor?
The septum pellucidum (G) forms the medial wall of the lateral ventricle, which separates the lateral ventricle on one side from the other side.
A 47-year-old male who had a reputation as a very friendly and quiet individual suddenly displayed marked changes in his personality. In particular, he became shorttempered, impulsive, and threatening to his colleagues in response to what most people would consider innocuous statements. He was referred to the psychiatric ward of the community hospital, and an MRI revealed a cortical tumor. Which of the structures in the illustration is most likely to contain this tumor?
The cingulate gyrus (H) is a prominent structure on the medial aspect of the cerebral cortex and constitutes a component of the limbic lobe. As part of the limbic system, its functions relate in part to the regulation of emotional behavior. Accordingly, tumors of this region have resulted in marked changes in emotionality.
An 83-year-old woman was brought to the hospital after having received a routine eye examination, which revealed that she could not see out of the lower half of her left visual field. An MRI revealed evidence that she had experienced a cerebrovascular accident. Which of the regions in the illustration was most likely affected by the stroke?
The primary visual cortex (B) lies on both sides of the calcarine fissure. Cells on the upper bank receives inputs that relate to the lower visual field.
An individual complained about having headaches and experiencing partial blindness, which were later identified as a bitemporal hemianopsia. A neurological examination, including an MRI, indicated that the patient had a brain tumor. Which of the structures shown on the illustration is affected by the tumor?
The optic chiasm (F) contains fibers that cross over to reach the lateral geniculate nucleus on the side contralateral to the retina from which they originated. Damage to the optic chiasm will cause blindness in the lateral half of each of the visual fields.
A patient presented with loss of capacity to experience the feeling of a tuning fork when applied to the right leg. Which region on the illustration is most likely to be affected by a cortical lesion?
The leg region of the left primary somatosensory cortex (A) lies immediately caudal to the central sulcus and is devoid of pyramidal cells. This region receives inputs from the right leg.
