What Does The Left Temporal Lobe Do And Why Is It Important
The left temporal lobe plays an important role in language and memory processing. But where is it located and how does it work? Heres what you need to know.
Our brain is like a complex machine, made of many numerous parts. Each part plays a role in the maintenance of our emotions, reactions, decisions, and actions.
One of the most important parts of the brain is the left temporal lobe.
Here, you will find out all about the functions of the left temporal lobe and how to identify symptoms of damage in this part of the brain.
Ataxia Caused By Stroke
Stroke is a clot or bleed in any part of the brain. The cerebellum is a less common site for stroke than the cerebrum, but it can still occur there.
A clot or bleed in the cerebellum can cause the following:
Treating the stroke might resolve the ataxia. Occupational and physical therapy can help manage any permanent damage.
Selecting Manipulating And Monitoring The Contents Of Working Memory
For many of the more complex memory tasks used in imaging experiments, simple updating and maintenance processes are insufficient for optimal performance. Rather, these tasks require selection from, or refinement of, information that is maintained on-line, together with ongoing evaluation of the sufficiency of that information for the current task. Referring once more to the terminology in the previous sections of this paper, this function corresponds to `manipulation’ in WM tasks, `organization’ in encoding tasks and `monitoring’ in retrieval tasks. The terms `organization’ and `manipulation’ may be used interchangeably in that they refer to any process whereby presented or retrieved material is modified. The term `selection’ is used in our formulation because it is frequently the case that tasks require not merely the rearrangement of material held on-line but also the selection of the most appropriate stimuli before a response can be made. This use is different from that for VLFC VLFC is involved in selecting information from LTM , whereas DLFC is involved in selecting information that is already active in WM.
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Task Effect: Recognition And Source Memory
Other retrieval studies have kept cues constant, but varied the retrieval instructions. In one study, for example, Henson and colleagues presented study words either high or low on the screen and in one of two temporally grouped lists . In the standard recognition task , subjects had to respond `yes’ to studied words, which were randomly intermixed with a set of new, unstudied words. In a second recognition condition , subjects responded `yes’ only to words that were studied in a specific spatial or temporal context, i.e. either high or low on the screen or in one of the two study lists. Direct comparison of the exclusion and inclusion tasks revealed bilateral DLFC activation. The authors attributed this activation to source monitoring, during which the feeling of familiarity associated with studied words had to be checked against explicit retrieval of the study context. Furthermore, though bilateral VLFC regions were more active in the inclusion condition than in a simple perceptual control condition, the activity of these regions did not appear to differ between the inclusion and exclusion tasks. The latter is consistent with the proposal of Fletcher and colleagues that VLFC is involved in retrieval cueing, given that the externally provided `copy’ cues differed between the inclusion and control conditions but not between the inclusion and exclusion conditions .
Broca And Wernicke’s Areas
Located at the front and middle of the left temporal lobe, respectively, Broca’s area and Wenicke’s area are the regions of the human brain that handle the formation and processing of language. Regardless of what language you’re using, these two regions allow you to form sentences, understand the meaning of what others are saying and pick up on verbal patterns. These regions are the reason why a left temporal lobe hemorrhage can leave a person unable to understand what someone is saying, or lead them to babble incoherently.
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Blood Supply To The Brain
Two sets of blood vessels supply blood and oxygen to the brain: the vertebral arteries and the carotid arteries.
The external carotid arteries extend up the sides of your neck, and are where you can feel your pulse when you touch the area with your fingertips. The internal carotid arteries branch into the skull and circulate blood to the front part of the brain.
The vertebral arteries follow the spinal column into the skull, where they join together at the brainstem and form the basilar artery, which supplies blood to the rear portions of the brain.
The circle of Willis, a loop of blood vessels near the bottom of the brain that connects major arteries, circulates blood from the front of the brain to the back and helps the arterial systems communicate with one another.
Brain Damage Aphasias And Agnosias
Damage to the temporal lobe, and the left temporal lobe in particular, can be debilitating. Most often, you see this result in an inability to recall memories or information, but when certain regions of the dominant temporal lobe are damaged, such as Broca or Wernicke’s areas, a certain type of brain damage known as an aphasia or an agnosia can develop. These forms of brain damage result in an inability to process a specific type of information. For example, someone with Broca’s aphasia alone can understand language but will have trouble speaking their sentences will seem garbled, but will still carry meaning. Whereas an agnosia can result in someone being unable to recognize someone’s face, or can lead to them misinterpreting what a given object is. These forms of brain damage can be adapted to and lived with but are one of the many reasons it’s important to protect your head from harm.
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Memory Systems In The Brain And Localization Of Amemory
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It is now clear that there are a number of different forms or aspects of learning and memory that involve different brain systems. Broadly, memory phenomena have been categorized as explicit or implicit. Thus, explicit memories for experience involve the hippocampusmedial temporal lobe system and implicit basic associative learning and memory involves the cerebellum, amygdala, and other systems. Under normal conditions, however, many of these brainmemory systems are engaged to some degree in learning situations. But each of these brain systems is learning something different about the situation. The cerebellum is necessary for classical conditioning of discrete behavioral responses under all conditions however, in the trace procedure where a period of no stimuli intervenes between the conditioned stimulus and the unconditioned stimulus the hippocampus plays a critical role. Trace conditioning appears to provide a simple model of explicit memory where analysis of brain substrates is feasible. Analysis of the role of the cerebellum in basic delay conditioning indicates that the memories are formed and stored in the cerebellum. The phenomenon of cerebellar long-term depression is considered as a putative mechanism of memory storage.
A tentative taxonomy of long-term memory and associated brain structures .
Hippocampus And Classical Conditioning
In eyeblink conditioning, neuronal unit cluster recordings in hippocampal fields CA1 and CA3 increase in discharge frequency in paired training trials very rapidly, shift forward in time as learning develops, and form a predictive temporal model of the learned behavioral response, both within trials and over the trials of training . To summarize a large body of research, the growth of the hippocampal unit response is, under normal conditions, an invariable and strongly predictive concomitant of subsequent behavioral learning . This increase in neuronal activity in the hippocampus becomes significant by the second or third trial of training, long before behavioral signs of learning develop, as would be expected of a declarative memory system. This initial hippocampal unit increase is in the US period increases in the CS period appear at about the time point in training when behavioral conditioned responses appear.
There are strikingly parallel and persisting increases in glutamate -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor binding on hippocampal membranes in the hippocampal subfields in both eyeblink conditioning and in in vivo expression of LTP by stimulation of the perforant path projection to hippocampal dentate gyrus. The pattern of increased binding is similar in both paradigms . GlutamateN-methyl-d-aspartate receptors play the critical role in induction of LTP and also appear to be involved in acquisition of the trace eyeblink CR .
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Do Different Brain Regions Control Different Functions
Doctors originally divided the brain into four separate regions for the sake of conveniently labeling anatomical functions. We now know that the lobes of the brain roughly correlate with a variety of functions. The temporal lobe, for instance, plays a key role in auditory processing, while the frontal lobe helps regulate attention and memory.
This doesn’t mean that brain regions control these functions. Many functions overlap across brain regions, and the functioning of one region often depends on another. Moreover, some research suggests that when there is damage to one region of the brain, other regions may compensate, suggesting that the brain is highly malleable.
This all means that the brain is an unpredictable organ. Much remains to be understood, and our understanding of which brain regions do what changes with each new brain study.
Understanding Parts Of The Brain
Learn about the parts of the brain and how dementia damages them, as well as about the symptoms the damage causes.
Dementia is caused when the brain is damaged by diseases, such as Alzheimers disease or a series of strokes. Alzheimers disease is the most common cause of dementia, but not the only one.
A person with dementia will experience symptoms depending on the parts of the brain that are damaged, and the disease that is causing the dementia.
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Diseases And Conditions Related To The Frontal Brain Lobe
One of the first conditions we will address is depression. Today, we know with certainty that one of the main characteristics of virtually all depressed persons – regardless of the underlying cause of depression – is a significant decrease in blood flow to the frontal lobe and its impaired activity.
This reduced activity is found in the most prominent part of the frontal lobe. It is called the “prefrontal cortex“. It is the part of the brain that truly represents the control center of the brain.
However, it is much more than that. We know that the prefrontal cortex is responsible for behavioral planning, decision making, emotional control, self-awareness, and independence from other people.
Depression can be caused by a stroke in the medial part of the frontal lobe. The consequences of these strokes include emotional instability. Generally speaking, depression is not caused by strokes in other parts of the brain.
Moreover, frontal brain lobe damage can result from surgical removal, injury, or stroke. It can also be a consequence of Alzheimer’s disease. Regardless of the process that damages the frontal lobe, the consequences are generally the same.
Patients suffering from Alzheimer’s disease who had frontal lobe damage were significantly more depressed. They were also much more likely to have other behavioral problems such as anxiety, self-delusions, and lack of self-discipline.
Damage to the inferolateral area causes motor aphasia .
Task Effects: Intentional Versus Incidental Retrieval
Environmental cues exert a great influence upon retrieval. Compared with free recall, in which no cues are provided, the provision of external cues dramatically improves the amount of information retrieved. The strength of these cues, i.e. the degree to which they specify the nature of material to be retrieved, can vary from a `copy’ cue of the target item itself, as in recognition memory tasks, to an associate that was previously paired with the target, as in paired associate-cued recall. Other types of cues include a word-stem or a word-fragment . The stronger the retrieval cue, the more likely it is that information will be retrieved and the less important are specific retrieval strategies. Different types of retrieval task are summarized in Fig. 4.
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Interesting Facts About Your Frontal Lobe
Check out some interesting facts about your frontal lobe:
- The frontal lobes are the largest of the lobes in your brain. Theyre located at the front of your brain. Its estimated they make up about one-third of your cerebrum.
- The frontal lobe of primates, particularly humans, is much larger than those of other species. You might say the frontal lobe is the most important area for our various human skills, such as reasoning and language.
- The frontal lobes are
Can You Live 20 Years After A Stroke
Long-Term Mortality Rate Study, Ages 1850 The majority of the 959 patients studied suffered from ischemic stroke. The study found that, among 30-day survivors, the risk of death by the twentieth year mark was highest for ischemic stroke patients, at 26.8 percent, with TIA sufferers close behind at 24.9 percent.
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Where Is The Auditory Cortex
A coronal section of the left hemisphere, showing the primary auditory cortex as well as surrounding auditory regions .
The auditory cortex is found in the temporal lobe. Most of it is hidden from view, buried deep within a fissure called the lateral sulcus. Some auditory cortex is visible on the external surface the brain, however, as it extends to a gyrus called the superior temporal gyrus.
The auditory cortex can be subdivided into multiple regions, although there is still some question about the most appropriate way to create those subdivisions in the human brain. There is general agreement, however, that the auditory cortex consists of a primary areawhich is often referred to as the core regionas well as multiple non-primary areas.
The primary auditory cortex in humans is hidden within the lateral sulcus on a collection of gyri known as Heschls gyri . The precise location of the primary region in humans is variable, however, as is the arrangement of Heschls gyri . For example, in some individuals the primary auditory cortex seems to occupy one Heschls gyrus, while in others it may extend past that gyrus into a neighboring sulcus .
Frontal Function In Long
Neuropsychological studies of patients with focal brain lesions have highlighted the importance of medial temporal and diencephalic structures in human long-term declarative memory . Functional neuroimaging studies of healthy subjects, however, have emphasized the engagement of FC structures during the performance of LTM tasks. FC lesions do not cause the same global amnesia that can result from medial temporal/diencephalic lesions, but they are associated with impairments in more complex memory tasks, such as memory for temporal order and tasks with high levels of interference . FC activations during LTM tasks are, therefore, likely to reflect control processes that aid and optimize memory encoding and retrieval, rather than more automatic storage processes.
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Left Frontal Cortex And Organization
We know from behavioural experiments that divided attention while the subject is at study impairs subsequent memory , and organization of study material aids subsequent memory . In a PET study, Fletcher and colleagues manipulated both the level of attention to and the degree of organization of study material . Subjects were presented with word lists and were required to engage in one of three levels of organization . Left DLFC activity was maximal when organizational demands were greatest. Furthermore, when attention was divided between encoding and a concurrent motor distraction task, the DLFC activation related to the most organizationally demanding task was attenuated. Subsequent retrieval was also correspondingly impaired. It was concluded that the left DLFC activation reflected the organization of study material, and that the distractor task disrupted this process.
Wagner and colleagues performed a similar study using fMRI in an attempt to relate LTM encoding to WM processes . Subjects were presented with three words that they had either to maintain in the same order for a short period or to reorder along some abstract semantic dimension . Both tasks activated left VLFC, but the reordering task produced greater additional activation of left DLFC . The reordering task led to better subsequent memory, also implicating this region in encoding. This result is consistent with an association between organization, encoding and DLFC .
Left Frontal Cortex And Semantic Maintenance
Further consideration of the left FC contribution to language and memory has led to the suggestion that it has a role in `domain-specific semantic WM’ . Gabrieli and colleagues acknowledge the relationship of this suggestion to the broader view that FC may be parcellated on the basis of the domains over which WM processes operate . A number of observations are cited to support their claim. First, of course, it is consistent with the observations made in the studies of semantic generation cited above. Furthermore, Gabrieli and colleagues produced evidence that the left FC activation reflects maintenance processes rather than the processes required to generate a response per se . They compared brain responses with two types of word-stem completion. In the first type, the word stem could be completed in many ways . In the second, they used word stems that could form the beginning of only a limited number of words . Subjects were instructed to complete each stem with the first word that came to mind. In this way, it was argued, they could dissociate the effort or search required in generating a response from the amount of material that subjects produce in making their response . They found greater left DLFC activation in association with word stems offering many rather than few possibilities, and concluded that this activation reflected the increased amount of material that was maintained in semantic WM.
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