Tálamo Flashcards
Núcleo Anterior del Tálamo
Afferent Neuronal Loop
Mammillothalamic tract, cingulate gyrus, hypothalamus
Efferent Neuronal Loop
Cingulate gyrus, hypothalamus
Function
Emotional tone, mechanisms of recent memory
Núcleo Dorsomedial del Tálamo
Afferent Neuronal Loop
- Prefrontal cortex
- hypothalamus
- other thalamic nuclei
Efferent Neuronal Loop
- Prefrontal cortex
- hypothalamus
- other thalamic nuclei
Function
- Integration of somatic, visceral, and olfactory information and relation to emotional feelings and subjective states
Núcleo Lateral dorsal/lateral posterior/pulvinar del tálamo
Afferent Neuronal Loop
- Cerebral cortex
- other thalamic nuclei
Efferent Neuronal Loop
- Cerebral cortex
- other thalamic nuclei
Function
- Unknown
Núcleo Ventral Anterior
Afferent Neuronal Loop
- Reticular formation
- substantia nigra
- corpus striatum
- premotor cortex
- other thalamic nuclei
Efferent Neuronal Loop
- Reticular formation
- substantia nigra
- corpus striatum
- premotor cortex
- other thalamic nuclei
Function
Influences activity of motor cortex
Núcleo Ventral Lateral del Tálamo
Afferent Neuronal Loop*
- Cerebellum
- Reticular formation
- substantia nigra
- corpus striatum
- premotor cortex
- other thalamic nuclei
- red nucleus
*As in ventral anterior nucleus but also major input from cerebellum and minor input from red nucleus
Efferent Neuronal Loop
- Reticular formation
- substantia nigra
- corpus striatum
- premotor cortex
- other thalamic nuclei
Function
Influences motor activity of motor cortex
Núcleo Ventral Posteromedial (VPM)
Afferent Neuronal Loop
- Trigeminal lemniscus
- gustatory fibers
Efferent Neuronal Loop
- Primary somatic sensory (areas 3, 1, and 2) cortex
Function
- Relays common sensations to consciousness
Núcleo Ventral Posterolateral (VPL)
Afferent Neuronal Loop
- Medial and spinal lemnisci
Efferent Neuronal Loop
- Primary somatic sensory (areas 3, 1, and 2) cortex
Function
- Relays common sensations to consciousness
Núcleo Intralaminar del Tálamo
Afferent Neuronal Loop
- Reticular formation
- spinothalamic
- trigeminothalamic tracts
Efferent Neuronal Loop
- cerebral cortex via other thalamic nuclei,
- corpus striatum
Function
- ** Influences levels of consciousness and alertness**
Núcleo de la Línea Media
Afferent Neuronal Loop
- Reticular formation
Efferent Neuronal Loop
- Unknown
Function
- Unknown
Núcleo Reticular del Tálamo
Afferent Neuronal Loop
- Cerebral cortex
- reticular formation
Efferent Neuronal Loop
Other thalamic nuclei
Function
? Cerebral cortex regulates thalamus
Cuerpo Geniculado Medial (Tálamo)
Afferent Neuronal Loop
- Inferior colliculus
- lateral lemniscus from both ears but predominantly the contralateral ear
Efferent Neuronal Loop
- Auditory radiation to superior temporal gyrus
Function
- Hearing
Cuerpo Geniculado Lateral (Tálamo)
Afferent Neuronal Loop
- Optic tract
Efferent Neuronal Loop
- Optic radiation to visual cortex of occipital lobe
Function
- Visual information from opposite field of vision
Principios importantes de la función del tálamo
- The thalamus is made up of complicated collections of nerve cells that are centrally placed in the brain and are interconnected.
- A vast amount of sensory information of all types (except smell) converges on the thalamus and presumably is integrated through the interconnections between the nuclei. The resulting information pattern is distributed to other parts of the central nervous system. It is probable that olfactory information is first integrated at a lower level with taste and other sensations and is relayed to the thalamus from the amygdaloid complex and hippocampus through the mammillothalamic tract.
- Anatomically and functionally, the thalamus and the cerebral cortex are closely linked. The fiber connections have been established, and it is known that following removal of the cortex, the thalamus can appreciate crude sensations. However, the cerebral cortex is required for the interpretation of sensations based on past experiences. For example, if the sensory cortex is destroyed, one can still appreciate the presence of a hot object in the hand; however, appreciation of the shape, weight, and exact temperature of the object would be impaired.
- The thalamus possesses certain very important nuclei whose connections have been clearly established. These include the ventral posteromedial nucleus, the ventral posterolateral nucleus, the medial geniculate body, and the lateral geniculate body. Their positions and connections should be learned.
- The ventroanterior and the ventrolateral nuclei of the thalamus form part of the basal nuclei circuit and thus are involved in the performance of voluntary movements. These nuclei receive input from the globus pallidus and send fibers to the prefrontal, supplemental, and premotor areas of the cerebral cortex.
- The large dorsomedial nucleus has extensive connections with the frontal lobe cortex and hypothalamus. There is considerable evidence that this nucleus lies on the pathway that is concerned with subjective feeling states and the personality of the individual.
- The intralaminar nuclei are closely connected with the activities of the reticular formation, and they receive much of their information from this source. Their strategic position enables them to control the level of overall activity of the cerebral cortex. The intralaminar nuclei are thus able to influence the levels of consciousness and alertness in an individual.
