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Activation of the mouse primary visual cortex by medial prefrontal subregion stimulation is not mediated by cholinergic basalo-cortical projections.

Nguyen HN, Huppé-Gourgues F, Vaucher E - Front Syst Neurosci (2015)

Bottom Line: The cholinergic projections to V1 originate from neurons in the horizontal limb of the diagonal band of Broca (HDB), which receive neuronal projections from the ventral part of the mPFC, composed of prelimbic (PrL) and infralimbic cortices (IL).A HDB cholinergic neuron-specific lesion by saporin administration reduced IL-induced c-Fos expression in layers II/III of V1 but not in layer V.These results suggest a functional link between the ventral mPFC and V1, but this function is only marginally supported by HDB cholinergic neurons and may involve other brain regions.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Neurobiologie de la Cognition Visuelle, École D'optométrie, Université de Montréal Montréal, QC, Canada.

ABSTRACT
The medial prefrontal cortex (mPFC) exerts top-down control of primary visual cortex (V1) activity. As there is no direct neuronal projection from mPFC to V1, this functional connection may use an indirect route, i.e., via basalo-cortical cholinergic projections. The cholinergic projections to V1 originate from neurons in the horizontal limb of the diagonal band of Broca (HDB), which receive neuronal projections from the ventral part of the mPFC, composed of prelimbic (PrL) and infralimbic cortices (IL). Therefore, the objective of this study was to determine whether electrical stimulation of mice mPFC subregions activate (1) V1 neurons; and (2) HDB cholinergic neurons, suggesting that the HDB serves as a relay point in the mPFC-V1 interaction. Neuronal activation was quantified using c-Fos immunocytochemistry or thallium autometallography for each V1 layer using automated particle analysis tools and optical density measurement. Stimulation of IL and PrL induced significantly higher c-Fos expression or thallium labeling in layers II/III and V of V1 in the stimulated hemisphere only. A HDB cholinergic neuron-specific lesion by saporin administration reduced IL-induced c-Fos expression in layers II/III of V1 but not in layer V. However, there was no c-Fos expression or thallium labeling in the HDB neurons, suggesting that this area was not activated by IL stimulation. Stimulation of another mPFC subarea, the anterior cingulate cortex (AC), which is involved in attention and receives input from V1, activated neither V1 nor HDB. The present results indicate that IL and PrL, but not AC, stimulation activates V1 with the minor involvement of the HDB cholinergic projections. These results suggest a functional link between the ventral mPFC and V1, but this function is only marginally supported by HDB cholinergic neurons and may involve other brain regions.

No MeSH data available.


Related in: MedlinePlus

Neuronal activity of the primary visual cortex induced by stimulation of medial prefrontal cortex subregions measured by c-Fos immunoreactivity. (A–C): Microphotographs of c-Fos immunostaining in the primary visual cortex following electrical stimulation of IL (A), PrL (B) and AC (C) (right panels) compared to the non-stimulated hemisphere (left panels) at low and high (indents) magnification. Histograms of the number of c-Fos immunoreactive neurons (per 13 µm2 area) in the layers II/III, IV and V of the primary visual cortex after medial prefrontal cortex subregions stimulation (far right) are shown. The expression of c-Fos in V1 is increased in layers II/III and V following IL and PrL stimulation, but not following the AC stimulation. AC, anterior cingulate cortex; IL, infralimbic cortex; PrL, prelimbic cortex. Error bars = Standard Deviation (SD). Scale bar = 500 µm (panels) and 50 µm (indents). ** = p < 0.01.
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Figure 3: Neuronal activity of the primary visual cortex induced by stimulation of medial prefrontal cortex subregions measured by c-Fos immunoreactivity. (A–C): Microphotographs of c-Fos immunostaining in the primary visual cortex following electrical stimulation of IL (A), PrL (B) and AC (C) (right panels) compared to the non-stimulated hemisphere (left panels) at low and high (indents) magnification. Histograms of the number of c-Fos immunoreactive neurons (per 13 µm2 area) in the layers II/III, IV and V of the primary visual cortex after medial prefrontal cortex subregions stimulation (far right) are shown. The expression of c-Fos in V1 is increased in layers II/III and V following IL and PrL stimulation, but not following the AC stimulation. AC, anterior cingulate cortex; IL, infralimbic cortex; PrL, prelimbic cortex. Error bars = Standard Deviation (SD). Scale bar = 500 µm (panels) and 50 µm (indents). ** = p < 0.01.

Mentions: In the cholinergic deficit group, a specific lesion of the cholinergic fibers was performed by intraventricular injection of the neurotoxin p75-Saporin (Berger-Sweeney et al., 2001; Dotigny et al., 2008; Kang et al., 2014) 2 weeks prior to electrical stimulation of the mPFC. Mice were anesthetized with isoflurane (5% for induction and 2.5% for maintenance) with an oxygen flow of 1 l/min and placed into a stereotaxic frame (Kopf instruments). A hole in the skull was opened and a 33 gauge needle was inserted into the right lateral ventricle at: AP: −0.4; ML: 1.0 from Bregma; DV: −2.0 from dura matter (Berger-Sweeney et al., 2001). The neurotoxin p75-Saporin (mu p75-SAP, lot #94–69, Advanced Targeting Systems, San Diego, CA, USA) was administered in the right hemisphere (1 µl per site, 1 µg/µl in saline) at a flow rate of approximately 0.2 µl/min for 5 min. The skin was sutured and the animals were returned to their home cage for 14 days. Animals were then processed for electrical stimulation and further c-Fos immunostaining. The expression of EGFP (Figure 4A) or ChAT (Figure 5A) immunostaining was examined in the HDB neurons and their projections to V1 to verify the efficacy of the cholinergic lesion.


Activation of the mouse primary visual cortex by medial prefrontal subregion stimulation is not mediated by cholinergic basalo-cortical projections.

Nguyen HN, Huppé-Gourgues F, Vaucher E - Front Syst Neurosci (2015)

Neuronal activity of the primary visual cortex induced by stimulation of medial prefrontal cortex subregions measured by c-Fos immunoreactivity. (A–C): Microphotographs of c-Fos immunostaining in the primary visual cortex following electrical stimulation of IL (A), PrL (B) and AC (C) (right panels) compared to the non-stimulated hemisphere (left panels) at low and high (indents) magnification. Histograms of the number of c-Fos immunoreactive neurons (per 13 µm2 area) in the layers II/III, IV and V of the primary visual cortex after medial prefrontal cortex subregions stimulation (far right) are shown. The expression of c-Fos in V1 is increased in layers II/III and V following IL and PrL stimulation, but not following the AC stimulation. AC, anterior cingulate cortex; IL, infralimbic cortex; PrL, prelimbic cortex. Error bars = Standard Deviation (SD). Scale bar = 500 µm (panels) and 50 µm (indents). ** = p < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321436&req=5

Figure 3: Neuronal activity of the primary visual cortex induced by stimulation of medial prefrontal cortex subregions measured by c-Fos immunoreactivity. (A–C): Microphotographs of c-Fos immunostaining in the primary visual cortex following electrical stimulation of IL (A), PrL (B) and AC (C) (right panels) compared to the non-stimulated hemisphere (left panels) at low and high (indents) magnification. Histograms of the number of c-Fos immunoreactive neurons (per 13 µm2 area) in the layers II/III, IV and V of the primary visual cortex after medial prefrontal cortex subregions stimulation (far right) are shown. The expression of c-Fos in V1 is increased in layers II/III and V following IL and PrL stimulation, but not following the AC stimulation. AC, anterior cingulate cortex; IL, infralimbic cortex; PrL, prelimbic cortex. Error bars = Standard Deviation (SD). Scale bar = 500 µm (panels) and 50 µm (indents). ** = p < 0.01.
Mentions: In the cholinergic deficit group, a specific lesion of the cholinergic fibers was performed by intraventricular injection of the neurotoxin p75-Saporin (Berger-Sweeney et al., 2001; Dotigny et al., 2008; Kang et al., 2014) 2 weeks prior to electrical stimulation of the mPFC. Mice were anesthetized with isoflurane (5% for induction and 2.5% for maintenance) with an oxygen flow of 1 l/min and placed into a stereotaxic frame (Kopf instruments). A hole in the skull was opened and a 33 gauge needle was inserted into the right lateral ventricle at: AP: −0.4; ML: 1.0 from Bregma; DV: −2.0 from dura matter (Berger-Sweeney et al., 2001). The neurotoxin p75-Saporin (mu p75-SAP, lot #94–69, Advanced Targeting Systems, San Diego, CA, USA) was administered in the right hemisphere (1 µl per site, 1 µg/µl in saline) at a flow rate of approximately 0.2 µl/min for 5 min. The skin was sutured and the animals were returned to their home cage for 14 days. Animals were then processed for electrical stimulation and further c-Fos immunostaining. The expression of EGFP (Figure 4A) or ChAT (Figure 5A) immunostaining was examined in the HDB neurons and their projections to V1 to verify the efficacy of the cholinergic lesion.

Bottom Line: The cholinergic projections to V1 originate from neurons in the horizontal limb of the diagonal band of Broca (HDB), which receive neuronal projections from the ventral part of the mPFC, composed of prelimbic (PrL) and infralimbic cortices (IL).A HDB cholinergic neuron-specific lesion by saporin administration reduced IL-induced c-Fos expression in layers II/III of V1 but not in layer V.These results suggest a functional link between the ventral mPFC and V1, but this function is only marginally supported by HDB cholinergic neurons and may involve other brain regions.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Neurobiologie de la Cognition Visuelle, École D'optométrie, Université de Montréal Montréal, QC, Canada.

ABSTRACT
The medial prefrontal cortex (mPFC) exerts top-down control of primary visual cortex (V1) activity. As there is no direct neuronal projection from mPFC to V1, this functional connection may use an indirect route, i.e., via basalo-cortical cholinergic projections. The cholinergic projections to V1 originate from neurons in the horizontal limb of the diagonal band of Broca (HDB), which receive neuronal projections from the ventral part of the mPFC, composed of prelimbic (PrL) and infralimbic cortices (IL). Therefore, the objective of this study was to determine whether electrical stimulation of mice mPFC subregions activate (1) V1 neurons; and (2) HDB cholinergic neurons, suggesting that the HDB serves as a relay point in the mPFC-V1 interaction. Neuronal activation was quantified using c-Fos immunocytochemistry or thallium autometallography for each V1 layer using automated particle analysis tools and optical density measurement. Stimulation of IL and PrL induced significantly higher c-Fos expression or thallium labeling in layers II/III and V of V1 in the stimulated hemisphere only. A HDB cholinergic neuron-specific lesion by saporin administration reduced IL-induced c-Fos expression in layers II/III of V1 but not in layer V. However, there was no c-Fos expression or thallium labeling in the HDB neurons, suggesting that this area was not activated by IL stimulation. Stimulation of another mPFC subarea, the anterior cingulate cortex (AC), which is involved in attention and receives input from V1, activated neither V1 nor HDB. The present results indicate that IL and PrL, but not AC, stimulation activates V1 with the minor involvement of the HDB cholinergic projections. These results suggest a functional link between the ventral mPFC and V1, but this function is only marginally supported by HDB cholinergic neurons and may involve other brain regions.

No MeSH data available.


Related in: MedlinePlus