Frontal+Lobes

The Frontal Lobe
The frontal lobes are the senior executive of the brain and personality. Over the course of evolution, the frontal lobes have greatly expanded in size, and are largely responsible for the incredible achievements in art, culture, music, science, and math which are uniquely human. Although the frontal lobes are not the seat of intelligence, it is this region of the brain which enables humans to effectively utilize that intelligence and to anticipate and plan for future possibilities.

The frontal lobes act to process, integrate, inhibit, assimilate, and remember perceptions and impulses received from the limbic system, striatum, temporal lobe, and neocortical sensory receiving areas. -Engages in decision making and goal formation, -Modulates and shapes character and personality -Directs attention -Maintains concentration -Participates in information storage and memory retrieval At the neocortical level they are also responsible for the vocalization of language including: -Organizing and and monitoring the processes involved in preparing to speak -The retrieval of semantic information -Insertion of syllables -Temporal sequences into autiory output -Programming and activating the primary motor areas subserving the oral-laryngeal musculature

The frontal neocortex is "interlocked" with the limbic system, striatum, and the primary and secondary receiving areas via converging and reciprocal connections, and receives verbal and ideational impulses transmitted from the multi-modality associational areas including Wernicke's area and the inferior parietal lobule. It is thus able to act at all levels of information analysis.

SUBSECTIONS:
<span style="font-family: 'Times New Roman',serif;">THE RIGHT FRONTAL LOBE AND THE REGULATION OF AROUSAL <span style="font-family: 'Times New Roman',serif;">THE LEFT FRONTAL LOBE: DEPRESSION, APATHY, APHASIA, SCHIZOPHRENIA SUPPLEMENTARY MOTOR AREAS SECONDARY/PREMOTOR MOTOR AREAS PRIMARY MOTOR AREA EXNER'S WRITING AREA THE FRONTAL EYE FIELDS THE CORTICOSPINAL TRACT STRIATUM

<span style="color: #000000; font-family: 'Times New Roman',serif;">-Excessive or diminished cortical and behavioral arousal <span style="color: #000000; font-family: 'Times New Roman',serif;">-Disintegration of personality and emotional functioning <span style="color: #000000; font-family: 'Times New Roman',serif;">-Difficulty planning or initiating activity <span style="color: #000000; font-family: 'Times New Roman',serif;">-Abnormal attention and ability to concentrate <span style="color: #000000; font-family: 'Times New Roman',serif;">-Severe apathy or euphoria <span style="color: #000000; font-family: 'Times New Roman',serif;">-Disinhibition and a reduced ability to monitor and control one's thoughts, speech, <span style="color: #000000; font-family: 'Times New Roman',serif;">- Disinhibited Sexuality <span style="color: #000000; font-family: 'Times New Roman',serif;">laughter and actions, including loss of memory.
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">If damaged there can result: **

<span style="color: #000000; font-family: 'Times New Roman',serif;">Moreover, frontal lobe abnormalities commonly result in major cognitive, perceptual, and emotional disturbances, such as <span style="color: #000000; font-family: 'Times New Roman',serif;">-Schizophrenia <span style="color: #000000; font-family: 'Times New Roman',serif;">-Catatonia <span style="color: #000000; font-family: 'Times New Roman',serif;">-Mania <span style="color: #000000; font-family: 'Times New Roman',serif;">-Depression <span style="color: #000000; font-family: 'Times New Roman',serif;">-Obsessive compulsions <span style="color: #000000; font-family: 'Times New Roman',serif;">-Aphasia <span style="color: #000000; font-family: 'Times New Roman',serif;">-Confabulatory delusions <span style="color: #000000; font-family: 'Times New Roman',serif;">-EMOTIONAL & PROSODIC SPEECH <span style="color: #000000; font-family: 'Times New Roman',serif;">-TANGENTIAL, PRESSURED SPEECH & CIRCUMLOCUTORY SPEECH -CONFABULATION (DELUSIONAL & FALSE MEMORIES) <span style="font-family: 'Times New Roman',serif; line-height: 1.5;">-The "frontal lobe personality."

<span style="color: #000000; font-family: 'Times New Roman',serif;">Patients may also develop paralysis of the extremities, or demonstrate severe unilateral neglect of visual-auditory space, or conversely, compulsively utilize tools or other objects, such that in the extreme the right or left hand may act completely independently of the "conscious" mind.

<span style="color: #000000; font-family: 'Times New Roman',serif;">The reason for such a wide range of potential disturbance is that rather than a single pair of frontal lobes there are several "frontal" regions which differ in regard to embryology, phylogeny, cellular composition, functional specificity and interconnection and interactions with other brain areas. Moreover, damage is seldomly restricted to one specific frontal area but commonly disrupts adjoining "frontal" tissues as well.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Broadly speaking, the frontal lobes can be functionally lateralized as well as subdivided into four major functional-anatomical regions. <span style="color: #000000; font-family: 'Times New Roman',serif;">As subzones within the right and left frontal lobes, these include the <span style="color: #000000; font-family: 'Times New Roman',serif;">posterior-lateral motor areas (Brodmann's areas 4, 6, 8, 44, 45), <span style="color: #000000; font-family: 'Times New Roman',serif;">the superior lateral convexity (areas 9,8,6,47,46,45,44), <span style="color: #000000; font-family: 'Times New Roman',serif;">the inferior/orbital (areas 47,44,10,11, 12, 13, 14, 25), <span style="color: #000000; font-family: 'Times New Roman',serif;">and the medial motor areas (areas 11,12,10,9,8, 6,32,33,25,24) which overlaps with the motor, lateral convexity, and orbital areas. <span style="color: #000000; font-family: 'Times New Roman',serif;">In addition, the anterior cingulate, and the head of the corpus striatum are intimately associated with and can be considered as part of the "extended frontal lobe."

<span style="color: #000000; font-family: 'Times New Roman',serif;">**FUNCTIONAL OVERVIEW:**
<span style="color: #000000; font-family: 'Times New Roman',serif;">The right and left frontal lobes appear to exert differing influences over arousal, attention, sexual, emotional, and memory functioning including even humor appreciation <span style="color: #000000; font-family: 'Times New Roman',serif;">When adults who have been traumatized recall traumatic imagery of when they view combat-related photographs, the right frontal lobe displays increased activity, and the left inferior-orbital region displays reduced activity.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Right frontal area mediates emotional and melodic speech <span style="color: #000000; font-family: 'Times New Roman',serif;">Left frontal area mediates the syntactical, lexical, semantic, and temporal sequential aspects of speech and is dominant. <span style="color: #000000; font-family: 'Times New Roman',serif;">The right frontal lobe is dominant for arousal and appears to exert bilateral inhibitory influences over arousal whereas the influences of the left frontal lobe are more unilateral and excitatory <span style="color: #000000; font-family: 'Times New Roman',serif;">Hence, if the left frontal lobe is injured, cognitive and expressive functions tend to become suppressed and inhibited--a function not only of the injury but right frontal suppressive influences. <span style="color: #000000; font-family: 'Times New Roman',serif;">By contrast, right frontal injuries are more likely to give rise to disinhibitory states, including the so called "frontal lobe personality" <span style="color: #000000; font-family: 'Times New Roman',serif;">Specifically, reduced speech output, Broca's aphasia, apathy, "blunted" schizophrenia and major depression are often associated with left lateral (and bilateral) frontal injuries <span style="color: #000000; font-family: 'Times New Roman',serif;">Adults with PTSD also display reduced left frontal lobe activity <span style="color: #000000; font-family: 'Times New Roman',serif;">Sadness can reduce right and bi-frontal activity, though in most instances depression is directly attributed to left frontal dysfunction and reduced left frontal activity. <span style="color: #000000; font-family: 'Times New Roman',serif;">In schizophrenia, lateral frontal gray matter reductions and decreased brain volume and activity have been repeatedly noted <span style="color: #000000; font-family: 'Times New Roman',serif;">By contrast, impulsiveness, confabulation, "motor mouth," grandiosity, and mania are often produced by right frontal (as well as bilateral) lesions. Pressured and/or confabulatory speech that may be melodically distorted.

<span style="color: #000000; font-family: 'Times New Roman',serif;">In some respects, orbital frontal dysfunction is similar to right frontal abnormalities: <span style="color: #000000; font-family: 'Times New Roman',serif;">-lability <span style="color: #000000; font-family: 'Times New Roman',serif;">-Impulsiveness <span style="color: #000000; font-family: 'Times New Roman',serif;">-Emotionally inappropriate behavior. <span style="color: #000000; font-family: 'Times New Roman',serif;">With massive injuries localized to the orbital/inferior areas, and/or which functionally disrupts the frontal-striatal pathways patients may have difficulty inhibiting unwanted movements or thoughts, and may develop perseverative, obsessive compulsive abnormalities. In part, these gross similarities in symptomology are due to the similar role these neocortices play in regard to the control over arousal, the right frontal area regulating neocortical and thalamic activity, the orbital areas exerting inhibitory control over the limbic system.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Medial frontal injuries: <span style="color: #000000; font-family: 'Times New Roman',serif;">in some respects grossly similar to those associated with left frontal injuries - <span style="color: #000000; font-family: 'Times New Roman',serif;">-Reduced speech output <span style="color: #000000; font-family: 'Times New Roman',serif;">-Mutism <span style="color: #000000; font-family: 'Times New Roman',serif;">-Severe apathy.

<span style="color: #000000; font-family: 'Times New Roman',serif;">With massive deep medial frontal dysfunction, the patient may become motionless, rigid, and completely catatonic. <span style="color: #000000; font-family: 'Times New Roman',serif;">However, with less severe injuries, although suffering from disturbances of "will" and volition, patients may also develop "alien hand".

<span style="color: #000000; font-family: 'Times New Roman',serif;">**CAVEATS ON FUNCTIONAL LOCALIZATION AND SIGNATURE SYMPTOMOLOGY**
<span style="color: #000000; font-family: 'Times New Roman',serif;">In some cases it is possible to localize a specific subtype of schizophrenia, mania, or depression, to a specific region of the brain based upon those symptoms. <span style="color: #000000; font-family: 'Times New Roman',serif;">Examples: <span style="color: #000000; font-family: 'Times New Roman',serif;">Smooth pursuit and sacadic eye movements are mediated by the frontal eye fields in conjunction with the striatum, midbrain, and cerebellum. <span style="color: #000000; font-family: 'Times New Roman',serif;">Frontal lobe deficits and reduced ability to perform frontal lobe tests such as the Wisconsin Card Sort, have been found among "Schizophrenics" with smooth pursuit and sacadic abnormalities <span style="color: #000000; font-family: 'Times New Roman',serif;">Deficits in volitional eye movements have also been documented among those diagnosed with autism nfortunately, psychiatric patients tend to be studied as a group based on a DSM-diagnosis and are seldom selected on the basis of similarities in signature symptomology. <span style="color: #000000; font-family: 'Times New Roman',serif;">Moreover, because the frontal lobes receive converging input from all limbic system structures, the striatum, as well as the primary and association sensory receiving areas, in some instances deficits associated with frontal injury can be produced secondary to abnormalities in these tissues due to disconnection or abnormal activity. <span style="color: #000000; font-family: 'Times New Roman',serif;">Because the frontal lobes are not a homologous structure but maintain extensive interconnections with a variety of brain regions, sometimes damage to the pathways linking the frontal lobes with these areas, or injuries to these "non-frontal" tissues, can produce similar symptoms. <span style="color: #000000; font-family: 'Times New Roman',serif;">For example, the caudate, putamen, and nucleus accumbens (striatum) are located in the paramedian depths of the right and left frontal lobe, and obsessive-compulsions have frequently been observed not only with frontal injuries, but in association with striatal abormalities. <span style="color: #000000; font-family: 'Times New Roman',serif;">Likewise, "schizophrenia" has been associated not only with left frontal injuries, but with left temporal or left frontal-temporal lobe injuries or with damage to the striatum, or the frontal-striatal or temporal (hippocampal/amygdala)-striatal pathways

<span style="color: #000000; font-family: 'Times New Roman',serif;">Similarly, mania and confabulatory delusions may be associated with right temporal, right frontal-temporal, and right frontal-parietal dysfunction depending on the diagnostic or research criterion employed as well as the nature of the lesion, e.g. stroke, vs tumor, vs seizure disorder.

<span style="color: #000000; font-family: 'Times New Roman',serif;">INTELLECTUAL DEFICITS AND LACK OF CONCERN FOR LONG TERM CONSEQUENCES
<span style="color: #000000; font-family: 'Times New Roman',serif;">It has frequently been claimed that intelligence is not effected even with massive injuries to the frontal lobes. However, even in mild cases, although intelligence per se may not seem to be reduced as based on IQ testing, the ability to effectively employ one's intelligence is almost always compromised. <span style="color: #000000; font-family: 'Times New Roman',serif;">Frontal lobe damage and lobotomy reduces one's ability to profit from experience, to anticipate consequences, or to learn from errors <span style="color: #000000; font-family: 'Times New Roman',serif;">There is a reduction in creativity, fantasy, dreaming, and abstract reasoning. <span style="color: #000000; font-family: 'Times New Roman',serif;">The capacity to synthesize ideas into concepts or to grasp situations in their entirety is lost, and interests of an intellectual nature are diminished, or sometimes abolished. <span style="color: #000000; font-family: 'Times New Roman',serif;">In mild or severe cases thinking may be contaminated by perseverative intrusions of irrelevant and tangential ideas, randomly formed associations, and illogical intellectual activity. <span style="color: #000000; font-family: 'Times New Roman',serif;">These patient are also often effected by the immediacy of their environment and have difficulty making plans or adequately meeting long term goals. <span style="color: #000000; font-family: 'Times New Roman',serif;">Even if highly intelligent, they may no longer be able to use that intelligence affectively, and they may undergo a complete personality change.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Frontal lobe patients also may have difficulty thinking up or considering alternative problem solving strategies and thus developing alternative lines of reasoning.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Some frontal lobe patients may also have extreme difficulty sorting even common everyday objects according to category, for example, sorting and grouping drinking containers (glasses) with other drinking containers (mugs), tools with tools, etc. Similarily, they may have difficulty performing the Wisconsin Card Sorting Task.

<span style="color: #000000; font-family: 'Times New Roman',serif;">In studies in which patients undergoing frontal leucotomy for intractable pain were administered the Wechsler Intelligence Scales both pre- and post surgery, a 20 point drop in the IQ was reported
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">I.Q. Testing **

<span style="color: #000000; font-family: 'Times New Roman',serif;">Likewise, in cases where the Raven's Progressive Matrices or Porteus Mazes were administered both before and after lobotomy, significant declines in intellectual functioning have been documented. As with most tests, the usual pattern is to improve with practice. Hence, these results (and those mentioned above) indicate that frontal lobe damage disrupts abstract reasoning skills, verbal-nonverbal pattern analysis, learning and intellectual ability, as well as the capacity to anticipate the consequences of one's actions or to profit from experience. <span style="color: #000000; font-family: 'Times New Roman',serif;">For example, left frontal patients show lower Wechsler IQs than those with right frontal lesions. Patients with left sided destruction perform as poorly as those with bilateral damage.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Left frontal lobotomy patients scored particularly poorly on Picture Completion (which requires identification of missing details). <span style="color: #000000; font-family: 'Times New Roman',serif;">This is presumably a consequence of the left cerebral hemisphere being more conerned with the perception of details (or parts, segments) vs wholes.

<span style="color: #000000; font-family: 'Times New Roman',serif;">In contrast, individuals with severe right frontal damage have difficulty performing Picture Arrangement--often leaving the cards in the same order in which they are laid. This may be a consequence of deficiencies in the capacity to discern social-emotional nuances, a function at which the right hemisphere excels.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Summary
<span style="color: #000000; font-family: 'Times New Roman',serif;">Reduced speech output, Broca's aphasia, apathy, "blunted" schizophrenia and major depression are often associated with left lateral (and bilateral) frontal injuries. <span style="color: #000000; font-family: 'Times New Roman',serif;">By contrast, impulsiveness, confabulatory verbosity, <span style="color: #000000; font-family: 'Times New Roman',serif;">pressured and/or confabulatory speech that may be melodically distorted, <span style="color: #000000; font-family: 'Times New Roman',serif;">grandiosity, and mania are often produced by right frontal (as well as bilateral) lesions.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Thus, where with left frontal injuries patients may seem apathetic, indifferent, and/or severely depressed and psychotic if not schizophrenic, right frontal injuries are associated with manic-like disinhibited states, including waxing and waning abnormalities associated with manic-depression. Patient's may become so disinhibited they develop the classic "frontal lobe personality," and become disinhibited, hyperactive, euphoric, extroverted, labile, overtalkative, and may develop perseveratory tendencies. Patients may become so disinhibited, delusional, grandiose, and emotionally labile that they develop what has classically been described as mania. <span style="color: #000000; font-family: 'Times New Roman',serif;">By contrast, with a left frontal lesion, rather than a loss of emotional control, there is a loss of emotion, and the patient will become severely apathetic, indifferent, and with massive lesions unresponsive, though classically left frontal injuries are associated with depression.

<span style="color: #000000; font-family: 'Times New Roman',serif;">These right and left frontal differences are a function of lateralized differences in the control over arousal. Whereas the orbital frontal lobes contral limbic arousal, the right and left frontal lobes control neocortical arousal, with the right frontal lobe exerting bilateral inhibitory and excitatory influences, whereas the left frontal lobe exerts unilateral excitatory influences.

<span style="color: #000000; font-family: 'Times New Roman',serif;">FRONTAL LOBE REGULATION OF THE NEOCORTEX
<span style="color: #000000; font-family: 'Times New Roman',serif;">With the exception of olfactory information (straight to the limbic system), all sensory impulses are first transferred to the thalamus before being transmitted to the primary auditory, visual, and somesthetic receiving areas. It is then sent 3 places;the immediately adjacent sensory association area, back to the thalamus, and to the motor cortex of the frontal lobes.

<span style="color: #000000; font-family: 'Times New Roman',serif;">The motor area then relays this information to the lateral convexity which simultaneously receives fiber projections from the sensory association areas and the inferior parietal lobule. Hence, the frontal cortex and right and left lateral convexity are "interlocked" with the posterior sensory areas via converging and reciprocal connections with the first, second, and third level of modality specific analysis, including the multimodal associational integration performed by the inferior parietal lobule. The frontal lobes, therefore able to sample activity within all cortical sensory/association regions at all levels of information analysis.

<span style="color: #000000; font-family: 'Times New Roman',serif;">THALAMIC CONTROL OVER NEOCORTICAL ACTIVITY
<span style="color: #000000; font-family: 'Times New Roman',serif;">The lateral convexity also involves regulation of information flow to and within the neocortex via projections linking the frontal lobes with the dorsal medial thalamic nucleus--a structure which participates in the transfer of information to the neocortex and which display neuroplasticity. <span style="color: #000000; font-family: 'Times New Roman',serif;">fibers passing to and from the thalamus and the cortical sensory receiving areas give off collaterals to the reticular thalamic nucleus--which in addition sends fibers which envelop and innervate most of the other thalamic nuclei. The reticular thalamus maintains reccurent inhibitory interconnections with other thalamic neurons and acts to synchronize and selectively gate transmission from the thalamus to the neocortex and continually samples thalamic-cortical activity.

<span style="color: #000000; font-family: 'Times New Roman',serif;">The reticular thalamus is controlled by the lateral convexity of the frontal lobes, and the lateral portion of the dorsal medial thalamus with which it maintains dense interconnections. The convexity and lateral dorsal medial nucleus (LDM) are also richly interconnected and together exert significant steering influences on the reticular thalamus. That is, the lateral frontal convexity appears to exert specific influences on the LDM so as to promote or diminish the flow of information to the cortex and thus modulate specific perceptual and cognitive activities occuring within the neocortex --activity which it is simultaneously sampling. This is in contrast to the orbital region with its connections to the reticular formation and the medial magnocellular segment of the dorsal medial thalamus, and its influences on generalized arousal and limbic activation/inhibition.
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">Thalamic Cortical Axons **

<span style="color: #000000; font-family: 'Times New Roman',serif;">To recapitulate, the lateral frontal system is able to influence cognitive/perceptual cortical functioning via the sampling of activity occurring throughout the neocortex at all levels of informational analysis, and via its modulating influences on the lateral portion of the dorsal medial and reticular thalamic nuclei. The lateral frontal region is thus able to act at any stage of processing, from initial reception to motor expression so as to facilitate or inhibit further analysis, selectively acting to determine exactly what type of processing occurs throughut the neocortex.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Via integration and inhibitory action and through its neocortical and thalamic links the lateral convexity it is able to coordinate interactions between various regions of the neuroaxis so as to organize, mobilize, and direct overall cortical and behavioral activity and to minimize conflicting demands, impulses, distractions and/or the processing of irrelevant information.

<span style="color: #000000; font-family: 'Times New Roman',serif;">-Behavioral disinhibition <span style="color: #000000; font-family: 'Times New Roman',serif;">-Flooding of the sensory association areas with irrelevant information <span style="color: #000000; font-family: 'Times New Roman',serif;">-Hyperreactively <span style="color: #000000; font-family: 'Times New Roman',serif;">-Distractability <span style="color: #000000; font-family: 'Times New Roman',serif;">-Memory loss <span style="color: #000000; font-family: 'Times New Roman',serif;">-Impulsiveness and/or apathy <span style="color: #000000; font-family: 'Times New Roman',serif;">-Reduced motor-expressive activities (e.g. speech arrest) <span style="color: #000000; font-family: 'Times New Roman',serif;">-Sensory neglect <span style="color: #000000; font-family: 'Times New Roman',serif;">Similar disturbances can result when the dorsal medial nucleus or the bi-directional pathways linking the thalamus and frontal lobe are severed
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">When damaged, depending on the site (e.g. inferior vs superior convexity) or laterality of th **
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">e lesion, there can result; **

<span style="color: #000000; font-family: 'Times New Roman',serif;">Hence, in summary, the oribtal region exerts modulating influences on subcortical and geralized limbic arousal. By contrast, the lateral convexity of the frontal lobes are "interlocked" with the the sensory receiving areas and maintains rich interconnections with the reticular and dorsal medial nucleus of the thalamus which relays sensory impressions to the neocortex.

<span style="color: #000000; font-family: 'Times New Roman',serif;">The lateral frontal lobes, therefore are able to sample perceptual input as it is received in the thalamus, and thus prior to and after it has been transferred to the neocortical receiving areas. Through its interconnections with the primary and association areas, the frontal lobes can also censor, inhibit, and thus control the processing of this data, and in this manner can control attention as well as facilitate or inhibit further analysis and thus information processing throughout the neocortex. These frontal capabilities include information storage and retrieval at the neocortical level; i.e. memory.

<span style="color: #000000; font-family: 'Times New Roman',serif;">In consequence, when the lateral regions are injured: <span style="color: #000000; font-family: 'Times New Roman',serif;">-Selective attention and memory functioning may become impaired (e.g. sensory-perceptual overload0 <span style="color: #000000; font-family: 'Times New Roman',serif;">-Become distractible <span style="color: #000000; font-family: 'Times New Roman',serif;">-Disinhibition <span style="color: #000000; font-family: 'Times New Roman',serif;"> -Difficulty keeping their mind on a certain tasks and/or recalling and acting upon events planned for the future. -Confusion <span style="color: #000000; font-family: 'Times New Roman',serif;">Similar disturbances can result when the dorsal medial nucleus or the bi-directional pathways linking the thalamus and frontal lobe are severed. However, the nature of these disturbances depends on if the right vs left frontal lobe has been negatively impacted.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Movement and motor functioning depend on <span style="color: #000000; font-family: 'Times New Roman',serif;">-The basal ganglia <span style="color: #000000; font-family: 'Times New Roman',serif;"> -Cerebellum -Brainstem <span style="color: #000000; font-family: 'Times New Roman',serif;">-Cranial nerve nuclei <span style="color: #000000; font-family: 'Times New Roman',serif;">-The motor thalamus <span style="color: #000000; font-family: 'Times New Roman',serif;">-Spinal cord <span style="color: #000000; font-family: 'Times New Roman',serif;">-Primary, secondary and supplementary motor areas of the frontal lobes
 * <span style="color: #000000; font-family: 'Times New Roman',serif;">MOVEMENT AND THE MOTOR AREAS OF THE FRONTAL LOBES - <span style="font-family: 'Times New Roman',serif;">FUNCTIONAL NEUROANATOMY OF THE FRONTAL MOTOR AREAS **

<span style="font-family: 'Times New Roman',serif; line-height: 1.5;">-Fine motor movements (including articulation of speech) are dependent on the primary motor areas <span style="color: #000000; font-family: 'Times New Roman',serif;">-The primary motor areas are dependent upon motoric impulses which are organized in premotor and the supplementary motor cortex <span style="font-family: 'Times New Roman',serif;">-Exner's writing area is in part, within areas 6 and becomes active prior to (as well as during) hand movements and appear to program hand movements <span style="font-family: 'Times New Roman',serif;">-The frontal eye fields (within areas 6,8,9) becomes active prior to (as well as during) eye movements and appears to program eye movements <span style="font-family: 'Times New Roman',serif;">-Broca's Area programs the oral-laryngeal musculature, is programmed by Broca's expressive speech area areas 45, 46. Broca's area also becomes active prior to vocalization and during subvocalization.

<span style="color: #000000; font-family: 'Times New Roman',serif;">Smooth, purposeful, coordinated movement requires sensory feedback which is provided by the primary and association/secondary somatosensory areas located in the parietal lobe and which contain neurons which guide the hand and arm in visual space. These cortices are intimately linked with the primary motor and the motor association/secondary and supplementary motor areas as well as the basal ganglia, brainstem, and cerebellum--regions which become highly active during and often prior to movement initiation. <span style="color: #000000; font-family: 'Times New Roman',serif;">Example: When humans learn a sequence of finger movements, functional imaging reveals increased activity in the primary and premotor cortex, and the primary and association somesthetic cortex, as well as in the cerebellum, striatum, ventral thalamus and cerebellum. In fact, most of the "motor" area also contain independent motor maps of the body, which is why, if a subject moves an arm, leg, or shoulder, each of these areas becomes active almost simultaneously..

<span style="color: #000000; font-family: 'Times New Roman',serif;">Hence, although some movements are programmed in parallel by a number of motor areas simultaneously, others are programmed in temporal sequences such that the SMA programs the premotor area which acts on the primary area which becomes maximally active when movements are actually performed. IN this regard it is noteworthy that whereas stimulation of the SMA can prevent movement, stimulation of the premotor area can give rise to the illusion that a movement is about to be made, that is, of an impending movement, whereas activation of the primary area can trigger twitching, and minor motor movements--which again suggests a hierarchical organization.

**<span style="color: #000000; font-family: 'Times New Roman',serif;">MEMORY AND MULTI-MODAL MOTOR NEURONS **
<span style="color: #000000; font-family: 'Times New Roman',serif;">The motor areas do not just program, but anticipate, as well as memorize certain movement programs. <span style="color: #000000; font-family: 'Times New Roman',serif;">Individual neurons within the motor cortex (of monkeys) have been shown to learn and neurally encode serial order when performing a context-recall visual-memory scanning task. <span style="color: #000000; font-family: 'Times New Roman',serif;"> Moreover, neural activity will change when the serial order is changed and in accordance with the direction of movement as well as stimulus position and movement. <span style="font-family: 'Times New Roman',serif; line-height: 1.5;">-"motor" neurons in the inferior-ventral portion of the (monkey) premotor cortex can code for the spatial location of nearby sounds, particularly those originating near the head These neurons appear to be "multi-modal" and can also respond to visual and tactile stimuli that impinge near or upon the face