10 Questions
The anterior thalamic nucleus is associated with _______.
emotion
What is the main function of the amygdala?
Signals the cortex of motivationally significant stimuli
The septal nuclei are related to reward and pleasure.
True
Match the function with the related limbic system component:
Signals the cortex of motivationally significant stimuli & social functions = Amygdala Formation of recognition memory = Mammillary bodies Reward & pleasure center = Septal nuclei Social emotions = Insular cortex
What is the function of association fibers in cerebral white matter?
Connect one part of the cerebral cortex to another part in the same hemisphere.
What do commissural fibers do in the brain?
Connect one part of a hemisphere to the corresponding part of the opposite hemisphere.
What is the primary function of projection fibers in the cerebral white matter?
Connect the cerebral cortex to subcortical nuclei and other brain areas.
Which part of the cerebral white matter is responsible for connecting the anterior part of the frontal lobe to occipital and temporal lobes?
Superior longitudinal fasciculus
Split-brain syndrome can occur when the corpus callosum is severed.
True
The ___ is the area between the body and splenium of the corpus callosum.
isthmus
Study Notes
Cerebral White Matter Fibers
-
Association Fibers: connect different parts of the same hemisphere
- Short: U-shaped, connect adjacent gyri in the same lobe
-
Long: connect different lobes, forming visible nerve bundles
- Superior longitudinal fasciculus: largest bundle, connects frontal to occipital and temporal lobes
- Cingulum: connects frontal and parietal lobes with the parahippocampal gyrus
- Inferior longitudinal fasciculus: connects occipital to temporal lobes
- Uncinate fasciculus: connects inferior frontal lobe to temporal lobe
-
Commissural Fibers: connect corresponding parts of opposite hemispheres
-
Corpus callosum: largest commissural fiber bundle
- Rostrum: tapered anterior end, connects orbital cortices
- Genu: sharp backward bend, connects frontal cortices
- Body: largest part, connects parietotemporal cortices
- Splenium: thick rounded posterior end, connects occipital cortices
- Anterior commissure: interconnects olfactory bulbs and temporal lobes
- Posterior commissure: involved in pupillary light reflex
- Habenular commissure: coordinates response to anxiety, pain, reward, stress, and sleep
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Corpus callosum: largest commissural fiber bundle
-
Projection Fibers: connect cerebral cortex to subcortical nuclei, brainstem, and spinal cord
- Ascending (afferent): carry sensory information to the cortex
- Descending (efferent): carry motor signals from the cortex
Corpus Callosum
- Median relations: related to the inferior sagittal sinus, septum pellucidum, and fornix
- Paramedian relations: related to the pericallosal branch of the anterior cerebral artery, cingulate gyrus, and post horn of the lateral ventricle
- Clinical importance: midline commissurotomy (corpus callosotomy) can prevent epileptic seizures and split-brain syndrome
Internal Capsule and Corona Radiata
- Internal capsule: a group of fibers that pass through the basal ganglia
- Corona radiata: a group of fibers that radiate from the internal capsule to the cerebral cortex
-
Parts and fibers of the internal capsule:
- Anterior limb: frontopontine fibers, corticonuclear and corticospinal fibers
- Genu: corticonuclear and corticospinal fibers
- Posterior limb: corticopontine fibers, optic radiation, and auditory radiation
- Retrolentiform part: some parietopontine and occipitopontine fibers
- Sublentiform part: some parietopontine and temporopontine fibers
Visual Pathways
- Optic nerve: receives visual information from the retina
- Optic chiasma: nasal fibers cross to the contralateral optic tract
- Optic tract: carries temporal fibers of the ipsilateral retina and nasal fibers of the contralateral retina
- Lateral geniculate body: receives visual fibers from the optic tract
- Optic radiation: carries visual information to the visual cortex
- Parietal part: carries fibers from the upper retinal quadrants (lower visual fields)
- Temporal part (Meyer's loop): carries fibers from the lower retinal quadrants (upper visual fields)
Auditory Pathways
- Cochlear nerve: carries auditory information from the organ of Corti
- Cochlear nuclei: receive auditory fibers from the cochlear nerve
- Superior olivary nucleus: receives auditory fibers from the cochlear nuclei
- Lateral lemniscus: carries auditory fibers to the inferior colliculus
- Medial geniculate body: receives auditory fibers from the inferior colliculus
- Auditory radiation: carries auditory information to the auditory cortex
Limbic System
- Definition: a group of structures that lie in the border zone between the cerebral cortex and the hypothalamus, concerned with regulating behaviors related to primitive life objectives
- Cortical areas: include the parahippocampal gyrus, uncus, cingulate gyrus, orbital frontal cortex, and subcallosal gyrus
- Subcortical areas: include the hippocampal formation and fornix
- Hippocampal formation: located in the temporal lobe, consists of the dentate gyrus, hippocampal gyrus, subiculum, and parahippocampal gyrus
- Fornix: a C-shaped tract that begins from each hippocampus, connects the hippocampi, and reaches the anterior commissure
- Affecters and responders: include the olfactory bulb/tract, hypothalamus, amygdala, septal nuclei, and mamillary bodies
- Related disorders: include anxiety, autism, depression, post-traumatic stress disorder, phobias, anterograde amnesia, Alzheimer's disease, navigational disability, and prosopagnosia
Learn about the different types of association fibers, including short and long fibers, and their connections within the brain.
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