Neural Bases - Chapter 6 Flashcards
- Located between the cerebrum and the brainstem, resting above the midbrain of the brainstem.
- Prime area for connecting the cerebral cortex to the rest of the body
- Connects the nervous system to the endocrine and hormone system
- Consists of four parts: thalamus, subthalamus, hypothalamus, and epithalamus
Diencephalon
- Inner chamber or bedroom: Lies on top of the midbrain and consists of two halves or hemispheres.
thalamus
blood supply
internal carotid artery (tuberothalamic branch), posterior cerebral artery
- Sensory fiber relay station or switchboard between cerebral cortex and subcortical areas
o Acts like a router that routes specific information to specific cortical areas
o Relay station
o Perception of pain, regulation of cortical arousal, control of sleep-wake cycle - Involves indirectly in motor functions – directs the extrapyramidal fibers to basal ganglia
thalamus
the thalamus is made up of several _______
nuclei
attention, eye-hand control, emotions, and autonomic control
medial nuclei
emotional processing
- Lateral dorsal, midline and anterior nuclei
o Posterior part: somatosensory functions; relay sensory information about the speech musculature movements
o Anterior & lateral part: executing motor movements and motor planning for speech production
o Medial geniculate body – auditory relay center
o Lateral geniculate body – vision relay center
lateral ventral nuclei
arousal and motor function
intralaminar nuclei
filter for information ascending to the cortex
reticular nuclei
Burning or tingling sensations and hypersensitivity to stimuli that would not cause pain normally (ex: light touch or temperature change)
thalamic pain syndrome
coma, excessive day time sleepiness, akinetic mutism (unable to more or talk; being passive)
specific thalamic region injury/damage
verbal fluent output but with jargon, less severe auditory comprehension deficit, minimal or intact repetition
thalamic aphasia
- Lies below the thalamus, and functions like basal ganglia.
- Key role in selection of actions and impulse control
- Damage to subthalamus – one side involuntary movements of limbs, obsessive-compulsive disorder, impulsivity, etc
subthalamus
- Under chamber, lies in the anterior ventral surface of thalamus.
- Connects the nervous system with endocrine system via pituitary gland.
- Regulates metabolism, body temperature, food intake, circadian rhythm, emotion, secondary sexual characteristics, homeostasis or maintaining body status
hypothalamus
- Lies superior and posterior to the thalamus
- Consists of:
o Pineal gland – regulates sleep-wake cycle, circadian rhythm, and gonad development
o Habenula – involved in stress response as well as reward processing system
epithalamus
- Made up of a group of structures in the subcortical Gray matter region
- Consists of three large nuclei the caudate nucleus (amygdala), Globus pallidus, and putamen
o Striatum – caudate and putamen together
o Lenticular nucleus – putamen and globus pallidus
the basal ganglia
fibers between the cortical surface and thalamus create a fan-shaped sheet of axons
corona radiata
narrow space between the caudate nucleus and the lenticular nucleus
internal capsule
- direct pathway – striatum to medial globus pallidus facilitates movement.
- Indirect pathway – stratum to lateral globus pallidus inhibits movement
the two major pathways of the basal ganglia
– involuntary movements
* Tremors – rhythmic shaking
* Athetosis – slow writhing movements of head and hands
* Chorea – quick abrupt flinging of a limb
* Tics – quick stereotyped motor or vocal behaviors
* Ballismus – quick flinging of a limb
damage to the basal ganglia: dyskinesia
involuntary posture – unable to direct movements and having involuntary postural alignment
* Rigidity – limb resistance to passive movement
* Dystonia – simultaneous agonist and antagonist muscle contraction resulting in distorted movements and postures
* Bradykinesia – slow movements
damage to the basal ganglia: akinesia
- Progressive extrapyramidal movement disorder involving degeneration of substantia nigra resulting in loss of dopamine
- Caused due to environmental toxins and genetics
- Typically begins around 60 years of age
- Bradykinesia, resting tremor, and rigidity – masked face
- Dopamine-based drugs may eleviate the symptoms
- Deep brain stimulation
damage to the basal ganglia: Parkinson’s disease
- Progressive hereditary neurological disorder; regeneration of the basal ganglia and enlarges the brain ventricles
- Commonly presents between ages of 35-42 years
- Caused by a mutation on chromosome 4 (autosomal dominant inheritance pattern)
- Fidgety and clumsiness - initially
damage to basal ganglia: huntington’s disease
