Do Rats Have Prefrontal Cortex? The Rose-Woolsey-Akert Program Reconsidered

1995 ◽  
Vol 7 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Todd M. Preuss
Keyword(s):  
Prefrontal Cortex ◽  
Frontal Cortex ◽  
Frontal Lobe ◽  
Dorsolateral Prefrontal Cortex ◽  
Delayed Reaction ◽  
Frontal Lobe Function ◽  
Mediodorsal Thalamic Nucleus ◽  
Dorsolateral Prefrontal ◽  
Prefrontal Region ◽  
Higher Cognitive Functions

Primates are unique among mammals in possessing a region of dorsolateral prefrontal cortex with a well-developed internal granular layer. This region is commonly implicated in higher cognitive functions. Despite the histological distinctiveness of primate dorsolateral prefrontal cortex, the work of Rose, Woolsey, and Akert produced a broad consensus among neuroscientists that homologues of primate granular frontal cortex exist in nonprimates and can be recognized by their dense innervation from the mediodorsal thalamic nucleus (MD). Additional characteristics have come to be identified with dorsolateral prefrontal cortex, including rich dopaminergic innervation and involvement in spatial delayed-reaction tasks. However, recent studies reveal that these characteristics are not distinctive of the dorsolateral prefrontal region in primates: MD and dopaminergic projections are widespread in the frontal lobe, and medial and orbital frontal areas may play a role in delay tasks. A reevaluation of rat frontal cortex suggests that the medial frontal cortex, usually considered to be homologous to the dorsolateral prefrontal cortex of primates, actually consists of cortex homologous to primate premotor and anterior cin-date cortex. The lateral MD-projection cortex of rats resembles portions of primate orbital cortex. If prefrontal cortex is construed broadly enough to include orbital and cingulate cortex, rats can be said to have prefrontal cortex. However, they evidently lack homologues of the dorsolateral prefrontal areas of primates. This assessment suggests that rats probably do not provide useful models of human dorsolateral frontal lobe function and dysfunction, although they might prove valuable for understanding other regions of frontal cortex.

The Effects of Frontal Lobe Lesions on Goal Achievement in the Water Jug Task

2001 ◽  
Vol 13 (8) ◽  
pp. 1129-1147 ◽  
Author(s):  
Mary Kathryn Colvin ◽  
Kevin Dunbar ◽  
Jordan Grafman
Keyword(s):  
Prefrontal Cortex ◽  
Problem Solving ◽  
Frontal Lobe ◽  
Dorsolateral Prefrontal Cortex ◽  
Functional Neuroimaging ◽  
Hill Climbing ◽  
Sorting Task ◽  
Card Sorting ◽  
Dorsolateral Prefrontal ◽  
Frontal Lobe Lesion

Patients with prefrontal cortex lesions are impaired on a variety of planning and problem-solving tasks. We examined the problem-solving performance of 27 patients with focal frontal lobe damage on the Water Jug task. The Water Jug task has never been used to assess problem-solving ability in neurologically impaired patients nor in functional neuroimaging studies, despite sharing structural similarities with other tasks sensitive to prefrontal cortex function, including the Tower of Hanoi, Tower of London, and Wisconsin Card Sorting Task (WCST). Our results demonstrate that the Water Jug task invokes a unique combination of problem-solving and planning strategies, allowing a more precise identification of frontal lobe lesion patients' cognitive deficits. All participants (patients and matched controls) appear to be utilizing a hill-climbing strategy that does not require sophisticated planning; however, frontal lobe lesion patients (FLLs) struggled to make required “counterintuitive moves” not predicted by this strategy and found within both solution paths. Left and bilateral FLLs were more impaired than right FLLs. Analysis of the left hemisphere brain regions encompassed by the lesions of these patients found that poor performance was linked to left dorsolateral prefrontal cortex damage. We propose that patients with left dorsolateral prefrontal cortex lesions have difficulty making a decision requiring the conceptual comparison of nonverbal stimuli, manipulation of select representations of potential solutions, and are unable to appropriately inhibit a response in keeping with the final goal.

scholarly journals Brain functional changes across the different phases of bipolar disorder

2015 ◽  
Vol 206 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Edith Pomarol-Clotet ◽  
Silvia Alonso-Lana ◽  
Noemi Moro ◽  
Salvador Sarró ◽  
Mar C. Bonnin ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Prefrontal Cortex ◽  
Frontal Cortex ◽  
Parietal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Cognitive Task ◽  
Memory Task ◽  
Mixed Effects ◽  
Linear Mixed Effects ◽  
Dorsolateral Prefrontal

BackgroundLittle is known about how functional imaging changes in bipolar disorder relate to different phases of the illness.AimsTo compare cognitive task activation in participants with bipolar disorder examined in different phases of illness.MethodParticipants with bipolar disorder in mania (n = 38), depression (n = 38) and euthymia (n = 38), as well as healthy controls (n = 38), underwent functional magnetic resonance imaging during performance of the n-back working memory task. Activations and de-activations were compared between the bipolar subgroups and the controls, and among the bipolar subgroups. All participants were also entered into a linear mixed-effects model.ResultsCompared with the controls, the mania and depression subgroups, but not the euthymia subgroup, showed reduced activation in the dorsolateral prefrontal cortex, the parietal cortex and other areas. Compared with the euthymia subgroup, the mania and depression subgroups showed hypoactivation in the parietal cortex. All three bipolar subgroups showed failure of de-activation in the ventromedial frontal cortex. Linear mixed-effects modelling revealed a further cluster of reduced activation in the left dorsolateral prefrontal cortex in the patients; this was significantly more marked in the mania than in the euthymia subgroup.ConclusionsBipolar disorder is characterised by mood state-dependent hypoactivation in the parietal cortex. Reduced dorsolateral prefrontal activation is a further feature of mania and depression, which may improve partially in euthymia. Failure of de-activation in the medial frontal cortex shows trait-like characteristics.

Reward-related Reversal Learning after Surgical Excisions in Orbito-frontal or Dorsolateral Prefrontal Cortex in Humans

2004 ◽  
Vol 16 (3) ◽  
pp. 463-478 ◽  
Author(s):  
J. Hornak ◽  
J. O'Doherty ◽  
J. Bramham ◽  
E. T. Rolls ◽  
R. G. Morris ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Frontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Normal Subjects ◽  
Brain Regions ◽  
Reversal Task ◽  
Neurophysiological Studies ◽  
Reward Value ◽  
Dorsolateral Prefrontal ◽  
Surgical Excisions

Neurophysiological studies in primates and neuroimaging studies in humans suggest that the orbito-frontal cortex is involved in representing the reward value of stimuli and in the rapid learning and relearning of associations between visual stimuli and rewarding or punishing outcomes. In the present study, we tested patients with circumscribed surgical lesions in different regions of the frontal lobe on a new visual discrimination reversal test, which, in an fMRI study (O'Doherty, Kringelbach, Rolls, Hornak, & Andrews, 2001), produced bilateral orbito-frontal cortex activation in normal subjects. In this task, touching one of two simultaneously presented patterns produced reward or loss of imaginary money delivered on a probabilistic basis to minimize the usefulness of verbal strategies. A number of types of feedback were present on the screen. The main result was that the group of patients with bilateral orbito-frontal cortex lesions were severely impaired at the reversal task, in that they accumulated less money. These patients often failed to switch their choice of stimulus after a large loss and often did switch their choice although they had just received a reward. The investigation showed that bilateral lesions were required for this deficit, since patients with unilateral orbito-frontal cortex (or medial prefrontal cortex) lesions were not impaired in the probabilistic reversal task. The task ruled out a simple motor disinhibition as an explanation of the deficit in the bilateral orbito-frontal cortex patients, in that the patients were required to choose one of two stimuli on each trial. A comparison group of patients with dorsolateral prefrontal cortex lesions was in some cases able to do the task, and in other cases, was impaired. Posttest debriefing showed that all the dorsolateral prefrontal patients who were impaired at the task had failed to pay attention to the crucial feedback provided on the screen after each trial about the amount won or lost on each trial. In contrast, all dorsolateral patients who paid attention to this crucial feedback performed normally on the reversal task. Further, it was confirmed that the bilateral orbito-frontal cortex patients had also paid attention to this crucial feedback, but in contrast had still performed poorly at the task. The results thus show that the orbital prefrontal cortex is required bilaterally for monitoring changes in the reward value of stimuli and using this to guide behavior in the task; whereas the dorsolateral prefrontal cortex, if it produces deficits in the task, does so for reasons related to executive functions, such as the control of attention. Thus, the ability to determine which information is relevant when making a choice of pattern can be disrupted by a dorsolateral lesion on either side, whereas the ability to use this information to guide behavior is not disrupted by a unilateral lesion in either the left or the right orbito-frontal cortex, but is severely impaired by a bilateral lesion in this region. Because both abilities are important in many of the tasks and decisions that arise in the course of daily life, the present results are relevant to understanding the difficulties faced by patients after surgical excisions in different frontal brain regions.

Learning of Sequences of Finger Movements and Timing: Frontal Lobe and Action-Oriented Representation

2002 ◽  
Vol 88 (4) ◽  
pp. 2035-2046 ◽  
Author(s):  
Katsuyuki Sakai ◽  
Narender Ramnani ◽  
Richard E. Passingham
Keyword(s):  
Prefrontal Cortex ◽  
Frontal Lobe ◽  
Dorsolateral Prefrontal Cortex ◽  
Intraparietal Sulcus ◽  
Motor Sequence ◽  
Finger Movements ◽  
Learning Mechanisms ◽  
Positron Emission ◽  
Learning Conditions ◽  
Dorsolateral Prefrontal

Motor sequence learning involves learning of a sequence of effectors with which to execute a series of movements and learning of a sequence of timings at which to execute the movements. In this study, we have segregated the neural correlates of the two learning mechanisms. Moreover, we have found an interaction between the two learning mechanisms in the frontal areas, which we claim as suggesting action-oriented coding in the frontal lobe. We used positron emission tomography and compared three learning conditions with a visuo-motor control condition. In two learning conditions, the subjects learned either a sequence of finger movements with random timing or a sequence of timing with random use of fingers. In the third condition the subjects learned to execute a sequence of specific finger movements at specific timing; we argue that it was only in this condition that the motor sequence was coded as an action-oriented representation. By looking for condition by session interactions (learning vs. control conditions over sessions), we have removed nonspecific time effects and identified areas that showed a learning-related increment of activation during learning. Learning of a finger sequence was associated with an increment of activation in the right intraparietal sulcus region and medial parietal cortex, whereas learning of a timing sequence was associated with an increment of activation in the lateral cerebellum, suggesting separate mechanisms for learning effector and temporal sequences. The left intraparietal sulcus region showed an increment of activation in learning of both finger and timing sequences, suggesting an overlap between the two learning mechanisms. We also found that the mid-dorsolateral prefrontal cortex, together with the medial and lateral premotor areas, became increasingly active when subjects learned a sequence that specified both fingers and timing, that is, when subjects were able to prepare specific motor action. These areas were not active when subjects learned a sequence that specified fingers or timing alone, that is, when subjects were still dependent on external stimuli as to the timing or fingers with which to execute the movements. Frontal areas may integrate the effector and temporal information of a motor sequence and implement an action-oriented representation so as to perform a motor sequence accurately and quickly. We also found that the mid-dorsolateral prefrontal cortex was distinguished from the ventrolateral prefrontal cortex and anterior fronto-polar cortex, which showed sustained activity throughout learning sessions and did not show either an increment or decrement of activation.

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