The Telencephalon Basal ganglia Limbic System Cerebral cortex

The Telencephalon – Basal ganglia – Limbic System – Cerebral cortex » “Basal Forebrain” » Basal ganglia » limbic system

Basal Ganglia • Neostriatum – Caudate (kaw-date) nucleus and putamen (pew-TAY-men) • Globus Pallidus ( GLOB-us PAL-i-dos) • Substantia nigra (included by functional anatomical relationship) • Subthalamus • others not

Basal ganglia- Complex ccts The basal ganglia are involved in motor regulation, but are only one component of the control of behavior. The way in which the basal ganglia controls movement is complicated and not completely understood, but at his time may be fairly described as the gate-keeper of movement. Disorders of the basal ganglia can either lead to too much behavior or too little behavior.

Basal Ganglia-Neostriatum ( composed of the caudate nucleus and the Putamen)

The Nigro-striatal pathway- the behavioral “grease” system

The Globus Pallidus ( the striato-pallidal circuit= the behavioral “brakes” system)

Basal Ganglia Syndromes too much or too little behavior • Damage to the Nigro-striatal pathway – Parkinsons (not enough behavior) – http: //video. google. com/videosearch? hl=en&rls=GGIC, GGIC: 200701, GGIC: en&um=1&q=parkinsons&ndsp=20&ie=UTF-8&sa=N&tab=iv#

Basal Ganglia syndromes • Strato-Pallidal Pathway- too much behavior – Huntingtons – Tourettes’ – Balisms – Others

Dr. George Huntington, a Long Island, N. Y. physician first described this disease in 1872. The most famous sufferer of this disorder was probably the celebrated folk singer Woody Guthrie, whose wife, Marjorie noticed her husband walking lopsidedly one day in the 1950 s. She then began to notice that his speech was becoming slurred but it was only when he began to fly into major rages that she realized something was severely wrong with her husband. Eventually, he lost all ability to talk, to read or walk. The only way he could communicate with his wife and children was by waving his arm at cards printed with the words 'Yes' and No'. .

• The disease was Huntington's Chorea, which is an inherited, degenerative disorder of the Central Nervous System, caused by a dominant gene. This means that everyone who inherits the gene from one of his/her parents WILL develop the disease, and the likelihood of doing so is therefore 50%. The specter of this cruel disease continues to hang over the entire Guthrie family

• Huntington's Chorea is a particularly devastating disease because symptoms normally do not occur until after the age of 35, but can onset later (the earlier the onset, the more severe the disease tends to be). It is principally a movement disorder, with the first observable symptoms manifesting themselves as 'clumsiness', but as the disease progresses the movements become uncontrollable. These movements appear to be very bizarre and include odd bodily postures. Other symptoms are also apparent including forgetfulness and irritability or withdrawing (in the early stages) progressing to dementia with severe memory loss and lack of reasoning.

• Huntington's Chorea is principally characterized by hyperkinesias abnormal, purposeless, involuntary motor movements that can occur spontaneously or only when the patient is trying to do something. These movements may be repetitive or non-repetitive.

Tourettes Syndrome • TS usually becomes apparent in children between ages 2 to 15, with approximately 50% of patients affected by age 7. The age of symptom onset is typically before the age of 18. TS is more frequent in males than females by a ratio of about 3 or 4 to 1. The disorder is thought to affect 0. 1% to 1. 0% of individuals in the general population.

Tourettes • Motor tics Initially, patients develop sudden, rapid, recurrent, involuntary movements (motor tics), particularly of the head and facial area. At symptom onset, motor tics usually consist of abrupt, brief, isolated movements known as simple motor tics, such as repeated eye blinking or facial twitching. Simple motor tics may also include repeated neck stretching, head jerking, or shoulder shrugging. Less commonly, motor tics are more "coordinated, " with distinct movements involving several muscle groups, such as repetitive squatting, skipping, or hopping. These tics, referred to as complex motor tics, may also include repetitive touching of others, deep knee bending, jumping, smelling of objects, hand gesturing, head shaking, leg kicking, or turning in a circle. In addition to affecting the head and facial area, motor tics also affect other parts of the body, such as the shoulders, torso, arms, and legs. The anatomical locations of motor tics may change over time. Rarely, motor tics evolve to include behaviors that may result in selfinjury, such as excessive scratching and lip biting.

Vocal tics • Vocal tics are sudden, involuntary, recurrent, often relatively loud vocalizations. Vocal tics usually begin as single, simple sounds that may eventually progress to involve more complex phrases and vocalizations. For example, patients may initially develop simple vocal tics, including grunting, throat clearing, sighing, barking, hissing, sniffing, tongue clicking, or snorting. Complex vocal tics may involve repeating certain phrases or words out of context, one's own words or sounds (palilalia), or the last words or phrases spoken by others (echolalia). Rarely, there may be involuntary, explosive cursing or compulsive utterance of obscene words or phrases (coprolalia).

LIMBIC SYSTEM • • • Basal forebrain Interconnected Affective responses Impulsive…low consciousness Reciprocally connected with frontal cortex – Many structures • • Hippocampus Amygdala Septum Nucleus accumbens

View of some limbic system structures

Hippocampus (seahorse? ) Based on early neuroanatomical observations and studies with psychoactive drugs, the septohippocampal circuit has been proposed as a model for anxiety disorders. Note*-Memory processes can be profoundly affected by life experiences. In particular, stress has proved to be a major modulator of memory function. 1– 4

Hippocampus and Memory: “H. M. ” Henry Gustav Molaison, lost completely the ability to form new memories following a radical surgical procedure to treat his severe and intractable epilepsy. 1953; William Scoville, a neurosurgeon removed both of H. M. 's hippocampi in their entirety, together with some of the surrounding structures. profound anterograde and retrograde amnesia H. M. 's amnesia was so severe that he never recognized Dr. Brenda Milner, despite working with her for more than 50 years.

Hippocampus and spatial processing an apparatus often used to study “Place cells” of the hippocampus

How action potentials from place cells may be recorded

Visual representation of action potentials recorded from one hippocampal Place cell • The cell fires predominantly in association with one environmental location

Amygdala (almond shaped? ) Connected with and anterior to the hippocampus

The Amygdala receives input from many other brain areas that would logically allow evaluation of emotional significance of experiences