Right positioning of school logo in title page

I am writing my Ph.D defense presentation using Beamer and I have a problem. I would like to add school logo at the top center of my title page. I tried to follow suggestions reported in other similar posts but I still have some problems. Here it is what I am doing at the moment.

\documentclass{beamer}

\mode<presentation> {

\usetheme{Berlin}
\usepackage{graphicx}
\usepackage{booktabs}
\usepackage[english]{babel}
\usepackage{tikz}
\titlegraphic{\vspace{2cm}}
\title[Essays]{\textbf{Essays}}
\institute[IMT] {
IMT School for Advanced Studies Lucca \\
\medskip
}
} % end mode<presentation>

\date{\today}

\begin{document}

\begin{frame}
\tikz [remember picture]
\node at
([yshift=2cm]current page.center)
{\includegraphics[trim=0cm 4cm 0cm 0.5cm,  width=.5\textwidth,height=.35\textheight]{Logo.pdf}};
\titlepage
\end{frame}

\end{document}


The problem is that the logo image is too far from the top bar and not centered, hence all the other features of title page are too down in the page. As I try to trim above to reduce the space, a blank space appears on the top bar. How can I solve this problem?

Thank you very much

P.S.: This is what I obtain after following the first answer

I do not want my logo overlap the top bar and I do not want logo to be far away from the top bar.

Edited to include a new solution at the top.

Is this what you want?

\hspace{0.25\textwidth}
\tikz [ remember picture]
\node at (current page.north)
{\includegraphics[trim=0cm 4cm 0cm 0.5cm,  width=.5\textwidth,height=.35\textheight]{Logo.pdf}};


\tikz [overlay, remember picture]
\node at
(current page.north)
{\includegraphics[trim=0cm 4cm 0cm 0.5cm,  width=.5\textwidth,height=.35\textheight]{Logo.pdf}};

• I tried but it doesn't work Nov 13 '16 at 15:05
• @nicknock82 what doesn't work? Did you compile twice? Nov 13 '16 at 16:25
• @percusse Yes I did but it does not work in the sense there is always a lot of space between logo and the top bar. If I add overlay, as suggested, it is even worse as the logo overlap the top bar and this is a thing i don't want. Nov 13 '16 at 16:42
• @percusse I added a picture of the result Nov 13 '16 at 16:56
• @nicknock82 I added a new solution. Nov 14 '16 at 8:26
\documentclass{beamer}
\usetheme{Berlin}
\usepackage{graphicx}
\usepackage{booktabs}
\usepackage[english]{babel}
\title[Essays]{\textbf{Essays}}
\institute[IMT] {
IMT School for Advanced Studies Lucca \\
\medskip
}
\date{\today}

\begin{document}
\begin{frame}
\centering
\includegraphics[scale=0.2]{logo.png}\par
\usebeamertemplate{title page}
\end{frame}

\end{document}


• a figure cannot be added inside setbeamertemplate{title page}{}? Jan 25 '18 at 23:40

What about using a box with centering alignment

\begin{frame}
\makebox[\textwidth][c]{
\tikz
\node {\includegraphics[trim=0cm 4cm 0cm 0.5cm, width=.5\textwidth,height=.35\textheight]{Logo.pdf}};
}
\vspace*{-0.0\textheight} % put whatever you want to remove some space
\titlepage
\end{frame}


This is the solution I found in the end by little modifying the solution proposed by @Piet van Oostrum

\begin{frame}
\vspace{-0.01cm}
\begin{center}
\tikz [remember picture]
\node at
(current page.north)
{\includegraphics[trim=0cm 6.5cm 0cm 1.5cm, width=.5\textwidth,height=.2\textheight]{Logo.pdf}};
\end{center}
\titlepage % Print the title page as the first slide
\end{frame}


It gives me the following result

This is not the best I desired to, as there is still too much space between the top bar and the logo itself, but, at the moment, it is the best I reached, I am still open to suggestions.