Subcortical Areas Of The Brain Flashcards
What are basal nuclei
Caudate nucleus
Putamen
Globes pallidus
Subthalamic nucleus
Substantia nigra
Where are the basal nuclei located
Collection of nucleus deep to the white matter of cerebral cortex
Striatum =
Caudate nucleus + putamen
Caudate nucleus + putamen =
Striatum
Describe caudate nucleus and putamen
Separated by ant. Limb of internal capsule
Both input nuclei to the basal nuclei
Receive excitatory input
Describe globes pallidus
Can be subdivided ; externa (Gpe) and interna (Gpi)
Output nucleus of basal nuclei
Both parts fucntionally different with different connections
Lentiform nucleis =
Globus pallidus + putamen
Subthalamic nucleus
Receives Afferent from the cortex and other basal nucleu structures
Output excitatory to globus pallidus and substantia nigra
Substantia nigra
In rostral midbrain
Dopaminergic neurons project to striatum and subthalamic nucleus
Describe the limbic system
Structures referred to as limbic lobe
Ring of cortex spanning frontal, parietal & temporal lobes
Influence ANS, endocrine secretions, emotional behaviour
What are the structures in the limbic system
Structures include:
• Subcallosal gyrus
• Cingulate gyrus
• Parahippocampal gyrus
• Hippocampal formation
• Amygdaloid nucleus
• Mammillary bodies
• Ant. Thalamic nucleus
What are the 3 parts of the hippocampus/hippocampal formation
Subiculum
Hippocampus proper (Ammon horn)
Dentate gyrus
Describe ht hippocampus
Hippocampus and subiculum fibres form fimbria becoming fornix (output pathway)
Send fibres to entorhinal cortex
Neurogenesis occurs in dentate gyrus
Hippocampus - memory
Describe the amygdala
Afferent include visual, somatosensory, gustatory and olfactory, thalamus and cortical
Plays a role in emotions, emotional memory and learning, fear and related behaviours and reward
If damaged normal facilitation of attention and memory of emotional stimuli affected
What does the Diencephalon consist of
Thalamus, hypothalamus, epithalamus
Describe the structure of the Diencephalon
Located between the brainstem and the cerebral hemisphere
Continuous with the rostral part of the midbrain
Forms the lateral wall of the 3rd ventricle
Describe the thalamus
2 thalami n eon each side of the 3rd ventricle
Connected by iterthalamic connection
Receives and processes all information coming from the cerebrum
Subcortical structures project to the cortex via thalamus
Mediates emotional response, arousal and emotion
Describe the input o the thalamus
Specific (drivers) information that must be forwarded to the cortex
Regulatory (modulators) modulate and regulate what is sent to the cortex
What are the functional nuclei of the thalamus
Relay - motor, sensory and limbic
Association - connect with cortex
Other- connect with basal nuclei, limbic system, reticular nucleus
What are relay nuclei in thalamus
Sensory relay nuclei
Input related to sensory receptors
MGN - medial geniculate nucleus
LGN - lateral geniculate nucleus
What are relay nuclei in thalamus
Input related to motor areas
VA - ventral anterior nucleus
VL - ventral lateral nucleus
Limbic relay nuclei in thalamus
Anterior nucleus ANT input from ipsilateral mammillary body, relayed to cingulate cortex and prefrontal and parietal cortices
Lateral dorsal nucleus LD input from entorhinal cortex relayed to cingulate and prefrontal and parietal cornices
What are limbic association nuclei in thalamus
Dorsomedial nuclei - connections throughout the limbic system
Association nuclei in thalamus Diencephalon
Pulvinar (PUL) – reciprocal extensive connections
• Receives input from retina & visual assoc. areas to integrate and evaluate. Visuospatial working memory
• Related to auditory processing, coordinates and engages areas important in language
Dorsomedial nucleus
• Afferent fibres from basal nuclei & amygdala also
• Plays a role in limbic circuit of motivational & emotional aspects of behaviour
Association nuclei
Modulators in interactions of one part of the cortex with another
Intralaminar nuceli
Centromedian (CM) & Parafasicular (PF) nuclei
• Play a role in arousal and in facilitating awareness & vigilance.
• Connections to striatum suggest a role in facilitating goal orientated behaviour
Thalamus reticular nucleus
Sheet of neurons surrounding the thalamus
Modulate excitatory projections between the thalamus & cortex influencing the flow of information from the thalamus
What is the hypothalamus
Floor of Diencephalon
Attached to pituitary gland at ventral side by infundibulum, penetrated by 3rd ventricle
Main homeostatic centre, direct contact with blood, monitors everything, secretes hormones
What nuclei does hypothalamus house
• Supraoptic
• Paraventricular
• Ventromedial
• Suprachiasmatic
• Dorsomedial
• Arcuate
• Tuberal
Afferent connections of hypothalamus
General somatic, visceral, gustatory
Limbic system
Olfactory information
Thalamohypothalamic
Retinohypothalamic
Efferent connections of the hypothalamus
Descending to visceral motor nuclei via brainstem and spinal cord (sympathetic and parasympathetic nuclei and ganglia)
Ascending to the thalamus
What is the epithalamus
Forms the roof of the Diencephalon
Consists of:
-pineal gland (plays a role in circadian rhythm)
-habenular nucleus (centre for integration for olfactory, visceral and somatic efferent pathways)
