Handout: Subcortical and Cerebellar Lesions: Behavioral Deficits

	PSY 448 Clinical Neuropsychology	Last revised:Sept. 28, 2013
Subcortical, Cerebellar, & Limbic System Lesions: Behavioral Deficits

Subcortical = Below the level of the cortex, i.e., related to structures under the 'grey' matter of the cortical surface.
This includes both association fiber tracts and non-cortical structures.

Material in this handout summarizes Lezak (1983), passim.

Medulla Oblongata [A in fig.]

Basic life maintenance functions, e.g, nervous control of respiration, blood pressure, and heartbeat

Damage leads generally to death

Reticular Activating System (within medulla) controls wakefulness and alertness

Damage leads to global disorders of consciousness, e.g., drowsiness, somnolence, stupor or coma

Pons [B in fig.] and Cerebellum [C in fig.]

Correlation of postural and kinesthetic (muscle movement) data

Damage leads to movement disorders involving:
1. Fine motor control
2. Coordination
3. Postural regulation

Midbrain [D in fig.]

Correlation of sensory and motor centers;

Integration of reflex & automatic responses involving the visual and auditory systems

Damage leads to specific movement disorders, e.g.,

1. certain types of tremor
2. rigidity
3. extraneous movements of local muscle groups

Thalamus [E in fig.]

Major sensory correlation center

Participates in exchanges between higher and lower brain structures, between sensory & motor or regulatory components at same level, and between cerebral cortical centers at highest levels function

Regulation of cortical activity via focusing & shifting attention as well as modality-specific alerting functions

Damage of Left thalamus may lead to decreased verbal fluency, speech spontaneity, verbal memory and learning disorders.

Damage to Right thalamus may lead to decreased face/pattern recognition, pattern matching, maze tracing.

Bilateral lesions may lead to general intellectual loss, gross memory problems, emotional apathy, development of mutism.

Hypothalamus [F in fig.]

Regulation of physiologically-based drives, e.g., appetite, sexual arousal, thirst

Physical protection behavioral patterns, e.g., fear, rage

Regulation of autonomic functions, e.g., weight, temperature, some mood states.
Damage leads to obesity, disorders of temperature control, changed appetitive drive (e.g., sexual arousal loss or hypersexuality)

Limbic System

Hippocampus is involved in the long-term storage of perceptions in memory.

Bilateral damage to hippocampus leads to massive anterograde and some retrograde amnesia for declarative (not procedural) memories.

Unilateral damage to hippocampus leads to expected types of memory storage and retrieval problems, i.e., left damage with verbal data and right damage with nonverbal data.

Mammillary Bodies are also involved in the long-term storage of memories.

Damage to mammillary bodies leads to anterograde and some retrograde amnesia (usually as a result of alcoholism)

Hippocampus-Amygdala-Uncus (and Temporal Lobe) are involved in emotional behaviors.

Damage leads to disturbances and alterations in subjective feeling, bizarre posturing, obsessional thoughts, initiation of elaborate, stereotyped, complex motor behaviors.

	Midbrain [D in fig.]
	Correlation of sensory and motor centers; Integration of reflex & automatic responses involving the visual and auditory systems	Damage leads to specific movement disorders, e.g., 1. certain types of tremor 2. rigidity 3. extraneous movements of local muscle groups
	Thalamus [E in fig.]
	Major sensory correlation center Participates in exchanges between higher and lower brain structures, between sensory & motor or regulatory components at same level, and between cerebral cortical centers at highest levels function Regulation of cortical activity via focusing & shifting attention as well as modality-specific alerting functions	Damage of Left thalamus may lead to decreased verbal fluency, speech spontaneity, verbal memory and learning disorders. Damage to Right thalamus may lead to decreased face/pattern recognition, pattern matching, maze tracing. Bilateral lesions may lead to general intellectual loss, gross memory problems, emotional apathy, development of mutism.
	Hypothalamus [F in fig.]
	Regulation of physiologically-based drives, e.g., appetite, sexual arousal, thirst Physical protection behavioral patterns, e.g., fear, rage Regulation of autonomic functions, e.g., weight, temperature, some mood states.	Damage leads to obesity, disorders of temperature control, changed appetitive drive (e.g., sexual arousal loss or hypersexuality)

	Medulla Oblongata [A in fig.]
	Basic life maintenance functions, e.g, nervous control of respiration, blood pressure, and heartbeat	Damage leads generally to death
	Reticular Activating System (within medulla) controls wakefulness and alertness	Damage leads to global disorders of consciousness, e.g., drowsiness, somnolence, stupor or coma
	Pons [B in fig.] and Cerebellum [C in fig.]
	Correlation of postural and kinesthetic (muscle movement) data	Damage leads to movement disorders involving: 1. Fine motor control 2. Coordination 3. Postural regulation

	Limbic System
	Hippocampus is involved in the long-term storage of perceptions in memory.	Bilateral damage to hippocampus leads to massive *anterograde* and some *retrograde* amnesia for declarative (not procedural) memories. Unilateral damage to hippocampus leads to expected types of memory storage and retrieval problems, i.e., left damage with verbal data and right damage with nonverbal data.
	Mammillary Bodies are also involved in the long-term storage of memories.	Damage to mammillary bodies leads to anterograde and some retrograde amnesia (usually as a result of alcoholism)
	Hippocampus-Amygdala-Uncus (and Temporal Lobe) are involved in emotional behaviors.	Damage leads to disturbances and alterations in subjective feeling, bizarre posturing, obsessional thoughts, initiation of elaborate, stereotyped, complex motor behaviors.