scholarly journals The prefrontal cortex: Projection area of the thalamic mediodorsal nucleus?

1979 ◽  
Vol 7 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Hans J. Markowitsch ◽  
Monika Pritzel
Keyword(s):  
Prefrontal Cortex ◽  
Projection Area ◽  
Mediodorsal Nucleus

Prefrontal Cortex of the Mouse Defined as Cortical Projection Area of the Thalamic Mediodorsal Nucleus

1981 ◽  
Vol 19 (3-4) ◽  
pp. 93-107 ◽  
Author(s):  
Wolfgang O. Guldin ◽  
Monika Pritzel ◽  
Hans J. Markowitsch
Keyword(s):  
Prefrontal Cortex ◽  
Projection Area ◽  
Cortical Projection ◽  
Mediodorsal Nucleus

An olfactory projection area in orbitofrontal cortex of the monkey

1975 ◽  
Vol 38 (5) ◽  
pp. 1269-1283 ◽  
Author(s):  
T. Tanabe ◽  
H. Yarita ◽  
M. Iino ◽  
Y. Ooshima ◽  
S. F. Takagi
Keyword(s):  
Prefrontal Cortex ◽  
Olfactory Bulb ◽  
Evoked Potentials ◽  
Entorhinal Cortex ◽  
Orbitofrontal Cortex ◽  
Projection Area ◽  
Olfactory Pathway ◽  
Mediodorsal Nucleus ◽  
Hypothalamic Region ◽  
Stimulation Of

An olfactory projection area was studied in monkeys anesthetized with Nembutal. 1. Evoked potentials were recorded when the olfactory bulb (OB) was electrically stimulated in the lateroposterior portion of the orbitofrontal cortex (LPOF). However, those potentials disappeared when the anterior pyriform cortex (AP) (probably together with the medial portion of the amygdala (MA)) was aspirated or electrically destroyed. 2. In nearly the entire hypothalamic region, evoked potentials were recorded by the same stimulation of the OB. When the hypothalamic region was stimulated, evoked potentials were recorded in the LPOF. 3. The evoked potentials in the LPOF due to the OB stimulation never disappeared even when the thalamus was extensively aspirated or destroyed electrically, but they did disappear when the anterolateral and dorsoposterior portions of the hypothalamus were absorbed or electrocoagulated. 4. Evoked potentials in the mediodorsal nucleus (MD) of the thalamus were recorded when the OB was stimulated. When this nucleus was stimulated, evoked potentials were observed in the broad extent of the orbitofrontal cortex anterior to the LPOF, but never in the LPOF itself. 5. Monkeys were conditioned to discriminate two odors. When the LPOF was removed, such ability strikingly decreased; but when other areas in the prefrontal cortex were removed, the ability decreased only slightly. 6. It was concluded that there exists an olfactory pathway from the OB to the LPOF through the AP (and probably the MA) and the hypothalamus, but none through the thalamus, and that the LPOF plays an important role in the discrimination of odors. 7. It was proved that the entorhinal cortex (ER) is neither located as an intermediate olfactory area nor is it situated as a higher area than the LPOF in the newly found olfactory pathway stated above. It may be a link between the high olfactory area and the limbic system.

Dissociation of Spatial-, Object-, and Sound-Coding Neurons in the Mediodorsal Nucleus of the Primate Thalamus

2003 ◽  
Vol 89 (2) ◽  
pp. 1067-1077 ◽  
Author(s):  
Ikuo Tanibuchi ◽  
Patricia S. Goldman-Rakic
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Single Neuron ◽  
Neuronal Responses ◽  
Mediodorsal Nucleus ◽  
Sound Coding ◽  
Spatial Tasks ◽  
Dorsolateral Prefrontal ◽  
Information Segregation ◽  
The Brain

The mediodorsal nucleus (MD) is the thalamic gateway to the prefrontal cortex, an area of the brain associated with spatial and object working memory functions. We have recorded single-neuron activities from the MD nucleus in monkeys trained to perform spatial tasks with peripheral visual stimuli and a nonspatial task with foveally presented pictures of objects and faces—tasks identical to those we have previously used to map regional specializations in the dorso- and ventro-lateral prefrontal cortex, respectively. We found that MD neurons exhibited categorical specificity—either responding selectively to locations in the spatial tasks or preferentially to specific representations of faces and objects in the nonspatial task. Spatially tuned neurons were located in parts of the MD connected with the dorsolateral prefrontal cortex while neurons responding to the identity of stimuli mainly occupied more ventral positions in the nucleus that has its connections with the inferior prefrontal convexity. Neuronal responses to auditory stimuli were also examined, and vocalization sensitive neurons were found in more posterior portions of the MD. We conclude that MD neurons are dissociable by their spatial and nonspatial coding properties in line with their cortical connections and that the principle of information segregation in cortico-cortical pathways extends to the “association” nuclei of the thalamus.

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