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127 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Where is the primary visual area located?
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Area 17, in the walls of the posterior part of the calcarine sulcus.
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What three areas does the primary visual area receive afferent fibers from?
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The lateral geniculate body, temporal half of the ipsilateral retina, and nasal half of the contralateral retina.
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What area of the brain represents the macula lutea?
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The posterior and anterior parts of area 17.
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What would a lesion involving the calcarine sulcus and its posterior part cause?
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Loss of vision in the opposite visual field (crossed homonymous hemianopia).
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What would a lesion to the occipital lobe cause?
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Central scotoma, or diminished central vision surrounded by a field of normal vision.
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What would a lesion above the calcarine sulcus cause?
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Inferior quadrant hemianopia.
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What would a lesion below the calcarine sulcus cause?
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Superior quadrant hemianopia.
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Where is the secondary visual area located?
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Areas 18 and 19, surrounding the primary visual area.
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Where does the secondary visual area receive afferent fibers from?
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Area 17 and the thalamus.
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What is the function of the secondary visual area?
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It relates visual information received by the primary visual area to past visual experience, enabling the individual to recognize and appreciate what they are seeing.
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The frontal eye field controls voluntary _____ movements of the eye and is _____ of visual stimuli.
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Scanning; independent.
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What kind of eye movement is the occipital eye field involved in?
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Involuntary conjugate movement of the eye to the opposite side when following an object.
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What would a lesion of the secondary visual area cause?
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Loss of ability to recognize objects seen in the opposite field of vision.
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Where is the primary auditory area located in the brain?
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Areas 41 and 42, in the inferior wall of the lateral sulcus (includes the gyrus of Heschl).
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What is the pathway for hearing?
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Organ of Corti --> cochlear nerve --> cochlear nuclei --> secondary cells cross to the opposite side to medial geniculate body --> third neurons project into areas 41 and 42 through auditory radiation.
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What does a lesion of the primary auditory area cause?
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Bilateral loss of hearing, which is greater on the opposite side. Inability to locate the source of a sound.
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Where is the secondary auditory area (auditory association area) located in the brain?
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Area 22, posterior to the primary auditory area and the superior temporal gyrus.
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What is the function of the secondary auditory area?
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Interpretation of sound.
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What does a lesion of the secondary auditory area cause?
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Inability to interpret sounds; word deafness or acoustic verbal agnosia (inability to recognize spoken word).
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Where is the taste area located in the brain?
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Area 43, situated at the lower part of the postcentral gyrus.
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Where does the taste area receive afferent fibers from?
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The nucleus solitarius and thalamus.
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What is an association area?
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Any area other than the primary motor and sensory areas, which only forms a small part of the cortical surface.
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What are association areas responsible for?
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Behavior, discrimination, and interpretation of sensory experiences.
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What are the three main association areas?
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Prefrontal, anterior temporal, and posterior parietal.
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What is the function of the anterior temporal association area?
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Storage of previous sensory experiences.
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What is the function of the posterior parietal association area?
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Stereognosis: sensory inputs such as touch, pressure, and proprioception (relative sense of the body's position) being integrated into concepts of size, form, and texture. Appreciation of the body image of the opposite side.
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What is the function of the prefrontal association area?
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Concerned with personality, initiatives, judgement, and emotions of the individual.
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What does a lesion of the association areas cause?
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Astereognosis: inability to combine touch, pressure, and proprioceptive impulses to appreciate size, form, and texture.
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What does damage to the posterior part of the parietal lobe cause?
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The individual fails to recognize the opposite side of the body as their own.
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turpis
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foul, ugly
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-e
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What three things does the non-dominant hemisphere interpret?
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Spatial perception, recognition of faces, and music.
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About _____% of adults are right handed (left hemisphere dominant), and about _____% of adults are left hemisphere dominant for speech.
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90%; 96%.
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By what age does one hemisphere become dominant?
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Age 10; young children with damage to the dominant hemisphere can learn to become left handed and speak well.
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What seven structures does the reticular formation extend through?
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The spinal cord, medulla, pons, midbrain, sub-thalamus, thalamus, and hypothalamus.
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What does the reticular formation consist of?
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A deeply placed continuous network of nerve cells and fibers that is continuous with the gray matter of the spinal cord.
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What are the six main functions of the reticular formation?
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Influences skeletal muscle activity, somatic sensations, visceral sensations, autonomic system, endocrine system, and the level of consciousness.
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What are the three longitudinal columns?
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Median, medial, and lateral.
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What three afferent fibers come to the reticular formation from the spinal cord?
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Spinoreticular, spinothalamic, and medial leminiscus.
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What three afferent fibers come to the reticular formation from the cranial nerve nuclei?
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Vestibular, acoustic, and visual pathways.
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What afferent fiber comes to the reticular formation from the cerebellum?
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Cerebelloreticular pathway.
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What two efferent fibers come from the reticular formation and go to the cranial nerve nuclei and spinal cord?
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Reticulobulbar and reticulospinal tracts.
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How do the reticulobulbar and reticulospinal tracts control skeletal muscles?
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They influence alpha and gamma motorneurons, modulate muscle tone, bring about the reciprocal inhibition of antagonistic muscles during a reflex, and control respiratory muscles.
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How does the reticular formation control somatic and visceral sensations?
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It affects the ascending pathways and is involved in the gating mechanism for perception of pain.
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How does the reticular formation control the autonomic nervous system?
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The reticulobulbar and reticulospinal tracts descend to the sympathetic and parasympathetic outflows.
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How does the reticular formation control the endocrine system?
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It directly or indirectly influences the hypothalamic nuclei; influences the synthesis of releasing or release-inhibiting factors to control hyphosis (pineal gland).
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How does the reticular formation influence the biological clocks?
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By influencing the hypothalamus.
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What causes a sleeping person to waken?
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Multiple ascending pathways that carry sensory information are channeled through the reticular formation to the cerebral cortex.
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What does the state of consciousness depend on?
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Continuous projection of sensory information to the cortex; degrees of wakefulness depend on the degree of activity of the reticular formation.
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What would a lesion to the reticular formation cause?
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Loss of consciousness and coma.
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Loss of consciousness in epilepsy may be due to _____ of the reticular formation.
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Inhibition.
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What is the limbic system?
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A group of structures that lie in the border zone between the cerebral cortex and the hypothalamus.
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What is the function of the limbic system?
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It is involved in the control of emotion, drive, behavior, and memory.
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What are the seven structures in the limbic system?
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Subcallosal gyrus, cingulate gyrus, parahippocampal gyrus, hippocampal formation, amygdaloid nucleus, mammilary bodies, and anterior thalamic nucleus.
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What three structures does the hippocampal formation consist of?
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The hippocampus, dentate gyrus, and parahippocampal gyrus.
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What is the hippocampus?
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A curved elevation of gray matter extending throughout the entire length of the floor of the inferior horn of the lateral ventricle.
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What is the alveus?
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A thin layer of white matter originating from the hippocampus that converges medially to form the fimbia --> becomes continuous with the crus of the fornix.
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What is the peshippocampus?
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The anterior end of the hippocampus.
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Where does the hippocampus terminate?
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Posteriorly beneath the splenium of the corpus callosum.
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What is the dentate gyrus?
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A narrow, notched band of gray matter between the fimbria and the parahippocampal gyrus.
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The parahippocampal gyrus is continuous with the hippocampus at the _____ border of the temporal lobe.
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Medial.
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Where is the amygdaloid nucleus located?
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In the temporal lobe, close to the uncus (tip of the inferior horn of the lateral ventricle). The stria terminalis emerges from it's posterior aspect.
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What are the five connecting pathways of the limbic system?
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Alveus, fimbria, fornix, mammillothalamic tract, and stria terminalis.
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The mammillothalamic tract is an important connection between what two structures?
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The mammillary body and the anterior nuclear group of the thalamus.
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What are the three layers of the hippocampus?
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Molecular layer, pyramidal cell layer, and inner polymorphic layer.
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What are the five afferent connections of the hippocampus?
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1. Cingulate gyrus
2. Septal nuclei (in the midline close to the anterior commissure) 3. Fibers from one hippocampus crossing though the fornix to the hippocampus on the other side 4. Entorhinal area or olfactory association cortex 5. Dentate and parahippocampal gyri |
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Axons of large pyramidal cells of the hippocampus form the _____ and the _____ and continue as the fornix.
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Alveus; fimbria.
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What are the five efferent fibers from the hippocampus?
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1. Mammillary body (medial nucleus)
2. Anterior thalamic nuclei 3. Tegmentum of the midbrain 4. Septal and lateral pre-optic area; anterior part of the hypothalamus 5. Habenular nuclei |
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The _____ is the major output of the limbic system.
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Hypothalamus.
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What disorders are related to malfunction of the limbic system?
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Psychiatric disorders including schizophrenia, depression, and senile dementia.
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What are the symptoms of schizophrenia?
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Chronically disordered thinking, blunted effect, emotional withdrawal, paranoid delusions, and auditory hallucinations.
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What is believed to be the cause of schizophrenia?
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Increased dopamine production in the nervous system. Antipsychotic drugs block limbic dopamine receptors, but have major motor side effects on the dopamine receptors of the extrapyramidal tracts.
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What does destruction of the amygdaloid nucleus cause?
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In patients suffering from increased aggression, it results in decreased aggressiveness, emotional instability, restlessness, increased food intake, and hypersexuality.
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What does bilateral destruction of the temporal lobe cause?
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Kluver-Bucy syndrome.
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What are the symptoms of Kluver-Bucy syndrome?
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No evidence of fear or anger, unable to appreciate objects visually, increased food intake, and hypersexuality.
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What are the three basal nuclei (masses of gray matter)?
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Corpus striatum, amygdaloid nucleus, and clustrum.
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What are the main functions of the basal nuclei?
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Control of posture and voluntary movement.
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Where is the corpus striatum located?
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Lateral to the thalamus.
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What are the two nuclei of the corpus striatum and what divides them?
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A band of nerve fibers called the internal capsule divides the corpus striatum into the lentiform nucleus and caudate nucleus.
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What are the two parts of the lentiform nucleus?
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The globus pallidus and putamen.
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Where does the tail of the caudate nucleus terminate?
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In the amygdaloid nucleus.
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What is the function of the corpus striatum?
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Muscular movement, through control of the cerebral cortex.
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What does the external capsule (white matter) separate?
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The lentiform nucleus from the claustrum (unknown function).
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What do corticostriate fibers connect? What is the neurotransmitter?
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Various parts of the cerebral cortex to the caudate nucleus and putamen. Glutamate (excitatory) is the neurotransmitter.
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What do thalamostriate fibers connect?
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The intralaminar nucleus of the thalamus to the caudate nucleus and putamen.
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What do nigrostriate fibers connect?
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Substantia nigra to the caudate nucleus and putamen. Dopamine (inhibitory) is the neurotransmitter.
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What do brainstem striatal fibers connect? What is the neurotransmitter?
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Ascending fibers of the brain stem to the caudate nucleus and putamen. Seratonin (inhibitory) is the neurotransmitter.
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What do striatopalladial fibers connect? What is the neurotransmitter?
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Caudate nucleus and putamen to the globus palladius. GABA (inhibitory) is the neurotransmitter.
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What do striatonigral fibers connect? What are the neurotransmitters?
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Caudate nucleus and putamen to the substantia nigra. GABA and substance P are the neurotransmitters.
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What are the four groups of pallidofugal fibers?
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1. Ansa lenticularis (to the thalamus)
2. Fasciculus lenticularis (to the subthalamus) 3. Pallidotegmental (to the midbrain) 4. Pallidosubthalamic |
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How is activity of the basal nuclei initiated?
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By information received from the sensory cortex, thalamus, and brain stem.
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Through what basal nuclei structure is outflow channeled?
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The globus pallidus, which then influences the activities of motor areas of the cortex or brain stem.
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Basal nuclei control muscular movements by influencing the _____ _____ rather than through direct descending pathways to the brain stem or spinal cord.
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Cerebral cortex.
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What is the function of the globus pallidus?
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Controlling axial and girdle (torso) movements of the body and positioning of the proximal limbs.
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What is chorea?
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The patient exhibits quick, jerky, irregular movements that are non-repetitive such as swift grimances and sudden movements of the head or limbs.
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What causes Huntington's chorea?
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Degeneration of the GABA and Ach secreting neurons of the striatonigral inhibiting pathway. This results in overactive dopamine-secreting neurons which inhibit the caudate nucelus and putamen.This inhibition produces the abnormal movements.
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What is athetosis?
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Slow, sinuous, writhing movements that most commonly involve the distal segments of the limbs.
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What causes athetosis?
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Degeneration of the globus pallidus with a breakdown of the circuitry involving the basal nuclei and cerebral cortex.
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What is hemiballismus?
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Involuntary movements of one side of the body. Usually involves the proximal extremities; the limb suddenly flies about in all directions.
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What causes hemiballismus?
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A lesion in the opposite subthalamic nucleus where normal smooth movements of different parts of the body are integrated.
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What are the symptoms of Parkinson's disease?
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Resting tremor, cogwheel rigidity (a combination of rigidity and tremor that results in jerky resistance to passive movement), bradykinesis (slowness of movement), and postural distrubances.
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What causes Parkinson's disease?
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Neuronal degeneration of the substantia nigra which results in a reduction in the release of dopamine within the corpus striatum. This leads to hypersensitivity of the dopamine receptors, which become overactive.
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Where is the thalamus located?
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In the diencephalon, the thalamus forms the lateral wall of the third ventricle. Its anterior part forms the boundary of the interventricular foramen on Monroe.
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What connects one thalamus to the thalamus of other side?
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Interthalamic adhesion.
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The _____ receives most of the sensory information and relays it to the sensory cortex for interpretation.
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Thalamus.
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The thalamus is covered superiorly by a layer of white matter called the _____ _____.
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Stratum zonale.
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The thalamus is covered laterally by a layer of white matter called the _____ _____ _____.
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External medullary lamina
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They gray matter of the thalamus is divided by a sheet of white matter called the _____ _____ _____.
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Internal medullary lamina.
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What three structures have connections with the anterior part of the thalamus?
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Mammillothalamic tract, cingulate gyrus, and hypothalamus.
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What are anterior thalamic nuclei associated with?
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The limbic system, emotion, and recent memory.
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What three structures have connections with the medial part of the thalamus?
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Prefrontal cortex, hypothalamus, and other thalamic nuclei.
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What is the function of the medial part of the thalamus?
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It is responsible for integration of somatic, visceral, and olfactory information, and the relation of this information to one's emotional feelings and subjective states.
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What three structures are found in the dorsal tier of the lateral thalamic nuclei?
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Lateral dorsal nucleus, lateral posterior nucleus, and pulvinar.
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What three structures are found in the ventral tier of the lateral thalamic nuclei?
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Ventral anterior nucleus, ventral lateral nucleus, and ventral posterior nucleus.
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What is the function of the ventral lateral nucleus of the thalamus?
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It influences motor activity.
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What two nuclei are part of the ventral posterior nucleus?
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Ventral posteromedial nucleus (VPMN), which receives trigeminal and gustatory pathways. Ventral posterolateral nucleus (VPLN) which receives the medial and spinal leminisci.
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What is the function of the interlaminar nuclei?
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Involved in the level of consciousness and alertness of the individual through afferents from the reticular formation.
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Where are the interlaminar nuclei of the thalamus located?
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In the internal medullary lamina.
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Where are the midline nuclei of the thalamus located?
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Close to the third ventricle; receives afferents from the reticular formation.
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What is the function of the reticular nucleus of the thalamus?
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Allows the cerebral cortex to regulate the thalamus.
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The medial geniculate body forms part of the _____ pathway.
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Auditory.
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Describe the auditory pathway.
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Cochlear nuclei --> inferior colliculus --> inferior brachium --> medial geniculate body --> auditory radiation --> areas 41 and 42 (superior temporal gyrus).
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The lateral geniculate body forms part of the _____ pathway.
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Visual.
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Describe the visual pathway.
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Retina --> optic nerve --> optic chiasm --> lateral geniculate body --> optic radiation --> area 17 (occipital lobe).
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What is the only sense that does not converge on the thalamus?
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Smell.
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Following the removal of the cortex, the thalamus can appreciate _____ based on past experience. However, the cerebral cortex is necessary for interpretation of _____ based on past experience.
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Sensation.
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What is thalamic syndrome?
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In patients recovering from a thalamic infarct, spontaneous pain occurs on the opposite side of the body; may be aroused by light touch or cold. Contralateral hemipaersis (weakness) can occur due to edema and compressing the nearby posterior limb of the internal capsule.
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Why might an individual have ataxia following a thalamic lesion?
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Loss of appreciation of muscle and joint movements.
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